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Sample records for presynaptic neurotransmitter release

  1. Presynaptic inhibition of the release of multiple major central nervous system neurotransmitter types by the inhaled anaesthetic isoflurane

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    Westphalen, R. I.; Desai, K. M.; Hemmings, H. C.

    2013-01-01

    Background Presynaptic effects of general anaesthetics are not well characterized. We tested the hypothesis that isoflurane exhibits transmitter-specific effects on neurotransmitter release from neurochemically and functionally distinct isolated mammalian nerve terminals. Methods Nerve terminals from adult male rat brain were prelabelled with [3H]glutamate and [14C]GABA (cerebral cortex), [3H]norepinephrine (hippocampus), [14C]dopamine (striatum), or [3H]choline (precursor of [3H]acetylcholine; striatum). Release evoked by depolarizing pulses of 4-aminopyridine (4AP) or elevated KCl was quantified using a closed superfusion system. Results Isoflurane at clinical concentrations (neurotransmitters tested in a concentration-dependent manner. Isoflurane was a more potent inhibitor [expressed as IC50 (sem)] of glutamate release [0.37 (0.03) mM; Pneurotransmitters with selectivity for glutamate release, consistent with both widespread inhibition and nerve terminal-specific presynaptic effects. Glutamate release was most sensitive to inhibition compared with GABA, acetylcholine, dopamine, and norepinephrine release due to presynaptic specializations in ion channel expression, regulation, and/or coupling to exocytosis. Reductions in neurotransmitter release by volatile anaesthetics could contribute to altered synaptic transmission, leading to therapeutic and toxic effects involving all major neurotransmitter systems. PMID:23213036

  2. Stereoselectivity of presynaptic autoreceptors modulating dopamine release

    International Nuclear Information System (INIS)

    Arbilla, S.; Langer, S.Z.

    1981-01-01

    The effects of the (R)- and (S)-enantiomers of sulpiride and butaclamol were studied on the spontaneous and field stimulation-evoked release of total radioactivity from slices of rabbit caudate nucleus prelabelled with [ 3 H]dopamine. (S)-Sulpiride in concentrations ranging from 0.01-1μM enhanced the electrically evoked release of [ 3 H]dopamine while (R)-sulpiride was 10 times less potent than (S)-sulpiride. Exposure to (S)-butaclamol (0.1-1 μM) but not to (R)-butaclamol (0.1-10μM) enhanced the field-stimulated release of [ 3 H]dopamine. The facilitatory effects of (S)- and (R)-sulpiride and (S)-butaclamol on the stimulated release of the labelled neurotransmitter were observed under conditions in which these drugs did not modify the spontaneous outflow of radioactivity. Only the active enantiomers of sulpiride and butaclamol antagonized the inhibition by apomorphine (1μM) of the stimulated release of [ 3 H]dopamine. Our results indicate that the presynaptic inhibitory dopamine autoreceptors modulating the stimulation-evoked release of [ 3 H]dopamine in the caudate nucleus are, like the classical postsynaptic dopamine receptors, chemically stereoselective. (Auth.)

  3. RIM genes differentially contribute to organizing presynaptic release sites.

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    Kaeser, Pascal S; Deng, Lunbin; Fan, Mingming; Südhof, Thomas C

    2012-07-17

    Tight coupling of Ca(2+) channels to the presynaptic active zone is critical for fast synchronous neurotransmitter release. RIMs are multidomain proteins that tether Ca(2+) channels to active zones, dock and prime synaptic vesicles for release, and mediate presynaptic plasticity. Here, we use conditional knockout mice targeting all RIM isoforms expressed by the Rims1 and Rims2 genes to examine the contributions and mechanism of action of different RIMs in neurotransmitter release. We show that acute single deletions of each Rims gene decreased release and impaired vesicle priming but did not alter the extracellular Ca(2+)-responsiveness of release (which for Rims gene mutants is a measure of presynaptic Ca(2+) influx). Moreover, single deletions did not affect the synchronization of release (which depends on the close proximity of Ca(2+) channels to release sites). In contrast, deletion of both Rims genes severely impaired the Ca(2+) responsiveness and synchronization of release. RIM proteins may act on Ca(2+) channels in two modes: They tether Ca(2+) channels to active zones, and they directly modulate Ca(2+)-channel inactivation. The first mechanism is essential for localizing presynaptic Ca(2+) influx to nerve terminals, but the role of the second mechanism remains unknown. Strikingly, we find that although the RIM2 C(2)B domain by itself significantly decreased Ca(2+)-channel inactivation in transfected HEK293 cells, it did not rescue any aspect of the RIM knockout phenotype in cultured neurons. Thus, RIMs primarily act in release as physical Ca(2+)-channel tethers and not as Ca(2+)-channel modulators. Different RIM proteins compensate for each other in recruiting Ca(2+) channels to active zones, but contribute independently and incrementally to vesicle priming.

  4. Calcium Assists Dopamine Release by Preventing Aggregation on the Inner Leaflet of Presynaptic Vesicles

    DEFF Research Database (Denmark)

    Mokkila, Sini; Postila, Pekka A.; Rissanen, Sami

    2017-01-01

    . The inner leaflets of presynaptic vesicles, which are responsible for releasing neurotransmitters into the synaptic cleft, are mainly composed of neutral lipids such as phosphatidylcholine and phosphatidylethanolamine. The neutrality of the lipid head group region, enhanced by a low pH level, should limit...

  5. Tetanus Toxin Action : Inhibition of Neurotransmitter Release Linked to Synaptobrevin Proteolysis

    NARCIS (Netherlands)

    Link, Egenhard; Edelmann, Lambert; Chou, Judy H.; Binz, Thomas; Yamasaki, Shinji; Eisel, Uli; Baumert, Marion; Südhof, Thomas C.; Niemann, Heiner; Jahn, Reinhard

    1992-01-01

    Tetanus toxin is a potent neurotoxin that inhibits the release of neurotransmitters from presynaptic nerve endings. The mature toxin is composed of a heavy and a light chain that are linked via a disulfide bridge. After entry of tetanus toxin into the cytoplasm, the released light chain causes block

  6. Imaging neurotransmitter release by drugs of abuse.

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    Martinez, Diana; Narendran, Rajesh

    2010-01-01

    Previous studies have shown that imaging with positron emission tomography (PET) and single photon emission computed tomography (SPECT) radiotracers that are specific for brain dopamine receptors can be used to indirectly image the change in the levels of neurotransmitters within the brain. Most of the studies in addiction have focused on dopamine, since the dopamine neurons that project to the striatum have been shown to play a critical role in mediating addictive behavior. These imaging studies have shown that increased extracellular dopamine produced by psychostimulants can be measured with PET and SPECT. However, there are some technical issues associated with imaging changes in dopamine, and these are reviewed in this chapter. Among these are the loss of sensitivity, the time course of dopamine pulse relative to PET and SPECT imaging, and the question of affinity state of the receptor. In addition, animal studies have shown that most drugs of abuse increase extracellular dopamine in the striatum, yet not all produce a change in neurotransmitter that can be measured. As a result, imaging with a psychostimulant has become the preferred method for imaging presynaptic dopamine transmission, and this method has been used in studies of addiction. The results of these studies suggest that cocaine and alcohol addiction are associated with a loss of dopamine transmission, and a number of studies show that this loss correlates with severity of disease.

  7. Levetiracetam inhibits neurotransmitter release associated with CICR.

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    Fukuyama, Kouji; Tanahashi, Shunsuke; Nakagawa, Masanori; Yamamura, Satoshi; Motomura, Eishi; Shiroyama, Takashi; Tanii, Hisashi; Okada, Motohiro

    2012-06-19

    To define the antiepileptic mechanisms of levetiracetam (LEV), the present study determined the concentration-dependent effects of locally perfused LEV on the releases of norepinephrine, dopamine, serotonin, l-glutamate and GABA induced by 50 mMK(+)-evoked stimulation and agonists of ryanodine receptor (RyR) and inositol-triphosphate receptor (IP3R) in the median prefrontal cortex (mPFC) using in vivo microdialysis. Local perfusion with LEV (10, 30 and 100 μM) alone did not affect the extracellular levels of all neurotransmitters in the mPFC. The release of neurotransmitters induced by K(+)-evoked stimulation was inhibited by perfusion with LEV in a concentration-dependent manner, and those induced by agonists of RyR and IP3R were also inhibited by LEV. Specifically, the RyR-induced release was inhibited by 10 μM LEV, whereas the IP3R-induced release was inhibited by 100 μM LEV, but not by 10 or 30 μM LEV. The above results suggest that LEV has little effect on the components of normal synaptic transmission but selectively inhibits transmission induced by neuronal hyperactivation. Thus, the mechanisms of the antiepileptic and neuroprotective actions of LEV seem to be mediated, at least in part, through the combination of these two inhibitory effects on depolarization-induced and CICR-associated neurotransmitter releases. Copyright © 2012. Published by Elsevier Ireland Ltd.

  8. Analysis of drug effects on neurotransmitter release

    International Nuclear Information System (INIS)

    Rowell, P.; Garner, A.

    1986-01-01

    The release of neurotransmitter is routinely studied in a superfusion system in which serial samples are collected and the effects of drugs or other treatments on the amount of material in the superfusate is determined. With frequent sampling interval, this procedure provides a mechanism for dynamically characterizing the release process itself. Using automated data collection in conjunction with polyexponential computer analysis, the equation which describes the release process in each experiment is determined. Analysis of the data during the nontreated phase of the experiment allows an internal control to be used for accurately assessing any changes in neurotransmitter release which may occur during a subsequent treatment phase. The use of internal controls greatly improves the signal to noise ratio and allows determinations of very low concentrations of drugs on small amounts of tissue to be made. In this presentation, the effects of 10 μM nicotine on 3 H-dopamine release in rat nucleus accumbens is described. The time course, potency and efficacy of the drug treatment is characterized using this system. Determinations of the exponential order of the release as well as the rate constants allow one to study the mechanism of the release process. A description of 3 H-dopamine release in normal as well as Ca ++ -free medium is presented

  9. Monitoring single-synapse glutamate release and presynaptic calcium concentration in organised brain tissue.

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    Jensen, Thomas P; Zheng, Kaiyu; Tyurikova, Olga; Reynolds, James P; Rusakov, Dmitri A

    2017-06-01

    Brain function relies in large part on Ca 2+ -dependent release of the excitatory neurotransmitter glutamate from neuronal axons. Establishing the causal relationship between presynaptic Ca 2+ dynamics and probabilistic glutamate release is therefore a fundamental quest across neurosciences. Its progress, however, has hitherto depended primarily on the exploration of either cultured nerve cells or giant central synapses accessible to direct experimental probing in situ. Here we show that combining patch-clamp with time-resolved imaging of Ca 2+ -sensitive fluorescence lifetime of Oregon Green BAPTA-1 (Tornado-FLIM) enables readout of single spike-evoked presynaptic Ca 2+ concentration dynamics, with nanomolar sensitivity, in individual neuronal axons in acute brain slices. In parallel, intensity Tornado imaging of a locally expressed extracellular optical glutamate sensor iGluSnFr provides direct monitoring of single-quantum, single-synapse glutamate releases in situ. These two methods pave the way for simultaneous registration of presynaptic Ca 2+ dynamics and transmitter release in an intact brain at the level of individual synapses. Copyright © 2017. Published by Elsevier Ltd.

  10. The dependence of neuronal encoding efficiency on Hebbian plasticity and homeostatic regulation of neurotransmitter release

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    Faramarz eFaghihi

    2015-04-01

    Full Text Available Synapses act as information filters by different molecular mechanisms including retrograde messenger that affect neuronal spiking activity. One of the well-known effects of retrograde messenger in presynaptic neurons is a change of the probability of neurotransmitter release. Hebbian learning describe a strengthening of a synapse between a presynaptic input onto a postsynaptic neuron when both pre- and postsynaptic neurons are coactive. In this work, a theory of homeostatic regulation of neurotransmitter release by retrograde messenger and Hebbian plasticity in neuronal encoding is presented. Encoding efficiency was measured for different synaptic conditions. In order to gain high encoding efficiency, the spiking pattern of a neuron should be dependent on the intensity of the input and show low levels of noise. In this work, we represent spiking trains as zeros and ones (corresponding to non-spike or spike in a time bin, respectively as words with length equal to three. Then the frequency of each word (here eight words is measured using spiking trains. These frequencies are used to measure neuronal efficiency in different conditions and for different parameter values. Results show that neurons that have synapses acting as band-pass filters show the highest efficiency to encode their input when both Hebbian mechanism and homeostatic regulation of neurotransmitter release exist in synapses. Specifically, the integration of homeostatic regulation of feedback inhibition with Hebbian mechanism and homeostatic regulation of neurotransmitter release in the synapses leads to even higher efficiency when high stimulus intensity is presented to the neurons. However, neurons with synapses acting as high-pass filters show no remarkable increase in encoding efficiency for all simulated synaptic plasticity mechanisms.

  11. Glycine receptors support excitatory neurotransmitter release in developing mouse visual cortex

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    Kunz, Portia A; Burette, Alain C; Weinberg, Richard J; Philpot, Benjamin D

    2012-01-01

    Glycine receptors (GlyRs) are found in most areas of the brain, and their dysfunction can cause severe neurological disorders. While traditionally thought of as inhibitory receptors, presynaptic-acting GlyRs (preGlyRs) can also facilitate glutamate release under certain circumstances, although the underlying molecular mechanisms are unknown. In the current study, we sought to better understand the role of GlyRs in the facilitation of excitatory neurotransmitter release in mouse visual cortex. Using whole-cell recordings, we found that preGlyRs facilitate glutamate release in developing, but not adult, visual cortex. The glycinergic enhancement of neurotransmitter release in early development depends on the high intracellular to extracellular Cl− gradient maintained by the Na+–K+–2Cl− cotransporter and requires Ca2+ entry through voltage-gated Ca2+ channels. The glycine transporter 1, localized to glial cells, regulates extracellular glycine concentration and the activation of these preGlyRs. Our findings demonstrate a developmentally regulated mechanism for controlling excitatory neurotransmitter release in the neocortex. PMID:22988142

  12. PRRT2 Is a Key Component of the Ca2+-Dependent Neurotransmitter Release Machinery

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    Pierluigi Valente

    2016-04-01

    Full Text Available Heterozygous mutations in proline-rich transmembrane protein 2 (PRRT2 underlie a group of paroxysmal disorders, including epilepsy, kinesigenic dyskinesia, and migraine. Most of the mutations lead to impaired PRRT2 expression, suggesting that loss of PRRT2 function may contribute to pathogenesis. We show that PRRT2 is enriched in presynaptic terminals and that its silencing decreases the number of synapses and increases the number of docked synaptic vesicles at rest. PRRT2-silenced neurons exhibit a severe impairment of synchronous release, attributable to a sharp decrease in release probability and Ca2+ sensitivity and associated with a marked increase of the asynchronous/synchronous release ratio. PRRT2 interacts with the synaptic proteins SNAP-25 and synaptotagmin 1/2. The results indicate that PRRT2 is intimately connected with the Ca2+-sensing machinery and that it plays an important role in the final steps of neurotransmitter release.

  13. PRRT2 Is a Key Component of the Ca2+-Dependent Neurotransmitter Release Machinery

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    Valente, Pierluigi; Castroflorio, Enrico; Rossi, Pia; Fadda, Manuela; Sterlini, Bruno; Cervigni, Romina Ines; Prestigio, Cosimo; Giovedì, Silvia; Onofri, Franco; Mura, Elisa; Guarnieri, Fabrizia C.; Marte, Antonella; Orlando, Marta; Zara, Federico; Fassio, Anna; Valtorta, Flavia; Baldelli, Pietro; Corradi, Anna; Benfenati, Fabio

    2016-01-01

    Summary Heterozygous mutations in proline-rich transmembrane protein 2 (PRRT2) underlie a group of paroxysmal disorders, including epilepsy, kinesigenic dyskinesia, and migraine. Most of the mutations lead to impaired PRRT2 expression, suggesting that loss of PRRT2 function may contribute to pathogenesis. We show that PRRT2 is enriched in presynaptic terminals and that its silencing decreases the number of synapses and increases the number of docked synaptic vesicles at rest. PRRT2-silenced neurons exhibit a severe impairment of synchronous release, attributable to a sharp decrease in release probability and Ca2+ sensitivity and associated with a marked increase of the asynchronous/synchronous release ratio. PRRT2 interacts with the synaptic proteins SNAP-25 and synaptotagmin 1/2. The results indicate that PRRT2 is intimately connected with the Ca2+-sensing machinery and that it plays an important role in the final steps of neurotransmitter release. PMID:27052163

  14. Modulation of neurotransmitter release in the region of the caudate nucleus by diet and neurotoxins

    International Nuclear Information System (INIS)

    Kurstjens, N.P.

    1987-01-01

    In this thesis the effects of dietary manipulation, ethanol and neurotoxins on the basal and electrically evoked release of dopamine and acetylcholine from the caudate nucleus of mature animals are presented together with an evaluation of the presynaptic acetylcholine and dopamine receptors controlling acetylcholine and dopamine release. A standardised superfusion technique was used to monitor the effect of apomorphine, in the presence of (R-S)- sulpiride or haloperidol, on the electrically induced release of ( 3 H)-acetylcholine in slices of rat corpus striatum. The effect of ethanol and dietary manipulation on the basal and electrically evoke release of ( 3 H)-acetylfholine from rat striatal slices, in the presence of specific agonists and antagonists was evaluated. From this study it is possible to deduce that diet and neurotoxins exerted a measurable effect on the mechanisms controlling release of neurotransmitters in the region of the caudate nucleus. These changes were determined in mature animals previously considered to have cerebral activity, which was not subject to dietary fluctuaations. No changes in the activity of the presynaptic dopamine receptor of the acetylcholine nerve terminals of the striatal slice could be measured

  15. HDAC6 Is a Bruchpilot Deacetylase that Facilitates Neurotransmitter Release

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    Katarzyna Miskiewicz

    2014-07-01

    Full Text Available Presynaptic densities are specialized structures involved in synaptic vesicle tethering and neurotransmission; however, the mechanisms regulating their function remain understudied. In Drosophila, Bruchpilot is a major constituent of the presynaptic density that tethers vesicles. Here, we show that HDAC6 is necessary and sufficient for deacetylation of Bruchpilot. HDAC6 expression is also controlled by TDP-43, an RNA-binding protein deregulated in amyotrophic lateral sclerosis (ALS. Animals expressing TDP-43 harboring pathogenic mutations show increased HDAC6 expression, decreased Bruchpilot acetylation, larger vesicle-tethering sites, and increased neurotransmission, defects similar to those seen upon expression of HDAC6 and opposite to hdac6 null mutants. Consequently, reduced levels of HDAC6 or increased levels of ELP3, a Bruchpilot acetyltransferase, rescue the presynaptic density defects in TDP-43-expressing flies as well as the decreased adult locomotion. Our work identifies HDAC6 as a Bruchpilot deacetylase and indicates that regulating acetylation of a presynaptic release-site protein is critical for maintaining normal neurotransmission.

  16. Release properties of individual presynaptic boutons expressed during homosynaptic depression and heterosynaptic facilitation of the Aplysia sensorimotor synapse

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    Guy eMalkinson

    2013-09-01

    Full Text Available Much of what we know about the mechanisms underlying Homosynaptic Depression (HSD and heterosynaptic facilitation is based on intracellular recordings of integrated postsynaptic potentials. This methodological approach views the presynaptic apparatus as a single compartment rather than taking a more realistic representation reflecting the fact that it is made up of tens to hundreds of individual and independent Presynaptic Release Boutons (PRBs. Using cultured Aplysia sensorimotor synapses, we reexamined HSD and its dishabituation by imaging the release properties of individual PRBs. We find that the PRB population is heterogeneous and can be clustered into three groups: approximately 25% of the PRBs consistently release neurotransmitter throughout the entire habituation paradigm (35 stimuli, 0.05Hz and have a relatively high quantal content, 36% of the PRBs display intermittent failures only after the tenth stimulation, and 39% are low quantal-content PRBs that exhibit intermittent release failures from the onset of the habituation paradigm. 5HT-induced synaptic dishabituation by a single 5HT application was generated by the enhanced recovery of the quantal content of the habituated PRBs and did not involve the recruitment of new release boutons. The characterization of the PRB population as heterogeneous in terms of its temporal pattern of release-probability and quantal content provides new insights into the mechanisms underlying HSD and its dishabituation.

  17. The effect of buffered calcium diffusion on neurotransmitter release

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    Ponce Dawson, Silvina; Uchitel, Osvaldo D.

    2002-08-01

    Calcium plays a major role in inter-neuron communication. It has recently been observed that the scaling relationship between extracellular calcium concentration and postsynaptic response is different depending on the channel through which calcium enters the presynaptic neuron. Experiments suggest that the two types of calcium channels probed in this regard are at different mean distances from the neurotransmitter-containing vesicles. In this work we investigate whether the effect of calcium buffers along the path from the channel to the vesicle sensor can be responsible for the differences observed. Our results show that buffers cannot account for this change. This study also allows us to probe the limitations of the rapid buffering approximation in the presence of strong and localized sources.

  18. Depolarization by K*O+ and glutamate activates different neurotransmitter release mechanisms in gabaergic neurons: vesicular versus non-vesicular release of gaba

    DEFF Research Database (Denmark)

    Belhage, Bo; Hansen, G.H.; Schousboe, Arne

    1993-01-01

    Neurotransmitter release, gaba release, membrane transporter, vesicles, intracellular CA*OH, neuron cultures......Neurotransmitter release, gaba release, membrane transporter, vesicles, intracellular CA*OH, neuron cultures...

  19. Tunable Molecular Logic Gates Designed for Imaging Released Neurotransmitters.

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    Klockow, Jessica L; Hettie, Kenneth S; Secor, Kristen E; Barman, Dipti N; Glass, Timothy E

    2015-08-03

    Tunable dual-analyte fluorescent molecular logic gates (ExoSensors) were designed for the purpose of imaging select vesicular primary-amine neurotransmitters that are released from secretory vesicles upon exocytosis. ExoSensors are based on the coumarin-3-aldehyde scaffold and rely on both neurotransmitter binding and the change in environmental pH associated with exocytosis to afford a unique turn-on fluorescence output. A pH-functionality was directly integrated into the fluorophore π-system of the scaffold, thereby allowing for an enhanced fluorescence output upon the release of labeled neurotransmitters. By altering the pH-sensitive unit with various electron-donating and -withdrawing sulfonamide substituents, we identified a correlation between the pKa of the pH-sensitive group and the fluorescence output from the activated fluorophore. In doing so, we achieved a twelvefold fluorescence enhancement upon evaluating the ExoSensors under conditions that mimic exocytosis. ExoSensors are aptly suited to serve as molecular imaging tools that allow for the direct visualization of only the neurotransmitters that are released from secretory vesicles upon exocytosis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Functional Connectomes in Time Domain from Simulated Neurotransmitter Release Based on Electrocorticograms

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    You Zhai

    2018-02-01

    Full Text Available This paper uses a newly defined functional connectome and connectome values calculated in time domain of simulated neurotransmitter release (NTR from an electrocorticogram (ECoG to distinguish between conditioned and unconditioned stimuli. The NTR derived from multiple channels releasing one quantum at the same time suggests that one functional connectome occurs across those channels at that time. During the first 600 ms after conditional stimulation, the connectome indexes of the 64-channel NTR trains were sorted from the 8 to 20 Hz band obtained from filtered rabbit ECoGs recorded from the visual cortices. In the small scale visual cortex area, this association was significantly larger than the habituation, even though the trial-to-trail variability of large scale synchrony after conditional stimulation is increased, which is also consistent with the hypothesis that attention decreases coherence of lower frequency within each cortical area. The increased conectome index suggests that the stimuli related to association are able to generate stronger substantial responses in the small scale visual cortex than habituation. That is, besides of the background cortical states as well as attention-related decreases in synchrony of lower frequency, the increased part of neurotransmitters released simultaneously from the pre-synaptic terminals of small scale visual cortex for association is larger than habituation.

  1. Presynaptic inhibition of spontaneous acetylcholine release induced by adenosine at the mouse neuromuscular junction.

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    De Lorenzo, Silvana; Veggetti, Mariela; Muchnik, Salomón; Losavio, Adriana

    2004-05-01

    inhibit the increases in mepp frequency evoked by 15 and 20 mm K(+). We demonstrated that, at high K(+) concentrations, endogenous AD occupies A1 receptors, impairing the action of CCPA, since incubation with 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, an A(1) receptor antagonist) and adenosine deaminase (ADA), which degrades AD into the inactive metabolite inosine, increased mepp frequency compared with that obtained in 15 and 20 mm K(+) in the absence of the drugs. Moreover, CCPA was able to induce presynaptic inhibition in the presence of ADA. It is concluded that, at high K(+) concentrations, the activation of A(1) receptors by endogenous AD prevents excessive neurotransmitter release.

  2. HDAC6 Is a Bruchpilot Deacetylase that Facilitates Neurotransmitter Release

    NARCIS (Netherlands)

    Miskiewicz, Katarzyna; Jose, Liya E.; Yeshaw, Wondwossen M.; Valadas, Jorge S.; Swerts, Jef; Munck, Sebastian; Feiguin, Fabian; Dermaut, Bart; Verstreken, Patrik

    2014-01-01

    Presynaptic densities are specialized structures involved in synaptic vesicle tethering and neurotransmission; however, the mechanisms regulating their function remain understudied. In Drosophila, Bruchpilot is a major constituent of the presynaptic density that tethers vesicles. Here, we show that

  3. Rosiglitazone Suppresses In Vitro Seizures in Hippocampal Slice by Inhibiting Presynaptic Glutamate Release in a Model of Temporal Lobe Epilepsy.

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    Shi-Bing Wong

    Full Text Available Peroxisomal proliferator-activated receptor gamma (PPARγ is a nuclear hormone receptor whose agonist, rosiglitazone has a neuroprotective effect to hippocampal neurons in pilocarpine-induced seizures. Hippocampal slice preparations treated in Mg2+ free medium can induce ictal and interictal-like epileptiform discharges, which is regarded as an in vitro model of N-methyl-D-aspartate (NMDA receptor-mediated temporal lobe epilepsy (TLE. We applied rosiglitazone in hippocampal slices treated in Mg2+ free medium. The effects of rosiglitazone on hippocampal CA1-Schaffer collateral synaptic transmission were tested. We also examined the neuroprotective effect of rosiglitazone toward NMDA excitotoxicity on cultured hippocampal slices. Application of 10 μM rosiglitazone significantly suppressed amplitude and frequency of epileptiform discharges in CA1 neurons. Pretreatment with the PPARγ antagonist GW9662 did not block the effect of rosiglitazone on suppressing discharge frequency, but reverse the effect on suppressing discharge amplitude. Application of rosiglitazone suppressed synaptic transmission in the CA1-Schaffer collateral pathway. By miniature excitatory-potential synaptic current (mEPSC analysis, rosiglitazone significantly suppressed presynaptic neurotransmitter release. This phenomenon can be reversed by pretreating PPARγ antagonist GW9662. Also, rosiglitazone protected cultured hippocampal slices from NMDA-induced excitotoxicity. The protective effect of 10 μM rosiglitazone was partially antagonized by concomitant high dose GW9662 treatment, indicating that this effect is partially mediated by PPARγ receptors. In conclusion, rosiglitazone suppressed NMDA receptor-mediated epileptiform discharges by inhibition of presynaptic neurotransmitter release. Rosiglitazone protected hippocampal slice from NMDA excitotoxicity partially by PPARγ activation. We suggest that rosiglitazone could be a potential agent to treat patients with TLE.

  4. Presynaptic molecular determinants of quantal size

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    Shigeo eTakamori

    2016-02-01

    Full Text Available The quantal hypothesis for the release of neurotransmitters at the chemical synapse has gained wide acceptance since it was first worked out at the motor endplate in frog skeletal muscle in the 1950s. Considering the morphological identification of synaptic vesicles at the nerve terminals that appeared to be homogeneous in size, the hypothesis proposed that signal transduction at synapses is mediated by the release of neurotransmitters packed in synaptic vesicles that are individually uniform in size; the amount of transmitter in a synaptic vesicle is called a quantum. Although quantal size – the amplitude of the postsynaptic response elicited by the release of neurotransmitters from a single vesicle – clearly depends on the number and sensitivity of the postsynaptic receptors, accumulating evidence has also indicated that the amount of neurotransmitters stored in synaptic vesicles can be altered by various presynaptic factors. Here, I provide an overview of the concepts and underlying presynaptic molecular underpinnings that may regulate quantal size.

  5. New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

    Science.gov (United States)

    2015-07-01

    and 280nm using a BioMate 5 UV- visible spectrophotometer (Thermo Spectronic, Waltham, Massachusetts, USA). The integrity of the extracted RNA was...presynaptic P/Q-type voltage-dependent calcium channel to reduce glutamate release. In a different study, local perfusion with LEV (10, 30 and 100M) alone...the brain was used for protein expression analysis (western blotting) as described above while the other hemisphere was used for mRNA extraction . As

  6. Presynaptic inhibition of spontaneous acetylcholine release mediated by P2Y receptors at the mouse neuromuscular junction.

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    De Lorenzo, S; Veggetti, M; Muchnik, S; Losavio, A

    2006-09-29

    At the neuromuscular junction, ATP is co-released with the neurotransmitter acetylcholine (ACh) and once in the synaptic space, it is degraded to the presynaptically active metabolite adenosine. Intracellular recordings were performed on diaphragm fibers of CF1 mice to determine the action of extracellular ATP (100 muM) and the slowly hydrolysable ATP analog 5'-adenylylimidodiphosphate lithium (betagamma-imido ATP) (30 muM) on miniature end-plate potential (MEPP) frequency. We found that application of ATP and betagamma-imido ATP decreased spontaneous secretion by 45.3% and 55.9% respectively. 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective A(1) adenosine receptor antagonist and alpha,beta-methylene ADP sodium salt (alphabeta-MeADP), which is an inhibitor of ecto-5'-nucleotidase, did not prevent the inhibitory effect of ATP, demonstrating that the nucleotide is able to modulate spontaneous ACh release through a mechanism independent of the action of adenosine. Blockade of Ca(2+) channels by both, Cd(2+) or the combined application of nitrendipine and omega-conotoxin GVIA (omega-CgTx) (L-type and N-type Ca(2+) channel antagonists, respectively) prevented the effect of betagamma-imido ATP, indicating that the nucleotide modulates Ca(2+) influx through the voltage-dependent Ca(2+) channels related to spontaneous secretion. betagamma-Imido ATP-induced modulation was antagonized by the non-specific P2 receptor antagonist suramin and the P2Y receptor antagonist 1-amino-4-[[4-[[4-chloro-6-[[3(or4)-sulfophenyl] amino]-1,3,5-triazin-2-yl]amino]-3-sulfophenyl] amino]-9,10-dihydro-9,10-dioxo-2-anthracenesulfonic acid (reactive blue-2), but not by pyridoxal phosphate-6-azo(benzene-2,4-disulfonic acid) tetrasodium salt (PPADS), which has a preferential antagonist effect on P2X receptors. Pertussis toxin and N-ethylmaleimide (NEM), which are blockers of G(i/o) proteins, prevented the action of the nucleotide, suggesting that the effect is mediated by P2Y receptors

  7. DYSFUNCTIONAL PRESYNAPTIC ALPHA-2-ADRENOCEPTORS EXPOSE FACILITATORY BETA-2-ADRENOCEPTORS IN THE VASCULATURE OF SPONTANEOUSLY HYPERTENSIVE RATS

    NARCIS (Netherlands)

    REMIE, R; VANROSSUM, JXM; COPPES, RP; ZAAGSMA, J

    1992-01-01

    Previous studies on spontaneously hypertensive rats (SHR) have yielded inconsistent information about functional aberrations of the presynaptic alpha(2)- and beta(2)-adrenoceptor-mediated modulation of sympathetic neurotransmitter release. In the present investigation we studied the capacity of

  8. Endophilin mutations block clathrin-mediated endocytosis but not neurotransmitter release

    DEFF Research Database (Denmark)

    Verstreken, Patrik; Kjaerulff, Ole; Lloyd, Thomas E

    2002-01-01

    We have identified mutations in Drosophila endophilin to study its function in vivo. Endophilin is required presynaptically at the neuromuscular junction, and absence of Endophilin dramatically impairs endocytosis in vivo. Mutant larvae that lack Endophilin fail to take up FM1-43 dye in synaptic...... boutons, indicating an inability to retrieve synaptic membrane. This defect is accompanied by an expansion of the presynaptic membrane, and a depletion of vesicles from the bouton lumen. Interestingly, mutant larvae are still able to sustain release at 15%-20% of the normal rate during high...

  9. Changes in presynaptic release, but not reuptake, of bioamines induced by long-term antidepressant treatment

    International Nuclear Information System (INIS)

    Dolzhenko, A.T.; Komissarov, I.V.

    1986-01-01

    This paper describes an investigation into the effect of long-term administration of antidepressants on neuronal uptake of NA and 5-HT and on their release, induced by electrical stimulation, in rat brain slices. The effects of the test substances on neuronal uptake of 14 C-NA and 3 H-5-HT by the slices was investigated. Values of IC 50 and EC 2 were found and compared in the experiments and control. The inhibitory effect of clonidine (10 -4 M) and of 5-HT (10 -5 M) on presynaptic release of 14 C-NA and 3 H-5-HT also was studied in brain slices from intact rats and rats treated for two weeks with antidepressants

  10. Experience-Dependent Regulation of Presynaptic NMDARs Enhances Neurotransmitter Release at Neocortical Synapses

    Science.gov (United States)

    Urban-Ciecko, Joanna; Wen, Jing A.; Parekh, Puja K.; Barth, Alison L.

    2015-01-01

    Sensory experience can selectively alter excitatory synaptic strength at neocortical synapses. The rapid increase in synaptic strength induced by selective whisker stimulation (single-row experience/SRE, where all but one row of whiskers has been removed from the mouse face) is due, at least in part, to the trafficking of AMPA receptors (AMPARs)…

  11. Relationship between presynaptic membrane potential and acetylcholine release in synaptosomes from Torpedo electric organ.

    Science.gov (United States)

    Meunier, F M

    1984-01-01

    The membrane potential of purely cholinergic synaptosomes isolated from Torpedo electric organ was monitored with fluorescent carbocyanine dyes. An increased fluorescence was associated with depolarization and a quenching with hyperpolarization. Fluorescence data provided evidence that Torpedo synaptosomes have a membrane potential mainly driven by a K+ diffusion potential and a membrane potential of about -50 mV could be estimated after calibration of fluorescence signals with ionophore antibiotics. The release of acetylcholine (ACh) from Torpedo synaptosomes was monitored continuously by measuring the light emitted by a chemiluminescent method (Israël & Lesbats, 1981 a). Using fluorescence data, the release of ACh was expressed as a function of membrane potential. The relationship between presynaptic potential and transmitter release as determined by biochemical methods at cholinergic nerve endings showed striking similarities to that observed at the squid giant synapse. Several substances were also tested with regard to their depolarizing and releasing properties and it was found that the toxin isolated from the venom of the annelid Glycera convoluta, which induced a large increase in quantal release of transmitter (Manaranche, Thieffry, & Israël, 1980) promoted a depolarization of Torpedo synaptosomes in addition to ACh release. PMID:6207289

  12. Distinct presynaptic control of dopamine release in striosomal and matrix areas of the cat caudate nucleus

    International Nuclear Information System (INIS)

    Kemel, M.L.; Desban, M.; Glowinski, J.; Gauchy, C.

    1989-01-01

    By use of a sensitive in vitro microsuperfusion method, the cholinergic presynaptic control of dopamine release was investigated in a prominent striosome (areas poor in acetylcholinesterase activity) located within the core of cat caudate nucleus and also in adjacent matrix area. The spontaneous release of [ 3 H]dopamine continuously synthesized from [ 3 H]tyrosine in the matrix area was found to be twice that in the striosomal area; the spontaneous and potassium-evoked releases of [ 3 H]dopamine were calcium-dependent in both compartments. With 10 -6 M tetrodotoxin, 5 x 10 -5 M acetylcholine stimulated [ 3 H]dopamine release in both striosomal and matrix areas, effects completely antagonized by atropine, thus showing the involvement of muscarinic receptors located on dopaminergic nerve terminals. Experiments without tetrodotoxin revealed a more complex regulation of dopamine release in the matrix: (i) in contrast to results seen in the striosome, acetylcholine induced only a transient stimulatory effect on matrix dopamine release. (ii) Although 10 -6 M atropine completely abolished the cholinergic stimulatory effect on [ 3 H]dopamine release in striosomal area, delayed and prolonged stimulation of [ 3 H] dopamine release was seen with atropine in the matrix. The latter effect was completely abolished by the nicotinic antagonist pempidine. Therefore, in the matrix, in addition to its direct (tetrodotoxin-insensitive) facilitatory action on [ 3 H]dopamine release, acetylcholine exerts two indirect (tetrodotoxin-sensitive) opposing effects: an inhibition and a stimulation of [ 3 H]dopamine release mediated by muscarinic and nicotinic receptors, respectively

  13. Parallel expression of synaptophysin and evoked neurotransmitter release during development of cultured neurons

    DEFF Research Database (Denmark)

    Ehrhart-Bornstein, M; Treiman, M; Hansen, Gert Helge

    1991-01-01

    by quantitative immunoblotting and light microscope immunocytochemistry, respectively. In both cell types, a close parallelism was found between the temporal pattern of development in synaptophysin expression and neurotransmitter release. This temporal pattern differed between the two types of neurons......Primary cultures of GABAergic cerebral cortex neurons and glutamatergic cerebellar granule cells were used to study the expression of synaptophysin, a synaptic vesicle marker protein, along with the ability of each cell type to release neurotransmitter upon stimulation. The synaptophysin expression...... and neurotransmitter release were measured in each of the culture types as a function of development for up to 8 days in vitro, using the same batch of cells for both sets of measurements to obtain optimal comparisons. The content and the distribution of synaptophysin in the developing cells were assessed...

  14. Parallel expression of synaptophysin and evoked neurotransmitter release during development of cultured neurons

    DEFF Research Database (Denmark)

    Ehrhart-Bornstein, M; Treiman, M; Hansen, Gert Helge

    1991-01-01

    Primary cultures of GABAergic cerebral cortex neurons and glutamatergic cerebellar granule cells were used to study the expression of synaptophysin, a synaptic vesicle marker protein, along with the ability of each cell type to release neurotransmitter upon stimulation. The synaptophysin expression...... and neurotransmitter release were measured in each of the culture types as a function of development for up to 8 days in vitro, using the same batch of cells for both sets of measurements to obtain optimal comparisons. The content and the distribution of synaptophysin in the developing cells were assessed...... by quantitative immunoblotting and light microscope immunocytochemistry, respectively. In both cell types, a close parallelism was found between the temporal pattern of development in synaptophysin expression and neurotransmitter release. This temporal pattern differed between the two types of neurons...

  15. Tyrosine 402 Phosphorylation of Pyk2 Is Involved in Ionomycin-Induced Neurotransmitter Release

    Science.gov (United States)

    Zhang, Zhao; Zhang, Yun; Mou, Zheng; Chu, Shifeng; Chen, Xiaoyu; He, Wenbin; Guo, Xiaofeng; Yuan, Yuhe; Takahashi, Masami; Chen, Naihong

    2014-01-01

    Protein tyrosine kinases, which are highly expressed in the central nervous system, are implicated in many neural processes. However, the relationship between protein tyrosine kinases and neurotransmitter release remains unknown. In this study, we found that ionomycin, a Ca2+ ionophore, concurrently induced asynchronous neurotransmitter release and phosphorylation of a non-receptor protein tyrosine kinase, proline-rich tyrosine kinase 2 (Pyk2), in clonal rat pheochromocytoma PC12 cells and cerebellar granule cells, whereas introduction of Pyk2 siRNA dramatically suppressed ionomycin-induced neurotransmitter release. Further study indicated that Tyr-402 (Y402) in Pyk2, instead of other tyrosine sites, underwent rapid phosphorylation after ionomycin induction in 1 min to 2 min. We demonstrated that the mutant of Pyk2 Y402 could abolish ionomycin-induced dopamine (DA) release by transfecting cells with recombinant Pyk2 and its mutants (Y402F, Y579F, Y580F, and Y881F). In addition, Src inhibition could prolong phosphorylation of Pyk2 Y402 and increase DA release. These findings suggested that Pyk2 was involved in ionomycin-induced neurotransmitter release through phosphorylation of Y402. PMID:24718602

  16. Amyloid-β acts as a regulator of neurotransmitter release disrupting the interaction between synaptophysin and VAMP2.

    Directory of Open Access Journals (Sweden)

    Claire L Russell

    Full Text Available It is becoming increasingly evident that deficits in the cortex and hippocampus at early stages of dementia in Alzheimer's disease (AD are associated with synaptic damage caused by oligomers of the toxic amyloid-β peptide (Aβ42. However, the underlying molecular and cellular mechanisms behind these deficits are not fully understood. Here we provide evidence of a mechanism by which Aβ42 affects synaptic transmission regulating neurotransmitter release.We first showed that application of 50 nM Aβ42 in cultured neurones is followed by its internalisation and translocation to synaptic contacts. Interestingly, our results demonstrate that with time, Aβ42 can be detected at the presynaptic terminals where it interacts with Synaptophysin. Furthermore, data from dissociated hippocampal neurons as well as biochemical data provide evidence that Aβ42 disrupts the complex formed between Synaptophysin and VAMP2 increasing the amount of primed vesicles and exocytosis. Finally, electrophysiology recordings in brain slices confirmed that Aβ42 affects baseline transmission.Our observations provide a necessary and timely insight into cellular mechanisms that underlie the initial pathological events that lead to synaptic dysfunction in Alzheimer's disease. Our results demonstrate a new mechanism by which Aβ42 affects synaptic activity.

  17. Presynaptic membrane receptors in acetylcholine release modulation in the neuromuscular synapse.

    Science.gov (United States)

    Tomàs, Josep; Santafé, Manel M; Garcia, Neus; Lanuza, Maria A; Tomàs, Marta; Besalduch, Núria; Obis, Teresa; Priego, Mercedes; Hurtado, Erica

    2014-05-01

    Over the past few years, we have studied, in the mammalian neuromuscular junction (NMJ), the local involvement in transmitter release of the presynaptic muscarinic ACh autoreceptors (mAChRs), purinergic adenosine autoreceptors (P1Rs), and trophic factor receptors (TFRs; for neurotrophins and trophic cytokines) during development and in the adult. At any given moment, the way in which a synapse works is largely the logical outcome of the confluence of these (and other) metabotropic signalling pathways on intracellular kinases, which phosphorylate protein targets and materialize adaptive changes. We propose an integrated interpretation of the complementary function of these receptors in the adult NMJ. The activity of a given receptor group can modulate a given combination of spontaneous, evoked, and activity-dependent release characteristics. For instance, P1Rs can conserve resources by limiting spontaneous quantal leak of ACh (an A1 R action) and protect synapse function, because stimulation with adenosine reduces the magnitude of depression during repetitive activity. The overall outcome of the mAChRs seems to contribute to upkeep of spontaneous quantal output of ACh, save synapse function by decreasing the extent of evoked release (mainly an M2 action), and reduce depression. We have also identified several links among P1Rs, mAChRs, and TFRs. We found a close dependence between mAChR and some TFRs and observed that the muscarinic group has to operate correctly if the tropomyosin-related kinase B receptor (trkB) is also to operate correctly, and vice versa. Likewise, the functional integrity of mAChRs depends on P1Rs operating normally. Copyright © 2014 Wiley Periodicals, Inc.

  18. Sustained synaptic-vesicle recycling by bulk endocytosis contributes to the maintenance of high-rate neurotransmitter release stimulated by glycerotoxin

    Science.gov (United States)

    Meunier, Frederic A.; Nguyen, Tam H.; Colasante, Cesare; Luo, Fujun; Sullivan, Robert K. P.; Lavidis, Nickolas A.; Molgó, Jordi; Meriney, Stephen D.; Schiavo, Giampietro

    2010-01-01

    Glycerotoxin (GLTx), a large neurotoxin isolated from the venom of the sea worm Glycera convoluta, promotes a long-lasting increase in spontaneous neurotransmitter release at the peripheral and central synapses by selective activation of Cav2.2 channels. We found that GLTx stimulates the very high frequency, long-lasting (more than 10 hours) spontaneous release of acetylcholine by promoting nerve terminal Ca2+ oscillations sensitive to the inhibitor ω-conotoxin GVIA at the amphibian neuromuscular junction. Although an estimate of the number of synaptic vesicles undergoing exocytosis largely exceeds the number of vesicles present in the motor nerve terminal, ultrastructural examination of GLTx-treated synapses revealed no significant change in the number of synaptic vesicles. However, we did detect the appearance of large pre-synaptic cisternae suggestive of bulk endocytosis. Using a combination of styryl dyes, photoconversion and horseradish peroxidase (HRP)-labeling electron microscopy, we demonstrate that GLTx upregulates presynaptic-vesicle recycling, which is likely to emanate from the limiting membrane of these large cisternae. Similar synaptic-vesicle recycling through bulk endocytosis also occurs from nerve terminals stimulated by high potassium. Our results suggest that this process might therefore contribute significantly to synaptic recycling under sustained levels of synaptic stimulation. PMID:20215402

  19. Activity-dependent, homeostatic regulation of neurotransmitter release from auditory nerve fibers

    OpenAIRE

    Ngodup, Tenzin; Goetz, Jack A.; McGuire, Brian C.; Sun, Wei; Lauer, Amanda M.; Xu-Friedman, Matthew A.

    2015-01-01

    Synapses with high probability of neurotransmitter release (Pr) depress during prolonged activity, which reduces the faithful transfer of information. Auditory nerve synapses onto bushy cells show particularly strong depression at physiologically relevant rates of activity, which raises the question of how bushy cells transmit information when sound levels are high for a prolonged period. After rearing mice in constant, nondamaging noise, auditory nerve synapses changed from high to low Pr, w...

  20. Synapse-specific and compartmentalized expression of presynaptic homeostatic potentiation.

    Science.gov (United States)

    Li, Xiling; Goel, Pragya; Chen, Catherine; Angajala, Varun; Chen, Xun; Dickman, Dion K

    2018-04-05

    Postsynaptic compartments can be specifically modulated during various forms of synaptic plasticity, but it is unclear whether this precision is shared at presynaptic terminals. Presynaptic Homeostatic Plasticity (PHP) stabilizes neurotransmission at the Drosophila neuromuscular junction, where a retrograde enhancement of presynaptic neurotransmitter release compensates for diminished postsynaptic receptor functionality. To test the specificity of PHP induction and expression, we have developed a genetic manipulation to reduce postsynaptic receptor expression at one of the two muscles innervated by a single motor neuron. We find that PHP can be induced and expressed at a subset of synapses, over both acute and chronic time scales, without influencing transmission at adjacent release sites. Further, homeostatic modulations to CaMKII, vesicle pools, and functional release sites are compartmentalized and do not spread to neighboring pre- or post-synaptic structures. Thus, both PHP induction and expression mechanisms are locally transmitted and restricted to specific synaptic compartments. © 2018, Li et al.

  1. The suppressor of cytokine signaling 2 (SOCS2) modulating the neurotransmitters release in Eriocheir sinensis.

    Science.gov (United States)

    Zhang, Ying; Zhou, Zhi; Wang, Lingling; Liu, Rui; Song, Linsheng

    2013-07-01

    The SOCS proteins appear to define an important mechanism for the negative regulation of the cytokine-JAK-STAT pathway. In the present study, the mRNA expression profiles of a SOCS2 from Chinese mitten crab Eriocheir sinensis (EsSOCS2) after pentachlorophenol (PCP) treatment or RNA interference (RNAi) were analyzed to understand its possible regulatory roles in modulating the neurotransmitter release. The EsSOCS2 expression level in the PCP treated group was significantly higher than that of blank at 1.5, 3, 12 and 24 h after exposure, suggesting that EsSOCS2 might be involved in controlling and reducing neuronal cell damage resulted from PCP treatment. After the expression of EsSOCS2 gene was silenced by RNAi, the concentrations of catecholamines and nitric oxide (NO) were examined to evaluate the modulation of EsSOCS2 on the release of neurotransmitters. At 48 h after the treatment with sequence-specific dsRNA targeting EsSOCS2, the expression of EsSOCS2 was reduced to half compared to the original level, and the concentrations of norepinephrine and NO increased, while dopamine decreased significantly in haemolymph. The preliminary results indicated that EsSOCS2 regulated catecholaminergic neuroendocrine system to release catecholamines into haemolymph and might be an important feedback inhibitor of tyrosine kinase signaling pathways in crab, which subsequently regulated NO synthesis and prevented excessive NO release. This information is helpful to further understand the modulation of EsSOCS2 on neurotransmitter release in crab. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Depolarization by K+ and glutamate activates different neurotransmitter release mechanisms in GABAergic neurons: vesicular versus non-vesicular release of GABA

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A

    1993-01-01

    Neurotransmitter release and changes in the concentration of intracellular free calcium ([Ca++]i) were studied in cultured GABAergic cerebral cortical neurons, from mice, upon depolarization with either an unphysiologically high potassium concentration (55 mM) or the physiological excitatory...... neurotransmitter glutamate (100 microM). Both depolarizing stimuli exerted prompt increases in the release of preloaded [3H]GABA as well as in [Ca++]i. However, the basic properties of transmitter release and the increase in [Ca++]i under a variety of conditions were different during stimulation with K...... in nature whereas that induced by the neurotransmitter glutamate is not....

  3. Loss of nitric oxide-mediated inhibition of purine neurotransmitter release in the colon in the absence of interstitial cells of Cajal.

    Science.gov (United States)

    Durnin, Leonie; Lees, Andrea; Manzoor, Sheerien; Sasse, Kent C; Sanders, Kenton M; Mutafova-Yambolieva, Violeta N

    2017-11-01

    Regulation of colonic motility depends on the integrity of enteric inhibitory neurotransmission mediated by nitric oxide (NO), purine neurotransmitters, and neuropeptides. Intramuscular interstitial cells of Cajal (ICC-IM) and platelet-derived growth factor receptor-α-positive (PDGFRα + ) cells are involved in generating responses to NO and purine neurotransmitters, respectively. Previous studies have suggested a decreased nitrergic and increased purinergic neurotransmission in Kit W /Kit W-v ( W/W v ) mice that display lesions in ICC-IM along the gastrointestinal tract. However, contributions of NO to these phenotypes have not been evaluated. We used small-chamber superfusion assays and HPLC to measure the spontaneous and electrical field stimulation (EFS)-evoked release of nicotinamide adenine dinucleotide (NAD + )/ADP-ribose, uridine adenosine tetraphosphate (Up4A), adenosine 5'-triphosphate (ATP), and metabolites from the tunica muscularis of human, monkey, and murine colons and circular muscle of monkey colon, and we tested drugs that modulate NO levels or blocked NO receptors. NO inhibited EFS-evoked release of purines in the colon via presynaptic neuromodulation. Colons from W/W v , Nos1 -/- , and Prkg1 -/- mice displayed augmented neural release of purines that was likely due to altered nitrergic neuromodulation. Colons from W/W v mice demonstrated decreased nitrergic and increased purinergic relaxations in response to nerve stimulation. W/W v mouse colons demonstrated reduced Nos1 expression and reduced NO release. Our results suggest that enhanced purinergic neurotransmission may compensate for the loss of nitrergic neurotransmission in muscles with partial loss of ICC. The interactions between nitrergic and purinergic neurotransmission in the colon provide novel insight into the role of neurotransmitters and effector cells in the neural regulation of gastrointestinal motility. NEW & NOTEWORTHY This is the first study investigating the role of nitric

  4. Neurotransmitter release in motor nerve terminals of a mouse model of mild spinal muscular atrophy.

    Science.gov (United States)

    Ruiz, Rocío; Tabares, Lucía

    2014-01-01

    Spinal muscular atrophy is a genetic disease which severity depends on the amount of SMN protein, the product of the genes SMN1 and SMN2. Symptomatology goes from severe neuromuscular impairment leading to early death in infants to slow progressing motor deficits during adulthood. Much of the knowledge about the pathophysiology of SMA comes from studies using genetically engineered animal models of the disease. Here we investigated one of the milder models, the homozygous A2G SMA mice, in which the level of the protein is restored to almost normal levels by the addition of a mutated transgene to the severe SMN-deficient background. We examined neuromuscular function and found that calcium-dependent neurotransmitter release was significantly decreased. In addition, the amplitude of spontaneous endplate potentials was decreased, the morphology of NMJ altered, and slight changes in short-term synaptic plasticity were found. In spite of these defects, excitation contraction coupling was well preserved, possibly due to the safety factor of this synapse. These data further support that the quasi-normal restoration of SMN levels in severe cases preserves neuromuscular function, even when neurotransmitter release is significantly decreased at motor nerve terminals. Nevertheless, this deficit could represent a greater risk of motor impairment during aging or after injuries. © 2013 Anatomical Society.

  5. Mechanisms involved in nicotinic acetylcholine receptor-induced neurotransmitter release from sympathetic nerve terminals in the mouse vas deferens.

    Directory of Open Access Journals (Sweden)

    Damian J Williams

    Full Text Available Prejunctional nicotinic acetylcholine receptors (nAChRs amplify postganglionic sympathetic neurotransmission, and there are indications that intraterminal Ca(2+ stores might be involved. However, the mechanisms by which nAChR activation stimulates neurotransmitter release at such junctions is unknown. Rapid local delivery (picospritzing of the nAChR agonist epibatidine was combined with intracellular sharp microelectrode recording to monitor spontaneous and field-stimulation-evoked neurotransmitter release from sympathetic nerve terminals in the mouse isolated vas deferens. Locally applied epibatidine (1 µM produced 'epibatidine-induced depolarisations' (EIDs that were similar in shape to spontaneous excitatory junction potentials (SEJPs and were abolished by nonselective nAChR antagonists and the purinergic desensitizing agonist α,β-methylene ATP. The amplitude distribution of EIDs was only slightly shifted towards lower amplitudes by the selective α7 nAChR antagonists α-bungarotoxin and methyllcaconitine, the voltage-gated Na(+ channel blocker tetrodotoxin or by blocking voltage-gated Ca(2+ channels with Cd(2+. Lowering the extracellular Ca(2+ concentration reduced the frequency of EIDs by 69%, but more surprisingly, the Ca(2+-induced Ca(2+ release blocker ryanodine greatly decreased the amplitude (by 41% and the frequency of EIDs by 36%. Ryanodine had no effect on electrically-evoked neurotransmitter release, paired-pulse facilitation, SEJP frequency, SEJP amplitude or SEJP amplitude distribution. These results show that activation of non-α7 nAChRs on sympathetic postganglionic nerve terminals induces high-amplitude junctional potentials that are argued to represent multipacketed neurotransmitter release synchronized by intraterminal Ca(2+-induced Ca(2+ release, triggered by Ca(2+ influx directly through the nAChR. This nAChR-induced neurotransmitter release can be targeted pharmacologically without affecting spontaneous or electrically

  6. The impact of calcium current reversal on neurotransmitter release in the electrically stimulated retina

    Science.gov (United States)

    Werginz, Paul; Rattay, Frank

    2016-08-01

    Objective. In spite of intense theoretical and experimental investigations on electrical nerve stimulation, the influence of reversed ion currents on network activity during extracellular stimulation has not been investigated so far. Approach. Here, the impact of calcium current reversal on neurotransmitter release during subretinal stimulation was analyzed with a computational multi-compartment model of a retinal bipolar cell (BC) that was coupled with a four-pool model for the exocytosis from its ribbon synapses. Emphasis was laid on calcium channel dynamics and how these channels influence synaptic release. Main results. Stronger stimulation with anodic pulses caused transmembrane voltages above the Nernst potential of calcium in the terminals and, by this means, forced calcium ions to flow in the reversed direction from inside to the outside of the cell. Consequently, intracellular calcium concentration decreased resulting in a reduced vesicle release or preventing release at all. This mechanism is expected to lead to a pronounced ring-shaped pattern of exocytosis within a group of neighbored BCs when the stronger stimulated cells close to the electrode fail in releasing vesicles. Significance. Stronger subretinal stimulation causes failure of synaptic exocytosis due to reversal of calcium flow into the extracellular space in cells close to the electrode.

  7. Can nanofluidic chemical release enable fast, high resolution neurotransmitter-based neurostimulation?

    Directory of Open Access Journals (Sweden)

    Peter D Jones

    2016-03-01

    Full Text Available Artificial chemical stimulation could provide improvements over electrical neurostimulation. Physiological neurotransmission between neurons relies on the nanoscale release and propagation of specific chemical signals to spatially-localized receptors. Current knowledge of nanoscale fluid dynamics and nanofluidic technology allows us to envision artificial mechanisms to achieve fast, high resolution neurotransmitter release. Substantial technological development is required to reach this goal. Nanofluidic technology — rather than microfluidic — will be necessary; this should come as no surprise given the nanofluidic nature of neurotransmission.This perspective reviews the state of the art of high resolution electrical neuroprostheses and their anticipated limitations. Chemical release rates from nanopores are compared to rates achieved at synapses and with iontophoresis. A review of microfluidic technology justifies the analysis that microfluidic control of chemical release would be insufficient. Novel nanofluidic mechanisms are discussed, and we propose that hydrophobic gating may allow control of chemical release suitable for mimicking neurotransmission. The limited understanding of hydrophobic gating in artificial nanopores and the challenges of fabrication and large-scale integration of nanofluidic components are emphasized. Development of suitable nanofluidic technology will require dedicated, long-term efforts over many years.

  8. Effects of propofol and pentobarbital on calcium concentration in presynaptic boutons on a rat hippocampal neuron.

    Science.gov (United States)

    Ito, Shinichi; Sugiyama, Hitomi; Kitahara, Seiko; Ikemoto, Yoshimi; Yokoyama, Takeshi

    2011-10-01

    Numerous reports suggest that intravenously administered (IV) anesthetics affect postsynaptic events in the central nervous system. However, there is little evidence about how general anesthetics influence the presynaptic processes. The level of presynaptic calcium (Ca(2+)) concentration ([Ca(2+)](pre)) regulates neurotransmitter release. In this study, we investigated the effects of anesthetic propofol IV and the barbiturate pentobarbital on neurotransmitter release by measuring [Ca(2+)](pre) in the presynaptic nerve terminals (boutons) on a dissociated single hippocampal rat neuron. Sprague-Dawley rats 10-14 days old were decapitated under pentobarbital anesthesia, and brain slices were prepared. The hippocampal CA1 area was touched with a fire-polished glass pipette, which vibrated horizontally, and neurons were dissociated, along with the attached presynaptic boutons. The presynaptic boutons were visualized under a confocal laser-scanning microscope after staining with FM1-43 dye, and [Ca(2+)](pre) was measured with acetoxymethyl ester of fluo-3 (fluo-3 AM). High potassium (K(+)) (15-90 mM) increased the [Ca(2+)](pre) in the Ca(2+)-containing solution in a concentration-dependent manner. Whereas propofol (10 μM) and pentobarbital (300 μM) suppressed the high K(+) (60 mM)-induced increase in [Ca(2+)](pre) in the boutons attached to the dendrite, they did not affect [Ca(2+)](pre) in the boutons attached to the soma or dendrite base. As a large majority of excitatory synapses are located on dendritic spines, these agents may affect Ca(2+) mobilization in the excitatory presynaptic boutons. Propofol and pentobarbital may affect neurotransmitter release from the excitatory presynaptic nerve terminals due to inhibition of increase in [Ca(2+)](pre).

  9. The estimation of neurotransmitter release probability in feedforward neuronal network based on adaptive synchronization.

    Science.gov (United States)

    Xue, Ming; Wang, Jiang; Jia, Chenhui; Yu, Haitao; Deng, Bin; Wei, Xile; Che, Yanqiu

    2013-03-01

    In this paper, we proposed a new approach to estimate unknown parameters and topology of a neuronal network based on the adaptive synchronization control scheme. A virtual neuronal network is constructed as an observer to track the membrane potential of the corresponding neurons in the original network. When they achieve synchronization, the unknown parameters and topology of the original network are obtained. The method is applied to estimate the real-time status of the connection in the feedforward network and the neurotransmitter release probability of unreliable synapses is obtained by statistic computation. Numerical simulations are also performed to demonstrate the effectiveness of the proposed adaptive controller. The obtained results may have important implications in system identification in neural science.

  10. Evaluation of common variants in 16 genes involved in the regulation of neurotransmitter release in ADHD.

    Science.gov (United States)

    Sánchez-Mora, Cristina; Cormand, Bru; Ramos-Quiroga, Josep Antoni; Hervás, Amaia; Bosch, Rosa; Palomar, Glòria; Nogueira, Mariana; Gómez-Barros, Núria; Richarte, Vanesa; Corrales, Montse; Garcia-Martinez, Iris; Corominas, Roser; Guijarro, Silvina; Bigorra, Aitana; Bayés, Mònica; Casas, Miguel; Ribasés, Marta

    2013-06-01

    Attention-deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder characterized by inappropriate difficulties to sustain attention, control impulses and modulate activity level. Although ADHD is one of the most prevalent childhood psychiatric disorders, it also persists into adulthood in around 30-50% of the cases. Based on the effect of psychostimulants used in the pharmacological treatment of ADHD, dysfunctions in neuroplasticity mechanisms and synapses have been postulated to be involved in the pathophysiology of ADHD. With this background, we evaluated, both in childhood and adulthood ADHD, the role of several genes involved in the control of neurotransmitter release through synaptic vesicle docking, fusion and recycling processes by means of a population-based association study. We analyzed single nucleotide polymorphisms across 16 genes in a clinical sample of 950 ADHD patients (506 adults and 444 children) and 905 controls. Single and multiple-marker analyses identified several significant associations after correcting for multiple testing with a false discovery rate (FDR) of 15%: (i) the SYT2 gene was strongly associated with both adulthood and childhood ADHD (p=0.001, OR=1.49 (1.18-1.89) and p=0.007, OR=1.37 (1.09-1.72), respectively) and (ii) STX1A was found associated with ADHD only in adults (p=0.0041; OR=1.28 (1.08-1.51)). These data provide preliminary evidence for the involvement of genes that participate in the control of neurotransmitter release in the genetic predisposition to ADHD through a gene-system association study. Further follow-up studies in larger cohorts and deep-sequencing of the associated genomic regions are required to identify sequence variants directly involved in ADHD. Copyright © 2012 Elsevier B.V. and ECNP. All rights reserved.

  11. Octyl-methoxycinnamate (OMC), an ultraviolet (UV) filter, alters LHRH and amino acid neurotransmitters release from hypothalamus of immature rats.

    Science.gov (United States)

    Szwarcfarb, B; Carbone, S; Reynoso, R; Bollero, G; Ponzo, O; Moguilevsky, J; Scacchi, P

    2008-02-01

    OMC (octyl-methoxycinnamate), is an endocrine disruptor with estrogenic activity, which is used in sunscreen creams as a UV filter. We studied its " IN VITRO" effects on the hypothalamic release of LHRH as well as on the amino acid neurotransmitter system in immature rats of 15 (prepubertal) and 30 (peripubertal) days of age. OMC decreased the LH-RH release significantly in male and female rats of both age. In male rats OMC increased the release of GABA while in the female ones It diminished the excitatory amino acid aspartate (ASP) and Glutamate (GLU) without modifications in the hypothalamic GABA release. These results suggest that during sexual maturation the inhibitory effect of OMC on LH-RH release appears to be related to its action on the inhibitory and excitatory amino acid neurotransmitters in male and female rats.

  12. F3/Contactin-Related Proteins in Helix pomatia Nervous Tissue (HCRPs): Distribution and Function in Neurite Growth and Neurotransmitter Release

    Science.gov (United States)

    Milanese, Chiara; Fiumara, Ferdinando; Bizzoca, Antonella; Giachello, Carlo; Leitinger, Gerd; Gennarini, Gianfranco; Montarolo, Pier Giorgio; Ghirardi, Mirella

    2010-01-01

    By using antibodies against mouse F3/contactin, we found immunologically related glycoproteins expressed in the nervous tissue of the snail Helix pomatia. Helix contactin-related proteins (HCRPs) include different molecules ranging in size from 90 to 240 kD. Clones isolated from a cDNA expression library allowed us to demonstrate that these proteins are translated from a unique 6.3-kb mRNA, suggesting that their heterogeneity depends on posttranslational processing. This is supported by the results of endoglycosidase F treatment, which indicate that the high-molecular-weight components are glycosylation variants of the 90-kD chain. In vivo and in cultures, HCRPs antibodies label neuronal soma and neurite extensions, giving the appearance of both cytoplasmic and cell surface immunostaining. On the other hand, no expression is found on nonneural tissues. Functionally, HCRPs are involved in neurite growth control and appear to modulate neurotransmitter release, as indicated by the inhibiting effects of specific antibodies on both functions. These data allow the definition of HCRPs glycoproteins as growth-promoting molecules, suggesting that they play a role in neurite development and presynaptic terminal maturation in the invertebrate nervous system. PMID:17941055

  13. Modulation of vesicular catecholamine release from rat PC12 cells

    NARCIS (Netherlands)

    Westerink, R.H.S.

    2002-01-01

    Intercellular communication is of vital importance for the nervous system, since the nervous system is the main coordinating system in animals. Nerve cell communication is initiated by the release of chemical messengers, neurotransmitters, from the presynaptic nerve cell. The neurotransmitters, such

  14. RIM proteins tether Ca2+-channels to presynaptic active zones via a direct PDZ-domain interaction

    Science.gov (United States)

    Kaeser, Pascal S.; Deng, Lunbin; Wang, Yun; Dulubova, Irina; Liu, Xinran; Rizo, Josep; Südhof, Thomas C.

    2011-01-01

    SUMMARY At a synapse, fast synchronous neurotransmitter release requires localization of Ca2+-channels to presynaptic active zones. How Ca2+-channels are recruited to active zones, however, remains unknown. Using unbiased yeast two-hybrid screens, we here identify a direct interaction of the central PDZ-domain of the active-zone protein RIM with the C-termini of presynaptic N- and P/Q-type Ca2+-channels, but not L-type Ca2+-channels. To test the physiological significance of this interaction, we generated conditional knockout mice lacking all presynaptic RIM isoforms. Deletion of all RIMs ablated most neurotransmitter release by simultaneously impairing the priming of synaptic vesicles and by decreasing the presynaptic localization of Ca2+-channels. Strikingly, rescue of the decreased Ca2+-channel localization required the RIM PDZ-domain, whereas rescue of vesicle priming required the RIM N-terminus. We propose that RIMs tether N- and P/Q-type Ca2+-channels to presynaptic active zones via a direct PDZ-domain mediated interaction, thereby enabling fast, synchronous triggering of neurotransmitter release at a synapse. PMID:21241895

  15. Nanoscale distribution of presynaptic Ca(2+) channels and its impact on vesicular release during development.

    Science.gov (United States)

    Nakamura, Yukihiro; Harada, Harumi; Kamasawa, Naomi; Matsui, Ko; Rothman, Jason S; Shigemoto, Ryuichi; Silver, R Angus; DiGregorio, David A; Takahashi, Tomoyuki

    2015-01-07

    Synaptic efficacy and precision are influenced by the coupling of voltage-gated Ca(2+) channels (VGCCs) to vesicles. But because the topography of VGCCs and their proximity to vesicles is unknown, a quantitative understanding of the determinants of vesicular release at nanometer scale is lacking. To investigate this, we combined freeze-fracture replica immunogold labeling of Cav2.1 channels, local [Ca(2+)] imaging, and patch pipette perfusion of EGTA at the calyx of Held. Between postnatal day 7 and 21, VGCCs formed variable sized clusters and vesicular release became less sensitive to EGTA, whereas fixed Ca(2+) buffer properties remained constant. Experimentally constrained reaction-diffusion simulations suggest that Ca(2+) sensors for vesicular release are located at the perimeter of VGCC clusters (<30 nm) and predict that VGCC number per cluster determines vesicular release probability without altering release time course. This "perimeter release model" provides a unifying framework accounting for developmental changes in both synaptic efficacy and time course. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Phospho-dependent Accumulation of GABABRs at Presynaptic Terminals after NMDAR Activation.

    Science.gov (United States)

    Hannan, Saad; Gerrow, Kim; Triller, Antoine; Smart, Trevor G

    2016-08-16

    Here, we uncover a mechanism for regulating the number of active presynaptic GABAB receptors (GABABRs) at nerve terminals, an important determinant of neurotransmitter release. We find that GABABRs gain access to axon terminals by lateral diffusion in the membrane. Their relative accumulation is dependent upon agonist activation and the presence of the two distinct sushi domains that are found only in alternatively spliced GABABR1a subunits. Following brief activation of NMDA receptors (NMDARs) using glutamate, GABABR diffusion is reduced, causing accumulation at presynaptic terminals in a Ca(2+)-dependent manner that involves phosphorylation of GABABR2 subunits at Ser783. This signaling cascade indicates how synaptically released glutamate can initiate, via a feedback mechanism, increased levels of presynaptic GABABRs that limit further glutamate release and excitotoxicity. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. Phospho-dependent Accumulation of GABABRs at Presynaptic Terminals after NMDAR Activation

    Directory of Open Access Journals (Sweden)

    Saad Hannan

    2016-08-01

    Full Text Available Here, we uncover a mechanism for regulating the number of active presynaptic GABAB receptors (GABABRs at nerve terminals, an important determinant of neurotransmitter release. We find that GABABRs gain access to axon terminals by lateral diffusion in the membrane. Their relative accumulation is dependent upon agonist activation and the presence of the two distinct sushi domains that are found only in alternatively spliced GABABR1a subunits. Following brief activation of NMDA receptors (NMDARs using glutamate, GABABR diffusion is reduced, causing accumulation at presynaptic terminals in a Ca2+-dependent manner that involves phosphorylation of GABABR2 subunits at Ser783. This signaling cascade indicates how synaptically released glutamate can initiate, via a feedback mechanism, increased levels of presynaptic GABABRs that limit further glutamate release and excitotoxicity.

  18. Spermidine Suppresses Age-Associated Memory Impairment by Preventing Adverse Increase of Presynaptic Active Zone Size and Release.

    Directory of Open Access Journals (Sweden)

    Varun K Gupta

    2016-09-01

    Full Text Available Memories are assumed to be formed by sets of synapses changing their structural or functional performance. The efficacy of forming new memories declines with advancing age, but the synaptic changes underlying age-induced memory impairment remain poorly understood. Recently, we found spermidine feeding to specifically suppress age-dependent impairments in forming olfactory memories, providing a mean to search for synaptic changes involved in age-dependent memory impairment. Here, we show that a specific synaptic compartment, the presynaptic active zone (AZ, increases the size of its ultrastructural elaboration and releases significantly more synaptic vesicles with advancing age. These age-induced AZ changes, however, were fully suppressed by spermidine feeding. A genetically enforced enlargement of AZ scaffolds (four gene-copies of BRP impaired memory formation in young animals. Thus, in the Drosophila nervous system, aging AZs seem to steer towards the upper limit of their operational range, limiting synaptic plasticity and contributing to impairment of memory formation. Spermidine feeding suppresses age-dependent memory impairment by counteracting these age-dependent changes directly at the synapse.

  19. Endophilin mutations block clathrin-mediated endocytosis but not neurotransmitter release

    DEFF Research Database (Denmark)

    Verstreken, Patrik; Kjaerulff, Ole; Lloyd, Thomas E

    2002-01-01

    We have identified mutations in Drosophila endophilin to study its function in vivo. Endophilin is required presynaptically at the neuromuscular junction, and absence of Endophilin dramatically impairs endocytosis in vivo. Mutant larvae that lack Endophilin fail to take up FM1-43 dye in synaptic ...

  20. Stress-Induced Synaptic Dysfunction and Neurotransmitter Release in Alzheimer's Disease: Can Neurotransmitters and Neuromodulators be Potential Therapeutic Targets?

    Science.gov (United States)

    Jha, Saurabh Kumar; Jha, Niraj Kumar; Kumar, Dhiraj; Sharma, Renu; Shrivastava, Abhishek; Ambasta, Rashmi K; Kumar, Pravir

    2017-01-01

    The communication between neurons at synaptic junctions is an intriguing process that monitors the transmission of various electro-chemical signals in the central nervous system. Albeit any aberration in the mechanisms associated with transmission of these signals leads to loss of synaptic contacts in both the neocortex and hippocampus thereby causing insidious cognitive decline and memory dysfunction. Compelling evidence suggests that soluble amyloid-β (Aβ) and hyperphosphorylated tau serve as toxins in the dysfunction of synaptic plasticity and aberrant neurotransmitter (NT) release at synapses consequently causing a cognitive decline in Alzheimer's disease (AD). Further, an imbalance between excitatory and inhibitory neurotransmission systems induced by impaired redox signaling and altered mitochondrial integrity is also amenable for such abnormalities. Defective NT release at the synaptic junction causes several detrimental effects associated with altered activity of synaptic proteins, transcription factors, Ca2+ homeostasis, and other molecules critical for neuronal plasticity. These detrimental effects further disrupt the normal homeostasis of neuronal cells and thereby causing synaptic loss. Moreover, the precise mechanistic role played by impaired NTs and neuromodulators (NMs) and altered redox signaling in synaptic dysfunction remains mysterious, and their possible interlink still needs to be investigated. Therefore, this review elucidates the intricate role played by both defective NTs/NMs and altered redox signaling in synaptopathy. Further, the involvement of numerous pharmacological approaches to compensate neurotransmission imbalance has also been discussed, which may be considered as a potential therapeutic approach in synaptopathy associated with AD.

  1. Chronic morphine selectively sensitizes the effect of D1 receptor agonist on presynaptic glutamate release in basolateral amygdala neurons that project to prelimbic cortex.

    Science.gov (United States)

    Song, Jiaojiao; Chen, Ming; Dong, Yi; Lai, Bin; Zheng, Ping

    2018-05-01

    Drug addiction is a brain disorder characterized by chronic, compulsive use of drugs. Previous studies have found a number of chronic morphine-induced changes in the brain at molecular levels. A study from our lab showed that chronic morphine-induced increase in the expression of presynaptic D1 receptors in basolateral amygdala (BLA) neurons played an important role in environmental cue-induced retrieval of morphine withdrawal memory. However, the downstream neurocircuitry of chronic morphine-induced increase presynaptic D1 receptors in the BLA remains to be elucidated. Using retrogradely labelling technique combined with whole-cell patch-clamp methods, our results showed that (1) chronic morphine sensitized the effect of D1 receptor agonist on presynaptic glutamate release in BLA neurons that projected to the prelimbic cortex (PrL), but had no influence on that in BLA neurons that projected to the nucleus accumbens (NAc) or the CA1 of the hippocampus; (2) chronic morphine sensitized the effect of D1 receptor agonist on action potential firing in BLA neurons that projected to the PrL, but without affecting the intrinsic excitability and the sensitivity of postsynaptic glutamate receptors to glutamate in BLA neurons that projected to the PrL. These results suggest that chronic morphine selectively sensitizes the effect of D1 receptor agonist on presynaptic glutamate release in BLA neurons that project to PrL and induces a sensitization of the effect of D1 receptor agonist on action potential firing in BLA neurons that project to the PrL. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. RIM determines Ca2+ channel density and vesicle docking at the presynaptic active zone

    Science.gov (United States)

    Han, Yunyun; Kaeser, Pascal S.; Südhof, Thomas C.; Schneggenburger, Ralf

    2012-01-01

    At presynaptic active zones, neurotransmitter release is initiated by the opening of voltage-gated Ca2+ channels close to docked vesicles. The mechanisms that enrich Ca2+ channels at active zones are, however, largely unknown, possibly because of the limited presynaptic accessibility of most synapses. Here, we have established a Cre-lox based conditional knock-out approach at a presynaptically accessible CNS synapse, the calyx of Held, to directly study the functions of RIM proteins. Removal of all RIM1/2 isoforms strongly reduced the presynaptic Ca2+ channel density, revealing a new role of RIM proteins in Ca2+ channel targeting. Removal of RIMs also reduced the readily-releasable pool, paralleled by a similar reduction of the number of docked vesicles, and the Ca2+ channel - vesicle coupling was decreased. Thus, RIM proteins co-ordinately regulate key functions for fast transmitter release: enabling a high presynaptic Ca2+ channel density, and vesicle docking at the active zone. PMID:21262468

  3. Closing the gap: long-term presynaptic plasticity in brain function and disease.

    Science.gov (United States)

    Monday, Hannah R; Castillo, Pablo E

    2017-08-01

    Synaptic plasticity is critical for experience-dependent adjustments of brain function. While most research has focused on the mechanisms that underlie postsynaptic forms of plasticity, comparatively little is known about how neurotransmitter release is altered in a long-term manner. Emerging research suggests that many of the features of canonical 'postsynaptic' plasticity, such as associativity, structural changes and bidirectionality, also characterize long-term presynaptic plasticity. Recent studies demonstrate that presynaptic plasticity is a potent regulator of circuit output and function. Moreover, aberrant presynaptic plasticity is a convergent factor of synaptopathies like schizophrenia, addiction, and Autism Spectrum Disorders, and may be a potential target for treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Intranasal exposure to manganese disrupts neurotransmitter release from glutamatergic synapses in the central nervous system in vivo

    Science.gov (United States)

    Moberly, Andrew H.; Czarnecki, Lindsey A.; Pottackal, Joseph; Rubinstein, Tom; Turkel, Daniel J.; Kass, Marley D.; McGann, John P.

    2012-01-01

    Chronic exposure to aerosolized manganese induces a neurological disorder that includes extrapyramidal motor symptoms and cognitive impairment. Inhaled manganese can bypass the blood-brain barrier and reach the central nervous system by transport down the olfactory nerve to the brain’s olfactory bulb. However, the mechanism by which Mn disrupts neural function remains unclear. Here we used optical imaging techniques to visualize exocytosis in olfactory nerve terminals in vivo in the mouse olfactory bulb. Acute Mn exposure via intranasal instillation of 2–200 μg MnCl2 solution caused a dose-dependent reduction in odorant-evoked neurotransmitter release, with significant effects at as little as 2 μg MnCl2 and a 90% reduction compared to vehicle controls with a 200 μg exposure. This reduction was also observed in response to direct electrical stimulation of the olfactory nerve layer in the olfactory bulb, demonstrating that Mn’s action is occurring centrally, not peripherally. This is the first direct evidence that Mn intoxication can disrupt neurotransmitter release, and is consistent with previous work suggesting that chronic Mn exposure limits amphetamine-induced dopamine increases in the basal ganglia despite normal levels of dopamine synthesis (Guilarte et al., J Neurochem 2008). The commonality of Mn’s action between glutamatergic neurons in the olfactory bulb and dopaminergic neurons in the basal ganglia suggests that a disruption of neurotransmitter release may be a general consequence wherever Mn accumulates in the brain and could underlie its pleiotropic effects. PMID:22542936

  5. Coupling of exocytosis and endocytosis at the presynaptic active zone.

    Science.gov (United States)

    Maritzen, Tanja; Haucke, Volker

    2018-02-01

    Brain function depends on the ability of neurons to communicate with each other via the regulated exocytosis of neurotransmitter-containing synaptic vesicles (SVs) at specialized presynaptic release sites termed active zones (AZs). The presynaptic AZ comprises an assembly of large multidomain proteins that link the machinery for vesicle fusion to sites of voltage-dependent Ca 2+ entry. Following SV fusion at AZ release sites SV membranes are retrieved by compensatory endocytosis, and SVs are reformed. Recent data suggest that Ca 2+ -triggered SV exocytosis at AZs and endocytic retrieval of SVs may be functionally and physically linked. Here we discuss the evidence supporting such exo-endocytic coupling as well as possible modes and mechanisms that may underlie coupling of exocytosis and endocytosis at and around AZs in presynaptic nerve terminals. As components of the exo-endocytic machinery at synapses have been linked to neurological and neuropsychiatric disorders, understanding the mechanisms that couple exocytosis and endocytosis at AZs may be of importance for developing novel therapies to treat these diseases. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  6. Aquatic contaminants alter genes involved in neurotransmitter synthesis and gonadotropin release in largemouth bass

    Energy Technology Data Exchange (ETDEWEB)

    Martyniuk, Christopher J. [Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611 (United States); Sanchez, Brian C. [Department of Forestry and Natural Resources and School of Civil Engineering, 195 Marsteller St., Purdue University, West Lafayette, IN 47907 (United States); Szabo, Nancy J.; Denslow, Nancy D. [Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida, Gainesville, FL 32611 (United States); Sepulveda, Maria S., E-mail: mssepulv@purdue.edu [Department of Forestry and Natural Resources and School of Civil Engineering, 195 Marsteller St., Purdue University, West Lafayette, IN 47907 (United States)

    2009-10-19

    Many aquatic contaminants potentially affect the central nervous system, however the underlying mechanisms of how toxicants alter normal brain function are not well understood. The objectives of this study were to compare the effects of emerging and prevalent environmental contaminants on the expression of brain transcripts with a role in neurotransmitter synthesis and reproduction. Adult male largemouth bass (Micropterus salmoides) were injected once for a 96 h duration with control (water or oil) or with one of two doses of a single chemical to achieve the following body burdens ({mu}g/g): atrazine (0.3 and 3.0), toxaphene (10 and 100), cadmium (CdCl{sub 2}) (0.000067 and 0.00067), polychlorinated biphenyl (PCB) 126 (0.25 and 2.5), and phenanthrene (5 and 50). Partial largemouth bass gene segments were cloned for enzymes involved in neurotransmitter (glutamic acid decarboxylase 65, GAD65; tyrosine hydroxylase) and estrogen (brain aromatase; CYP19b) synthesis for real-time PCR assays. In addition, neuropeptides regulating feeding (neuropeptide Y) and reproduction (chicken GnRH-II, cGnRH-II; salmon GnRH, sGnRH) were also investigated. Of the chemicals tested, only cadmium, PCB 126, and phenanthrene showed any significant effects on the genes tested, while atrazine and toxaphene did not. Cadmium (0.000067 {mu}g/g) significantly increased cGnRH-II mRNA while PCB 126 (0.25 {mu}g/g) decreased GAD65 mRNA. Phenanthrene decreased GAD65 and tyrosine hydroxylase mRNA levels at the highest dose (50 {mu}g/g) but increased cGnRH-II mRNA at the lowest dose (5 {mu}g/g). CYP19b, NPY, and sGnRH mRNA levels were unaffected by any of the treatments. A hierarchical clustering dendrogram grouped PCB 126 and phenanthrene more closely than other chemicals with respect to the genes tested. This study demonstrates that brain transcripts important for neurotransmitter synthesis neuroendocrine function are potential targets for emerging and prevalent aquatic contaminants.

  7. Atypical Neurotransmitters and the Neurobiology of Depression.

    Science.gov (United States)

    Joca, Samia Regiane; Moreira, Fabricio Araujo; Wegener, Gregers

    2015-01-01

    Since the first report that the mechanism of action of antidepressants involves the facilitation of monoaminergic neurotransmission in the brain in the 1960s, the leading hypothesis about the neurobiology of depression has been the so called "monoaminergic hypothesis". However, a growing body of evidence from the last two decades also supports important involvement of non-monoaminergic mechanisms in the neurobiology of depression and antidepressant action. The discovery of nitric oxide (NO) and endocannabinoid signaling in the brain during the 1990s challenged the wellestablished criteria of classical neurotransmission. These transmitters are synthesized and released on demand by the postsynaptic neurons, and may act as a retrograde messenger on the presynaptic terminal, modulating neurotransmitter release. These unconventional signaling mechanisms and the important role as neural messengers have classified NO and endocannabinoids as atypical neurotransmitters. They are able to modulate neural signaling mediated by the main conventional neurotransmitters systems in the brain, including the monoaminergic, glutamatergic and GABAergic signaling systems. This review aims at discussing the fundamental aspects of NO- and endocannabinoid-mediated signaling in the brain, and how they can be related to the neurobiology of depression. Both preclinical and clinical evidence supporting the involvement of these atypical neurotransmitters in the neurobiology of depression, and in the antidepressant effects are presented here. The evidence is discussed on basis of their ability to modulate different neurotransmitter systems in the brain, including monoaminergic and glutamatergic ones. A better comprehension of NO and endocannabinoid signaling mechanisms in the neurobiology depression could provide new avenues for the development of novel non-monoamine based antidepressants.

  8. Development of paradigm for the study of amino acid neurotransmitter release in human autopsy brain samples

    International Nuclear Information System (INIS)

    Kuo, K.-W.; Dodd, P.R.

    2001-01-01

    Full text: This study attempted to establish a release protocol to characterize both the vesicular and cytoplasmic components of amino acid transmitter release in human synaptosomes. Experiments with rat synaptosomes showed that, with depolarizing concentrations of K + ions, vesicular release could be successfully differentiated from cytoplasmic release for preloaded L-[ 3 H ]glutamate and [ 14 C ]GABA. However, human tissue studies did not give clear-cut results. Experiments were carried out to optimize the release paradigm as well as to improve the vesicular uptake of labeled transmitters. A 'pulse- chase' protocol, with an unlabelled D-aspartate chase, was performed in human tissue samples in order to enhance the L-[ 3 H ] glutamate release signal derived from exocytosis by removing the cytoplasmic pool of L-[ 3 H ] glutamate first. However, the results showed that total release was not enhanced effectively in comparison with the non-pulse-chase protocol. In brief, the pulse-chase protocol did not build up the vesicular pool of L-[ 3 H ]glutamate, though the cytoplasmic L- [ 3 H ] glutamate pool was effectively depressed by D-aspartate. Further studies applied 4- aminopyridine (4-AP) to trigger release, to circumvent the problem of the reversal of plasma membrane transporters caused by raised K + ion concentrations. The results showed that the application of 4-AP elicited the release of amino acid transmitters from rat synaptosomes, but failed to produce successful release signals in the human tissue experiments. Our findings suggest that the vesicular compartment may be impaired by freezing and affected by post-mortem delay (PMD). Rat studies showed that the freezing step had a major effect on Ca 2+-dependent release, as less L- [3 H ]glutamate and [ 14 C ]GABA were released from the frozen rat tissue preparations. Moreover, there was an indication of a decline in L-[ 3 H ]glutamate release with increasing PMD. Copyright (2001) Australian Neuroscience Society

  9. Role of the Wnt receptor Frizzled-1 in presynaptic differentiation and function

    Directory of Open Access Journals (Sweden)

    Alvarez Alejandra R

    2009-11-01

    Full Text Available Abstract Background The Wnt signaling pathway regulates several fundamental developmental processes and recently has been shown to be involved in different aspects of synaptic differentiation and plasticity. Some Wnt signaling components are localized at central synapses, and it is thus possible that this pathway could be activated at the synapse. Results We examined the distribution of the Wnt receptor Frizzled-1 in cultured hippocampal neurons and determined that this receptor is located at synaptic contacts co-localizing with presynaptic proteins. Frizzled-1 was found in functional synapses detected with FM1-43 staining and in synaptic terminals from adult rat brain. Interestingly, overexpression of Frizzled-1 increased the number of clusters of Bassoon, a component of the active zone, while treatment with the extracellular cysteine-rich domain (CRD of Frizzled-1 decreased Bassoon clustering, suggesting a role for this receptor in presynaptic differentiation. Consistent with this, treatment with the Frizzled-1 ligand Wnt-3a induced presynaptic protein clustering and increased functional presynaptic recycling sites, and these effects were prevented by co-treatment with the CRD of Frizzled-1. Moreover, in synaptically mature neurons Wnt-3a was able to modulate the kinetics of neurotransmitter release. Conclusion Our results indicate that the activation of the Wnt pathway through Frizzled-1 occurs at the presynaptic level, and suggest that the synaptic effects of the Wnt signaling pathway could be modulated by local activation through synaptic Frizzled receptors.

  10. The Nitric Oxide Donor SNAP-Induced Amino Acid Neurotransmitter Release in Cortical Neurons. Effects of Blockers of Voltage-Dependent Sodium and Calcium Channels

    Science.gov (United States)

    Merino, José Joaquín; Arce, Carmen; Naddaf, Ahmad; Bellver-Landete, Victor; Oset-Gasque, Maria Jesús; González, María Pilar

    2014-01-01

    Background The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neuronal communication. NO induces the release of amino acid neurotransmitters but the underlying mechanisms remain to be elucidated. Findings The aim of this work was to study the effect of NO on amino acid neurotransmitter release (Asp, Glu, Gly and GABA) in cortical neurons as well as the mechanism underlying the release of these neurotransmitters. Cortical neurons were stimulated with SNAP, a NO donor, and the release of different amino acid neurotransmitters was measured by HPLC. The involvement of voltage dependent Na+ and Ca2+ channels as well as cGMP in its mechanism of action was evaluated. Conclusions Our results indicate that NO induces release of aspartate, glutamate, glycine and GABA in cortical neurons and that this release is inhibited by ODQ, an inhibitor of soluble guanylate cyclase. Thus, the NO effect on amino acid neurotransmission could be mediated by cGMP formation in cortical neurons. Our data also demonstrate that the Na+ and Ca2+ voltage- dependent calcium channels are involved in the NO effects on cortical neurons. PMID:24598811

  11. Depolarization by K+ and glutamate activates different neurotransmitter release mechanisms in GABAergic neurons: vesicular versus non-vesicular release of GABA

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, Gert Helge; Schousboe, A

    1993-01-01

    differences in the mode of action of the two depolarizing stimuli were reflected in the properties of the increase in [Ca++]i elicited by 55 mM K+ and 100 microM glutamate, respectively. The K(+)-induced increase in [Ca++]i was reduced by both verapamil and Ca(++)-free media whereas the corresponding...... neurotransmitter glutamate (100 microM). Both depolarizing stimuli exerted prompt increases in the release of preloaded [3H]GABA as well as in [Ca++]i. However, the basic properties of transmitter release and the increase in [Ca++]i under a variety of conditions were different during stimulation with K...... was also reduced by organic (verapamil) and inorganic (Co++) Ca++ channel blockers but was insensitive to the GABA transport inhibitor SKF 89976A. In contrast, the second phase was less sensitive to nocodazole and Ca++ channel antagonists but could be inhibited by SKF 89976A. The glutamate-induced [3H...

  12. Presynaptic adenosine receptor-mediated regulation of diverse thalamocortical short-term plasticity in the mouse whisker pathway

    Directory of Open Access Journals (Sweden)

    Giovanni eFerrati

    2016-02-01

    Full Text Available Short-term synaptic plasticity (STP sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In driver thalamocortical (TC synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors, modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release.

  13. Classical neurotransmitters and neuropeptides involved in major depression in a multi-neurotransmitter system: a focus on antidepressant drugs.

    Science.gov (United States)

    Werner, Felix-Martin; Coveñas, R

    2013-01-01

    We summarize the alterations of classical neurotransmitters and neuropeptides and the corresponding subreceptors involved in major depression. Neuronal circuits in the brainstem, hippocampus and hypothalamus are developed, since they can be used to derive a multimodal pharmacotherapy. In this sense, serotonin hypoactivity could occur through a strong presynaptic inhibition of glutaminergic neurons via the subtype 5 of metabotropic glutaminergic receptors, and noradrenaline hypoactivity could be due to an enhanced presynaptic inhibition of GABAergic neurons via GABAB receptors. In the hippocampus, dopamine hypoactivity leads to a decreased positive effect. In clinical trials, the antidepressant effect of drugs interfering with the mentioned subreceptors, for example the triple reuptake inhibitor amitifadine, is being investigated. Moreover, the alterations of neuropeptides, such as corticotropin-releasing hormone, neuropeptide Y and galanin are pointed out. The additional antidepressant effect of analogs, agonists and antagonists of the mentioned neuropeptides should be examined.

  14. Amnesia produced by altered release of neurotransmitters after intraamygdala injections of a protein synthesis inhibitor

    OpenAIRE

    Canal, Clinton E.; Chang, Qing; Gold, Paul E.

    2007-01-01

    Amnesia produced by protein synthesis inhibitors such as anisomycin provides major support for the prevalent view that the formation of long-lasting memories requires de novo protein synthesis. However, inhibition of protein synthesis might disrupt other neural functions to interfere with memory formation. Intraamygdala injections of anisomycin before inhibitory avoidance training impaired memory in rats tested 48 h later. Release of norepinephrine (NE), dopamine (DA), and serotonin, measured...

  15. In vitro effect of octyl - methoxycinnamate (OMC) on the release of Gn-RH and amino acid neurotransmitters by hypothalamus of adult rats.

    Science.gov (United States)

    Carbone, S; Szwarcfarb, B; Reynoso, R; Ponzo, O J; Cardoso, N; Ale, E; Moguilevsky, J A; Scacchi, P

    2010-05-01

    OMC (octyl-methoxycinnamate), an endocrine disruptor having estrogenic activity, is used in sunscreen creams as UV filter. We studied its "in vitro" effects on the hypothalamic release of Gn-RH as well as on the amino acid neurotransmitter system. OMC significantly decreased Gn-RH release in normal male and female rats as well as in castrated rats with substitutive therapy. No effects were observed in castrated rats without substitutive therapy. In males OMC increases the release of GABA, decreasing the production of glutamate (GLU) while in the female decreases the excitatory amino acid aspartate (ASP) and GLU without modifications in the hypothalamic GABA release. These results suggest that OMC acting as endocrine disruptor could alter the sex hormone-neurotransmitter-Gn-RH axis relationships in adult rats.

  16. Single cell amperometry reveals curcuminoids modulate the release of neurotransmitters during exocytosis from PC12 cells

    Science.gov (United States)

    Li, Xianchan; Mohammadi, Amir Saeid; Ewing, Andrew G.

    2016-01-01

    We used single cell amperometry to examine whether curcumin and bisdemethoxycurcumin (BDMC), substances that are suggested to affect learning and memory, can modulate monoamine release from PC12 cells. Our results indicate both curcumin and BDMC need long-term treatment (72 h in this study) to influence exocytosis effectively. By analyzing the parameters calculated from single exocytosis events, it can be concluded that curcumin and BDMC affect exocytosis through different mechanisms. Curcumin accelerates the event dynamics with no significant change of the monoamine amount released from single exocytotic events, whereas BDMC attenuates the amount from single exocytotic event with no significant change of the event dynamics. This comparison of the effect of curcumin and BDMC on exocytosis at the single cell level brings insight into their different mechanisms, which might lead to different biological actions. The effect of curcumin and BDMC on the opening and closing of the exocytotic fusion pore were also investigated. These results might be helpful for understanding the improvement of learning and memory and the anti-depression properties of curcuminoids. PMID:28579928

  17. Degeneracy in the regulation of short-term plasticity and synaptic filtering by presynaptic mechanisms.

    Science.gov (United States)

    Mukunda, Chinmayee L; Narayanan, Rishikesh

    2017-04-15

    We develop a new biophysically rooted, physiologically constrained conductance-based synaptic model to mechanistically account for short-term facilitation and depression, respectively through residual calcium and transmitter depletion kinetics. We address the specific question of how presynaptic components (including voltage-gated ion channels, pumps, buffers and release-handling mechanisms) and interactions among them define synaptic filtering and short-term plasticity profiles. Employing global sensitivity analyses (GSAs), we show that near-identical synaptic filters and short-term plasticity profiles could emerge from disparate presynaptic parametric combinations with weak pairwise correlations. Using virtual knockout models, a technique to address the question of channel-specific contributions within the GSA framework, we unveil the differential and variable impact of each ion channel on synaptic physiology. Our conclusions strengthen the argument that parametric and interactional complexity in biological systems should not be viewed from the limited curse-of-dimensionality standpoint, but from the evolutionarily advantageous perspective of providing functional robustness through degeneracy. Information processing in neurons is known to emerge as a gestalt of pre- and post-synaptic filtering. However, the impact of presynaptic mechanisms on synaptic filters has not been quantitatively assessed. Here, we developed a biophysically rooted, conductance-based model synapse that was endowed with six different voltage-gated ion channels, calcium pumps, calcium buffer and neurotransmitter-replenishment mechanisms in the presynaptic terminal. We tuned our model to match the short-term plasticity profile and band-pass structure of Schaffer collateral synapses, and performed sensitivity analyses to demonstrate that presynaptic voltage-gated ion channels regulated synaptic filters through changes in excitability and associated calcium influx. These sensitivity analyses

  18. Presynaptic transporter-mediated release of glutamate evoked by the protonophore FCCP increases under altered gravity conditions

    Science.gov (United States)

    Borisova, T. A.; Krisanova, N. V.

    2008-12-01

    High-affinity Na +-dependent glutamate transporters of the plasma membrane mediate the glutamate uptake into neurons, and thus maintain low levels of extracellular glutamate in the synaptic cleft. The study focused on the release of glutamate by reversal of Na +-dependent glutamate transporters from rat brain nerve terminals (synaptosomes) under conditions of centrifuge-induced hypergravity. Flow cytometric analysis revealed similarity in the size and cytoplasmic granularity between synaptosomal preparations obtained from control and G-loaded animals (10 G, 1 h). The release of cytosolic L-[ 14C]glutamate from synaptosomes was evaluated using the protonophore FCCP, which dissipated synaptic vesicle proton gradient, thus synaptic vesicles were not able to keep glutamate inside and the latter enriched cytosol. FCCP per se induced the greater release of L-[ 14C]glutamate in hypergravity as compared to control (4.8 ± 1.0% and 8.0 ± 1.0% of total label). Exocytotic release of L-[ 14C]glutamate evoked by depolarization was reduced down to zero after FCCP application under both conditions studied. Depolarization stimulated release of cytosolic L-[ 14C]glutamate from synaptosomes preliminary treated with FCCP was considerably increased from 27.0 ± 2.2% of total label in control to 35.0 ± 2.3% in hypergravity. Non-transportable inhibitor of glutamate transporter DL-threo-β-benzyloxyaspartate was found to significantly inhibit high-KCl and FCCP-stimulated release of L-[ 14C]glutamate, confirming the release by reversal of glutamate transporters. The enhancement of transporter-mediated release of glutamate in hypergravity was found to result at least partially from the inhibition of the activity of Na/K-ATPase in the plasma membrane of synaptosomes. We suggested that hypergravity-induced alteration in transporter-mediated release of glutamate indicated hypoxic injury of neurons.

  19. Distinct presynaptic regulation of dopamine release through NMDA receptors in striosome- and matrix-enriched areas of the rat striatum

    International Nuclear Information System (INIS)

    Krebs, M.O.; Trovero, F.; Desban, M.; Gauchy, C.; Glowinski, J.; Kemel, M.L.

    1991-01-01

    Striosome- and matrix-enriched striatal zones were defined in coronal and sagittal brain sections of the rat, on the basis of 3 H-naloxone binding to mu-opiate receptors (a striosome-specific marker). Then, using a new in vitro microsuperfusion device, the NMDA (50 microM)-evoked release of newly synthesized 3 H-dopamine ( 3 H-DA) was examined in these four striatal areas under Mg(2+)-free conditions. The amplitudes of the responses were different in striosomal (171 +/- 6% and 161 +/- 5% of the spontaneous release) than in matrix areas (223 +/- 6% and 248 +/- 12%), even when glycine (1 or 100 microM) was coapplied (in the presence of 1 microM strychnine). In the four areas, the NMDA-evoked release of 3 H-DA was blocked completely by Mg 2+ (1 mM) or (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine maleate (MK-801; 1 microM) and almost totally abolished by kynurenate (100 microM). Because the tetrodotoxin (TTX)-resistant NMDA-evoked release of 3 H-DA was similar in striosome- (148 +/- 5% and 152 +/- 6%) or matrix-enriched (161 +/- 5% and 156 +/- 7%) areas, the indirect (TTX-sensitive) component of NMDA-evoked responses, which involves striatal neurons and/or afferent fibers, seems more important in the matrix- than in the striosome-enriched areas. The modulation of DA release by cortical glutamate and/or aspartate-containing inputs through NMDA receptors in the matrix appears thus to be partly distinct from that observed in the striosomes, providing some functional basis for the histochemical striatal heterogeneity

  20. Distinct presynaptic regulation of dopamine release through NMDA receptors in striosome- and matrix-enriched areas of the rat striatum

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, M.O.; Trovero, F.; Desban, M.; Gauchy, C.; Glowinski, J.; Kemel, M.L. (College de France, Paris (France))

    1991-05-01

    Striosome- and matrix-enriched striatal zones were defined in coronal and sagittal brain sections of the rat, on the basis of {sup 3}H-naloxone binding to mu-opiate receptors (a striosome-specific marker). Then, using a new in vitro microsuperfusion device, the NMDA (50 microM)-evoked release of newly synthesized {sup 3}H-dopamine ({sup 3}H-DA) was examined in these four striatal areas under Mg(2+)-free conditions. The amplitudes of the responses were different in striosomal (171 +/- 6% and 161 +/- 5% of the spontaneous release) than in matrix areas (223 +/- 6% and 248 +/- 12%), even when glycine (1 or 100 microM) was coapplied (in the presence of 1 microM strychnine). In the four areas, the NMDA-evoked release of {sup 3}H-DA was blocked completely by Mg{sup 2}{sup +} (1 mM) or (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine maleate (MK-801; 1 microM) and almost totally abolished by kynurenate (100 microM). Because the tetrodotoxin (TTX)-resistant NMDA-evoked release of {sup 3}H-DA was similar in striosome- (148 +/- 5% and 152 +/- 6%) or matrix-enriched (161 +/- 5% and 156 +/- 7%) areas, the indirect (TTX-sensitive) component of NMDA-evoked responses, which involves striatal neurons and/or afferent fibers, seems more important in the matrix- than in the striosome-enriched areas. The modulation of DA release by cortical glutamate and/or aspartate-containing inputs through NMDA receptors in the matrix appears thus to be partly distinct from that observed in the striosomes, providing some functional basis for the histochemical striatal heterogeneity.

  1. Presynaptic nicotinic α7 and non-α7 receptors stimulate endogenous GABA release from rat hippocampal synaptosomes through two mechanisms of action.

    Directory of Open Access Journals (Sweden)

    Stefania Zappettini

    Full Text Available BACKGROUND: Although converging evidence has suggested that nicotinic acetylcholine receptors (nAChR play a role in the modulation of GABA release in rat hippocampus, the specific involvement of different nAChR subtypes at presynaptic level is still a matter of debate. In the present work we investigated, using selective α7 and α4β2 nAChR agonists, the presence of different nAChR subtypes on hippocampal GABA nerve endings to assess to what extent and through which mechanisms they stimulate endogenous GABA release. METHODOLOGY/FINDINGS: All agonists elicited GABA overflow. Choline (Ch-evoked GABA overflow was dependent to external Ca(2+, but unaltered in the presence of Cd(2+, tetrodotoxin (TTX, dihydro-β-erythroidine (DHβE and 1-(4,4-Diphenyl-3-butenyl-3-piperidinecarboxylic acid hydrochloride SKF 89976A. The effect of Ch was blocked by methyllycaconitine (MLA, α-bungarotoxin (α-BTX, dantrolene, thapsigargin and xestospongin C, suggesting that GABA release might be triggered by Ca(2+ entry into synaptosomes through the α7 nAChR channel with the involvement of calcium from intracellular stores. Additionally, 5-Iodo-A-85380 dihydrochloride (5IA85380 elicited GABA overflow, which was Ca(2+ dependent, blocked by Cd(2+, and significantly inhibited by TTX and DHβE, but unaffected by MLA, SKF 89976A, thapsigargin and xestospongin C and dantrolene. These findings confirm the involvement of α4β2 nAChR in 5IA85380-induced GABA release that seems to occur following membrane depolarization and opening calcium channels. CONCLUSIONS/SIGNIFICANCE: Rat hippocampal synaptosomes possess both α7 and α4β2 nAChR subtypes, which can modulate GABA release via two distinct mechanisms of action. The finding that GABA release evoked by the mixture of sub-maximal concentration of 5IA85380 plus sub-threshold concentrations of Ch was significantly larger than that elicited by the sum of the effects of the two agonists is compatible with the possibility that

  2. Zn2+ modulation of neurotransmitter transporters

    DEFF Research Database (Denmark)

    Nørgaard-Nielsen, K.; Gether, U.

    2006-01-01

    Neurotransmitter transporters located at the presynaptic or glial cell membrane are responsible for the stringent and rapid clearance of the transmitter from the synapse, and hence they terminate signaling and control the duration of synaptic inputs in the brain. Two distinct families of neurotra...... indirectly suggested the possibility that several of the transporters are modulated by Zn2+ in vivo, and thus that Zn2+ can play a role as a neuromodulator by affecting the function of neurotransmitter transporters....

  3. Fast methods for analysis of neurotransmitters from single cell and monitoring their releases in central nervous system by capillary electrophoresis, fluorescence microscopy and luminescence imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ziqiang [Iowa State Univ., Ames, IA (United States)

    1999-12-10

    Fast methods for separation and detection of important neurotransmitters and the releases in central nervous system (CNS) were developed. Enzyme based immunoassay combined with capillary electrophoresis was used to analyze the contents of amino acid neurotransmitters from single neuron cells. The release of amino acid neurotransmitters from neuron cultures was monitored by laser induced fluorescence imaging method. The release and signal transduction of adenosine triphosphate (ATP) in CNS was studied with sensitive luminescence imaging method. A new dual-enzyme on-column reaction method combined with capillary electrophoresis has been developed for determining the glutamate content in single cells. Detection was based on monitoring the laser-induced fluorescence of the reaction product NADH, and the measured fluorescence intensity was related to the concentration of glutamate in each cell. The detection limit of glutamate is down to 10-8 M level, which is 1 order of magnitude lower than the previously reported detection limit based on similar detection methods. The mass detection limit of a few attomoles is far superior to that of any other reports. Selectivity for glutamate is excellent over most of amino acids. The glutamate content in single human erythrocyte and baby rat brain neurons were determined with this method and results agreed well with literature values.

  4. Axonal and presynaptic RNAs are locally transcribed in glial cells.

    Science.gov (United States)

    Giuditta, Antonio; Chun, Jong Tai; Eyman, Maria; Cefaliello, Carolina; Bruno, Anna Paola; Crispino, Marianna

    2007-01-01

    In the last few years, the long-standing opinion that axonal and presynaptic proteins are exclusively derived from the neuron cell body has been substantially modified by the demonstration that active systems of protein synthesis are present in axons and nerve terminals. These observations have raised the issue of the cellular origin of the involved RNAs, which has been generally attributed to the neuron soma. However, data gathered in a number of model systems indicated that axonal RNAs are synthesized in the surrounding glial cells. More recent experiments on the perfused squid giant axon have definitively proved that axoplasmic RNAs are transcribed in periaxonal glia. Their delivery to the axon occurs by a modulatory mechanism based on the release of neurotransmitters from the stimulated axon and on their binding to glial receptors. In additional experiments on squid optic lobe synaptosomes, presynaptic RNA has been also shown to be synthesized locally, presumably in nearby glia. Together with a wealth of literature data, these observations indicate that axons and nerve terminals are endowed with a local system of gene expression that supports the maintenance and plasticity of these neuronal domains.

  5. SNAP-25, a known presynaptic protein with emerging postsynaptic functions.

    Directory of Open Access Journals (Sweden)

    Flavia eAntonucci

    2016-03-01

    Full Text Available A hallmark of synaptic specializations is their dependence on highly organized complexes of proteins that interact with each other. The loss or modification of key synaptic proteins directly affects the properties of such networks, ultimately impacting synaptic function. SNAP-25 is a component of the SNARE complex, which is central to synaptic vesicle exocytosis, and, by directly interacting with different calcium channels subunits, it negatively modulates neuronal voltage-gated calcium channels, thus regulating intracellular calcium dynamics. The SNAP-25 gene has been associated with distinct brain diseases, including Attention Deficit Hyperactivity Disorder (ADHD, schizophrenia and bipolar disorder, indicating that the protein may act as a shared biological substrate among different synaptopathies. The mechanisms by which alterations in SNAP-25 may concur to these psychiatric diseases are still undefined, although alterations in neurotransmitter release have been indicated as potential causative processes. This review summarizes recent work showing that SNAP-25 not only controls exo/endocytic processes at the presynaptic terminal, but also regulates postsynaptic receptor trafficking, spine morphogenesis and plasticity, thus opening the possibility that SNAP-25 defects may contribute to psychiatric diseases by impacting not only presynaptic but also postsynaptic functions.

  6. Electrochemical Analysis of Neurotransmitters

    Science.gov (United States)

    Bucher, Elizabeth S.; Wightman, R. Mark

    2016-01-01

    Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements. PMID:25939038

  7. Electrochemical Analysis of Neurotransmitters

    Science.gov (United States)

    Bucher, Elizabeth S.; Wightman, R. Mark

    2015-07-01

    Chemical signaling through the release of neurotransmitters into the extracellular space is the primary means of communication between neurons. More than four decades ago, Ralph Adams and his colleagues realized the utility of electrochemical methods for the study of easily oxidizable neurotransmitters, such as dopamine, norepinephrine, and serotonin and their metabolites. Today, electrochemical techniques are frequently coupled to microelectrodes to enable spatially resolved recordings of rapid neurotransmitter dynamics in a variety of biological preparations spanning from single cells to the intact brain of behaving animals. In this review, we provide a basic overview of the principles underlying constant-potential amperometry and fast-scan cyclic voltammetry, the most commonly employed electrochemical techniques, and the general application of these methods to the study of neurotransmission. We thereafter discuss several recent developments in sensor design and experimental methodology that are challenging the current limitations defining the application of electrochemical methods to neurotransmitter measurements.

  8. Perivascular neurotransmitters

    DEFF Research Database (Denmark)

    Frederiksen, Simona D; Haanes, Kristian A; Warfvinge, Karin

    2018-01-01

    In order to understand the nature of the relationship between cerebral blood flow (CBF) and primary headaches, we have conducted a literature review with particular emphasis on the role of perivascular neurotransmitters. Primary headaches are in general considered complex polygenic disorders (gen...... such as the somatosensory cortex, brainstem and thalamus. In regulation of CBF, the individual roles of neurotransmitters are partly known, but much needs to be unraveled with respect to headache disorders....

  9. Neurotransmitter transporters

    DEFF Research Database (Denmark)

    Gether, Ulrik; Andersen, Peter H; Larsson, Orla M

    2006-01-01

    The concentration of neurotransmitters in the extracellular space is tightly controlled by distinct classes of membrane transport proteins. This review focuses on the molecular function of two major classes of neurotransmitter transporter that are present in the cell membrane of neurons and....../or glial cells: the solute carrier (SLC)1 transporter family, which includes the transporters that mediate the Na(+)-dependent uptake of glutamate, and the SLC6 transporter family, which includes the transporters that mediate the Na(+)-dependent uptake of dopamine, 5-HT, norepinephrine, glycine and GABA....... Recent research has provided substantial insight into the structure and function of these transporters. In particular, the recent crystallizations of bacterial homologs are of the utmost importance, enabling the first reliable structural models of the mammalian neurotransmitter transporters...

  10. Presynaptic active zones of mammalian neuromuscular junctions: Nanoarchitecture and selective impairments in aging.

    Science.gov (United States)

    Badawi, Yomna; Nishimune, Hiroshi

    2018-02-01

    Neurotransmitter release occurs at active zones, which are specialized regions of the presynaptic membrane. A dense collection of proteins at the active zone provides a platform for molecular interactions that promote recruitment, docking, and priming of synaptic vesicles. At mammalian neuromuscular junctions (NMJs), muscle-derived laminin β2 interacts with presynaptic voltage-gated calcium channels to organize active zones. The molecular architecture of presynaptic active zones has been revealed using super-resolution microscopy techniques that combine nanoscale resolution and multiple molecular identification. Interestingly, the active zones of adult NMJs are not stable structures and thus become impaired during aging due to the selective degeneration of specific active zone proteins. This review will discuss recent progress in the understanding of active zone nanoarchitecture and the mechanisms underlying active zone organization in mammalian NMJs. Furthermore, we will summarize the age-related degeneration of active zones at NMJs, and the role of exercise in maintaining active zones. Copyright © 2017 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  11. Alternative Splicing of P/Q-Type Ca2+ Channels Shapes Presynaptic Plasticity

    Directory of Open Access Journals (Sweden)

    Agnes Thalhammer

    2017-07-01

    Full Text Available Alternative splicing of pre-mRNAs is prominent in the mammalian brain, where it is thought to expand proteome diversity. For example, alternative splicing of voltage-gated Ca2+ channel (VGCC α1 subunits can generate thousands of isoforms with differential properties and expression patterns. However, the impact of this molecular diversity on brain function, particularly on synaptic transmission, which crucially depends on VGCCs, is unclear. Here, we investigate how two major splice isoforms of P/Q-type VGCCs (Cav2.1[EFa/b] regulate presynaptic plasticity in hippocampal neurons. We find that the efficacy of P/Q-type VGCC isoforms in supporting synaptic transmission is markedly different, with Cav2.1[EFa] promoting synaptic depression and Cav2.1[EFb] synaptic facilitation. Following a reduction in network activity, hippocampal neurons upregulate selectively Cav2.1[EFa], the isoform exhibiting the higher synaptic efficacy, thus effectively supporting presynaptic homeostatic plasticity. Therefore, the balance between VGCC splice variants at the synapse is a key factor in controlling neurotransmitter release and presynaptic plasticity.

  12. Nanosensors for neurotransmitters.

    Science.gov (United States)

    Polo, Elena; Kruss, Sebastian

    2016-04-01

    Neurotransmitters are an important class of messenger molecules. They govern chemical communication between cells for example in the brain. The spatiotemporal propagation of these chemical signals is a crucial part of communication between cells. Thus, the spatial aspect of neurotransmitter release is equally important as the mere time-resolved measurement of these substances. In conclusion, without tools that provide the necessary spatiotemporal resolution, chemical signaling via neurotransmitters cannot be studied in greater detail. In this review article we provide a critical overview about sensors/probes that are able to monitor neurotransmitters. Our focus are sensing concepts that provide or could in the future provide the spatiotemporal resolution that is necessary to 'image' dynamic changes of neurotransmitter concentrations around cells. These requirements set the bar for the type of sensors we discuss. The sensor must be small enough (if possible on the nanoscale) to provide the envisioned spatial resolution and it should allow parallel (spatial) detection. In this article we discuss both optical and electrochemical concepts that meet these criteria. We cover techniques that are based on fluorescent building blocks such as nanomaterials, proteins and organic dyes. Additionally, we review electrochemical array techniques and assess limitations and possible future directions.

  13. Exceptionally tight membrane-binding may explain the key role of the synaptotagmin-7 C 2 A domain in asynchronous neurotransmitter release

    Energy Technology Data Exchange (ETDEWEB)

    Voleti, Rashmi; Tomchick, Diana R.; Südhof, Thomas C.; Rizo, Josep

    2017-09-18

    Synaptotagmins (Syts) act as Ca2+ sensors in neurotransmitter release by virtue of Ca2+-binding to their two C2 domains, but their mechanisms of action remain unclear. Puzzlingly, Ca2+-binding to the C2B domain appears to dominate Syt1 function in synchronous release, whereas Ca2+-binding to the C2A domain mediates Syt7 function in asynchronous release. Here we show that crystal structures of the Syt7 C2A domain and C2AB region, and analyses of intrinsic Ca2+-binding to the Syt7 C2 domains using isothermal titration calorimetry, did not reveal major differences that could explain functional differentiation between Syt7 and Syt1. However, using liposome titrations under Ca2+ saturating conditions, we show that the Syt7 C2A domain has a very high membrane affinity and dominates phospholipid binding to Syt7 in the presence or absence of L-α-phosphatidylinositol 4,5-diphosphate (PIP2). For Syt1, the two Ca2+-saturated C2 domains have similar affinities for membranes lacking PIP2, but the C2B domain dominates binding to PIP2-containing membranes. Mutagenesis revealed that the dramatic differences in membrane affinity between the Syt1 and Syt7 C2A domains arise in part from apparently conservative residue substitutions, showing how striking biochemical and functional differences can result from the cumulative effects of subtle residue substitutions. Viewed together, our results suggest that membrane affinity may be a key determinant of the functions of Syt C2 domains in neurotransmitter release.

  14. Neurotransmitter: Sodium Symporters: Caught in the Act!

    DEFF Research Database (Denmark)

    Malinauskaite, Lina

    The neurotransmitter: sodium symporters in the neurons. Communication between neurons is mediated by the release of molecules called neurotransmitters (blue dots) from first neuron and sensed by receptors on the surface of the second (purple sphere). The signal is ended by active reuptake...... of these neurotransmitters by a family of proteins called neurotransmitter: sodium symporters (NSS), which are driven using the large concentration difference of sodium (orange dots) between the outside and the inside of the cell...

  15. The release of sympathetic neurotransmitters is impaired in aged rats after an inflammatory stimulus. A possible link between cytokine production and sympathetic transmission

    Science.gov (United States)

    Donoso, Verónica; Gomez, Christian R.; Orriantia, Miguel Ángel; Pérez, Viviana; Torres, Claudio; Coddou, Claudio; Nelson, Pablo; Maisey, Kevin; Morales, Bernardo; Fernandez, Ricardo; Imarai, Mónica; Huidobro-Toro, Juan Pablo; Sierra, Felipe; Acuña-Castillo, Claudio

    2009-01-01

    Aging results in a general decline in the response to external insults, including acute inflammatory challenges. In young animals, the inflammatory response requires activation of the sympathetic system, including neurotransmitters such as ATP, and catecholamines (epinephrine and norepinephrine). To test whether aging affects activation of this axis, and whether this in turn might affect cytokine release, we administered lipopolysaccharide (LPS) i.p. to adult, middle-aged and aged Fisher 344 rats (6, 15 and 23-month old, respectively) and evaluated the early (0–12 hours) serum levels of Neuropeptide-Y (NP-Y), ATP and vanillyl mandelic acid (VMA, as an indirect measurement of catecholamine levels). In addition, we evaluated the association between these factors and serum levels of the cytokines tumor necrosis factor-alpha (TNFα)3 and interleukin-10 (IL-10). Induction of both ATP and NP-Y was markedly reduced in the serum of aged animals, when compared to their younger counterparts, while induction of VMA was not affected by age. In spite of these changes, serum levels of TNFα and IL-10 were strongly hyper induced and delayed in aged rats. The results suggest that during aging there is a dysregulation in sympathetic neurotransmitter regulatory mechanisms, and this might play a role in the impairment of the inflammatory response. PMID:18973771

  16. Administration of caffeine inhibited adenosine receptor agonist-induced decreases in motor performance, thermoregulation, and brain neurotransmitter release in exercising rats.

    Science.gov (United States)

    Zheng, Xinyan; Hasegawa, Hiroshi

    2016-01-01

    We examined the effects of an adenosine receptor agonist on caffeine-induced changes in thermoregulation, neurotransmitter release in the preoptic area and anterior hypothalamus, and endurance exercise performance in rats. One hour before the start of exercise, rats were intraperitoneally injected with either saline alone (SAL), 10 mg kg(-1) caffeine and saline (CAF), a non-selective adenosine receptor agonist (5'-N-ethylcarboxamidoadenosine [NECA]: 0.5 mg kg(-1)) and saline (NECA), or the combination of caffeine and NECA (CAF+NECA). Rats ran until fatigue on the treadmill with a 5% grade at a speed of 18 m min(-1) at 23 °C. Compared to the SAL group, the run time to fatigue (RTTF) was significantly increased by 52% following caffeine administration and significantly decreased by 65% following NECA injection (SAL: 91 ± 14.1 min; CAF: 137 ± 25.8 min; NECA: 31 ± 13.7 min; CAF+NECA: 85 ± 11.8 min; pcaffeine injection inhibited the NECA-induced decreases in the RTTF, Tcore, heat production, heat loss, and extracellular DA release. Neither caffeine nor NECA affected extracellular noradrenaline or serotonin release. These results support the findings of previous studies showing improved endurance performance and overrides in body limitations after caffeine administration, and imply that the ergogenic effects of caffeine may be associated with the adenosine receptor blockade-induced increases in brain DA release. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Homeostatic Presynaptic Plasticity Is Specifically Regulated by P/Q-type Ca2+ Channels at Mammalian Hippocampal Synapses

    Directory of Open Access Journals (Sweden)

    Alexander F. Jeans

    2017-10-01

    Full Text Available Voltage-dependent Ca2+ channels (VGCC represent the principal source of Ca2+ ions driving evoked neurotransmitter release at presynaptic boutons. In mammals, presynaptic Ca2+ influx is mediated mainly via P/Q-type and N-type VGCC, which differ in their properties. Changes in their relative contributions tune neurotransmission both during development and in Hebbian plasticity. However, whether this represents a functional motif also present in other forms of activity-dependent regulation is unknown. Here, we study the role of VGCC in homeostatic plasticity (HSP in mammalian hippocampal neurons using optical techniques. We find that changes in evoked Ca2+ currents specifically through P/Q-type, but not N-type, VGCC mediate bidirectional homeostatic regulation of both neurotransmitter release efficacy and the size of the major synaptic vesicle pools. Selective dependence of HSP on P/Q-type VGCC in mammalian terminals has important implications for phenotypes associated with P/Q-type channelopathies, including migraine and epilepsy.

  18. Characterization of In Vitro Release of Neurochemicals from the Intermediate Area of the Rat Thoracic Spinal Cord: Regulation by Coexisting Neurochemical and Presynaptic Autoreceptors

    Science.gov (United States)

    1995-06-16

    led to the proposal of 5-HT as a eNS neurotransmitter ( TWarog and Page, 1953) • Immunofluorescence studies found that 5-HT-IR cell bodies are...35.403-406. Twarog , B.M. and Page, J.H. (1953) Serotonin content of some mammalian tissues and urine and a method for its determination. J. Physiol

  19. Zn2+ modulation of neurotransmitter transporters

    DEFF Research Database (Denmark)

    Nørgaard-Nielsen, K.; Gether, U.

    2006-01-01

    Neurotransmitter transporters located at the presynaptic or glial cell membrane are responsible for the stringent and rapid clearance of the transmitter from the synapse, and hence they terminate signaling and control the duration of synaptic inputs in the brain. Two distinct families of neurotra......Neurotransmitter transporters located at the presynaptic or glial cell membrane are responsible for the stringent and rapid clearance of the transmitter from the synapse, and hence they terminate signaling and control the duration of synaptic inputs in the brain. Two distinct families...... of neurotransmitter transporters have been identified based on sequence homology: (1) the neurotransmitter sodium symporter family (NSS), which includes the Na+/C1(-)-dependent transporters for dopamine, norepinephrine, and serotonin; and (2) the dicarboxylate/amino acid cation symporter family (DAACS), which...... indirectly suggested the possibility that several of the transporters are modulated by Zn2+ in vivo, and thus that Zn2+ can play a role as a neuromodulator by affecting the function of neurotransmitter transporters....

  20. Immunoglobulin Fc gamma receptor promotes immunoglobulin uptake, immunoglobulin-mediated calcium increase, and neurotransmitter release in motor neurons

    Science.gov (United States)

    Mohamed, Habib A.; Mosier, Dennis R.; Zou, Ling L.; Siklos, Laszlo; Alexianu, Maria E.; Engelhardt, Jozsef I.; Beers, David R.; Le, Wei-dong; Appel, Stanley H.

    2002-01-01

    Receptors for the Fc portion of immunoglobulin G (IgG; FcgammaRs) facilitate IgG uptake by effector cells as well as cellular responses initiated by IgG binding. In earlier studies, we demonstrated that amyotrophic lateral sclerosis (ALS) patient IgG can be taken up by motor neuron terminals and transported retrogradely to the cell body and can alter the function of neuromuscular synapses, such as increasing intracellular calcium and spontaneous transmitter release from motor axon terminals after passive transfer. In the present study, we examined whether FcgammaR-mediated processes can contribute to these effects of ALS patient immunoglobulins. F(ab')(2) fragments (which lack the Fc portion) of ALS patient IgG were not taken up by motor axon terminals and were not retrogradely transported. Furthermore, in a genetically modified mouse lacking the gamma subunit of the FcR, the uptake of whole ALS IgG and its ability to enhance intracellular calcium and acetylcholine release were markedly attenuated. These data suggest that FcgammaRs appear to participate in IgG uptake into motor neurons as well as IgG-mediated increases in intracellular calcium and acetylcholine release from motor axon terminals. Copyright 2002 Wiley-Liss, Inc.

  1. Presynaptic Adenosine Receptor-Mediated Regulation of Diverse Thalamocortical Short-Term Plasticity in the Mouse Whisker Pathway

    Science.gov (United States)

    Ferrati, Giovanni; Martini, Francisco J.; Maravall, Miguel

    2016-01-01

    Short-term synaptic plasticity (STP) sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In “driver” thalamocortical (TC) synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here, we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors (KARs), modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release. PMID:26941610

  2. In vitro screening of major neurotransmitter systems possibly involved in the mechanism of action of antibodies to S100 protein in released-active form

    Directory of Open Access Journals (Sweden)

    Gorbunov EA

    2015-11-01

    Full Text Available Evgeniy A Gorbunov, Irina A Ertuzun, Evgeniya V Kachaeva, Sergey A Tarasov, Oleg I EpsteinOOO “NPF “MATERIA MEDICA HOLDING”, Moscow, Russian FederationAbstract: Experimentally and clinically, it was shown that released-active form of antibodies to S100 protein (RAF of Abs to S100 exerts a wide range of pharmacological activities: anxiolytic, antiasthenic, antiaggressive, stress-protective, antihypoxic, antiischemic, neuroprotective, and nootropic. The purpose of this study was to determine the influence of RAF of Abs to S100 on major neurotransmitter systems (serotoninergic, GABAergic, dopaminergic, and on sigma receptors as well which are possibly involved in its mechanism of pharmacological activity. Radioligand binding assays were used for assessment of the drug influence on ligand–receptor interaction. [35S]GTPγS binding assay, cyclic adenosine monophosphate HTRF™, cellular dielectric spectroscopy assays, and assays based on measurement of intracellular concentration of Ca2+ ions were used for assessment of agonist or antagonist properties of the drug toward receptors. RAF of Abs to S100 increased radioligand binding to 5-HT1F, 5-HT2B, 5-HT2Cedited, 5-HT3, and to D3 receptors by 142.0%, 131.9%, 149.3%, 120.7%, and 126.3%, respectively. Also, the drug significantly inhibited specific binding of radioligands to GABAB1A/B2 receptors by 25.8%, and to both native and recombinant human sigma1 receptors by 75.3% and 40.32%, respectively. In the functional assays, it was shown that the drug exerted antagonism at 5-HT1B, D3, and GABAB1A/B2 receptors inhibiting agonist-induced responses by 23.24%, 32.76%, and 30.2%, respectively. On the contrary, the drug exerted an agonist effect at 5-HT1A receptors enhancing receptor functional activity by 28.0%. The pharmacological profiling of RAF of Abs to S100 among 27 receptor provides evidence for drug-related modification of major neurotransmitter systems.Keywords: dopamine agent, released

  3. Neurotransmitter signaling in white matter.

    Science.gov (United States)

    Butt, Arthur M; Fern, Robert F; Matute, Carlos

    2014-11-01

    White matter (WM) tracts are bundles of myelinated axons that provide for rapid communication throughout the CNS and integration in grey matter (GM). The main cells in myelinated tracts are oligodendrocytes and astrocytes, with small populations of microglia and oligodendrocyte precursor cells. The prominence of neurotransmitter signaling in WM, which largely exclude neuronal cell bodies, indicates it must have physiological functions other than neuron-to-neuron communication. A surprising aspect is the diversity of neurotransmitter signaling in WM, with evidence for glutamatergic, purinergic (ATP and adenosine), GABAergic, glycinergic, adrenergic, cholinergic, dopaminergic and serotonergic signaling, acting via a wide range of ionotropic and metabotropic receptors. Both axons and glia are potential sources of neurotransmitters and may express the respective receptors. The physiological functions of neurotransmitter signaling in WM are subject to debate, but glutamate and ATP-mediated signaling have been shown to evoke Ca(2+) signals in glia and modulate axonal conduction. Experimental findings support a model of neurotransmitters being released from axons during action potential propagation acting on glial receptors to regulate the homeostatic functions of astrocytes and myelination by oligodendrocytes. Astrocytes also release neurotransmitters, which act on axonal receptors to strengthen action potential propagation, maintaining signaling along potentially long axon tracts. The co-existence of multiple neurotransmitters in WM tracts suggests they may have diverse functions that are important for information processing. Furthermore, the neurotransmitter signaling phenomena described in WM most likely apply to myelinated axons of the cerebral cortex and GM areas, where they are doubtless important for higher cognitive function. © 2014 Wiley Periodicals, Inc.

  4. Neurotransmitters behind pain relief with transcranial magnetic stimulation - positron emission tomography evidence for release of endogenous opioids.

    Science.gov (United States)

    Lamusuo, S; Hirvonen, J; Lindholm, P; Martikainen, I K; Hagelberg, N; Parkkola, R; Taiminen, T; Hietala, J; Helin, S; Virtanen, A; Pertovaara, A; Jääskeläinen, S K

    2017-10-01

    Repetitive transcranial magnetic stimulation (rTMS) at M1/S1 cortex has been shown to alleviate neuropathic pain. To investigate the possible neurobiological correlates of cortical neurostimulation for the pain relief. We studied the effects of M1/S1 rTMS on nociception, brain dopamine D2 and μ-opioid receptors using a randomized, sham-controlled, double-blinded crossover study design and 3D-positron emission tomography (PET). Ten healthy subjects underwent active and sham rTMS treatments to the right M1/S1 cortex with E-field navigated device. Dopamine D2 and μ-receptor availabilities were assessed with PET radiotracers [ 11 C]raclopride and [ 11 C]carfentanil after each rTMS treatment. Thermal quantitative sensory testing (QST), contact heat evoked potential (CHEP) and blink reflex (BR) recordings were performed between the PET scans. μ-Opioid receptor availability was lower after active than sham rTMS (P ≤ 0.0001) suggested release of endogenous opioids in the right ventral striatum, medial orbitofrontal, prefrontal and anterior cingulate cortices, and left insula, superior temporal gyrus, dorsolateral prefrontal cortex and precentral gyrus. There were no differences in striatal dopamine D2 receptor availability between active and sham rTMS, consistent with lack of long-lasting measurable dopamine release. Active rTMS potentiated the dopamine-regulated habituation of the BR compared to sham (P = 0.02). Thermal QST and CHEP remained unchanged after active rTMS. rTMS given to M1/S1 activates the endogenous opioid system in a wide brain network associated with processing of pain and other salient stimuli. Direct enhancement of top-down opioid-mediated inhibition may partly explain the clinical analgesic effects of rTMS. Neurobiological correlates of rTMS for the pain relief are unclear. rTMS on M1/S1 with 11 C-carfentanyl-PET activates endogenous opioids. Thermal and heat pain thresholds remain unchanged. rTMS induces top-down opioid-mediated inhibition

  5. Glutamate acts as a neurotransmitter for gastrin releasing peptide-sensitive and insensitive itch-related synaptic transmission in mammalian spinal cord

    Directory of Open Access Journals (Sweden)

    Ling Jennifer

    2011-06-01

    Full Text Available Abstract Itch sensation is one of the major sensory experiences of human and animals. Recent studies have proposed that gastrin releasing peptide (GRP is a key neurotransmitter for itch in spinal cord. However, no direct evidence is available to indicate that GRP actually mediate responses between primary afferent fibers and dorsal horn neurons. Here we performed integrative neurobiological experiments to test this question. We found that a small population of rat dorsal horn neurons responded to GRP application with increases in calcium signaling. Whole-cell patch-clamp recordings revealed that a part of superficial dorsal horn neurons responded to GRP application with the increase of action potential firing in adult rats and mice, and these dorsal horn neurons received exclusively primary afferent C-fiber inputs. On the other hands, few Aδ inputs receiving cells were found to be GRP positive. Finally, we found that evoked sensory responses between primary afferent C fibers and GRP positive superficial dorsal horn neurons are mediated by glutamate but not GRP. CNQX, a blocker of AMPA and kainate (KA receptors, completely inhibited evoked EPSCs, including in those Fos-GFP positive dorsal horn cells activated by itching. Our findings provide the direct evidence that glutamate is the principal excitatory transmitter between C fibers and GRP positive dorsal horn neurons. Our results will help to understand the neuronal mechanism of itch and aid future treatment for patients with pruritic disease.

  6. The amyloid precursor protein – a novel player within the molecular array of presynaptic nanomachines

    Directory of Open Access Journals (Sweden)

    Melanie eLassek

    2016-01-01

    Full Text Available More than 20 years ago the amyloid precursor protein (APP was identified as the precursor protein of the Aβ peptide, the main component of senile plaques in brains affected by Alzheimer´s disease. The pathophysiology of AD, characterized by a massive loss of synapses, cognitive decline, and behavioral changes was in principle attributed to the accumulation of Aβ. Within the last decades, much effort has gone into understanding the molecular basis of the progression of Alzheimer´s disease. However, little is known about the actual physiological function of amyloid precursor proteins. Allocating APP to the proteome of the structurally and functionally dynamic presynaptic active zone highlights APP as a hitherto unknown player within the setting of the presynapse. The molecular array of presynaptic nanomachines comprising the life cycle of synaptic vesicles, exo- and endocytosis, cytoskeletal rearrangements, and mitochondrial activity provides a balance between structural and functional maintenance and diversity. The generation of genetically designed mouse models further deciphered APP as an essential player in synapse formation and plasticity. Deletion of APP causes an age-dependent phenotype: while younger mice revealed almost no physiological impairments, this condition was changed in the elderly mice. Interestingly, the proteomic composition of neurotransmitter release sites already revealed substantial changes at young age. These changes point to a network that incorporates APP into a cluster of nanomachines. Currently, the underlying mechanism of how APP acts within these machines is still elusive. Within the scope of this review, we shall construct a network of APP interaction partners within the presynaptic active zone. Furthermore, we intend to outline how deletion of APP affects this network during space and time leading to impairments in learning and memory. These alterations may provide a molecular link to the pathogenesis of

  7. MAM-2201, a synthetic cannabinoid drug of abuse, suppresses the synaptic input to cerebellar Purkinje cells via activation of presynaptic CB1 receptors.

    Science.gov (United States)

    Irie, Tomohiko; Kikura-Hanajiri, Ruri; Usami, Makoto; Uchiyama, Nahoko; Goda, Yukihiro; Sekino, Yuko

    2015-08-01

    Herbal products containing synthetic cannabinoids-initially sold as legal alternatives to marijuana-have become major drugs of abuse. Among the synthetic cannabinoids, [1-(5-fluoropentyl)-1H-indol-3-yl](4-methyl-1-naphthalenyl)-methanone (MAM-2201) has been recently detected in herbal products and has psychoactive and intoxicating effects in humans, suggesting that MAM-2201 alters brain function. Nevertheless, the pharmacological actions of MAM-2201 on cannabinoid receptor type 1 (CB1R) and neuronal functions have not been elucidated. We found that MAM-2201 acted as an agonist of human CB1Rs expressed in AtT-20 cells. In whole-cell patch-clamp recordings made from Purkinje cells (PCs) in slice preparations of the mouse cerebellum, we also found that MAM-2201 inhibited glutamate release at parallel fiber-PC synapses via activation of presynaptic CB1Rs. MAM-2201 inhibited neurotransmitter release with an inhibitory concentration 50% of 0.36 μM. MAM-2201 caused greater inhibition of neurotransmitter release than Δ(9)-tetrahydrocannabinol within the range of 0.1-30 μM and JWH-018, one of the most popular and potent synthetic cannabinoids detected in the herbal products, within the range of 0.03-3 μM. MAM-2201 caused a concentration-dependent suppression of GABA release onto PCs. Furthermore, MAM-2201 induced suppression of glutamate release at climbing fiber-PC synapses, leading to reduced dendritic Ca(2+) transients in PCs. These results suggest that MAM-2201 is likely to suppress neurotransmitter release at CB1R-expressing synapses in humans. The reduction of neurotransmitter release from CB1R-containing synapses could contribute to some of the symptoms of synthetic cannabinoid intoxication including impairments in cerebellum-dependent motor coordination and motor learning. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Plasma membrane ordering agent pluronic F-68 (PF-68) reduces neurotransmitter uptake and release and produces learning and memory deficits in rats

    Science.gov (United States)

    Clarke, M. S.; Prendergast, M. A.; Terry, A. V. Jr

    1999-01-01

    A substantial body of evidence indicates that aged-related changes in the fluidity and lipid composition of the plasma membrane contribute to cellular dysfunction in humans and other mammalian species. In the CNS, reductions in neuronal plasma membrane order (PMO) (i.e., increased plasma membrane fluidity) have been attributed to age as well as the presence of the beta-amyloid peptide-25-35, known to play an important role in the neuropathology of Alzheimer's disease (AD). These PMO increases may influence neurotransmitter synthesis, receptor binding, and second messenger systems as well as signal transduction pathways. The effects of neuronal PMO on learning and memory processes have not been adequately investigated, however. Based on the hypothesis that an increase in PMO may alter a number of aspects of synaptic transmission, we investigated several neurochemical and behavioral effects of the membrane ordering agent, PF-68. In cell culture, PF-68 (nmoles/mg SDS extractable protein) reduced [3H]norepinephrine (NE) uptake into differentiated PC-12 cells as well as reduced nicotine stimulated [3H]NE release. The compound (800-2400 microg/kg, i.p., resulting in nmoles/mg SDS extractable protein in the brain) decreased step-through latencies and increased the frequencies of crossing into the unsafe side of the chamber in inhibitory avoidance training. In the Morris water maze, PF-68 increased the latencies and swim distances required to locate a hidden platform and reduced the time spent and distance swam in the previous target quadrant during transfer (probe) trials. PF-68 did not impair performance of a well-learned working memory task, the rat delayed stimulus discrimination task (DSDT), however. Studies with 14C-labeled PF-68 indicated that significant (pmoles/mg wet tissue) levels of the compound entered the brain from peripheral (i.p.) injection. No PF-68 related changes were observed in swim speeds or in visual acuity tests in water maze experiments, rotorod

  9. Reduced levels of neurotransmitter-degrading enzyme PRCP promote obesity

    OpenAIRE

    Palmiter, Richard D.

    2009-01-01

    The level of neurotransmitters present in the synaptic cleft is a function of the delicate balance among neurotransmitter synthesis, recycling, and degradation. While much is known about the processes controlling neurotransmitter synthesis and release, the enzymes that degrade peptide neurotransmitters are poorly understood. A new study in this issue of the JCI reveals the important role of neuropeptide degradation in regulating obesity (see the related article beginning on page 2291). Wallin...

  10. The interaction of mammalian Class C Vps with nSec-1/Munc18-a and syntaxin 1A regulates pre-synaptic release

    International Nuclear Information System (INIS)

    Kim, Bong Yoon; Sahara, Yoshinori; Yamamoto, Akitsugu; Kominami, Eiki; Kohsaka, Shinichi; Akazawa, Chihiro

    2006-01-01

    Membrane docking and fusion in neurons is a highly regulated process requiring the participation of a large number of SNAREs (soluble N-ethylmaleimide sensitive factor attachment protein receptors) and SNARE-interacting proteins. We found that mammalian Class C Vps protein complex associated specifically with nSec-1/Munc18-a, and syntaxin 1A both in vivo and in vitro. In contrast, VAMP2 and SNAP-25, other neuronal core complex proteins, did not interact. When co-transfected with the human growth hormone (hGH) reporter gene, mammalian Class C Vps proteins enhanced Ca 2+ -dependent exocytosis, which was abolished by the Ca 2+ -channel blocker nifedipine. In hippocampal primary cultures, the lentivirus-mediated overexpression of hVps18 increased asynchronous spontaneous synaptic release without changing mEPSCs. These results indicate that mammalian Class C Vps proteins are involved in the regulation of membrane docking and fusion through an interaction with neuronal specific SNARE molecules, nSec-1/Munc18-a and syntaxin 1A

  11. Subtype-Selective Small Molecule Inhibitors Reveal a Fundamental Role for Nav1.7 in Nociceptor Electrogenesis, Axonal Conduction and Presynaptic Release.

    Directory of Open Access Journals (Sweden)

    Aristos J Alexandrou

    Full Text Available Human genetic studies show that the voltage gated sodium channel 1.7 (Nav1.7 is a key molecular determinant of pain sensation. However, defining the Nav1.7 contribution to nociceptive signalling has been hampered by a lack of selective inhibitors. Here we report two potent and selective arylsulfonamide Nav1.7 inhibitors; PF-05198007 and PF-05089771, which we have used to directly interrogate Nav1.7's role in nociceptor physiology. We report that Nav1.7 is the predominant functional TTX-sensitive Nav in mouse and human nociceptors and contributes to the initiation and the upstroke phase of the nociceptor action potential. Moreover, we confirm a role for Nav1.7 in influencing synaptic transmission in the dorsal horn of the spinal cord as well as peripheral neuropeptide release in the skin. These findings demonstrate multiple contributions of Nav1.7 to nociceptor signalling and shed new light on the relative functional contribution of this channel to peripheral and central noxious signal transmission.

  12. In vivo impact of presynaptic calcium channel dysfunction on motor axons in episodic ataxia type 2.

    Science.gov (United States)

    Tomlinson, Susan E; Tan, S Veronica; Burke, David; Labrum, Robyn W; Haworth, Andrea; Gibbons, Vaneesha S; Sweeney, Mary G; Griggs, Robert C; Kullmann, Dimitri M; Bostock, Hugh; Hanna, Michael G

    2016-02-01

    Ion channel dysfunction causes a range of neurological disorders by altering transmembrane ion fluxes, neuronal or muscle excitability, and neurotransmitter release. Genetic neuronal channelopathies affecting peripheral axons provide a unique opportunity to examine the impact of dysfunction of a single channel subtype in detail in vivo. Episodic ataxia type 2 is caused by mutations in CACNA1A, which encodes the pore-forming subunit of the neuronal voltage-gated calcium channel Cav2.1. In peripheral motor axons, this channel is highly expressed at the presynaptic neuromuscular junction where it contributes to action potential-evoked neurotransmitter release, but it is not expressed mid-axon or thought to contribute to action potential generation. Eight patients from five families with genetically confirmed episodic ataxia type 2 underwent neurophysiological assessment to determine whether axonal excitability was normal and, if not, whether changes could be explained by Cav2.1 dysfunction. New mutations in the CACNA1A gene were identified in two families. Nerve conduction studies were normal, but increased jitter in single-fibre EMG studies indicated unstable neuromuscular transmission in two patients. Excitability properties of median motor axons were compared with those in 30 age-matched healthy control subjects. All patients had similar excitability abnormalities, including a high electrical threshold and increased responses to hyperpolarizing (P ataxia type 2 thus has unexpected effects on axon excitability, which may reflect an indirect effect of abnormal calcium current fluxes during development. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved.

  13. Glycolysis selectively shapes the presynaptic action potential waveform.

    Science.gov (United States)

    Lujan, Brendan; Kushmerick, Christopher; Banerjee, Tania Das; Dagda, Ruben K; Renden, Robert

    2016-12-01

    Mitochondria are major suppliers of cellular energy in neurons; however, utilization of energy from glycolysis vs. mitochondrial oxidative phosphorylation (OxPhos) in the presynaptic compartment during neurotransmission is largely unknown. Using presynaptic and postsynaptic recordings from the mouse calyx of Held, we examined the effect of acute selective pharmacological inhibition of glycolysis or mitochondrial OxPhos on multiple mechanisms regulating presynaptic function. Inhibition of glycolysis via glucose depletion and iodoacetic acid (1 mM) treatment, but not mitochondrial OxPhos, rapidly altered transmission, resulting in highly variable, oscillating responses. At reduced temperature, this same treatment attenuated synaptic transmission because of a smaller and broader presynaptic action potential (AP) waveform. We show via experimental manipulation and ion channel modeling that the altered AP waveform results in smaller Ca 2+ influx, resulting in attenuated excitatory postsynaptic currents (EPSCs). In contrast, inhibition of mitochondria-derived ATP production via extracellular pyruvate depletion and bath-applied oligomycin (1 μM) had no significant effect on Ca 2+ influx and did not alter the AP waveform within the same time frame (up to 30 min), and the resultant EPSC remained unaffected. Glycolysis, but not mitochondrial OxPhos, is thus required to maintain basal synaptic transmission at the presynaptic terminal. We propose that glycolytic enzymes are closely apposed to ATP-dependent ion pumps on the presynaptic membrane. Our results indicate a novel mechanism for the effect of hypoglycemia on neurotransmission. Attenuated transmission likely results from a single presynaptic mechanism at reduced temperature: a slower, smaller AP, before and independent of any effect on synaptic vesicle release or receptor activity. Copyright © 2016 the American Physiological Society.

  14. The presynaptic Munc13-1 binds alcohol and modulates alcohol self-administration in Drosophila

    Science.gov (United States)

    Das, Joydip; Xu, Shiyu; Pany, Satyabrata; Guillory, Ashley; Shah, Vrutant; Roman, Gregg W.

    2013-01-01

    Munc13-1 is a presynaptic active-zone protein essential for neurotransmitter release and involved in presynaptic plasticity in brain. Ethanol, butanol and octanol quenched the intrinsic fluorescence of the C1 domain of Munc13-1 with EC50s of 52 mM, 26 mM and 0.7 mM, respectively. Photoactive azialcohols photolabeled Munc13-1 C1 exclusively at Glu-582, which was identified by mass spectrometry. Mutation of Glu-582 to alanine, leucine and histidine reduced the alcohol binding two- to five-fold. Circular dichroism studies suggested that binding of alcohol increased the stability of the wild type Munc13-1 compared with the mutants. If Munc13-1 plays some role in the neural effects of alcohol in vivo, changes in the activity of this protein should produce differences in the behavioral responses to ethanol. We tested this prediction with a loss-of-function mutation in the conserved Dunc-13 in Drosophila melanogaster. The Dunc-13P84200/+ heterozygotes have 50% wild type levels of Dunc-13 mRNA and display a very robust increase in ethanol self-administration. This phenotype is reversed by the expression of the rat Munc13-1 protein within the Drosophila nervous system. The present studies indicate that Munc13-1 C1 has binding site(s) for alcohols and Munc13-1 activity is sufficient to restore normal self-administration to Drosophila mutants deficient in Dunc-13 activity. PMID:23692447

  15. Calcium-sensing beyond neurotransmitters

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Han, Weiping

    2009-01-01

    Neurotransmitters, neuropeptides and hormones are released through the regulated exocytosis of SVs (synaptic vesicles) and LDCVs (large dense-core vesicles), a process that is controlled by calcium. Synaptotagmins are a family of type 1 membrane proteins that share a common domain structure. Most....... Also, we discuss potential roles of synaptotagmins in non-traditional endocrine systems....... synaptotagmins are located in brain and endocrine cells, and some of these synaptotagmins bind to phospholipids and calcium at levels that trigger regulated exocytosis of SVs and LDCVs. This led to the proposed synaptotagmin-calcium-sensor paradigm, that is, members of the synaptotagmin family function...... as calcium sensors for the regulated exocytosis of neurotransmitters, neuropeptides and hormones. Here, we provide an overview of the synaptotagmin family, and review the recent mouse genetic studies aimed at understanding the functions of synaptotagmins in neurotransmission and endocrine-hormone secretion...

  16. Shaping Neuronal Network Activity by Presynaptic Mechanisms.

    Directory of Open Access Journals (Sweden)

    Ayal Lavi

    2015-09-01

    Full Text Available Neuronal microcircuits generate oscillatory activity, which has been linked to basic functions such as sleep, learning and sensorimotor gating. Although synaptic release processes are well known for their ability to shape the interaction between neurons in microcircuits, most computational models do not simulate the synaptic transmission process directly and hence cannot explain how changes in synaptic parameters alter neuronal network activity. In this paper, we present a novel neuronal network model that incorporates presynaptic release mechanisms, such as vesicle pool dynamics and calcium-dependent release probability, to model the spontaneous activity of neuronal networks. The model, which is based on modified leaky integrate-and-fire neurons, generates spontaneous network activity patterns, which are similar to experimental data and robust under changes in the model's primary gain parameters such as excitatory postsynaptic potential and connectivity ratio. Furthermore, it reliably recreates experimental findings and provides mechanistic explanations for data obtained from microelectrode array recordings, such as network burst termination and the effects of pharmacological and genetic manipulations. The model demonstrates how elevated asynchronous release, but not spontaneous release, synchronizes neuronal network activity and reveals that asynchronous release enhances utilization of the recycling vesicle pool to induce the network effect. The model further predicts a positive correlation between vesicle priming at the single-neuron level and burst frequency at the network level; this prediction is supported by experimental findings. Thus, the model is utilized to reveal how synaptic release processes at the neuronal level govern activity patterns and synchronization at the network level.

  17. A presynaptic role for PKA in synaptic tagging and memory.

    Science.gov (United States)

    Park, Alan Jung; Havekes, Robbert; Choi, Jennifer Hk; Luczak, Vince; Nie, Ting; Huang, Ted; Abel, Ted

    2014-10-01

    Protein kinase A (PKA) and other signaling molecules are spatially restricted within neurons by A-kinase anchoring proteins (AKAPs). Although studies on compartmentalized PKA signaling have focused on postsynaptic mechanisms, presynaptically anchored PKA may contribute to synaptic plasticity and memory because PKA also regulates presynaptic transmitter release. Here, we examine this issue using genetic and pharmacological application of Ht31, a PKA anchoring disrupting peptide. At the hippocampal Schaffer collateral CA3-CA1 synapse, Ht31 treatment elicits a rapid decay of synaptic responses to repetitive stimuli, indicating a fast depletion of the readily releasable pool of synaptic vesicles. The interaction between PKA and proteins involved in producing this pool of synaptic vesicles is supported by biochemical assays showing that synaptic vesicle protein 2 (SV2), Rim1, and SNAP25 are components of a complex that interacts with cAMP. Moreover, acute treatment with Ht31 reduces the levels of SV2. Finally, experiments with transgenic mouse lines, which express Ht31 in excitatory neurons at the Schaffer collateral CA3-CA1 synapse, highlight a requirement for presynaptically anchored PKA in pathway-specific synaptic tagging and long-term contextual fear memory. These results suggest that a presynaptically compartmentalized PKA is critical for synaptic plasticity and memory by regulating the readily releasable pool of synaptic vesicles. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Action potential broadening in a presynaptic channelopathy

    Science.gov (United States)

    Begum, Rahima; Bakiri, Yamina; Volynski, Kirill E.; Kullmann, Dimitri M.

    2016-07-01

    Brain development and interictal function are unaffected in many paroxysmal neurological channelopathies, possibly explained by homoeostatic plasticity of synaptic transmission. Episodic ataxia type 1 is caused by missense mutations of the potassium channel Kv1.1, which is abundantly expressed in the terminals of cerebellar basket cells. Presynaptic action potentials of small inhibitory terminals have not been characterized, and it is not known whether developmental plasticity compensates for the effects of Kv1.1 dysfunction. Here we use visually targeted patch-clamp recordings from basket cell terminals of mice harbouring an ataxia-associated mutation and their wild-type littermates. Presynaptic spikes are followed by a pronounced afterdepolarization, and are broadened by pharmacological blockade of Kv1.1 or by a dominant ataxia-associated mutation. Somatic recordings fail to detect such changes. Spike broadening leads to increased Ca2+ influx and GABA release, and decreased spontaneous Purkinje cell firing. We find no evidence for developmental compensation for inherited Kv1.1 dysfunction.

  19. Intra-axonal Synthesis of SNAP25 Is Required for the Formation of Presynaptic Terminals

    Directory of Open Access Journals (Sweden)

    Andreia F.R. Batista

    2017-09-01

    Full Text Available Localized protein synthesis is a mechanism for developing axons to react acutely and in a spatially restricted manner to extracellular signals. As such, it is important for many aspects of axonal development, but its role in the formation of presynapses remains poorly understood. We found that the induced assembly of presynaptic terminals required local protein synthesis. Newly synthesized proteins were detectable at nascent presynapses within 15 min of inducing synapse formation in isolated axons. The transcript for the t-SNARE protein SNAP25, which is required for the fusion of synaptic vesicles with the plasma membrane, was recruited to presynaptic sites and locally translated. Inhibition of intra-axonal SNAP25 synthesis affected the clustering of SNAP25 and other presynaptic proteins and interfered with the release of synaptic vesicles from presynaptic sites. This study reveals a critical role for the axonal synthesis of SNAP25 in the assembly of presynaptic terminals.

  20. Presynaptic G Protein-Coupled Receptors: Gatekeepers of Addiction?

    Directory of Open Access Journals (Sweden)

    Kari A Johnson

    2016-11-01

    Full Text Available Drug abuse and addiction cause widespread social and public health problems, and the neurobiology underlying drug actions and drug use and abuse is an area of intensive research. Drugs of abuse alter synaptic transmission, and these actions contribute to acute intoxication as well as the chronic effects of abused substances. Transmission at most mammalian synapses involves neurotransmitter activation of two receptor subtypes, ligand-gated ion channels that mediate fast synaptic responses, and G protein-coupled receptors (GPCRs that have slower neuromodulatory actions. The GPCRs represent a large proportion of neurotransmitter receptors involved in almost all facets of nervous system function. In addition, these receptors are targets for many pharmacotherapeutic agents. Drugs of abuse directly or indirectly affect neuromodulation mediated by GPCRs, with important consequences for intoxication, drug taking and responses to prolonged drug exposure, withdrawal and addiction. Among the GPCRs are several subtypes involved in presynaptic inhibition, most of which are coupled to the Gi/o class of G protein. There is increasing evidence that these presynaptic Gi/o-coupled GPCRs have important roles in the actions of drugs of abuse, as well as behaviors related to these drugs. This topic will be reviewed, with particular emphasis on receptors for three neurotransmitters, dopamine (D1- and D2-like receptors, endocannabinoids (CB1 receptors and glutamate (group II metabotropic glutamate (mGlu receptors. The focus is on recent evidence from laboratory animal models (and some evidence in humans implicating these receptors in the acute and chronic effects of numerous abused drugs, as well as in the control of drug seeking and taking. The ability of drugs targeting these receptors to modify drug seeking behavior has raised the possibility of using compounds targeting these receptors for addiction pharmacotherapy. This topic is also discussed, with emphasis on

  1. Presynaptic Dopamine D2 Receptors Modulate [3H]GABA Release at StriatoPallidal Terminals via Activation of PLC → IP3 → Calcineurin and Inhibition of AC → cAMP → PKA Signaling Cascades.

    Science.gov (United States)

    Jijón-Lorenzo, Rafael; Caballero-Florán, Isaac Hiram; Recillas-Morales, Sergio; Cortés, Hernán; Avalos-Fuentes, José Arturo; Paz-Bermúdez, Francisco Javier; Erlij, David; Florán, Benjamín

    2018-02-21

    Striatal dopamine D2 receptors activate the PLC → IP3 → Calcineurin-signaling pathway to modulate the neural excitability of En+ Medium-sized Spiny GABAergic neurons (MSN) through the regulation of L-type Ca 2+ channels. Presynaptic dopaminergic D2 receptors modulate GABA release at striatopallidal terminals through L-type Ca 2+ channels as well, but their signaling pathway is still undetermined. Since D2 receptors are Gi/o-coupled and negatively modulate adenylyl cyclase (AC), we investigated whether presynaptic D2 receptors modulate GABA release through the same signaling cascade that controls excitability in the striatum or by the inhibition of AC and decreased PKA activity. Activation of D2 receptors stimulated formation of [ 3 H]IP 1 and decreased Forskolin-stimulated [ 3 H]cAMP accumulation in synaptosomes from rat Globus Pallidus. D2 receptor activation with Quinpirole in the presence of L 745,870 decreased, in a dose-dependent manner, K + -induced [ 3 H]GABA release in pallidal slices. The effect was prevented by the pharmacological blockade of Gi/o βγ subunit effects with Gallein, PLC with U 73122, IP3 receptor activation with 4-APB, Calcineurin with FK506. In addition, when release was stimulated with Forskolin to activate AC, D2 receptors also decreased K + -induced [ 3 H]GABA release, an effect occluded with the effect of the blockade of PKA with H89 or stimulation of release with the cAMP analog 8-Br-cAMP. These data indicate that D2 receptors modulate [ 3 H]GABA release at striatopallidal terminals by activating the PLC → IP3 → Calcineurin-signaling cascade, the same one that modulates excitability in soma. Additionally, D2 receptors inhibit release when AC is active. Both mechanisms appear to converge to regulate the activity of presynaptic L-type Ca 2+ channels. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  2. Rapid neurotransmitter uncaging in spatially defined patterns.

    Science.gov (United States)

    Shoham, Shy; O'Connor, Daniel H; Sarkisov, Dmitry V; Wang, Samuel S-H

    2005-11-01

    Light-sensitive 'caged' molecules provide a means of rapidly and noninvasively manipulating biochemical signals with submicron spatial resolution. Here we describe a new optical system for rapid uncaging in arbitrary patterns to emulate complex neural activity. This system uses TeO(2) acousto-optical deflectors to steer an ultraviolet beam rapidly and can uncage at over 20,000 locations per second. The uncaging beam is projected into the focal plane of a two-photon microscope, allowing us to combine patterned uncaging with imaging and electrophysiology. By photolyzing caged neurotransmitter in brain slices we can generate precise, complex activity patterns for dendritic integration. The method can also be used to activate many presynaptic neurons at once. Patterned uncaging opens new vistas in the study of signal integration and plasticity in neuronal circuits and other biological systems.

  3. Focus On: Neurotransmitter Systems

    Science.gov (United States)

    Valenzuela, C. Fernando; Puglia, Michael P.; Zucca, Stefano

    2011-01-01

    Neurotransmitter systems have been long recognized as important targets of the developmental actions of alcohol (i.e., ethanol). Short- and long-term effects of ethanol on amino acid (e.g., γ-aminobutyric acid and glutamate) and biogenic amine (e.g., serotonin and dopamine) neurotransmitters have been demonstrated in animal models of fetal alcohol spectrum disorders (FASD). Researchers have detected ethanol effects after exposure during developmental periods equivalent to the first, second, and third trimesters of human pregnancy. Results support the recommendation that pregnant women should abstain from drinking—even small quantities—as effects of ethanol on neurotransmitter systems have been detected at low levels of exposure. Recent studies have elucidated new mechanisms and/or consequences of the actions of ethanol on amino acid and biogenic amine neurotransmitter systems. Alterations in these neurotransmitter systems could, in part, be responsible for many of the conditions associated with FASD, including (1) learning, memory, and attention deficits; (2) motor coordination impairments; (3) abnormal responsiveness to stress; and (4) increased susceptibility to neuropsychiatric disorders, such as substance abuse and depression, and also neurological disorders, such as epilepsy and sudden infant death syndrome. However, future research is needed to conclusively establish a causal relationship between these conditions and developmental dysfunctions in neurotransmitter systems. PMID:23580048

  4. Protective effects of gastrodia elata on aluminium-chloride-induced learning impairments and alterations of amino acid neurotransmitter release in adult rats

    Science.gov (United States)

    Shuchang, He; Qiao, Niu; Piye, Niu; Mingwei, He; Xiaoshu, Sun; Feng, Shao; Sheng, Wang; Opler, Mark

    2009-01-01

    Purpose High brain levels of aluminum (Al) can be neurotoxic and cause learning and memory deficits. Gastrodia elata (GE) is a Chinese herb widely used for improving mental function in traditional Chinese medicine. We measured changes in Al-induced neurotransmitter alteration and performance on a learning and memory task to elucidate the mechanism of Al toxicity and to assess whether these alterations could be attenuated by GE. Methods Thirty-six adult, male rats were randomly divided into six groups. Four Al-exposed groups were given aluminum chloride at 5 mg/kg/day or 10 mg/kg/day (i.p.) for two months, with two of these groups (one for each dose of Al) receiving GE (0.4 g/kg, via oral intubation, with the GE powder mixed in the drinking water) while the other two groups received vehicle. A GE control group was given injections of saline plus GE and a saline control group was given injections of saline and with 3 injection days and one day off. A step-down test was used to measure learning and memory ability. Al concentrations in the neocortex were assayed with a graphite furnace atomic absorption spectrophotometer. Amino acid neurotransmitter levels in the neocortex were determined by high performance liquid chromatogram-fluorescence. Results Al-exposed rats showed impaired learning and memory ability as indicated by shorter step down latency and more retention errors. Cortical concentrations (mean ± SEM) of Al were: 56.22 ± 34.10 ng/g (wet weight) in the Saline control group; 172.87 ± 111.06 in the 5 mg/kg/dayAl group; 289.15 ± 102.55 in the 10mg Al group; 74.98 ± 19.00 in the GE control group; 232.55 ± 35.74 in 5 mg Al+GE group; and 291.35 ± 98.38 in 10 mg Al+GE group respectively. Al exposure produced a significant increase in cortical GABA levels. Gastrodia elata reduced learning and memory deficits without affecting brain Al levels. Conclusions Rats exposed to AlCl3 suffer from deficits in learning and memory, accompanied by increases in GABA levels

  5. PRESYNAPTIC DOPAMINE MODULATION BY STIMULANT SELF ADMINISTRATION

    Science.gov (United States)

    España, Rodrigo A.; Jones, Sara R.

    2013-01-01

    The mesolimbic dopamine system is an essential participant in the initiation and modulation of various forms of goal-directed behavior, including drug reinforcement and addiction processes. Dopamine neurotransmission is increased by acute administration of all drugs of abuse, including the stimulants cocaine and amphetamine. Chronic exposure to these drugs via voluntary self-administration provides a model of stimulant abuse that is useful in evaluating potential behavioral and neurochemical adaptations that occur during addiction. This review describes commonly used methodologies to measure dopamine and baseline parameters of presynaptic dopamine regulation, including exocytotic release and reuptake through the dopamine transporter in the nucleus accumbens core, as well as dramatic adaptations in dopamine neurotransmission and drug sensitivity that occur with acute non-contingent and chronic, contingent self-administration of cocaine and amphetamine. PMID:23277050

  6. A Markov State-based Quantitative Kinetic Model of Sodium Release from the Dopamine Transporter

    Science.gov (United States)

    Razavi, Asghar M.; Khelashvili, George; Weinstein, Harel

    2017-01-01

    The dopamine transporter (DAT) belongs to the neurotransmitter:sodium symporter (NSS) family of membrane proteins that are responsible for reuptake of neurotransmitters from the synaptic cleft to terminate a neuronal signal and enable subsequent neurotransmitter release from the presynaptic neuron. The release of one sodium ion from the crystallographically determined sodium binding site Na2 had been identified as an initial step in the transport cycle which prepares the transporter for substrate translocation by stabilizing an inward-open conformation. We have constructed Markov State Models (MSMs) from extensive molecular dynamics simulations of human DAT (hDAT) to explore the mechanism of this sodium release. Our results quantify the release process triggered by hydration of the Na2 site that occurs concomitantly with a conformational transition from an outward-facing to an inward-facing state of the transporter. The kinetics of the release process are computed from the MSM, and transition path theory is used to identify the most probable sodium release pathways. An intermediate state is discovered on the sodium release pathway, and the results reveal the importance of various modes of interaction of the N-terminus of hDAT in controlling the pathways of release.

  7. N-cadherin induces partial differentiation of cholinergic presynaptic terminals in heterologous cultures of brainstem neurons and CHO cells

    Directory of Open Access Journals (Sweden)

    Richard J Flannery

    2012-12-01

    Full Text Available N-cadherin is a calcium-sensitive cell adhesion molecule commonly expressed at synaptic junctions and contributes to formation and maturation of synaptic contacts. This study used heterologous cell cultures of brainstem cholinergic neurons and transfected Chinese Hamster Ovary (CHO cells to examine whether N-cadherin is sufficient to induce differentiation of cholinergic presynaptic terminals. Brainstem nuclei isolated from transgenic mice expressing EGFP under the control of choline acetyltransferase transcriptional regulatory elements (ChATBACEGFP were cultured as tissue explants for five days and cocultured with transfected CHO cells for an additional two days. Immunostaining for synaptic vesicle proteins SV2 and synapsin I revealed a ~3-fold increase in the area of SV2 immunolabeling over N-cadherin expressing CHO cells, and this effect was enhanced by coexpression of p120-catenin. Synapsin I immunolabeling per axon length was also increased on N-cadherin expressing CHO cells but required coexpression of p120-catenin. To determine whether N-cadherin induces formation of neurotransmitter release sites, whole-cell voltage-clamp recordings of CHO cells expressing alpha-3 and beta-4 nicotinic acetylcholine receptor (nAChR subunits in contact with cholinergic axons were used to monitor excitatory postsynaptic potentials (EPSPs and miniature EPSPs (mEPSPs. EPSPs and mEPSPs were not detected in both, control and in N-cadherin expressing CHO cells in the absence or presence of tetrodotoxin. These results indicate that expression of N-cadherin in non-neuronal cells is sufficient to initiate differentiation of presynaptic cholinergic terminals by inducing accumulation of synaptic vesicles; however, development of readily detectable mature cholinergic release sites and/or clustering of postsynaptic nAChR may require expression of additional synaptogenic proteins.

  8. Porters and neurotransmitter transporters.

    Science.gov (United States)

    Nelson, N; Lill, H

    1994-11-01

    Uptake of neurotransmitters involves multiple transporters acting in different brain locations under different physiological conditions. The vesicular transporters are driven by a proton-motive force generated by a V-ATPase and their substrates are taken up via proton/substrate exchange. The plasma membrane transporters are driven by an electrochemical gradient of sodium generated by a Na+/K(+)-ATPase. Two distinct families of transporters were identified in this group. One cotransports sodium with glutamate and other amino acids and requires additionally an outwardly directed potassium gradient. The second cotransports sodium, chloride and a variety of neurotransmitters, including gamma-aminobutyric acid (GABA), glycine and monoamines. Genes and cDNA encoding several members of the latter family have been cloned and studied in detail. The structure and function as well as the evolutionary relationships among these neurotransmitter transporters are discussed.

  9. Porters and neurotransmitter transporters

    NARCIS (Netherlands)

    Nelson, Nathan; Lill, H

    1994-01-01

    Uptake of neurotransmitters involves multiple transporters acting in different brain locations under different physiological conditions. The vesicular transporters are driven by a proton-motive force generated by a V-ATPase and their substrates are taken up via proton/substrate exchange. The plasma

  10. Neurotransmitters, more than meets the eye--neurotransmitters and their perspectives in cancer development and therapy.

    Science.gov (United States)

    Li, Zhi Jie; Cho, Chi Hin

    2011-09-30

    The neurotransmitter/receptor system has been shown to modulate various aspects of tumor development including cell proliferation, angiogenesis, invasion, migration and metastasis. It has been found that tumor tissues can not only synthesize and release a wide range of neurotransmitters but also produce different biological effects via respective receptors. These tissues are also innervated by nerve fibers but the biological significance is unknown. Nevertheless neurotransmitters can produce either stimulatory or inhibitory effect in normal and tumor tissues. These effects are dependent on the types of tissues and the kinds of neurotransmitter as well as the subtypes of corresponding receptors being involved. These findings clearly extend the conventional role of neurotransmitters in nervous system to the actions in oncogenesis. In this regard, intervention or stimulation of these neuronal pathways in different cancer diseases would have significant clinical implications in cancer treatments. Here, we summarize the influences of various well-characterized neurotransmitters and their receptors on tumor growth and further discuss the respective possible strategies and perspectives for cancer therapy in the future. Copyright © 2011. Published by Elsevier B.V.

  11. Detection of marine neurotoxins and characterization of the presynaptic activity of iotrochotin from the sponge Iotrochota birotulata

    International Nuclear Information System (INIS)

    Martin, J.V.

    1987-01-01

    In order to detect novel presynaptic neurotoxins, a total of 766 extracts from marine organisms collected during expeditions of the research vessel Alpha Helix around the peninsula of Baja Mexico in 1974 and through the Caribbean in 1978 were tested for activity in a synaptosomal assay for the release of acetylcholine (ACh). To eliminate from consideration sample extracts which lysed the synaptosomal membrane, lactate dehydrogenase (LDH) activity was measured as a cytoplasmic marker. On the basis of the screening studies the extract of the sponge lotrochota birotulata was chosen for more detailed characterization. The active factor, iotrochotin (IOT), was sensitive to thermal inactivation, was partially activated by trypsin treatment and had a molecular weight of 12,000-13,000. The activity of IOT was found to be complete by one minute. The maximal release of radioactivity from synaptosomes preloaded with [ 3 H]choline was found to be dependent on the concentration of IOT irrespective of the time of further incubation. The concentration-response curve of IOT activity showed a sigmoid shape which did not fit the Hill equation. IOT caused release of both ACh and choline. Of the radioactivity released by IOT from synaptosomes preloaded with [ 3 H]choline, 50-60% was [ 3 H]ACh. IOT also released [ 3 H]GABA and [ 3 H]norepinephrine from synaptosomes preincubated with these labeled neurotransmitters. The activity of IOT was only minimally sensitive to reduction in Na + or Ca 2+ levels, and was not sensitive to tetrodotoxin. IOT did not dramatically change the fluorescence of synaptosomes incubated with a depolarization-indicating dye. However, depolarization of synaptosomes with high concentrations of K + was still detectable by this method in the presence of IOT

  12. Deficits in the activity of presynaptic γ-aminobutyric acid type B receptors contribute to altered neuronal excitability in fragile X syndrome.

    Science.gov (United States)

    Kang, Ji-Yong; Chadchankar, Jayashree; Vien, Thuy N; Mighdoll, Michelle I; Hyde, Thomas M; Mather, Robert J; Deeb, Tarek Z; Pangalos, Menelas N; Brandon, Nicholas J; Dunlop, John; Moss, Stephen J

    2017-04-21

    The behavioral and anatomical deficits seen in fragile X syndrome (FXS) are widely believed to result from imbalances in the relative strengths of excitatory and inhibitory neurotransmission. Although modified neuronal excitability is thought to be of significance, the contribution that alterations in GABAergic inhibition play in the pathophysiology of FXS are ill defined. Slow sustained neuronal inhibition is mediated by γ-aminobutyric acid type B (GABA B ) receptors, which are heterodimeric G-protein-coupled receptors constructed from R1a and R2 or R1b and R2 subunits. Via the activation of G i/o , they limit cAMP accumulation, diminish neurotransmitter release, and induce neuronal hyperpolarization. Here we reveal that selective deficits in R1a subunit expression are seen in Fmr1 knock-out mice (KO) mice, a widely used animal model of FXS, but the levels of the respective mRNAs were unaffected. Similar trends of R1a expression were seen in a subset of FXS patients. GABA B receptors (GABA B Rs) exert powerful pre- and postsynaptic inhibitory effects on neurotransmission. R1a-containing GABA B Rs are believed to mediate presynaptic inhibition in principal neurons. In accordance with this result, deficits in the ability of GABA B Rs to suppress glutamate release were seen in Fmr1-KO mice. In contrast, the ability of GABA B Rs to suppress GABA release and induce postsynaptic hyperpolarization was unaffected. Significantly, this deficit contributes to the pathophysiology of FXS as the GABA B R agonist ( R )-baclofen rescued the imbalances between excitatory and inhibitory neurotransmission evident in Fmr1-KO mice. Collectively, our results provided evidence that selective deficits in the activity of presynaptic GABA B Rs contribute to the pathophysiology of FXS. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Simultaneous determination of the repertoire of classical neurotransmitters released from embryonal carcinoma stem cells using online microdialysis coupled with hydrophilic interaction chromatography–tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ya-Bin [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Sun, Fan [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Teng, Lin [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Department of Cardiology and Institute of Cardiovascular Diseases, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang 443000, Hubei (China); Li, Wen-Bin; An, Shi-Min [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Zhang, Chun; Yang, Xin-Jie; Lv, Hao-Yu; Ding, Xu-Ping [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Zhu, Liang, E-mail: zhuliang17@gmail.com [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); and others

    2014-11-07

    Highlights: • An online MD-HILIC–MS/MS method for simultaneously measuring the repertoire of classical transmitters was developed and validated. • Hydrophilic interaction chromatography (HILIC) was successfully employed to online system. • Stable isotope labeled internal standards and authentic matrix have been applied to guarantee reliable results. • The method features simple procedure (no sample preparation), high recovery (≥73%), high accuracy (89.36% ≤ RE ≤ 116.89%), good reproducibility (2.18% ≤ RSD ≤ 14.56%), and sensitive limits of detection (2 pg for acetylcholine, serotonin, and glutamate, 10 pg for dopamine, norepinephrine, GABA, and glycine). - Abstract: Dynamic, continuous, and simultaneous multi-analysis of transmitters is important for the delineation of the complex interactions between the neuronal and intercellular communications. But the analysis of the whole repertoire of classical transmitters of diverse structure is challenging due to their different physico-chemical properties and to their high polarity feature which leads to poor retention in traditional reversed-phase columns during LC–MS analysis. Here, an online microdialysis coupled with hydrophilic interaction chromatography–tandem mass spectrometry (online MD-HILIC–MS/MS) detection method was developed for the simultaneous measurement of the repertoire of classical transmitters (acetylcholine, serotonin, dopamine, norepinephrine, glutamate, GABA, and glycine). Stable isotope labeled internal standards and authentic matrix have been applied to guarantee reliable results. The method was successfully employed to reveal the characteristics of transmitter release from embryonal carcinoma stem cells. The method features simple procedure (no sample preparation), high recovery (≥73%), high accuracy (89.36% ≤ RE ≤ 116.89%), good reproducibility (2.18% ≤ RSD ≤ 14.56%), and sensitive limits of detection (2 pg for acetylcholine, serotonin, and glutamate, 10 pg

  14. Classical neurotransmitters and neuropeptides involved in generalized epilepsy in a multi-neurotransmitter system: How to improve the antiepileptic effect?

    Science.gov (United States)

    Werner, Felix-Martin; Coveñas, Rafael

    2017-06-01

    Here, we describe in generalized epilepsies the alterations of classical neurotransmitters and neuropeptides acting at specific subreceptors. In order to consider a network context rather than one based on focal substrates and in order to make the interaction between neurotransmitters and neuropeptides and their specific subreceptors comprehensible, neural networks in the hippocampus, thalamus, and cerebral cortex are described. In this disease, a neurotransmitter imbalance between dopaminergic and serotonergic neurons and between presynaptic GABAergic neurons (hypoactivity) and glutaminergic neurons (hyperactivity) occurs. Consequently, combined GABA A agonists and NMDA antagonists could furthermore stabilize the neural networks in a multimodal pharmacotherapy. The antiepileptic effect and the mechanisms of action of conventional and recently developed antiepileptic drugs are reviewed. The GASH:Sal animal model can contribute to examine the efficacy of antiepileptic drugs. The issues of whether the interaction of classical neurotransmitters with other subreceptors (5-HT 7 , metabotropic 5 glutaminergic, A 2A adenosine, and alpha nicotinic 7 cholinergic receptors) or whether the administration of agonists/antagonists of neuropeptides might improve the therapeutic effect of antiepileptic drugs should be addressed. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic". Copyright © 2015 Elsevier Inc. All rights reserved.

  15. The Role of Ion Selectivity of the Fusion Pore on Transmission and the Exocytosis of Neurotransmitters and Hormones

    Science.gov (United States)

    Delacruz, Joannalyn Bongar

    Healthy nervous system function depends on proper transmission. Synaptic transmission occurs by the release of transmitters from vesicles that fuse to the plasma membrane of a pre-synaptic cell. Regulated release of neurotransmitters, neuropeptides, and hormones occurs by exocytosis, initiated by the formation of the fusion pore. The initial fusion pore has molecular dimensions with a diameter of 1-2 nm and a rapid lifetime on the millisecond time scale. It connects the vesicular lumen and extracellular space, serving as an important step for regulating the release of charged transmitters. Comprehending the molecular structure and biophysical properties of the fusion pore is essential for a mechanistic understanding of vesicle-plasma membrane fusion and transmitter release. Release of charged transmitter molecules such as glutamate, acetylcholine, dopamine, or noradrenaline through a narrow fusion pore requires compensation of change in charge. Transmitter release through the fusion pore is therefore an electrodiffusion process. If the fusion pore is selective for specific ions, then its selectivity will affect the rate of transmitter release via the voltage gradient that develops across the fusion pore. The elucidation of these mechanisms can lead to a better understanding of nervous system cell biology, neural and endocrine signaling, learning, memory, motor control, sensory function and integration, and in particular synaptic transmission. This investigation can advance our understanding of neurological disorders in which noradrenergic and dopaminergic exocytosis is disturbed, leading to neurological consequences of developmental disorders, epilepsy, Parkinson's disease, and other neurodegenerative diseases. Ultimately, understanding the role of selectivity in the fusion pore and its effects on exocytosis can contribute to the development of more effective therapies. This study investigates the selectivity of the fusion pore by observing the effects of ion

  16. Presynaptic Ionotropic Receptors Controlling and Modulating the Rules for Spike Timing-Dependent Plasticity

    Directory of Open Access Journals (Sweden)

    Matthijs B. Verhoog

    2011-01-01

    Full Text Available Throughout life, activity-dependent changes in neuronal connection strength enable the brain to refine neural circuits and learn based on experience. In line with predictions made by Hebb, synapse strength can be modified depending on the millisecond timing of action potential firing (STDP. The sign of synaptic plasticity depends on the spike order of presynaptic and postsynaptic neurons. Ionotropic neurotransmitter receptors, such as NMDA receptors and nicotinic acetylcholine receptors, are intimately involved in setting the rules for synaptic strengthening and weakening. In addition, timing rules for STDP within synapses are not fixed. They can be altered by activation of ionotropic receptors located at, or close to, synapses. Here, we will highlight studies that uncovered how network actions control and modulate timing rules for STDP by activating presynaptic ionotropic receptors. Furthermore, we will discuss how interaction between different types of ionotropic receptors may create “timing” windows during which particular timing rules lead to synaptic changes.

  17. Presynaptic Active Zone Density during Development and Synaptic Plasticity.

    Science.gov (United States)

    Clarke, Gwenaëlle L; Chen, Jie; Nishimune, Hiroshi

    2012-01-01

    Neural circuits transmit information through synapses, and the efficiency of synaptic transmission is closely related to the density of presynaptic active zones, where synaptic vesicles are released. The goal of this review is to highlight recent insights into the molecular mechanisms that control the number of active zones per presynaptic terminal (active zone density) during developmental and stimulus-dependent changes in synaptic efficacy. At the neuromuscular junctions (NMJs), the active zone density is preserved across species, remains constant during development, and is the same between synapses with different activities. However, the NMJ active zones are not always stable, as exemplified by the change in active zone density during acute experimental manipulation or as a result of aging. Therefore, a mechanism must exist to maintain its density. In the central nervous system (CNS), active zones have restricted maximal size, exist in multiple numbers in larger presynaptic terminals, and maintain a constant density during development. These findings suggest that active zone density in the CNS is also controlled. However, in contrast to the NMJ, active zone density in the CNS can also be increased, as observed in hippocampal synapses in response to synaptic plasticity. Although the numbers of known active zone proteins and protein interactions have increased, less is known about the mechanism that controls the number or spacing of active zones. The following molecules are known to control active zone density and will be discussed herein: extracellular matrix laminins and voltage-dependent calcium channels, amyloid precursor proteins, the small GTPase Rab3, an endocytosis mechanism including synaptojanin, cytoskeleton protein spectrins and β-adducin, and a presynaptic web including spectrins. The molecular mechanisms that organize the active zone density are just beginning to be elucidated.

  18. Presynaptic active zone density during development and synaptic plasticity.

    Directory of Open Access Journals (Sweden)

    Gwenaëlle L Clarke

    2012-02-01

    Full Text Available Neural circuits transmit information through synapses, and the efficiency of synaptic transmission is closely related to the density of presynaptic active zones, where synaptic vesicles are released. The goal of this review is to highlight recent insights into the molecular mechanisms that control the number of active zones per presynaptic terminal (active zone density during developmental and stimulus-dependent changes in synaptic efficacy. At the neuromuscular junctions (NMJs, the active zone density is preserved across species, remains constant during development, and is the same between synapses with different activities. However, the NMJ active zones are not always stable, as exemplified by the change in active zone density during acute experimental manipulation or as a result of aging. Therefore, a mechanism must exist to maintain its density. In the central nervous system (CNS, active zones have restricted maximal size, exist in multiple numbers in larger presynaptic terminals, and maintain a constant density during development. These findings suggest that active zone density in the CNS is also controlled. However, in contrast to the NMJ, active zone density in the CNS can also be increased, as observed in hippocampal synapses in response to synaptic plasticity. Although the numbers of known active zone proteins and protein interactions have increased, less is known about the mechanism that controls the number or spacing of active zones. The following molecules are known to control active zone density and will be discussed herein: extracellular matrix laminins and voltage-dependent calcium channels, amyloid precursor proteins, the small GTPase Rab3, an endocytosis mechanism including synaptojanin, cytoskeleton protein spectrins and β-adducin, and a presynaptic web including spectrins. The molecular mechanisms that organize the active zone density are just beginning to be elucidated.

  19. Genetic susceptibility and neurotransmitters in Tourette syndrome.

    Science.gov (United States)

    Paschou, Peristera; Fernandez, Thomas V; Sharp, Frank; Heiman, Gary A; Hoekstra, Pieter J

    2013-01-01

    Family studies have consistently shown that Tourette syndrome (TS) is a familial disorder and twin studies have clearly indicated a genetic contribution in the etiology of TS. Whereas early segregation studies of TS suggested a single-gene autosomal dominant disorder, later studies have pointed to more complex models including additive and multifactorial inheritance and likely interaction with genetic factors. While the exact cellular and molecular base of TS is as yet elusive, neuroanatomical and neurophysiological studies have pointed to the involvement of cortico-striato-thalamocortical circuits and abnormalities in dopamine, glutamate, gamma-aminobutyric acid, and serotonin neurotransmitter systems, with the most consistent evidence being available for involvement of dopamine-related abnormalities, that is, a reduction in tonic extracellular dopamine levels along with hyperresponsive spike-dependent dopamine release, following stimulation. Genetic and gene expression findings are very much supportive of involvement of these neurotransmitter systems. Moreover, intriguingly, genetic work on a two-generation pedigree has opened new research pointing to a role for histamine, a so far rather neglected neurotransmitter, with the potential of the development of new treatment options. Future studies should be aimed at directly linking neurotransmitter-related genetic and gene expression findings to imaging studies (imaging genetics), which enables a better understanding of the pathways and mechanisms through which the dynamic interplay of genes, brain, and environment shapes the TS phenotype. © 2013 Elsevier Inc. All rights reserved.

  20. Radioenzymatic analysis of neurotransmitters

    Energy Technology Data Exchange (ETDEWEB)

    Philips, S.R.

    1987-08-17

    Since the late 1960's, radioenzymatic assays have gradually come to replace the less sensitive and less specific spectrofluorometric and bioassay procedures previously used to determine many of the neurotransmitters. These assays provide the means to measure picogram quantities of most of these substances, and have enabled determinations to be made in very small volumes of body fluids, in brain perfusates and individual brain nuclei, and in large individual cells of some simple animals. This paper reviews briefly some of the radioenzymatic techniques presently available for assaying norepinephrine (NE), epinephrine (E), dopamine (DA), serotonin, and the trace amines octopamine (OA), phenylethanolamine (PEOHA), phenylethylamine (PEA), tyramine (TA) and tryptamine (T).

  1. Studies of two naturally occurring compounds which effect release of acetylcholine from synaptosomes

    International Nuclear Information System (INIS)

    Koenig, M.L.

    1985-01-01

    Two naturally occurring compounds which effect the release of neurotransmitter from synaptosomes have been purified to apparent homogeneity. Iotrochotin (IOT) isolated from wound exudate of the Caribbean purple bleeder sponge promotes release in a manner that is independent of the extracellular Ca 2+ ion concentration. Leptinotarsin (LPT-d), a protein taken from hemolymph of the Colorado potato beetle, Leptinotarsa decemlineata, stimulates Ca 2+ -dependent release. IOT is slightly acidic and has a molecular weight of approximately 18 kD. [ 3 H]acetylcholine which has been introduced into synaptosomes as [ 3 H]choline can be released by IOT. The toxin releasable pool of labelled neurotransmitter is not depleted by depolarization of the synaptosomes with high potassium, and therefore seems to be primarily extravesicular. LPT-d is a larger protein (molecular weight = 45 kD) than IOT, and seems to effect primarily vesicular release by opening at least one type of presynaptic Ca 2+ channel. The facilitatory effects of the toxin on synaptosomal release can be inhibited by inorganic Ca 2+ channel antagonists, but are not generally affected by organic antagonists

  2. Development of neurotransmitter systems during critical periods.

    Science.gov (United States)

    Herlenius, Eric; Lagercrantz, Hugo

    2004-11-01

    Neurotransmitters are released from neurons and mediate neuronal communication. Neuromodulators can also be released from other cells and influence the neuronal signaling. Both neurotransmitters and neuromodulators play an important role in the shaping and the wiring of the nervous system possibly during critical windows of the development. Monoamines are expressed in the very early embryo, at which stage the notochord already contains high noradrenaline levels. Purines and neuropeptides are probably also expressed at an early stage, in a similar way as they occur during early phylogenesis. The levels of most neurotransmitters and neuromodulators increase concomitantly with synapse formation. Some of them surge during the perinatal period (such as glutamate, catecholamines, and some neuropeptides) and then level off. The interesting question is to what extent the expression of neuroactive agents is related to the functional state of the fetus and the newborn. Monoamines are expressed in the very early embryo, at which stage the notochord already contains high noradrenaline levels. They may have an important role for neurotransmission in the fetus. In the adult mammal, the fast switching excitatory amino acids dominate. However, they also seem to be important for the wiring of the brain and the plasticity before birth. NMDA receptors that are supposed to mediate these effects dominate and are then substituted by AMPA receptors. The main inhibitory amino acids gamma-aminobutyric acid (GABA) and glycine are excitatory in the developing brain by depolarizing developing neurons that have high Cl- concentrations. This seems to be of major importance for the wiring of neuronal circuits. Prenatal or neonatal stress, for example, hypoxia, can affect the programming of neurotransmitter and receptor expression, which can lead to long-term behavioral effects.

  3. Vesicular and Plasma Membrane Transporters for Neurotransmitters

    Science.gov (United States)

    Blakely, Randy D.; Edwards, Robert H.

    2012-01-01

    The regulated exocytosis that mediates chemical signaling at synapses requires mechanisms to coordinate the immediate response to stimulation with the recycling needed to sustain release. Two general classes of transporter contribute to release, one located on synaptic vesicles that loads them with transmitter, and a second at the plasma membrane that both terminates signaling and serves to recycle transmitter for subsequent rounds of release. Originally identified as the target of psychoactive drugs, these transport systems have important roles in transmitter release, but we are only beginning to understand their contribution to synaptic transmission, plasticity, behavior, and disease. Recent work has started to provide a structural basis for their activity, to characterize their trafficking and potential for regulation. The results indicate that far from the passive target of psychoactive drugs, neurotransmitter transporters undergo regulation that contributes to synaptic plasticity. PMID:22199021

  4. Greater ethanol-induced locomotor activation in DBA/2J versus C57BL/6J mice is not predicted by presynaptic striatal dopamine dynamics.

    Directory of Open Access Journals (Sweden)

    Jamie H Rose

    Full Text Available A large body of research has aimed to determine the neurochemical factors driving differential sensitivity to ethanol between individuals in an attempt to find predictors of ethanol abuse vulnerability. Here we find that the locomotor activating effects of ethanol are markedly greater in DBA/2J compared to C57BL/6J mice, although it is unclear as to what neurochemical differences between strains mediate this behavior. Dopamine elevations in the nucleus accumbens and caudate-putamen regulate locomotor behavior for most drugs, including ethanol; thus, we aimed to determine if differences in these regions predict strain differences in ethanol-induced locomotor activity. Previous studies suggest that ethanol interacts with the dopamine transporter, potentially mediating its locomotor activating effects; however, we found that ethanol had no effects on dopamine uptake in either strain. Ex vivo voltammetry allows for the determination of ethanol effects on presynaptic dopamine terminals, independent of drug-induced changes in firing rates of afferent inputs from either dopamine neurons or other neurotransmitter systems. However, differences in striatal dopamine dynamics did not predict the locomotor-activating effects of ethanol, since the inhibitory effects of ethanol on dopamine release were similar between strains. There were differences in presynaptic dopamine function between strains, with faster dopamine clearance in the caudate-putamen of DBA/2J mice; however, it is unclear how this difference relates to locomotor behavior. Because of the role of the dopamine system in reinforcement and reward learning, differences in dopamine signaling between the strains could have implications for addiction-related behaviors that extend beyond ethanol effects in the striatum.

  5. Presynaptic calcium signalling in cerebellar mossy fibres

    DEFF Research Database (Denmark)

    Thomsen, Louiza Bohn; Jörntell, Henrik; Midtgaard, Jens

    2010-01-01

    affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could......Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX......)-sensitive fast Na(+) spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers...

  6. Role of perisynaptic parameters in neurotransmitter homeostasis - computational study of a general synapse

    Science.gov (United States)

    Pendyam, Sandeep; Mohan, Ashwin; Kalivas, Peter W.; Nair, Satish S.

    2015-01-01

    Extracellular neurotransmitter concentrations vary over a wide range depending on the type of neurotransmitter and location in the brain. Neurotransmitter homeostasis near a synapse is achieved by a balance of several mechanisms including vesicular release from the presynapse, diffusion, uptake by transporters, non-synaptic production, and regulation of release by autoreceptors. These mechanisms are also affected by the glia surrounding the synapse. However, the role of these mechanisms in achieving neurotransmitter homeostasis is not well understood. A biophysical modeling framework was proposed to reverse engineer glial configurations and parameters related to homeostasis for synapses that support a range of neurotransmitter gradients. Model experiments reveal that synapses with extracellular neurotransmitter concentrations in the micromolar range require non-synaptic neurotransmitter sources and tight synaptic isolation by extracellular glial formations. The model was used to identify the role of perisynaptic parameters on neurotransmitter homeostasis, and to propose glial configurations that could support different levels of extracellular neurotransmitter concentrations. Ranking the parameters based on their effect on neurotransmitter homeostasis, non-synaptic sources were found to be the most important followed by transporter concentration and diffusion coefficient. PMID:22460547

  7. Beta-amyloid peptides undergo regulated co-secretion with neuropeptide and catecholamine neurotransmitters.

    Science.gov (United States)

    Toneff, Thomas; Funkelstein, Lydiane; Mosier, Charles; Abagyan, Armen; Ziegler, Michael; Hook, Vivian

    2013-08-01

    Beta-amyloid (Aβ) peptides are secreted from neurons, resulting in extracellular accumulation of Aβ and neurodegeneration of Alzheimer's disease. Because neuronal secretion is fundamental for the release of neurotransmitters, this study assessed the hypothesis that Aβ undergoes co-release with neurotransmitters. Model neuronal-like chromaffin cells were investigated, and results illustrate regulated, co-secretion of Aβ(1-40) and Aβ(1-42) with peptide neurotransmitters (galanin, enkephalin, and NPY) and catecholamine neurotransmitters (dopamine, norepinephrine, and epinephrine). Regulated secretion from chromaffin cells was stimulated by KCl depolarization and nicotine. Forskolin, stimulating cAMP, also induced co-secretion of Aβ peptides with peptide and catecholamine neurotransmitters. These data suggested the co-localization of Aβ with neurotransmitters in dense core secretory vesicles (DCSV) that store and secrete such chemical messengers. Indeed, Aβ was demonstrated to be present in DCSV with neuropeptide and catecholamine transmitters. Furthermore, the DCSV organelle contains APP and its processing proteases, β- and γ-secretases, that are necessary for production of Aβ. Thus, Aβ can be generated in neurotransmitter-containing DCSV. Human IMR32 neuroblastoma cells also displayed regulated secretion of Aβ(1-40) and Aβ(1-42) with the galanin neurotransmitter. These findings illustrate that Aβ peptides are present in neurotransmitter-containing DCSV, and undergo co-secretion with neuropeptide and catecholamine neurotransmitters that regulate brain functions. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Exocytosis: using amperometry to study presynaptic mechanisms of neurotoxicity

    NARCIS (Netherlands)

    Westerink, R.H.S.

    2004-01-01

    The development of carbon fiber microelectrode amperometry enabled detailed investigation of the presynaptic response at the single cell level with single vesicle resolution. Consequently, amperometry allowed for detailed studies into the presynaptic mechanisms underlying neurotoxicity. This review

  9. Article Neurotransmitters – A biochemical view | Shalayel | Sudan ...

    African Journals Online (AJOL)

    The neurotransmission at most if not all synapses is chemical and is of great biochemical, physiological and pharmacological importance. Neurons communicate with each other at synapses by a process called synaptic transmission in which the release of small quantities of chemical messengers, called neurotransmitters ...

  10. Regarding the unitary theory of agonist and antagonist action at presynaptic adrenoceptors.

    Science.gov (United States)

    Kalsner, S; Abdali, S A

    2001-06-01

    1. The linkage between potentiation of field stimulation-induced noradrenaline release and blockade of the presynaptic inhibitory effect of exogenous noradrenaline by a presynaptic antagonist was examined in superfused rabbit aorta preparations. 2. Rauwolscine clearly potentiated the release of noradrenaline in response to 100 pulses at 2 Hz but reduced the capacity of noradrenaline to inhibit transmitter release to a questionable extent, and then only when comparisons were made with untreated, rather then to rauwolscine-treated, controls. 3. Aortic preparations exposed for 60 min to rauwolscine followed by superfusion with antagonist-free Krebs for 60 min retained the potentiation of stimulation-induced transmitter release but no antagonism of the noradrenaline-induced inhibition could be detected at either of two noradrenaline concentrations when comparisons were made with rauwolscine treated controls. 4. Comparisons of the inhibitory effect of exogenous noradrenaline (1.8 x 10-6 M) on transmitter efflux in the presence and absence of rauwolscine pretreatment revealed that the antagonist enhanced rather than antagonized the presynaptic inhibition by noradrenaline. 5 It is concluded that the unitary hypothesis that asserts that antagonist enhancement of transmitter release and its blockade of noradrenaline induced inhibition are manifestations of a unitary event are not supportable.

  11. THE PURINERGIC NEUROTRANSMITTER REVISITED: A SINGLE SUBSTANCE OR MULTIPLE PLAYERS?

    Science.gov (United States)

    Mutafova-Yambolieva, Violeta N.; Durnin, Leonie

    2014-01-01

    The past half century has witnessed tremendous advances in our understanding of extracellular purinergic signaling pathways. Purinergic neurotransmission, in particular, has emerged as a key contributor in the efficient control mechanisms in the nervous system. The identity of the purine neurotransmitter, however, remains controversial. Identifying it is difficult because purines are present in all cell types, have a large variety of cell sources, and are released via numerous pathways. Moreover, studies on purinergic neurotransmission have relied heavily on indirect measurements of integrated postjunctional responses that do not provide direct information for neurotransmitter identity. This paper discusses experimental support for adenosine 5′-triphosphate (ATP) as a neurotransmitter and recent evidence for possible contribution of other purines, in addition to or instead of ATP, in chemical neurotransmission in the peripheral, enteric and central nervous systems. Sites of release and action of purines in model systems such as vas deferens, blood vessels, urinary bladder and chromaffin cells are discussed. This is preceded by a brief discussion of studies demonstrating storage of purines in synaptic vesicles. We examine recent evidence for cell type targets (e.g., smooth muscle cells, interstitial cells, neurons and glia) for purine neurotransmitters in different systems. This is followed by brief discussion of mechanisms of terminating the action of purine neurotransmitters, including extracellular nucleotide hydrolysis and possible salvage and reuptake in the cell. The significance of direct neurotransmitter release measurements is highlighted. Possibilities for involvement of multiple purines (e.g., ATP, ADP, NAD+, ADP-ribose, adenosine, and diadenosine polyphosphates) in neurotransmission are considered throughout. PMID:24887688

  12. Thin film microelectrodes for electrochemical detection of neurotransmitters

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard

    An important signaling process in the nervous system is the release of chemical messengers called neurotransmitters from neurons. In this thesis alternative thin film electrode materials for applications targeting electrochemical detection of neurotransmitters in chip devices were evaluated....... For this application a very low current noise is needed together with a large temporal resolution. It was shown, that resistive and capacitive properties of thin film electrode materials are determining their usefulness in low-noise amperometric measurements. An analytical expression for the noise was derived...

  13. Presynaptic mechanisms of L-DOPA-induced dyskinesia: the findings, the debate, the therapeutic implications.

    Directory of Open Access Journals (Sweden)

    M Angela eCenci

    2014-12-01

    Full Text Available The dopamine precursor L-DOPA has been the most effective treatment for Parkinson´s disease (PD for over 40 years. However, the response to this treatment changes during the progression of PD, and most patients develop dyskinesias (abnormal involuntary movements and motor fluctuations within a few years of L-DOPA therapy. There is wide consensus that these motor complications depend on both pre- and post-synaptic disturbances of nigrostriatal dopamine transmission. Several presynaptic mechanisms converge to generate large dopamine swings in the brain concomitant with the peaks-and-troughs of plasma L-DOPA levels, while post-synaptic changes engender abnormal functional responses in dopaminoceptive neurons. While this general picture is well-accepted, the relative contribution of different factors remains a matter of debate. A particularly animated debate has been growing around putative players on the presynaptic side of the cascade. To what extent do presynaptic disturbances in dopamine transmission depend on deficiency/dysfunction of the dopamine transporter, aberrant release of dopamine from serotonin neurons, or gliovascular mechanisms? And does noradrenaline (which is synthetized from dopamine play a role? This review article will summarize key findings, controversies, and pending questions regarding the presynaptic mechanisms of L-DOPA-induced dyskinesia. Intriguingly, the debate around these mechanisms has spurred research into previously unexplored facets of brain plasticity that have far-reaching implications to the treatment of neuropsychiatric disease.

  14. Presynaptic Glycine Receptors Increase GABAergic Neurotransmission in Rat Periaqueductal Gray Neurons

    Directory of Open Access Journals (Sweden)

    Kwi-Hyung Choi

    2013-01-01

    Full Text Available The periaqueductal gray (PAG is involved in the central regulation of nociceptive transmission by affecting the descending inhibitory pathway. In the present study, we have addressed the functional role of presynaptic glycine receptors in spontaneous glutamatergic transmission. Spontaneous EPSCs (sEPSCs were recorded in mechanically dissociated rat PAG neurons using a conventional whole-cell patch recording technique under voltage-clamp conditions. The application of glycine (100 µM significantly increased the frequency of sEPSCs, without affecting the amplitude of sEPSCs. The glycine-induced increase in sEPSC frequency was blocked by 1 µM strychnine, a specific glycine receptor antagonist. The results suggest that glycine acts on presynaptic glycine receptors to increase the probability of glutamate release from excitatory nerve terminals. The glycine-induced increase in sEPSC frequency completely disappeared either in the presence of tetrodotoxin or Cd2+, voltage-gated Na+, or Ca2+ channel blockers, suggesting that the activation of presynaptic glycine receptors might depolarize excitatory nerve terminals. The present results suggest that presynaptic glycine receptors can regulate the excitability of PAG neurons by enhancing glutamatergic transmission and therefore play an important role in the regulation of various physiological functions mediated by the PAG.

  15. LeuT-Desipramine Structure Reveals How Antidepressants Block Neurotransmitter Reuptake

    Energy Technology Data Exchange (ETDEWEB)

    Zhou,Z.; Zhen, J.; Karpowich, N.; Goetz, R.; Law, C.; Reith, M.; Wang, D.

    2007-01-01

    Tricyclic antidepressants exert their pharmacological effect -- inhibiting the reuptake of serotonin, norepinephrine, and dopamine -- by directly blocking neurotransmitter transporters (SERT, NET, and DAT, respectively) in the presynaptic membrane. The drug-binding site and the mechanism of this inhibition are poorly understood. We determined the crystal structure at 2.9 angstroms of the bacterial leucine transporter (LeuT), a homolog of SERT, NET, and DAT, in complex with leucine and the antidepressant desipramine. Desipramine binds at the inner end of the extracellular cavity of the transporter and is held in place by a hairpin loop and by a salt bridge. This binding site is separated from the leucine-binding site by the extracellular gate of the transporter. By directly locking the gate, desipramine prevents conformational changes and blocks substrate transport. Mutagenesis experiments on human SERT and DAT indicate that both the desipramine-binding site and its inhibition mechanism are probably conserved in the human neurotransmitter transporters.

  16. APP and APLP2 interact with the synaptic release machinery and facilitate transmitter release at hippocampal synapses

    Science.gov (United States)

    Fanutza, Tomas; Del Prete, Dolores; Ford, Michael J; Castillo, Pablo E; D’Adamio, Luciano

    2015-01-01

    The amyloid precursor protein (APP), whose mutations cause familial Alzheimer’s disease, interacts with the synaptic release machinery, suggesting a role in neurotransmission. Here we mapped this interaction to the NH2-terminal region of the APP intracellular domain. A peptide encompassing this binding domain -named JCasp- is naturally produced by a γ-secretase/caspase double-cut of APP. JCasp interferes with the APP-presynaptic proteins interaction and, if linked to a cell-penetrating peptide, reduces glutamate release in acute hippocampal slices from wild-type but not APP deficient mice, indicating that JCasp inhibits APP function.The APP-like protein-2 (APLP2) also binds the synaptic release machinery. Deletion of APP and APLP2 produces synaptic deficits similar to those caused by JCasp. Our data support the notion that APP and APLP2 facilitate transmitter release, likely through the interaction with the neurotransmitter release machinery. Given the link of APP to Alzheimer’s disease, alterations of this synaptic role of APP could contribute to dementia. DOI: http://dx.doi.org/10.7554/eLife.09743.001 PMID:26551565

  17. Acute desensitization of presynaptic GABA(B)-mediated inhibition and induction of epileptiform discharges in the neonatal rat hippocampus

    NARCIS (Netherlands)

    Tosetti, P; Bakels, R; Colin-Le Brun, [No Value; Ferrand, N; Gaiarsa, JL; Caillard, O

    The consequences of sustained activation of GABA(B) receptors on GABA(B)-mediated inhibition and network activity were investigated in the neonatal rat hippocampus using whole-cell and extracellular field recordings. GABA(B)-mediated presynaptic control of gamma-aminobutyric acid (GABA) release

  18. Presynaptic inhibition of synaptic transmission in the rat hippocampus by activation of muscarinic receptors: involvement of presynaptic calcium influx

    OpenAIRE

    Qian, Jing; Saggau, Peter

    1997-01-01

    Modulation of presynaptic voltage-dependent calcium channels (VDCCs) by muscarinic receptors at the CA3–CA1 synapse of rat hippocampal slices was investigated by using the calcium indicator fura-2. Stimulation-evoked presynaptic calcium transients ([Capre]t) and field excitatory postsynaptic potentials (fe.p.s.ps) were simultaneously recorded. The relationship between presynaptic calcium influx and synaptic transmission was studied.Activation of muscarinic receptors inhibited [Capre]t, thereb...

  19. Presynaptic GABAB Receptors Regulate Hippocampal Synapses during Associative Learning in Behaving Mice.

    Directory of Open Access Journals (Sweden)

    M Teresa Jurado-Parras

    Full Text Available GABAB receptors are the G-protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the central nervous system. Pharmacological activation of GABAB receptors regulates neurotransmission and neuronal excitability at pre- and postsynaptic sites. Electrophysiological activation of GABAB receptors in brain slices generally requires strong stimulus intensities. This raises the question as to whether behavioral stimuli are strong enough to activate GABAB receptors. Here we show that GABAB1a-/- mice, which constitutively lack presynaptic GABAB receptors at glutamatergic synapses, are impaired in their ability to acquire an operant learning task. In vivo recordings during the operant conditioning reveal a deficit in learning-dependent increases in synaptic strength at CA3-CA1 synapses. Moreover, GABAB1a-/- mice fail to synchronize neuronal activity in the CA1 area during the acquisition process. Our results support that activation of presynaptic hippocampal GABAB receptors is important for acquisition of a learning task and for learning-associated synaptic changes and network dynamics.

  20. Tetrahydrobiopterin regulates monoamine neurotransmitter sulfonation.

    Science.gov (United States)

    Cook, Ian; Wang, Ting; Leyh, Thomas S

    2017-07-03

    Monoamine neurotransmitters are among the hundreds of signaling small molecules whose target interactions are switched "on" and "off" via transfer of the sulfuryl-moiety (-SO 3 ) from PAPS (3'-phosphoadenosine 5'-phosphosulfate) to the hydroxyls and amines of their scaffolds. These transfer reactions are catalyzed by a small family of broad-specificity enzymes-the human cytosolic sulfotransferases (SULTs). The first structure of a SULT allosteric-binding site (that of SULT1A1) has recently come to light. The site is conserved among SULT1 family members and is promiscuous-it binds catechins, a naturally occurring family of flavanols. Here, the catechin-binding site of SULT1A3, which sulfonates monoamine neurotransmitters, is modeled on that of 1A1 and used to screen in silico for endogenous metabolite 1A3 allosteres. Screening predicted a single high-affinity allostere, tetrahydrobiopterin (THB), an essential cofactor in monoamine neurotransmitter biosynthesis. THB is shown to bind and inhibit SULT1A3 with high affinity, 23 (±2) nM, and to bind weakly, if at all, to the four other major SULTs found in brain and liver. The structure of the THB-bound binding site is determined and confirms that THB binds the catechin site. A structural comparison of SULT1A3 with SULT1A1 (its immediate evolutionary progenitor) reveals how SULT1A3 acquired high affinity for THB and that the majority of residue changes needed to transform 1A1 into 1A3 are clustered at the allosteric and active sites. Finally, sequence records reveal that the coevolution of these sites played an essential role in the evolution of simian neurotransmitter metabolism.

  1. Localization of Presynaptic Plasticity Mechanisms Enables Functional Independence of Synaptic and Ectopic Transmission in the Cerebellum

    Directory of Open Access Journals (Sweden)

    Katharine L. Dobson

    2015-01-01

    Full Text Available In the cerebellar molecular layer parallel fibre terminals release glutamate from both the active zone and from extrasynaptic “ectopic” sites. Ectopic release mediates transmission to the Bergmann glia that ensheathe the synapse, activating Ca2+-permeable AMPA receptors and glutamate transporters. Parallel fibre terminals exhibit several forms of presynaptic plasticity, including cAMP-dependent long-term potentiation and endocannabinoid-dependent long-term depression, but it is not known whether these presynaptic forms of long-term plasticity also influence ectopic transmission to Bergmann glia. Stimulation of parallel fibre inputs at 16 Hz evoked LTP of synaptic transmission, but LTD of ectopic transmission. Pharmacological activation of adenylyl cyclase by forskolin caused LTP at Purkinje neurons, but only transient potentiation at Bergmann glia, reinforcing the concept that ectopic sites lack the capacity to express sustained cAMP-dependent potentiation. Activation of mGluR1 caused depression of synaptic transmission via retrograde endocannabinoid signalling but had no significant effect at ectopic sites. In contrast, activation of NMDA receptors suppressed both synaptic and ectopic transmission. The results suggest that the signalling mechanisms for presynaptic LTP and retrograde depression by endocannabinoids are restricted to the active zone at parallel fibre synapses, allowing independent modulation of synaptic transmission to Purkinje neurons and ectopic transmission to Bergmann glia.

  2. Evidence against the unitary hypothesis of agonist and antagonist action at presynaptic adrenoceptors.

    Science.gov (United States)

    Kalsner, S.

    1982-01-01

    1 The concept that presynaptic receptors regulate noradrenergic transmitter release via a system of inhibitory receptors mediating negative feedback relies on a supposed association between increases in stimulation-induced efflux of [3H]-noradrenaline by antagonists and blockade by them of the inhibitory effects of exogenous noradrenaline. 2 It was shown in guinea-pig ureter, that yohimbine (3 X 10(-7)M), a presumed selective presynaptic antagonist, increased transmitter efflux substantially at 1 Hz and 5 Hz with 100 pulses, purportedly representing antagonism of the inhibitory effect of locally released noradrenaline but did not reduce the inhibitory effect of exogenous noradrenaline (1.8 X 10(-6)M or 1.8 X 10(-7)M) except in one case. 3 Additionally, the inhibitory effect of oxymetazoline (1.0 X 10(-7)M or 1.0 X 10(-8)M) on stimulation-induced efflux was in no way antagonized by yohimbine (3 X 10(-7)M). 4 It is concluded that the increased efflux of [3H]-noradrenaline produced by antagonists and the decreased efflux produced by exogenous agonists may represent actions at different loci and that the hypothesis of presynaptic feedback regulatory sites is still not substantiated. PMID:6128040

  3. Optogenetic probing and manipulation of the calyx-type presynaptic terminal in the embryonic chick ciliary ganglion.

    Science.gov (United States)

    Egawa, Ryo; Hososhima, Shoko; Hou, Xubin; Katow, Hidetaka; Ishizuka, Toru; Nakamura, Harukazu; Yawo, Hiromu

    2013-01-01

    The calyx-type synapse of chick ciliary ganglion (CG) has been intensively studied for decades as a model system for the synaptic development, morphology and physiology. Despite recent advances in optogenetics probing and/or manipulation of the elementary steps of the transmitter release such as membrane depolarization and Ca(2+) elevation, the current gene-manipulating methods are not suitable for targeting specifically the calyx-type presynaptic terminals. Here, we evaluated a method for manipulating the molecular and functional organization of the presynaptic terminals of this model synapse. We transfected progenitors of the Edinger-Westphal (EW) nucleus neurons with an EGFP expression vector by in ovo electroporation at embryonic day 2 (E2) and examined the CG at E8-14. We found that dozens of the calyx-type presynaptic terminals and axons were selectively labeled with EGFP fluorescence. When a Brainbow construct containing the membrane-tethered fluorescent proteins m-CFP, m-YFP and m-RFP, was introduced together with a Cre expression construct, the color coding of each presynaptic axon facilitated discrimination among inter-tangled projections, particularly during the developmental re-organization period of synaptic connections. With the simultaneous expression of one of the chimeric variants of channelrhodopsins, channelrhodopsin-fast receiver (ChRFR), and R-GECO1, a red-shifted fluorescent Ca(2+)-sensor, the Ca(2+) elevation was optically measured under direct photostimulation of the presynaptic terminal. Although this optically evoked Ca(2+) elevation was mostly dependent on the action potential, a significant component remained even in the absence of extracellular Ca(2+). It is suggested that the photo-activation of ChRFR facilitated the release of Ca(2+) from intracellular Ca(2+) stores directly or indirectly. The above system, by facilitating the molecular study of the calyx-type presynaptic terminal, would provide an experimental platform for unveiling

  4. Optogenetic probing and manipulation of the calyx-type presynaptic terminal in the embryonic chick ciliary ganglion.

    Directory of Open Access Journals (Sweden)

    Ryo Egawa

    Full Text Available The calyx-type synapse of chick ciliary ganglion (CG has been intensively studied for decades as a model system for the synaptic development, morphology and physiology. Despite recent advances in optogenetics probing and/or manipulation of the elementary steps of the transmitter release such as membrane depolarization and Ca(2+ elevation, the current gene-manipulating methods are not suitable for targeting specifically the calyx-type presynaptic terminals. Here, we evaluated a method for manipulating the molecular and functional organization of the presynaptic terminals of this model synapse. We transfected progenitors of the Edinger-Westphal (EW nucleus neurons with an EGFP expression vector by in ovo electroporation at embryonic day 2 (E2 and examined the CG at E8-14. We found that dozens of the calyx-type presynaptic terminals and axons were selectively labeled with EGFP fluorescence. When a Brainbow construct containing the membrane-tethered fluorescent proteins m-CFP, m-YFP and m-RFP, was introduced together with a Cre expression construct, the color coding of each presynaptic axon facilitated discrimination among inter-tangled projections, particularly during the developmental re-organization period of synaptic connections. With the simultaneous expression of one of the chimeric variants of channelrhodopsins, channelrhodopsin-fast receiver (ChRFR, and R-GECO1, a red-shifted fluorescent Ca(2+-sensor, the Ca(2+ elevation was optically measured under direct photostimulation of the presynaptic terminal. Although this optically evoked Ca(2+ elevation was mostly dependent on the action potential, a significant component remained even in the absence of extracellular Ca(2+. It is suggested that the photo-activation of ChRFR facilitated the release of Ca(2+ from intracellular Ca(2+ stores directly or indirectly. The above system, by facilitating the molecular study of the calyx-type presynaptic terminal, would provide an experimental platform for

  5. Macrocyclic Gd(3+) complexes with pendant crown ethers designed for binding zwitterionic neurotransmitters.

    Science.gov (United States)

    Oukhatar, Fatima; Meudal, Hervé; Landon, Céline; Logothetis, Nikos K; Platas-Iglesias, Carlos; Angelovski, Goran; Tóth, Éva

    2015-07-27

    A series of Gd(3+) complexes exhibiting a relaxometric response to zwitterionic amino acid neurotransmitters was synthesized. The design concept involves ditopic interactions 1) between a positively charged and coordinatively unsaturated Gd(3+) chelate and the carboxylate group of the neurotransmitters and 2) between an azacrown ether appended to the chelate and the amino group of the neurotransmitters. The chelates differ in the nature and length of the linker connecting the cyclen-type macrocycle that binds the Ln(3+) ion and the crown ether. The complexes are monohydrated, but they exhibit high proton relaxivities (up to 7.7 mM(-1)  s(-1) at 60 MHz, 310 K) due to slow molecular tumbling. The formation of ternary complexes with neurotransmitters was monitored by (1) H relaxometric titrations of the Gd(3+) complexes and by luminescence measurements on the Eu(3+) and Tb(3+) analogues at pH 7.4. The remarkable relaxivity decrease (≈80 %) observed on neurotransmitter binding is related to the decrease in the hydration number, as evidenced by luminescence lifetime measurements on the Eu(3+) complexes. These complexes show affinity for amino acid neurotransmitters in the millimolar range, which can be suited to imaging concentrations of synaptically released neurotransmitters. They display good selectivity over non-amino acid neurotransmitters (acetylcholine, serotonin, and noradrenaline) and hydrogenphosphate, but selectivity over hydrogencarbonate was not achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A neurotransmitter transporter encoded by the Drosophila inebriated gene

    Science.gov (United States)

    Soehnge, Holly; Huang, Xi; Becker, Marie; Whitley, Penn; Conover, Diana; Stern, Michael

    1996-01-01

    Behavioral and electrophysiological studies on mutants defective in the Drosophila inebriated (ine) gene demonstrated increased excitability of the motor neuron. In this paper, we describe the cloning and sequence analysis of ine. Mutations in ine were localized on cloned DNA by restriction mapping and restriction fragment length polymorphism (RFLP) mapping of ine mutants. DNA from the ine region was then used to isolate an ine cDNA. In situ hybridization of ine transcripts to developing embryos revealed expression of this gene in several cell types, including the posterior hindgut, Malpighian tubules, anal plate, garland cells, and a subset of cells in the central nervous system. The ine cDNA contains an open reading frame of 658 amino acids with a high degree of sequence similarity to members of the Na+/Cl−-dependent neurotransmitter transporter family. Members of this family catalyze the rapid reuptake of neurotransmitters released into the synapse and thereby play key roles in controlling neuronal function. We conclude that ine mutations cause increased excitability of the Drosophila motor neuron by causing the defective reuptake of the substrate neurotransmitter of the ine transporter and thus overstimulation of the motor neuron by this neurotransmitter. From this observation comes a unique opportunity to perform a genetic dissection of the regulation of excitability of the Drosophila motor neuron. PMID:8917579

  7. [Brain repair after ischemic stroke: role of neurotransmitters in post-ischemic neurogenesis].

    Science.gov (United States)

    Sánchez-Mendoza, Eduardo; Bellver-Landete, Víctor; González, María Pilar; Merino, José Joaquín; Martínez-Murillo, Ricardo; Oset-Gasque, María Jesús

    2012-11-01

    Brain ischemia and reperfusion produce alterations in the microenvironment of the parenchyma, including ATP depletion, ionic homeostasis alterations, inflammation, release of multiple cytokines and abnormal release of neurotransmitters. As a consequence, the induction of proliferation and migration of neural stem cells towards the peri-infarct region occurs. The success of new neurorestorative treatments for damaged brain implies the need to know, with greater accuracy, the mechanisms in charge of regulating adult neurogenesis, both under physiological and pathological conditions. Recent evidence demonstrates that many neurotransmitters, glutamate in particular, control the subventricular zone, thus being part of the complex signalling network that influences the production of new neurons. Neurotransmitters provide a link between brain activity and subventricular zone neurogenesis. Therefore, a deeper knowledge of the role of neurotransmitters systems, such as glutamate and its transporters, in adult neurogenesis, may provide a valuable tool to be used as a neurorestorative therapy in this pathology.

  8. Hypoxia. 3. Hypoxia and neurotransmitter synthesis

    OpenAIRE

    Kumar, Ganesh K.

    2011-01-01

    Central and peripheral neurons as well as neuroendocrine cells express a variety of neurotransmitters/modulators that play critical roles in regulation of physiological systems. The synthesis of several neurotransmitters/modulators is regulated by O2-requiring rate-limiting enzymes. Consequently, hypoxia resulting from perturbations in O2 homeostasis can affect neuronal functions by altering neurotransmitter synthesis. Two broad categories of hypoxia are frequently encountered: continuous hyp...

  9. Clinical Use of CSF Neurotransmitters.

    Science.gov (United States)

    Rodan, Lance H; Gibson, K Michael; Pearl, Phillip L

    2015-10-01

    Cerebrospinal fluid neurotransmitter collection, analysis, and follow-up are integral to the diagnosis and management of multiple inborn metabolic errors, some of which require prompt identification and intervention to improve outcome. Cerebrospinal fluid pterins and monoamine metabolites are diagnostic in a range of primary neurotransmitter disorders, including disorders of biogenic amine synthesis, metabolism, and transport. Recently described mutations of the human dopamine transporter are associated with an elevated cerebrospinal fluid homovanillic acid:hydroxyindoleacetic acid ratio. Disorders of pyridoxine metabolism are also detectable via cerebrospinal fluid quantification of bioamines, amino acids, and pyridoxal-5-phosphate levels. Cerebrospinal fluid amino acids are diagnostic in disorders of gamma aminobutyric acid, glycine, and serine metabolism. A wide range of acquired and genetic disorders has also been associated with secondary alterations in cerebrospinal fluid levels of monoamine metabolites, glycine, and neopterin. Lumbar puncture is required to detect abnormal cerebrospinal fluid metabolites in a significant proportion of these disorders, including treatable entities such as dopa-responsive deficiencies of guanosine-5'-triphosphate cyclohydrolase I (Segawa disease), sepiapterin reductase, and tyrosine hydroxylase. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Sharp Ca²⁺ nanodomains beneath the ribbon promote highly synchronous multivesicular release at hair cell synapses.

    Science.gov (United States)

    Graydon, Cole W; Cho, Soyoun; Li, Geng-Lin; Kachar, Bechara; von Gersdorff, Henrique

    2011-11-16

    Hair cell ribbon synapses exhibit several distinguishing features. Structurally, a dense body, or ribbon, is anchored to the presynaptic membrane and tethers synaptic vesicles; functionally, neurotransmitter release is dominated by large EPSC events produced by seemingly synchronous multivesicular release. However, the specific role of the synaptic ribbon in promoting this form of release remains elusive. Using complete ultrastructural reconstructions and capacitance measurements of bullfrog amphibian papilla hair cells dialyzed with high concentrations of a slow Ca²⁺ buffer (10 mM EGTA), we found that the number of synaptic vesicles at the base of the ribbon correlated closely to those vesicles that released most rapidly and efficiently, while the rest of the ribbon-tethered vesicles correlated to a second, slower pool of vesicles. Combined with the persistence of multivesicular release in extreme Ca²⁺ buffering conditions (10 mM BAPTA), our data argue against the Ca²⁺-dependent compound fusion of ribbon-tethered vesicles at hair cell synapses. Moreover, during hair cell depolarization, our results suggest that elevated Ca²⁺ levels enhance vesicle pool replenishment rates. Finally, using Ca²⁺ diffusion simulations, we propose that the ribbon and its vesicles define a small cytoplasmic volume where Ca²⁺ buffer is saturated, despite 10 mM BAPTA conditions. This local buffer saturation permits fast and large Ca²⁺ rises near release sites beneath the synaptic ribbon that can trigger multiquantal EPSCs. We conclude that, by restricting the available presynaptic volume, the ribbon may be creating conditions for the synchronous release of a small cohort of docked vesicles.

  11. A presynaptic role for PKA in synaptic tagging and memory

    NARCIS (Netherlands)

    Park, Alan Jung; Havekes, Robbert; Choi, Jennifer H K; Luczak, Vincent; Nie, Ting; Huang, Ted; Abel, Ted

    2014-01-01

    Protein kinase A (PKA) and other signaling molecules are spatially restricted within neurons by A-kinase anchoring proteins (AKAPs). Although studies on compartmentalized PKA signaling have focused on postsynaptic mechanisms, presynaptically anchored PKA may contribute to synaptic plasticity and

  12. Signal regulatory proteins (SIRPS) are secreted presynaptic organizing molecules.

    Science.gov (United States)

    Umemori, Hisashi; Sanes, Joshua R

    2008-12-05

    Formation of chemical synapses requires exchange of organizing signals between the synaptic partners. Using synaptic vesicle aggregation in cultured neurons as a marker of presynaptic differentiation, we purified candidate presynaptic organizers from mouse brain. A major bioactive species was the extracellular domain of signal regulatory protein alpha (SIRP-alpha), a transmembrane immunoglobulin superfamily member concentrated at synapses. The extracellular domain of SIRP-alpha is cleaved and shed in a developmentally regulated manner. The presynaptic organizing activity of SIRP-alpha is mediated in part by CD47. SIRP-alpha homologues, SIRP-beta and -gamma also have synaptic vesicle clustering activity. The effects of SIRP-alpha are distinct from those of another presynaptic organizer, FGF22: the two proteins induced vesicle clusters of different sizes, differed in their ability to promote neurite branching, and acted through different receptors and signaling pathways. SIRP family proteins may act together with other organizing molecules to pattern synapses.

  13. What is new for monoamine neurotransmitter disorders?

    Science.gov (United States)

    Marecos, Clara; Ng, Joanne; Kurian, Manju A

    2014-07-01

    The monoamine neurotransmitter disorders are increasingly recognized as an expanding group of inherited neurometabolic syndromes caused by disturbances in the synthesis, transport and metabolism of the biogenic amines, including the catecholamines (dopamine, norepinephrine, and epinephrine) and serotonin. Disturbances in monoamine metabolism lead to neurological syndromes that frequently mimic other conditions, such as hypoxic ischemic encephalopathy, cerebral palsy, parkinsonism-dystonia syndromes, primary genetic dystonia and paroxysmal disorders. As a consequence, neurotransmitter disorders are frequently misdiagnosed. Early and accurate diagnosis of these neurotransmitter disorders is important, as many are highly amenable to, and some even cured by, therapeutic intervention. In this review, we highlight recent advances in the field, particularly the recent extensive characterization of known neurotransmitter disorders and identification of novel neurotransmitter disorders. We also provide an overview of current and future research in the field focused on developing novel treatment strategies.

  14. Therapeutics of Neurotransmitters in Alzheimer's Disease.

    Science.gov (United States)

    Kandimalla, Ramesh; Reddy, P Hemachandra

    2017-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease, characterized by the loss of memory, multiple cognitive impairments and changes in the personality and behavior. Several decades of intense research have revealed that multiple cellular changes are involved in disease process, including synaptic damage, mitochondrial abnormalities and inflammatory responses, in addition to formation and accumulation of amyloid-β (Aβ) and phosphorylated tau. Although tremendous progress has been made in understanding the impact of neurotransmitters in the progression and pathogenesis of AD, we still do not have a drug molecule associated with neurotransmitter(s) that can delay disease process in elderly individuals and/or restore cognitive functions in AD patients. The purpose of our article is to assess the latest developments in neurotransmitters research using cell and mouse models of AD. We also updated the current status of clinical trials using neurotransmitters' agonists/antagonists in AD.

  15. Hypoxia. 3. Hypoxia and neurotransmitter synthesis.

    Science.gov (United States)

    Kumar, Ganesh K

    2011-04-01

    Central and peripheral neurons as well as neuroendocrine cells express a variety of neurotransmitters/modulators that play critical roles in regulation of physiological systems. The synthesis of several neurotransmitters/modulators is regulated by O(2)-requiring rate-limiting enzymes. Consequently, hypoxia resulting from perturbations in O(2) homeostasis can affect neuronal functions by altering neurotransmitter synthesis. Two broad categories of hypoxia are frequently encountered: continuous hypoxia (CH) and intermittent hypoxia (IH). CH is often seen during high altitude sojourns, whereas IH is experienced in sleep-disordered breathing with recurrent apneas (i.e., brief, repetitive cessations of breathing). This article presents what is currently known on the effects of both forms of hypoxia on neurotransmitter levels and neurotransmitter synthesizing enzymes in the central and peripheral nervous systems.

  16. The structure and function of presynaptic endosomes

    Energy Technology Data Exchange (ETDEWEB)

    Jähne, Sebastian, E-mail: sebastian.jaehne1@stud.uni-goettingen.de [Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen (Germany); International Max Planck Research School for Neurosciences, 37077 Göttingen (Germany); Rizzoli, Silvio O. [Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen (Germany); Helm, Martin S., E-mail: martin.helm@med.uni-goettingen.de [Department of Neuro- and Sensory Physiology, University of Göttingen Medical Center, Cluster of Excellence Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen (Germany); International Max Planck Research School for Molecular Biology, 37077 Göttingen (Germany)

    2015-07-15

    The function of endosomes and of endosome-like structures in the presynaptic compartment is still controversial. This is in part due to the absence of a consensus on definitions and markers for these compartments. Synaptic endosomes are sometimes seen as stable organelles, permanently present in the synapse. Alternatively, they are seen as short-lived intermediates in synaptic vesicle recycling, arising from the endocytosis of large vesicles from the plasma membrane, or from homotypic fusion of small vesicles. In addition, the potential function of the endosome is largely unknown in the synapse. Some groups have proposed that the endosome is involved in the sorting of synaptic vesicle proteins, albeit others have produced data that deny this possibility. In this review, we present the existing evidence for synaptic endosomes, we discuss their potential functions, and we highlight frequent technical pitfalls in the analysis of this elusive compartment. We also sketch a roadmap to definitely determine the role of synaptic endosomes for the synaptic vesicle cycle. Finally, we propose a common definition of synaptic endosome-like structures.

  17. Neurotransmitters activate T-cells and elicit crucial functions via neurotransmitter receptors.

    Science.gov (United States)

    Levite, Mia

    2008-08-01

    Neurotransmitters are traditionally viewed as nerve-secreted molecules that trigger or inhibit neuronal functions. Yet, neurotransmitters bind also their neurotransmitter receptors in T-cells and directly activate or suppress T-cell functions. This review focuses only on the activating effects of neurotransmitters on T-cells, primarily naïve/resting cells, and covers dopamine, glutamate, serotonin, and few neuropeptides: GnRH-I, GnRH-II, substance P, somatostatin, CGRP, and neuropeptide Y. T-cells express many neurotransmitter receptors. These are regulated by TCR-activation, cytokines, or the neurotransmitters themselves, and are upregulated/downregulated in some human diseases. The context - whether the T-cells are naïve/resting or antigen/mitogen/cytokine-activated, the T-cell subset (CD4/CD8/Th1/Th2/Teff/Treg), neurotransmitter dose (low/optimal or high/excess), exact neurotransmitter receptors expressed, and the cytokine milieu - is crucial, and can determine either activation or suppression of T-cells by the same neurotransmitter. T-cells also produce many neurotransmitters. In summary, neurotransmitters activate vital T-cell functions in a direct, potent and specific manner, and may serve for communicating between the brain and the immune system to elicit an effective and orchestrated immune function, and for new therapeutic avenues, to improve T-cell eradication of cancer and infectious organisms.

  18. Deformation of attractor landscape via cholinergic presynaptic modulations: a computational study using a phase neuron model.

    Directory of Open Access Journals (Sweden)

    Takashi Kanamaru

    Full Text Available Corticopetal acetylcholine (ACh is released transiently from the nucleus basalis of Meynert (NBM into the cortical layers and is associated with top-down attention. Recent experimental data suggest that this release of ACh disinhibits layer 2/3 pyramidal neurons (PYRs via muscarinic presynaptic effects on inhibitory synapses. Together with other possible presynaptic cholinergic effects on excitatory synapses, this may result in dynamic and temporal modifications of synapses associated with top-down attention. However, the system-level consequences and cognitive relevance of such disinhibitions are poorly understood. Herein, we propose a theoretical possibility that such transient modifications of connectivity associated with ACh release, in addition to top-down glutamatergic input, may provide a neural mechanism for the temporal reactivation of attractors as neural correlates of memories. With baseline levels of ACh, the brain returns to quasi-attractor states, exhibiting transitive dynamics between several intrinsic internal states. This suggests that top-down attention may cause the attention-induced deformations between two types of attractor landscapes: the quasi-attractor landscape (Q-landscape, present under low-ACh, non-attentional conditions and the attractor landscape (A-landscape, present under high-ACh, top-down attentional conditions. We present a conceptual computational model based on experimental knowledge of the structure of PYRs and interneurons (INs in cortical layers 1 and 2/3 and discuss the possible physiological implications of our results.

  19. SLC6 Neurotransmitter Transporters: Structure, Function, and Regulation

    DEFF Research Database (Denmark)

    Kristensen, Anders S; Andersen, Jacob; Jørgensen, Trine N

    2011-01-01

    of released neurotransmitters from the extracellular space into neurons and glial cells. The transporters are targets for a wide range of therapeutic drugs used in treatment of psychiatric diseases, including major depression, anxiety disorders, attention deficit hyperactivity disorder and epilepsy....... Furthermore, psychostimulants such as cocaine and amphetamines have the SLC6 NTTs as primary targets. Beginning with the determination of a high-resolution structure of a prokaryotic homolog of the mammalian SLC6 transporters in 2005, the understanding of the molecular structure, function, and pharmacology...

  20. Neurobeachin regulates neurotransmitter receptor trafficking to synapses

    NARCIS (Netherlands)

    Nair, R.; Lauks, J.; Jung, S; Cooke, N.E.; de Wit, H.; Brose, N.; Kilimann, M.W.; Verhage, M.; Rhee, J.

    2013-01-01

    The surface density of neurotransmitter receptors at synapses is a key determinant of synaptic efficacy. Synaptic receptor accumulation is regulated by the transport, postsynaptic anchoring, and turnover of receptors, involving multiple trafficking, sorting, motor, and scaffold proteins. We found

  1. Measuring endogenous 5-HT release by emission tomography: promises and pitfalls

    DEFF Research Database (Denmark)

    Paterson, Louise M; Tyacke, Robin J; Nutt, David J

    2010-01-01

    Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron ...

  2. Quantal analysis reveals a functional correlation between presynaptic and postsynaptic efficacy in excitatory connections from rat neocortex.

    Science.gov (United States)

    Hardingham, Neil R; Read, Jenny C A; Trevelyan, Andrew J; Nelson, J Charmaine; Jack, J Julian B; Bannister, Neil J

    2010-01-27

    At many central synapses, the presynaptic bouton and postsynaptic density are structurally correlated. However, it is unknown whether this correlation extends to the functional properties of the synapses. To investigate this, we made recordings from synaptically coupled pairs of pyramidal neurons in rat visual cortex. The mean peak amplitude of EPSPs recorded from pairs of L2/3 neurons ranged between 40 microV and 2.9 mV. EPSP rise times were consistent with the majority of the synapses being located on basal dendrites; this was confirmed by full anatomical reconstructions of a subset of connected pairs. Over a third of the connections could be described using a quantal model that assumed simple binomial statistics. Release probability (P(r)) and quantal size (Q), as measured at the somatic recording site, showed considerable heterogeneity between connections. However, across the population of connections, values of P(r) and Q for individual connections were positively correlated with one another. This correlation also held for inputs to layer 5 pyramidal neurons from both layer 2/3 and neighboring layer 5 pyramidal neurons, suggesting that during development of cortical connections presynaptic and postsynaptic strengths are dependently scaled. For 2/3 to 2/3 connections, mean EPSP amplitude was correlated with both Q and P(r) values but uncorrelated with N, the number of functional release sites mediating the connection. The efficacy of a cortical connection is thus set by coordinated presynaptic and postsynaptic strength.

  3. Neurotransmitter transporters in schistosomes: structure, function and prospects for drug discovery.

    Science.gov (United States)

    Ribeiro, Paula; Patocka, Nicholas

    2013-12-01

    Neurotransmitter transporters (NTTs) play a fundamental role in the control of neurotransmitter signaling and homeostasis. Sodium symporters of the plasma membrane mediate the cellular uptake of neurotransmitter from the synaptic cleft, whereas proton-driven vesicular transporters sequester the neurotransmitter into synaptic vesicles for subsequent release. Together these transporters control how much transmitter is released and how long it remains in the synaptic cleft, thereby regulating the intensity and duration of signaling. NTTs have been the subject of much research in mammals and there is growing interest in their activities among invertebrates as well. In this review we will focus our attention on NTTs of the parasitic flatworm Schistosoma mansoni. Bloodflukes of the genus Schistosoma are the causative agents of human schistosomiasis, a devastating disease that afflicts over 200 million people worldwide. Schistosomes have a well-developed nervous system and a rich diversity of neurotransmitters, including many of the small-molecule ("classical") neurotransmitters that normally employ NTTs in their mechanism of signaling. Recent advances in schistosome genomics have unveiled numerous NTTs in this parasite, some of which have now been cloned and characterized in vitro. Moreover new genetic and pharmacological evidence suggests that NTTs are required for proper control of neuromuscular signaling and movement of the worm. Among these carriers are proteins that have been successfully targeted for drug discovery in other organisms, in particular sodium symporters for biogenic amine neurotransmitters such as serotonin and dopamine. Our goal in this chapter is to review the current status of research on schistosome NTTs, with emphasis on biogenic amine sodium symporters, and to evaluate their potential for anti-schistosomal drug targeting. Through this discussion we hope to draw attention to this important superfamily of parasite proteins and to identify new

  4. Cultured neurons as model systems for biochemical and pharmacological studies on receptors for neurotransmitter amino acids

    DEFF Research Database (Denmark)

    Schousboe, A; Drejer, J; Hansen, Gert Helge

    1985-01-01

    action of GABA on evoked release of glutamate, which is the neurotransmitter in cerebellar granule cells. Also glutamate receptors have been studied with regard to the 2 types of neurons. Both cerebral cortex neurons (GABAergic) and cerebellar granule cells (glutamatergic) possess glutamate receptors...

  5. NEUROTRANSMITTERS AND IMMUNITY: 1. DOPAMINE

    Directory of Open Access Journals (Sweden)

    Lucian Hritcu

    2007-08-01

    Full Text Available Dopamine is one of the principal neurotransmitters in the central nervous system (CNC, and its neuronal pathways are involved in several key functions such as behavior (Hefco et al., 2003a,b, control of movement, endocrine regulation, immune response (Fiserova et al., 2002; Levite et al., 2001, Hritcu et al., 2006a,b,c, and cardiovascular function. Dopamine has at least five G-protein, coupled receptor subtypes, D1-D5, each arising from a different gene (Sibley et al., 1993. Traditionally, these receptors have been classified into D1-like (the D1 and D5 and D2-like (D2, D3 and D4 receptors subtypes, primarily according to their ability to stimulate or inhibit adenylate cyclase, respectively, and to their pharmacological characteristics (Seeman et al., 1993. Receptors for dopamine (particularly of D2 subclass are the primary therapeutic target in a number of neuropathological disorders including schizophrenia, Parkinson’s disease and Huntington’s chorea (Seeman et al., 1987. Neither dopamine by itself, nor dopaminergic agonists by themselves, has been shown to activate T cell function. Nevertheless, lymphocytes are most probably exposed to dopamine since the primary and secondary lymphoid organs of various mammals are markedly innervated, and contain nerve fibers which stain for tyrosine hydroxylase (Weihe et al., 1991, the enzyme responsible for dopamine synthesis. Moreover, cathecolamines and their metabolites are present in single lymphocytes and in extracts of T and B cell clones, and pharmacological inhibition of tyrosine hydroxylase reduces catecholamine levels, suggesting catecholamine synthesis by lymphocytes (Bergquist et al., 1994. The existence of putative dopamine receptors of D2, D3, D4 and D5 subtypes on immune cells has been proposed of several authors, primarily on the basis of dopaminergic ligand binding assays and specific mRNA expression as monitored by reverse transcription-PCR. Several experiments evoked the idea of a

  6. Do neurotransmitters sampled by brain microdialysis reflect functional release?

    NARCIS (Netherlands)

    Westerink, BHC; Timmerman, W

    1999-01-01

    Brain microdialysis is an invasive sampling technique and will always cause damage to nervous tissue. For proper interpretation of the results, possible sources of interference need to be identified. The present review discusses the possible artefacts of the microdialysis technique and evaluates

  7. Neurotransmitter alteration in a testosterone propionate-induced polycystic ovarian syndrome rat model.

    Science.gov (United States)

    Chaudhari, Nirja K; Nampoothiri, Laxmipriya P

    2017-02-01

    Polycystic ovarian syndrome (PCOS), one of the leading causes of infertility seen in women, is characterized by anovulation and hyperandrogenism, resulting in ovarian dysfunction. In addition, associations of several metabolic complications like insulin resistance, obesity, dyslipidemia and psychological co-morbidities are well known in PCOS. One of the major factors influencing mood and the emotional state of mind is neurotransmitters. Also, these neurotransmitters are very crucial for GnRH release. Hence, the current study investigates the status of neurotransmitters in PCOS. A PCOS rat model was developed using testosterone. Twenty-one-day-old rats were subcutaneously injected with 10 mg/kg body weight of testosterone propionate (TP) for 35 days. The animals were validated for PCOS characteristics by monitoring estrus cyclicity, serum testosterone and estradiol levels and by histological examination of ovarian sections. Neurotransmitter estimation was carried out using fluorometric and spectrophotometric methods. TP-treated animals demonstrated increased serum testosterone levels with unaltered estradiol content, disturbed estrus cyclicity and many peripheral cysts in the ovary compared to control rats mimicking human PCOS. Norepinephrine (NE), dopamine, serotonin, γ-amino butyric acid (GABA) and epinephrine levels were significantly low in TP-induced PCOS rats compared to control ones, whereas the activity of acetylcholinesterase in the PCOS brain was markedly elevated. Neurotransmitter alteration could be one of the reasons for disturbed gonadotropin-releasing hormone (GnRH) release, consequently directing the ovarian dysfunction in PCOS. Also, decrease in neurotransmitters, mainly NE, serotonin and dopamine (DA) attributes to mood disorders like depression and anxiety in PCOS.

  8. Neurotransmitter properties of the newborn human retina

    International Nuclear Information System (INIS)

    Hollyfield, J.G.; Frederick, J.M.; Rayborn, M.E.

    1983-01-01

    Human retinal tissue from a newborn was examined autoradiographically for the presence of high-affinity uptake and localization of the following putative neurotransmitters: dopamine, glycine, GABA, aspartate, and glutamate. In addition, the dopamine content of this newborn retina was measured by high pressure liquid chromatography. Our study reveals that specific uptake mechanisms for 3 H-glycine, 3 H-dopamine, and 3 H-GABA are present at birth. However, the number and distribution of cells labeled with each of these 3 H-transmitters are not identical to those observed in adult human retinas. Furthermore, the amount of endogenous dopamine in the newborn retina is approximately 1/20 the adult level. Photoreceptor-specific uptake of 3 H-glutamate and 3 H-aspartate are not observed. These findings indicate that, while some neurotransmitter-specific properties are present at birth, significant maturation of neurotransmitter systems occurs postnatally

  9. Altered Expression of Genes Encoding Neurotransmitter Receptors in GnRH Neurons of Proestrous Mice

    OpenAIRE

    Vastagh, Csaba; Rodolosse, Annie; Solymosi, Norbert; Liposits, Zsolt

    2016-01-01

    Gonadotropin-releasing hormone (GnRH) neurons play a key role in the central regulation of reproduction. In proestrous female mice, estradiol triggers the pre-ovulatory GnRH surge, however, its impact on the expression of neurotransmitter receptor genes in GnRH neurons has not been explored yet. We hypothesized that proestrus is accompanied by substantial changes in the expression profile of genes coding for neurotransmitter receptors in GnRH neurons. We compared the transcriptome of GnRH neu...

  10. Altered expression of genes encoding neurotransmitter receptors in GnRH neurons of proestrous mice

    OpenAIRE

    Csaba Vastagh; Annie Rodolosse; Norbert Solymosi; Zsolt Liposits; Zsolt Liposits

    2016-01-01

    Gonadotropin-releasing hormone (GnRH) neurons play a key role in the central regulation of reproduction. In proestrous female mice, estradiol triggers the pre-ovulatory GnRH surge, however, its impact on the expression of neurotransmitter receptor genes in GnRH neurons has not been explored yet. We hypothesized that proestrus is accompanied by substantial changes in the expression profile of genes coding for neurotransmitter receptors in GnRH neurons. We compared the transcriptome of GnRH neu...

  11. A linear model for estimation of neurotransmitter response profiles from dynamic PET data

    OpenAIRE

    Normandin, M.D.; Schiffer, W.K.; Morris, E.D.

    2011-01-01

    The parametric ntPET model (p-ntPET) estimates the kinetics of neurotransmitter release from dynamic PET data with receptor-ligand radiotracers. Here we introduce a linearization (lp-ntPET) that is computationally efficient and can be applied to single-scan data. lp-ntPET employs a non-invasive reference region input function and extends the LSRRM of Alpert et al. (2003) using basis functions to characterize the time course of neurotransmitter activation. In simulation studies, the temporal p...

  12. Chloride binding site of neurotransmitter sodium symporters

    DEFF Research Database (Denmark)

    Kantcheva, Adriana Krassimirova; Quick, Matthias; Shi, Lei

    2013-01-01

    Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs...... have a serine. The LeuT-E290S mutant displays chloride-dependent activity. We show that, in LeuT-E290S cocrystallized with bromide or chloride, the anion is coordinated by side chain hydroxyls from Tyr47, Ser290, and Thr254 and the side chain amide of Gln250. The bound anion and the nearby sodium ion...

  13. Endogenous opioid peptides as neurotransmitters in the rat hippocampus

    International Nuclear Information System (INIS)

    Neumaier, J.F.

    1989-01-01

    The role of endogenous opioid peptides as neurotransmitters in the rat hippocampus was investigated by using extracellular recording and radioligand binding techniques in the hippocampal slice preparation. Synaptic conductances from endogenously released opioid peptides have been difficult to detect. This problem was approach by designing a novel assay of opioid peptide release, in which release was detected by measuring binding competition between endogenous opioids and added radioligand. Membrane depolarization displaced [ 3 H]-diprenorphine binding in a transient, calcium-dependent, and peptidase-sensitive manner. Autoradiographic localization of the sites of [ 3 H]-diprenorphine binding displacement showed that significant opioid peptide release and receptor occupancy occurred in each major subregion of the hippocampal slices. This assay method can not be used to define optimal electrical stimulation conditions for releasing endogenous opioids. The binding displacement method was extended to the study of the sigma receptor. Depolarization of hippocampal slices was found to reduce the binding of the sigma-selective radioligand [ 3 H]-ditolylguanidine in a transient and calcium-dependent manner with no apparent direct effects on sigma receptor affinity

  14. Neurotransmitters and Neuropeptides: New Players in the Control of Islet of Langerhans' Cell Mass and Function.

    Science.gov (United States)

    Di Cairano, Eliana S; Moretti, Stefania; Marciani, Paola; Sacchi, Vellea Franca; Castagna, Michela; Davalli, Alberto; Folli, Franco; Perego, Carla

    2016-04-01

    Islets of Langerhans control whole body glucose homeostasis, as they respond, releasing hormones, to changes in nutrient concentrations in the blood stream. The regulation of hormone secretion has been the focus of attention for a long time because it is related to many metabolic disorders, including diabetes mellitus. Endocrine cells of the islet use a sophisticate system of endocrine, paracrine and autocrine signals to synchronize their activities. These signals provide a fast and accurate control not only for hormone release but also for cell differentiation and survival, key aspects in islet physiology and pathology. Among the different categories of paracrine/autocrine signals, this review highlights the role of neurotransmitters and neuropeptides. In a manner similar to neurons, endocrine cells synthesize, accumulate, release neurotransmitters in the islet milieu, and possess receptors able to decode these signals. In this review, we provide a comprehensive description of neurotransmitter/neuropetide signaling pathways present within the islet. Then, we focus on evidence supporting the concept that neurotransmitters/neuropeptides and their receptors are interesting new targets to preserve β-cell function and mass. A greater understanding of how this network of signals works in physiological and pathological conditions would advance our knowledge of islet biology and physiology and uncover potentially new areas of pharmacological intervention. J. Cell. Physiol. 231: 756-767, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  15. Effects of the aminoglycoside antibiotics, streptomycin and neomycin, on neuromuscular transmission. I. Presynaptic considerations.

    Science.gov (United States)

    Fiekers, J F

    1983-06-01

    The effects of two aminoglycoside antibiotics, streptomycin and neomycin, were studied in voltage-clamped transected twitch fibers of the costocutaneous muscles of garter snakes (species Thamnophis). The concentration-dependent effects of each antibiotic were quantitated by measuring miniature end-plate currents (mepcs) and evoked end-plate currents (epcs) in a single fiber before and in the presence of a wide range of concentrations of each antibiotic. The amplitude and the kinetics of these currents were studied and estimates of the quantal content of evoked transmitter release determined by the direct method of mean ratios, epc/mepc. A distinct separation was obtained between the concentrations of each antibiotic which demonstrated either pre- or postsynaptic actions. Both streptomycin and neomycin produced a concentration-dependent reduction in epc amplitude at concentrations which did not reduce mepc amplitude. Thus, the primary site of action for these antibiotics was considered of presynaptic origin. Streptomycin was approximately one-tenth as active as neomycin in reducing quantal release of acetylcholine. The marked depression in epc amplitude and quantal content produced by high concentrations of each antibiotic were reversed by elevating the external calcium concentration. Double logarithmic plots of the relationship between external calcium concentration and epc amplitude yielded a slope of approximately 3.8 in control physiological solution. In the presence of blocking concentrations of each antibiotic, increasing the external calcium concentration caused a parallel shift to the right of this relationship. These results suggest that the major mechanism for the neuromuscular depression produced by these aminoglycoside antibiotics is a competitive antagonism with calcium for a common presynaptic site required for evoked transmitter release.

  16. A Critical Assessment of Research on Neurotransmitters in Alzheimer's Disease.

    Science.gov (United States)

    Reddy, P Hemachandra

    2017-01-01

    The purpose of this mini-forum, "Neurotransmitters and Alzheimer's Disease", is to critically assess the current status of neurotransmitters in Alzheimer's disease. Neurotransmitters are essential neurochemicals that maintain synaptic and cognitive functions in mammals, including humans, by sending signals across pre- to post-synaptic neurons. Authorities in the fields of synapses and neurotransmitters of Alzheimer's disease summarize the current status of basic biology of synapses and neurotransmitters, and also update the current status of clinical trials of neurotransmitters in Alzheimer's disease. This article discusses the prevalence, economic impact, and stages of Alzheimer's dementia in humans.

  17. Dynamic regulation of neurotransmitter specification: Relevance to nervous system homeostasis

    Science.gov (United States)

    Borodinsky, Laura N.; Belgacem, Yesser Hadj; Swapna, Immani; Sequerra, Eduardo Bouth

    2013-01-01

    During nervous system development the neurotransmitter identity changes and coexpression of several neurotransmitters is a rather generalized feature of developing neurons. In the mature nervous system, different physiological and pathological circumstances recreate this phenomenon. The rules of neurotransmitter respecification are multiple. Among them, the goal of assuring balanced excitability appears as an important driving force for the modifications in neurotransmitter phenotype expression. The functional consequences of these dynamic revisions in neurotransmitter identity span a varied range, from fine-tuning the developing neural circuit to modifications in addictive and locomotor behaviors. Current challenges include determining the mechanisms underlying neurotransmitter phenotype respecification and how they intersect with genetic programs of neuronal specialization. PMID:23270605

  18. Dopamine synapse is a neuroligin-2–mediated contact between dopaminergic presynaptic and GABAergic postsynaptic structures

    Science.gov (United States)

    Uchigashima, Motokazu; Ohtsuka, Toshihisa; Kobayashi, Kazuto; Watanabe, Masahiko

    2016-01-01

    Midbrain dopamine neurons project densely to the striatum and form so-called dopamine synapses on medium spiny neurons (MSNs), principal neurons in the striatum. Because dopamine receptors are widely expressed away from dopamine synapses, it remains unclear how dopamine synapses are involved in dopaminergic transmission. Here we demonstrate that dopamine synapses are contacts formed between dopaminergic presynaptic and GABAergic postsynaptic structures. The presynaptic structure expressed tyrosine hydroxylase, vesicular monoamine transporter-2, and plasmalemmal dopamine transporter, which are essential for dopamine synthesis, vesicular filling, and recycling, but was below the detection threshold for molecules involving GABA synthesis and vesicular filling or for GABA itself. In contrast, the postsynaptic structure of dopamine synapses expressed GABAergic molecules, including postsynaptic adhesion molecule neuroligin-2, postsynaptic scaffolding molecule gephyrin, and GABAA receptor α1, without any specific clustering of dopamine receptors. Of these, neuroligin-2 promoted presynaptic differentiation in axons of midbrain dopamine neurons and striatal GABAergic neurons in culture. After neuroligin-2 knockdown in the striatum, a significant decrease of dopamine synapses coupled with a reciprocal increase of GABAergic synapses was observed on MSN dendrites. This finding suggests that neuroligin-2 controls striatal synapse formation by giving competitive advantage to heterologous dopamine synapses over conventional GABAergic synapses. Considering that MSN dendrites are preferential targets of dopamine synapses and express high levels of dopamine receptors, dopamine synapse formation may serve to increase the specificity and potency of dopaminergic modulation of striatal outputs by anchoring dopamine release sites to dopamine-sensing targets. PMID:27035941

  19. Biochemical Alterations Of Amino Acids, Neurotransmitters And ...

    African Journals Online (AJOL)

    Egyptian Journal of Biochemistry and Molecular Biology ... At the sametime, brain neurotransmitters, serum ALT, AST, ALP and γ-GT levels were also assayed. ... There was increasing tendency in brain concentration of norepinephrine and dopamine, while the level of brain serotonin showed a pronounced decrease after ...

  20. Mutations in STX1B, encoding a presynaptic protein, cause fever-associated epilepsy syndromes

    DEFF Research Database (Denmark)

    Schubert, J.; Siekierska, A.; Langlois, M.

    2014-01-01

    Febrile seizures affect 2-4% of all children(1) and have a strong genetic component(2). Recurrent mutations in three main genes (SCN1A, SCN1B and GABRG2)(3-5) have been identified that cause febrile seizures with or without epilepsy. Here we report the identification of mutations in STX1B, encoding...... syntaxin-1B(6), that are associated with both febrile seizures and epilepsy. Whole-exome sequencing in independent large pedigrees(7,8) identified cosegregating STX1B mutations predicted to cause an early truncation or an in-frame insertion or deletion. Three additional nonsense or missense mutations....... Wild-type human syntaxin-1B but not a mutated protein rescued the effects of stx1b knockdown in zebrafish. Our results thus implicate STX1B and the presynaptic release machinery in fever-associated epilepsy syndromes....

  1. Effects of spinal transection on presynaptic markers for glutamatergic neurons in the rat

    International Nuclear Information System (INIS)

    Singer, H.S.; Coyle, J.T.; Frangia, J.; Price, D.L.

    1981-01-01

    To evaluate the hypothesis that glutamic acid may be the neurotransmitter of descending, excitatory supraspinal pathways, the uptake and release of L-[3H] glutamate and the levels of endogenous glutamate were measured in preparations from rat lumbar spinal cord following complete mid-thoracic transection. Following transection, the activity of the synaptosomal high-affinity glutamate uptake process was increased in both dorsal and ventral halves of lumbar cord between 1 and 14 days after transection and returned to control levels by 21 days posttransection. At 7 days, the increased activity of the uptake process for L-[3H]glutamate resulted in elevation of Vmax with no significant alteration in KT as compared to age-matched controls. Depolarization-induced release of L-[3H]glutamate from prelabeled slices did not differ significantly from control in the lesioned rat except at 21 days after lesion when the amount of tritium release was significantly greater in the transected preparations than in control. Amino acid analysis of the lumbar cord from control and transected rats indicated only a 10% decrease in the level of endogenous glutamate and no alterations in the concentration of GABA and glycine 7 days after lesion. These findings do not support the hypothesis that glutamate serves as a major excitatory neurotransmitter in supraspinal pathways innervating the lumbar cord of the rat

  2. Dual effect of beta-amyloid on α7 and α4β2 nicotinic receptors controlling the release of glutamate, aspartate and GABA in rat hippocampus.

    Directory of Open Access Journals (Sweden)

    Elisa Mura

    Full Text Available BACKGROUND: We previously showed that beta-amyloid (Aβ, a peptide considered as relevant to Alzheimer's Disease, is able to act as a neuromodulator affecting neurotransmitter release in absence of evident sign of neurotoxicity in two different rat brain areas. In this paper we focused on the hippocampus, a brain area which is sensitive to Alzheimer's Disease pathology, evaluating the effect of Aβ (at different concentrations on the neurotransmitter release stimulated by the activation of pre-synaptic cholinergic nicotinic receptors (nAChRs, α4β2 and α7 subtypes. Particularly, we focused on some neurotransmitters that are usually involved in learning and memory: glutamate, aspartate and GABA. METHODOLOGY/FINDINGS: WE USED A DUAL APPROACH: in vivo experiments (microdialysis technique on freely moving rats in parallel to in vitro experiments (isolated nerve endings derived from rat hippocampus. Both in vivo and in vitro the administration of nicotine stimulated an overflow of aspartate, glutamate and GABA. This effect was greatly inhibited by the highest concentrations of Aβ considered (10 µM in vivo and 100 nM in vitro. In vivo administration of 100 nM Aβ (the lowest concentration considered potentiated the GABA overflow evoked by nicotine. All these effects were specific for Aβ and for nicotinic secretory stimuli. The in vitro administration of either choline or 5-Iodo-A-85380 dihydrochloride (α7 and α4β2 nAChRs selective agonists, respectively elicited the hippocampal release of aspartate, glutamate, and GABA. High Aβ concentrations (100 nM inhibited the overflow of all three neurotransmitters evoked by both choline and 5-Iodo-A-85380 dihydrochloride. On the contrary, low Aβ concentrations (1 nM and 100 pM selectively acted on α7 subtypes potentiating the choline-induced release of both aspartate and glutamate, but not the one of GABA. CONCLUSIONS/SIGNIFICANCE: The results reinforce the concept that Aβ has relevant

  3. Sepsis causes presynaptic histamine H3 and alpha2-adrenergic dysfunction in canine myocardium.

    Science.gov (United States)

    Cheng, Zao-Qin; Bose, Deepak; Jacobs, Han; Light, R Bruce; Mink, Steven N

    2002-11-01

    Histamine H3 receptors and alpha2-adrenoceptors are presynaptic receptors that modulate norepinephrine (NE) release from sympathetic nerves innervating the cardiovascular system. We previously showed that cardiac H3 receptors are activated in sepsis, and that this activation leads to a decrease in the adrenergic response (AR) [J. Appl. Physiol. 85 (1998) 1693-1701] H3-receptors and alpha2-receptors appear to be coupled to GTP binding regulatory proteins (G) that modulate transmitter release by reducing calcium current into the nerve terminals through neuronal calcium channels. There may also be interaction between H3-receptors and alpha2-receptors on AR that may occur either at the receptor or a more downstream level. In the present study, we examined the effect of septic plasma on AR in a canine ventricular preparation in which field stimulation was used to produce AR. We determined whether there was interaction between H(3)-receptors and alpha2-adrenoceptors and tested whether H3 activation would attenuate the alpha2-agonist and alpha2-antagonist effects of clonidine and yohimbine, respectively. We also determined whether the mechanism by which septic plasma decreases the adrenergic response involves inactivation of an inhibitory G protein and used pertussis toxin (PTX) to assess this effect. We found that septic plasma attenuated AR produced by field stimulation, and that this decrease was mediated by a PTX sensitive inhibitory G protein. H3 activation also attenuated the alpha2-agonist and alpha2-antagonist effects on adrenergic activation as compared with nonseptic plasma. We conclude that presynaptic sympathetic dysfunction may contribute to cardiovascular collapse in sepsis.

  4. Single cocaine exposure does not alter striatal pre-synaptic dopamine function in mice: an [18 F]-FDOPA PET study.

    Science.gov (United States)

    Bonsall, David R; Kokkinou, Michelle; Veronese, Mattia; Coello, Christopher; Wells, Lisa A; Howes, Oliver D

    2017-12-01

    Cocaine is a recreational drug of abuse that binds to the dopamine transporter, preventing reuptake of dopamine into pre-synaptic terminals. The increased presence of synaptic dopamine results in stimulation of both pre- and post-synaptic dopamine receptors, considered an important mechanism by which cocaine elicits its reinforcing properties. However, the effects of acute cocaine administration on pre-synaptic dopamine function remain unclear. Non-invasive imaging techniques such as positron emission tomography have revealed impaired pre-synaptic dopamine function in chronic cocaine users. Similar impairments have been seen in animal studies, with microdialysis experiments indicating decreased basal dopamine release. Here we use micro positron emission tomography imaging techniques in mice to measure dopamine synthesis capacity and determine the effect of acute cocaine administration of pre-synaptic dopamine function. We show that a dose of 20 mg/kg cocaine is sufficient to elicit hyperlocomotor activity, peaking 15-20 min post treatment (p cocaine treatment (KiCer: 0.0097 per min vs. 0.0112 per min in vehicle controls, p > 0.05). Furthermore, expression levels of two key enzymes related to dopamine synthesis, tyrosine hydroxylase and aromatic l-amino acid decarboxylase, within the striatum of scanned mice were not significantly affected by acute cocaine pre-treatment (p > 0.05). Our findings suggest that while the regulation of dopamine synthesis and release in the striatum have been shown to change with chronic cocaine use, leading to a reduced basal tone, these adaptations to pre-synaptic dopaminergic neurons are not initiated following a single exposure to the drug. © 2017 International Society for Neurochemistry.

  5. Xanomeline quasi-irreversibly bound to an ectopic site can stimulate presynaptic M2 receptors via the orthosteric binding site

    Czech Academy of Sciences Publication Activity Database

    Machová, Eva; El-Fakahany, E. E.; Doležal, Vladimír

    2005-01-01

    Roč. 94, č. S2 (2005), s. 90-90 ISSN 0022-3042. [Biennial Meeting of the International Society for Neurochemistry and the European Society for Neurochemistry /20./. 21.08.2005-26.08.2005, Innsbruck] R&D Projects: GA AV ČR(CZ) IAA5011206; GA ČR(CZ) GA305/05/0452 Institutional research plan: CEZ:AV0Z50110509 Keywords : xanomeline * presynaptic M2 receptor * acetylcholine release * brain cortex * wash-resistant binding Subject RIV: ED - Physiology

  6. Food reward-induced neurotransmitter changes in cognitive brain regions.

    Science.gov (United States)

    Fallon, Shaun; Shearman, Erin; Sershen, Henry; Lajtha, Abel

    2007-10-01

    Recent evidence indicates that mechanisms involved in reward and mechanisms involved in learning interact, in that reward includes learning processes and learning includes reward processes. In spite of such interactions, reward and learning represent distinct functions. In the present study, as part of an examination of the differences in learning and reward mechanisms, it was assumed that food principally affects reward mechanisms. After a brief period of fasting, we assayed the release of three neurotransmitters and their associated metabolites in eight brain areas associated with learning and memory as a response to feeding. Using microdialysis for the assay, we found changes in the hippocampus, cortex, amygdala, and the thalamic nucleus, (considered cognitive areas), in addition to those in the nucleus accumbens and ventral tegmental area (considered reward areas). Extracellular dopamine levels increased in the nucleus accumbens, ventral tegmental area, amygdala, and thalamic nucleus, while they decreased in the hippocampus and prefrontal cortex. Dopamine metabolites increased in all areas tested (except the dorsal hippocampus); changes in norepinephrine varied with decreases in the accumbens, dorsal hippocampus, amygdala, and thalamic nucleus, and increases in the prefrontal cortex; serotonin levels decreased in all the areas tested; although its metabolite 5HIAA increased in two regions (the medial temporal cortex, and thalamic nucleus). Our assays indicate that in reward activities such as feeding, in addition to areas usually associated with reward such as the mesolimbic dopamine system, other areas associated with cognition also participate. Results also indicate that several transmitter systems play a part, with several neurotransmitters and several receptors involved in the response to food in a number of brain structures, and the changes in transmitter levels may be affected by metabolism and transport in addition to changes in release in a regionally

  7. Pattern recognition of neurotransmitters using multimode sensing.

    Science.gov (United States)

    Stefan-van Staden, Raluca-Ioana; Moldoveanu, Iuliana; van Staden, Jacobus Frederick

    2014-05-30

    Pattern recognition is essential in chemical analysis of biological fluids. Reliable and sensitive methods for neurotransmitters analysis are needed. Therefore, we developed for pattern recognition of neurotransmitters: dopamine, epinephrine, norepinephrine a method based on multimode sensing. Multimode sensing was performed using microsensors based on diamond paste modified with 5,10,15,20-tetraphenyl-21H,23H-porphyrine, hemin and protoporphyrin IX in stochastic and differential pulse voltammetry modes. Optimized working conditions: phosphate buffer solution of pH 3.01 and KCl 0.1mol/L (as electrolyte support), were determined using cyclic voltammetry and used in all measurements. The lowest limits of quantification were: 10(-10)mol/L for dopamine and epinephrine, and 10(-11)mol/L for norepinephrine. The multimode microsensors were selective over ascorbic and uric acids and the method facilitated reliable assay of neurotransmitters in urine samples, and therefore, the pattern recognition showed high reliability (RSDneurotransmitters on biological fluids at a lower determination level than chromatographic methods. The sampling of the biological fluids referees only to the buffering (1:1, v/v) with a phosphate buffer pH 3.01, while for chromatographic methods the sampling is laborious. Accordingly with the statistic evaluation of the results at 99.00% confidence level, both modes can be used for pattern recognition and quantification of neurotransmitters with high reliability. The best multimode microsensor was the one based on diamond paste modified with protoporphyrin IX. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. New effects of GABAB receptor allosteric modulator rac-BHFF on ambient GABA, uptake/release, Em and synaptic vesicle acidification in nerve terminals.

    Science.gov (United States)

    Pozdnyakova, N; Dudarenko, M; Borisova, T

    2015-09-24

    Positive allosteric modulators of GABAB receptors have great therapeutic potential for medications of anxiety, depression, etc. The effects of recently discovered modulator rac-BHFF on the key characteristics of GABAergic neurotransmission were investigated in cortical and hippocampal presynaptic nerve terminals of rats (synaptosomes). The ambient level of [(3)H]GABA that is a balance between release and uptake of the neurotransmitter increased significantly in the presence of rac-BHFF (at concentrations 10-30μM). The initial velocity of synaptosomal [(3)H]GABA uptake was suppressed by the modulator. In the presence of GABA transporter blocker NO-711, it was shown that rac-BHFF increased tonic release of [(3)H]GABA from synaptosomes (at concentrations 3-30μM). Rac-BHFF within the concentration range of 0.3-30μM did not enhance inhibiting effect of (±)-baclofen on depolarization-induced exocytotic release of [(3)H]GABA. Rac-BHFF (0.3-30μM) caused dose-dependent depolarization of the plasma membrane and dissipation of the proton gradient of synaptic vesicles in synaptosomes that was shown in the absence/presence of GABAB receptor antagonist saclofen using fluorescent dyes rhodamine 6G and acridine orange, respectively, and so, the above effects of rac-BHFF were not associated with the modulation of presynaptic GABAB receptors. Therefore, drug development strategy of positive allosteric modulation of GABAB receptors is to eliminate the above side effects of rac-BHFF in presynapse, and vice versa, these new properties of rac-BHFF may be exploited appropriately. Copyright © 2015. Published by Elsevier Ltd.

  9. Dynamic neurotransmitter interactions measured with PET

    International Nuclear Information System (INIS)

    Schiffer, W.K.; Dewey, S.L.

    2001-01-01

    Positron emission tomography (PET) has become a valuable interdisciplinary tool for understanding physiological, biochemical and pharmacological functions at a molecular level in living humans, whether in a healthy or diseased state. The utility of tracing chemical activity through the body transcends the fields of cardiology, oncology, neurology and psychiatry. In this, PET techniques span radiochemistry and radiopharmaceutical development to instrumentation, image analysis, anatomy and modeling. PET has made substantial contributions in each of these fields by providing a,venue for mapping dynamic functions of healthy and unhealthy human anatomy. As diverse as the disciplines it bridges, PET has provided insight into an equally significant variety of psychiatric disorders. Using the unique quantitative ability of PET, researchers are now better able to non-invasively characterize normally occurring neurotransmitter interactions in the brain. With the knowledge that these interactions provide the fundamental basis for brain response, many investigators have recently focused their efforts on an examination of the communication between these chemicals in both healthy volunteers and individuals suffering from diseases classically defined as neurotransmitter specific in nature. In addition, PET can measure the biochemical dynamics of acute and sustained drug abuse. Thus, PET studies of neurotransmitter interactions enable investigators to describe a multitude of specific functional interactions in the human brain. This information can then be applied to understanding side effects that occur in response to acute and chronic drug therapy, and to designing new drugs that target multiple systems as opposed to single receptor types. Knowledge derived from PET studies can be applied to drug discovery, research and development (for review, see (Fowler et al., 1999) and (Burns et al., 1999)). Here, we will cover the most substantial contributions of PET to understanding

  10. Dynamic neurotransmitter interactions measured with PET

    Energy Technology Data Exchange (ETDEWEB)

    Schiffer, W.K.; Dewey, S.L.

    2001-04-02

    Positron emission tomography (PET) has become a valuable interdisciplinary tool for understanding physiological, biochemical and pharmacological functions at a molecular level in living humans, whether in a healthy or diseased state. The utility of tracing chemical activity through the body transcends the fields of cardiology, oncology, neurology and psychiatry. In this, PET techniques span radiochemistry and radiopharmaceutical development to instrumentation, image analysis, anatomy and modeling. PET has made substantial contributions in each of these fields by providing a,venue for mapping dynamic functions of healthy and unhealthy human anatomy. As diverse as the disciplines it bridges, PET has provided insight into an equally significant variety of psychiatric disorders. Using the unique quantitative ability of PET, researchers are now better able to non-invasively characterize normally occurring neurotransmitter interactions in the brain. With the knowledge that these interactions provide the fundamental basis for brain response, many investigators have recently focused their efforts on an examination of the communication between these chemicals in both healthy volunteers and individuals suffering from diseases classically defined as neurotransmitter specific in nature. In addition, PET can measure the biochemical dynamics of acute and sustained drug abuse. Thus, PET studies of neurotransmitter interactions enable investigators to describe a multitude of specific functional interactions in the human brain. This information can then be applied to understanding side effects that occur in response to acute and chronic drug therapy, and to designing new drugs that target multiple systems as opposed to single receptor types. Knowledge derived from PET studies can be applied to drug discovery, research and development (for review, see (Fowler et al., 1999) and (Burns et al., 1999)). Here, we will cover the most substantial contributions of PET to understanding

  11. Long-distance mechanism of neurotransmitter recycling mediated by glial network facilitates visual function in Drosophila.

    Science.gov (United States)

    Chaturvedi, Ratna; Reddig, Keith; Li, Hong-Sheng

    2014-02-18

    Neurons rely on glia to recycle neurotransmitters such as glutamate and histamine for sustained signaling. Both mammalian and insect glia form intercellular gap-junction networks, but their functional significance underlying neurotransmitter recycling is unknown. Using the Drosophila visual system as a genetic model, here we show that a multicellular glial network transports neurotransmitter metabolites between perisynaptic glia and neuronal cell bodies to mediate long-distance recycling of neurotransmitter. In the first visual neuropil (lamina), which contains a multilayer glial network, photoreceptor axons release histamine to hyperpolarize secondary sensory neurons. Subsequently, the released histamine is taken up by perisynaptic epithelial glia and converted into inactive carcinine through conjugation with β-alanine for transport. In contrast to a previous assumption that epithelial glia deliver carcinine directly back to photoreceptor axons for histamine regeneration within the lamina, we detected both carcinine and β-alanine in the fly retina, where they are found in photoreceptor cell bodies and surrounding pigment glial cells. Downregulating Inx2 gap junctions within the laminar glial network causes β-alanine accumulation in retinal pigment cells and impairs carcinine synthesis, leading to reduced histamine levels and photoreceptor synaptic vesicles. Consequently, visual transmission is impaired and the fly is less responsive in a visual alert analysis compared with wild type. Our results suggest that a gap junction-dependent laminar and retinal glial network transports histamine metabolites between perisynaptic glia and photoreceptor cell bodies to mediate a novel, long-distance mechanism of neurotransmitter recycling, highlighting the importance of glial networks in the regulation of neuronal functions.

  12. Prophylactic versus Therapeutic Fingolimod: Restoration of Presynaptic Defects in Mice Suffering from Experimental Autoimmune Encephalomyelitis.

    Directory of Open Access Journals (Sweden)

    Tommaso Bonfiglio

    Full Text Available Fingolimod, the first oral, disease-modifying therapy for MS, has been recently proposed to modulate glutamate transmission in the central nervous system (CNS of mice suffering from Experimental Autoimmune Encephalomyelitis (EAE and in MS patients. Our study aims at investigating whether oral fingolimod recovers presynaptic defects that occur at different stages of disease in the CNS of EAE mice. In vivo prophylactic (0.3 mg/kg for 14 days, from the 7th day post immunization, d.p.i, the drug dissolved in the drinking water fingolimod significantly reduced the clinical symptoms and the anxiety-related behaviour in EAE mice. Spinal cord inflammation, demyelination and glial cell activation are markers of EAE progression. These signs were ameliorated following oral fingolimod administration. Glutamate exocytosis was shown to be impaired in cortical and spinal cord terminals isolated from EAE mice at 21 ± 1 d.p.i., while GABA alteration emerged only at the spinal cord level. Prophylactic fingolimod recovered these presynaptic defects, restoring altered glutamate and GABA release efficiency. The beneficial effect occurred in a dose-dependent, region-specific manner, since lower (0.1-0.03 mg/kg doses restored, although to a different extent, synaptic defects in cortical but not spinal cord terminals. A delayed reduction of glutamate, but not of GABA, exocytosis was observed in hippocampal terminals of EAE mice at 35 d.p.i. Therapeutic (0.3 mg/kg, from 21 d.p.i. for 14 days fingolimod restored glutamate exocytosis in the cortex and in the hippocampus of EAE mice at 35 ± 1 d.p.i. but not in the spinal cord, where also GABAergic defects remained unmodified. These results improve our knowledge of the molecular events accounting for the beneficial effects elicited by fingolimod in demyelinating disorders.

  13. Wireless Instantaneous Neurotransmitter Concentration Sensing System (WINCS) for intraoperative neurochemical monitoring.

    Science.gov (United States)

    Kimble, Christopher J; Johnson, David M; Winter, Bruce A; Whitlock, Sidney V; Kressin, Kenneth R; Horne, April E; Robinson, Justin C; Bledsoe, Jonathan M; Tye, Susannah J; Chang, Su-Youne; Agnesi, Filippo; Griessenauer, Christoph J; Covey, Daniel; Shon, Young-Min; Bennet, Kevin E; Garris, Paul A; Lee, Kendall H

    2009-01-01

    The Wireless Instantaneous Neurotransmitter Concentration Sensing System (WINCS) measures extracellular neurotransmitter concentration in vivo and displays the data graphically in nearly real time. WINCS implements two electroanalytical methods, fast-scan cyclic voltammetry (FSCV) and fixed-potential amperometry (FPA), to measure neurotransmitter concentrations at an electrochemical sensor, typically a carbon-fiber microelectrode. WINCS comprises a battery-powered patient module and a custom software application (WINCSware) running on a nearby personal computer. The patient module impresses upon the electrochemical sensor either a constant potential (for FPA) or a time-varying waveform (for FSCV). A transimpedance amplifier converts the resulting current to a signal that is digitized and transmitted to the base station via a Bluetooth radio link. WINCSware controls the operational parameters for FPA or FSCV, and records the transmitted data stream. Filtered data is displayed in various formats, including a background-subtracted plot of sequential FSCV scans - a representation that enables users to distinguish the signatures of various analytes with considerable specificity. Dopamine, glutamate, adenosine and serotonin were selected as analytes for test trials. Proof-of-principle tests included in vitro flow-injection measurements and in vivo measurements in rat and pig. Further testing demonstrated basic functionality in a 3-Tesla MRI unit. WINCS was designed in compliance with consensus standards for medical electrical device safety, and it is anticipated that its capability for real-time intraoperative monitoring of neurotransmitter release at an implanted sensor will prove useful for advancing functional neurosurgery.

  14. Sympathetic Neurotransmitters and Tumor Angiogenesis—Link between Stress and Cancer Progression

    Directory of Open Access Journals (Sweden)

    Jason Tilan

    2010-01-01

    Full Text Available Recent evidence supports a longstanding hypothesis that chronic stress can influence tumor growth and progression. It has been shown that sympathetic neurotransmitters, such as catecholamines and neuropeptides, can affect both cancer cell growth and tumor vascularization. Depending on neurotransmitter and type of tumor, these effects can be both stimulatory and inhibitory. Norepinephrine (NE and epinephrine (E are potent stimulators of vascularization, acting both by inducing the release of angiogenic factors from tumor cells and directly on endothelial cell (EC functions. As a result, activation of the adrenergic system increases growth of various types of tumors and has been shown to mediate stress-induced augmentation of tumor progression. Dopamine (DA, on the other hand, interferes with VEGF signaling in endothelial cells, blocks its angiogenic functions and inhibits tumor growth. Another sympathetic neurotransmitter coreleased with NE, neuropeptide Y (NPY, directly stimulates angiogenesis. However, proangiogenic actions of NPY can be altered by its direct effect on tumor cell proliferation and survival. In consequence, NPY can either stimulate or inhibit tumor growth, depending on tumor type. Hence, sympathetic neurotransmitters are powerful modulators of tumor growth and can become new targets in cancer therapy.

  15. Antidepressant Binding Site in a Bacterial Homologue of Neurotransmitter Transporters

    International Nuclear Information System (INIS)

    Singh, S.; Yamashita, A.; Gouaux, E.

    2007-01-01

    Sodium-coupled transporters are ubiquitous pumps that harness pre-existing sodium gradients to catalyse the thermodynamically unfavourable uptake of essential nutrients, neurotransmitters and inorganic ions across the lipid bilayer. Dysfunction of these integral membrane proteins has been implicated in glucose/galactose malabsorption, congenital hypothyroidism, Bartter's syndrome, epilepsy, depression, autism and obsessive-compulsive disorder. Sodium-coupled transporters are blocked by a number of therapeutically important compounds, including diuretics, anticonvulsants and antidepressants, many of which have also become indispensable tools in biochemical experiments designed to probe antagonist binding sites and to elucidate transport mechanisms. Steady-state kinetic data have revealed that both competitive and noncompetitive modes of inhibition exist. Antagonist dissociation experiments on the serotonin transporter (SERT) have also unveiled the existence of a low-affinity allosteric site that slows the dissociation of inhibitors from a separate high-affinity site. Despite these strides, atomic-level insights into inhibitor action have remained elusive. Here we screen a panel of molecules for their ability to inhibit LeuT, a prokaryotic homologue of mammalian neurotransmitter sodium symporters, and show that the tricyclic antidepressant (TCA) clomipramine noncompetitively inhibits substrate uptake. Cocrystal structures show that clomipramine, along with two other TCAs, binds in an extracellular-facing vestibule about 11 (angstrom) above the substrate and two sodium ions, apparently stabilizing the extracellular gate in a closed conformation. Off-rate assays establish that clomipramine reduces the rate at which leucine dissociates from LeuT and reinforce our contention that this TCA inhibits LeuT by slowing substrate release. Our results represent a molecular view into noncompetitive inhibition of a sodium-coupled transporter and define principles for the rational

  16. Antidepressant Binding Site in a Bacterial Homologue of Neurotransmitter Transporters

    Energy Technology Data Exchange (ETDEWEB)

    Singh,S.; Yamashita, A.; Gouaux, E.

    2007-01-01

    Sodium-coupled transporters are ubiquitous pumps that harness pre-existing sodium gradients to catalyse the thermodynamically unfavourable uptake of essential nutrients, neurotransmitters and inorganic ions across the lipid bilayer. Dysfunction of these integral membrane proteins has been implicated in glucose/galactose malabsorption, congenital hypothyroidism, Bartter's syndrome, epilepsy, depression, autism and obsessive-compulsive disorder. Sodium-coupled transporters are blocked by a number of therapeutically important compounds, including diuretics, anticonvulsants and antidepressants, many of which have also become indispensable tools in biochemical experiments designed to probe antagonist binding sites and to elucidate transport mechanisms. Steady-state kinetic data have revealed that both competitive and noncompetitive modes of inhibition exist. Antagonist dissociation experiments on the serotonin transporter (SERT) have also unveiled the existence of a low-affinity allosteric site that slows the dissociation of inhibitors from a separate high-affinity site. Despite these strides, atomic-level insights into inhibitor action have remained elusive. Here we screen a panel of molecules for their ability to inhibit LeuT, a prokaryotic homologue of mammalian neurotransmitter sodium symporters, and show that the tricyclic antidepressant (TCA) clomipramine noncompetitively inhibits substrate uptake. Cocrystal structures show that clomipramine, along with two other TCAs, binds in an extracellular-facing vestibule about 11 {angstrom} above the substrate and two sodium ions, apparently stabilizing the extracellular gate in a closed conformation. Off-rate assays establish that clomipramine reduces the rate at which leucine dissociates from LeuT and reinforce our contention that this TCA inhibits LeuT by slowing substrate release. Our results represent a molecular view into noncompetitive inhibition of a sodium-coupled transporter and define principles for the

  17. Characterizing Enzymatic Deposition for Microelectrode Neurotransmitter Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hosein, W. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Yorita, A. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tolosa, V. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-12

    The enzyme immobilization process, one step in creating an enzymatic biosensor, was characterized and analyzed as a function of its physical properties. The neural glutamic biosensor is a flexible device, effectively minimizing trauma to the area of implantation. The Multielectrode Array (MEA) is composed primarily of a proprietary polymer which has been successfully implanted into human subjects in recent years. This polymer allows the device the pliability that other devices normally lack, though this poses some challenges to implantation. The electrodes are made of Platinum (Pt), and can range in number from eight to thirty two electrodes per device. These electrodes are electroplated with a semipermeable polymer layer to improve selectivity of the electrode to the neurotransmitter of interest, in this case glutamate. A signal is created from the interaction of glutamate in the brain with the glutamate oxidase (GluOx) which is immobilized on the surface of the electrode by using crosslinking chemistry in conjunction with glutaraldehyde and Bovine Serum Albumin (BSA). The glutamate is oxidized by glutamate oxidase, producing α-ketoglutarate and hydrogen peroxide (H2O2) as a by-product. The production of H2O2 is crucial for detection of the presence of the glutamate within the enzymatic coating, as it diffuses through the enzyme layer and oxidizes at the surface of the electrode. This oxidation is detectable by measurable change in the current using amperometry. Hence, the MEA allows for in vivo monitoring of neurotransmitter activity in real time. The sensitivity of the sensor to these neurotransmitters is dependent on the thickness of the layer, which is investigated in these experiments in order to optimize the efficacy of the device to detecting the substrate, once implanted.

  18. Substrates for Neuronal Cotransmission With Neuropeptides and Small Molecule Neurotransmitters in Drosophila

    Science.gov (United States)

    Nässel, Dick R.

    2018-01-01

    It has been known for more than 40 years that individual neurons can produce more than one neurotransmitter and that neuropeptides often are colocalized with small molecule neurotransmitters (SMNs). Over the years much progress has been made in understanding the functional consequences of cotransmission in the nervous system of mammals. There are also some excellent invertebrate models that have revealed roles of coexpressed neuropeptides and SMNs in increasing complexity, flexibility, and dynamics in neuronal signaling. However, for the fly Drosophila there are surprisingly few functional studies on cotransmission, although there is ample evidence for colocalization of neuroactive compounds in neurons of the CNS, based both on traditional techniques and novel single cell transcriptome analysis. With the hope to trigger interest in initiating cotransmission studies, this review summarizes what is known about Drosophila neurons and neuronal circuits where different neuropeptides and SMNs are colocalized. Coexistence of neuroactive substances has been recorded in different neuron types such as neuroendocrine cells, interneurons, sensory cells and motor neurons. Some of the circuits highlighted here are well established in the analysis of learning and memory, circadian clock networks regulating rhythmic activity and sleep, as well as neurons and neuroendocrine cells regulating olfaction, nociception, feeding, metabolic homeostasis, diuretic functions, reproduction, and developmental processes. One emerging trait is the broad role of short neuropeptide F in cotransmission and presynaptic facilitation in a number of different neuronal circuits. This review also discusses the functional relevance of coexisting peptides in the intestine. Based on recent single cell transcriptomics data, it is likely that the neuronal systems discussed in this review are just a fraction of the total set of circuits where cotransmission occurs in Drosophila. Thus, a systematic search for

  19. Substrates for Neuronal Cotransmission With Neuropeptides and Small Molecule Neurotransmitters in Drosophila

    Directory of Open Access Journals (Sweden)

    Dick R. Nässel

    2018-03-01

    Full Text Available It has been known for more than 40 years that individual neurons can produce more than one neurotransmitter and that neuropeptides often are colocalized with small molecule neurotransmitters (SMNs. Over the years much progress has been made in understanding the functional consequences of cotransmission in the nervous system of mammals. There are also some excellent invertebrate models that have revealed roles of coexpressed neuropeptides and SMNs in increasing complexity, flexibility, and dynamics in neuronal signaling. However, for the fly Drosophila there are surprisingly few functional studies on cotransmission, although there is ample evidence for colocalization of neuroactive compounds in neurons of the CNS, based both on traditional techniques and novel single cell transcriptome analysis. With the hope to trigger interest in initiating cotransmission studies, this review summarizes what is known about Drosophila neurons and neuronal circuits where different neuropeptides and SMNs are colocalized. Coexistence of neuroactive substances has been recorded in different neuron types such as neuroendocrine cells, interneurons, sensory cells and motor neurons. Some of the circuits highlighted here are well established in the analysis of learning and memory, circadian clock networks regulating rhythmic activity and sleep, as well as neurons and neuroendocrine cells regulating olfaction, nociception, feeding, metabolic homeostasis, diuretic functions, reproduction, and developmental processes. One emerging trait is the broad role of short neuropeptide F in cotransmission and presynaptic facilitation in a number of different neuronal circuits. This review also discusses the functional relevance of coexisting peptides in the intestine. Based on recent single cell transcriptomics data, it is likely that the neuronal systems discussed in this review are just a fraction of the total set of circuits where cotransmission occurs in Drosophila. Thus, a

  20. Relationship of neurotransmitters to the symptoms of major depressive disorder.

    Science.gov (United States)

    Nutt, David J

    2008-01-01

    A relationship appears to exist between the 3 main monoamine neurotransmitters in the brain (i.e., dopamine, norepinephrine, and serotonin) and specific symptoms of major depressive disorder. Specific symptoms are associated with the increase or decrease of specific neurotransmitters, which suggests that specific symptoms of depression could be assigned to specific neurochemical mechanisms, and subsequently specific antidepressant drugs could target symptom-specific neurotransmitters. Research on electroconvulsive therapy has supported a correlation between neurotransmitters and depression symptoms. A 2-dimensional model of neurotransmitter functions is discussed that describes depression as a mixture of 2 separate components--negative affect and the loss of positive affect--that can be considered in relation to the 3 amine neurotransmitters. Owing to the different methods of action of available antidepressant agents and the depression symptoms thought to be associated with dopamine, serotonin, and norepinephrine, current treatments can be targeted toward patients' specific symptoms.

  1. Does human presynaptic striatal dopamine function predict social conformity?

    Science.gov (United States)

    Stokes, Paul R A; Benecke, Aaf; Puraite, Julita; Bloomfield, Michael A P; Shotbolt, Paul; Reeves, Suzanne J; Lingford-Hughes, Anne R; Howes, Oliver; Egerton, Alice

    2014-03-01

    Socially desirable responding (SDR) is a personality trait which reflects either a tendency to present oneself in an overly positive manner to others, consistent with social conformity (impression management (IM)), or the tendency to view one's own behaviour in an overly positive light (self-deceptive enhancement (SDE)). Neurochemical imaging studies report an inverse relationship between SDR and dorsal striatal dopamine D₂/₃ receptor availability. This may reflect an association between SDR and D₂/₃ receptor expression, synaptic dopamine levels or a combination of the two. In this study, we used a [¹⁸F]-DOPA positron emission tomography (PET) image database to investigate whether SDR is associated with presynaptic dopamine function. Striatal [¹⁸F]-DOPA uptake, (k(i)(cer), min⁻¹), was determined in two independent healthy participant cohorts (n=27 and 19), by Patlak analysis using a cerebellar reference region. SDR was assessed using the revised Eysenck Personality Questionnaire (EPQ-R) Lie scale, and IM and SDE were measured using the Paulhus Deception Scales. No significant associations were detected between Lie, SDE or IM scores and striatal [¹⁸F]-DOPA k(i)(cer). These results indicate that presynaptic striatal dopamine function is not associated with social conformity and suggests that social conformity may be associated with striatal D₂/₃ receptor expression rather than with synaptic dopamine levels.

  2. Laurate Biosensors Image Brain Neurotransmitters In Vivo: Can an Antihypertensive Medication Alter Psychostimulant Behavior?

    Directory of Open Access Journals (Sweden)

    Vivek Murthy

    2008-07-01

    Full Text Available Neuromolecular Imaging (NMI with novel biosensors enables the selective detection of neurotransmitters in vivo within seconds, on line and in real time. Biosensors remain in place for continuing studies over a period of months. This biotechnological advance is based on conventional electrochemistry; the biosensors detect neurotransmitters by electron transfer. Simply stated, biosensors adsorb electrons from each neurotransmitter at specific oxidation potentials; the current derived from electron transfer is proportional to neurotransmitter concentration. Selective electron transfer properties of these biosensors permit the imaging of neurotransmitters, metabolites and precursors. The novel BRODERICK PROBE® biosensors we have developed, differ in formulation and detection capabilities from biosensors/electrodes used in conventional electrochemistry/ voltammetry. In these studies, NMI, specifically, the BRODERICK PROBE® laurate biosensor images neurotransmitter signals within mesolimbic neuronal terminals, nucleus accumbens (NAc; dopamine (DA, serotonin (5-HT, homovanillic acid (HVA and Ltryptophan (L-TP are selectively imaged. Simultaneously, we use infrared photobeams to monitor open-field movement behaviors on line with NMI in the same animal subjects. The goals are to investigate integrated neurochemical and behavioral effects of cocaine and caffeine alone and co-administered and further, to use ketanserin to decipher receptor profiles for these psychostimulants, alone and co-administered. The rationale for selecting this medication is: ketanserin (a is an antihypertensive and cocaine and caffeine produce hypertension and (b acts at 5-HT2A/2C receptors, prevalent in NAc and implicated in hypertension and cocaine addiction. Key findings are: (a the moderate dose of caffeine simultaneously potentiates cocaine's neurochemical and behavioral responses. (b ketanserin simultaneously inhibits cocaine-increased DA and 5-HT release in

  3. Integrated Carbon Nanostructures for Detection of Neurotransmitters.

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    Sainio, Sami; Palomäki, Tommi; Tujunen, Noora; Protopopova, Vera; Koehne, Jessica; Kordas, Krisztian; Koskinen, Jari; Meyyappan, M; Laurila, Tomi

    2015-10-01

    Carbon-based materials, such as diamond-like carbon (DLC), carbon nanofibers (CNFs), and carbon nanotubes (CNTs), are inherently interesting for neurotransmitter detection due to their good biocompatibility, low cost and relatively simple synthesis. In this paper, we report on new carbon-hybrid materials, where either CNTs or CNFs are directly grown on top of tetrahedral amorphous carbon (ta-C). We show that these hybrid materials have electrochemical properties that not only combine the best characteristics of the individual "building blocks" but their synergy makes the electrode performance superior compared to conventional carbon based electrodes. By combining ta-C with CNTs, we were able to realize electrode materials that show wide and stable water window, almost reversible electron transfer properties and high sensitivity and selectivity for detecting dopamine in the presence of ascorbic acid. Furthermore, the sensitivity of ta-C + CNF hybrids towards dopamine as well as glutamate has been found excellent paving the road for actual in vivo measurements. The wide and stable water window of these sensors enables detection of other neurotransmitters besides DA as well as capability of withstanding higher potentials without suffering from oxygen and hydrogen evolution.

  4. Clinical features and pharmacotherapy of childhood monoamine neurotransmitter disorders.

    Science.gov (United States)

    Ng, J; Heales, S J R; Kurian, M A

    2014-08-01

    Childhood neurotransmitter disorders are increasingly recognised as an expanding group of inherited neurometabolic syndromes. They are caused by disturbance in synthesis, metabolism, and homeostasis of the monoamine neurotransmitters, including the catecholamines (dopamine, norepinephrine, and epinephrine) and serotonin. Disturbances in monoamine neurotransmission will lead to neurological symptoms that often overlap with clinical features of other childhood neurological disorders (such as hypoxic ischaemic encephalopathy, cerebral palsy, other movement disorders, and paroxysmal conditions); consequently, neurotransmitter disorders are frequently misdiagnosed. The diagnosis of neurotransmitter disorders is made through detailed clinical assessment, analysis of cerebrospinal fluid neurotransmitters, and further supportive diagnostic investigations. Early and accurate diagnosis of neurotransmitter disorders is important, as many are amenable to therapeutic intervention. The principles of treatment for monoamine neurotransmitter disorders are mainly directly derived from understanding these metabolic pathways. In disorders characterized by enzyme deficiency, we aim to increase monoamine substrate availability, boost enzyme co-factor levels, reduce monoamine breakdown, and replace depleted levels of monoamines with pharmacological analogs as clinically indicated. Most monoamine neurotransmitter disorders lead to reduced levels of central dopamine and/or serotonin. Complete amelioration of motor symptoms is achievable in some disorders, such as Segawa's syndrome, and, in other conditions, significant improvement in quality of life can be attained with pharmacotherapy. In this review, we provide an overview of the clinical features and current treatment strategies for childhood monoamine neurotransmitter disorders.

  5. Panel discussion: cCinical pet neurotransmitter metabolism and receptor binding studies of brain

    International Nuclear Information System (INIS)

    Frey, K.A.

    1991-01-01

    Following presentations on applications and results of PET imaging in Parkinson's disease (PD), Alzheimer's disease (AD), and refractory temporal lobe epilepsy, additional aspects of PET use in evaluating neurologic disease were discussed. Several questions addressed imaging of the dopamine (DA) synapse in PD. Discussion centered around reasons for focal hypometabolism of the association cortex in AD but not of the striatum in PD as well as potential applications of metabolic and presynaptic DA measurements in the diagnostic evaluation of Parkinsonian syndromes. The specificity of fluoroDOPA (FD) uptake following PD treatment by adrenal or substantia nigra transplantation was addressed. Blood-brain-barrier disruption and the metabolic instability of FD were discussed as underlying causes of increased tracer accumulation reported in the literature. The session then turned to dementia and the problem of establishing a definite diagnosis.The roles of PET and SPECT imaging in these areas is relatively new but is very promising. The session concluded with discussion of the possibility of activation studies with neurotransmitter ligands. The design and interpretation of such studies are quite complex. Physiologic stimulation studies frequently result in altered local cerebral perfusion; it will be necessary to distinguish differences in ligand distribution arising form blood flow changes from possible alterations in receptor availability. These interactions may also confound radioligand studies following pharmacologic interventions with unlabeled drugs

  6. Secondary Abnormalities of Neurotransmitters in Infants with Neurological Disorders

    Science.gov (United States)

    Garcia-Cazorla, A.; Serrano, M.; Perez-Duenas, B.; Gonzalez, V.; Ormazabal, A.; Pineda, M.; Fernandez-Alvarez, E.; Campistol, J. M. D.; Artuch, R. M. D.

    2007-01-01

    Neurotransmitters are essential in young children for differentiation and neuronal growth of the developing nervous system. We aimed to identify possible factors related to secondary neurotransmitter abnormalities in pediatric patients with neurological disorders. We analyzed cerebrospinal fluid (CSF) and biogenic amine metabolites in 56 infants…

  7. REM Sleep at its Core – Circuits, Neurotransmitters, and Pathophysiology

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    Fraigne, Jimmy J.; Torontali, Zoltan A.; Snow, Matthew B.; Peever, John H.

    2015-01-01

    Rapid eye movement (REM) sleep is generated and maintained by the interaction of a variety of neurotransmitter systems in the brainstem, forebrain, and hypothalamus. Within these circuits lies a core region that is active during REM sleep, known as the subcoeruleus nucleus (SubC) or sublaterodorsal nucleus. It is hypothesized that glutamatergic SubC neurons regulate REM sleep and its defining features such as muscle paralysis and cortical activation. REM sleep paralysis is initiated when glutamatergic SubC cells activate neurons in the ventral medial medulla, which causes release of GABA and glycine onto skeletal motoneurons. REM sleep timing is controlled by activity of GABAergic neurons in the ventrolateral periaqueductal gray and dorsal paragigantocellular reticular nucleus as well as melanin-concentrating hormone neurons in the hypothalamus and cholinergic cells in the laterodorsal and pedunculo-pontine tegmentum in the brainstem. Determining how these circuits interact with the SubC is important because breakdown in their communication is hypothesized to underlie narcolepsy/cataplexy and REM sleep behavior disorder (RBD). This review synthesizes our current understanding of mechanisms generating healthy REM sleep and how dysfunction of these circuits contributes to common REM sleep disorders such as cataplexy/narcolepsy and RBD. PMID:26074874

  8. REM sleep at its core—Circuits, neurotransmitters and pathophysiology

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    John ePeever

    2015-05-01

    Full Text Available REM sleep is generated and maintained by the interaction of a variety of neurotransmitter systems in the brainstem, forebrain and hypothalamus. Within these circuits lies a core region that is active during REM sleep, known as the subcoeruleus nucleus (SubC or sublaterodorsal nucleus. It is hypothesized that glutamatergic SubC neurons regulate REM sleep and its defining features such as muscle paralysis and cortical activation. REM sleep paralysis is initiated when glutamatergic SubC activate neurons in the ventral medial medulla (VMM, which causes release of GABA and glycine onto skeletal motoneurons. REM sleep timing is controlled by activity of GABAergic neurons in the ventrolateral periaqueductal gray (vlPAG and dorsal paragigantocellular reticular nucleus (DPGi as well as melanin-concentrating hormone (MCH neurons in the hypothalamus and cholinergic cells in the laterodorsal (LDT and pedunculo-pontine tegmentum (PPT in the brainstem. Determining how these circuits interact with the SubC is important because breakdown in their communication is hypothesized to underlie cataplexy/narcolepsy and REM sleep behaviour disorder (RBD. This review synthesizes our current understanding of mechanisms generating healthy REM sleep and how dysfunction of these circuits contributes to common REM sleep disorders such as cataplexy/narcolepsy and RBD.

  9. Four-dimensional multi-site photolysis of caged neurotransmitters

    Directory of Open Access Journals (Sweden)

    Mary Ann eGo

    2013-12-01

    Full Text Available Neurons receive thousands of synaptic inputs that are distributed in space and time. The systematic study of how neurons process these inputs requires a technique to stimulate multiple yet highly targeted points of interest along the neuron's dendritic tree. Three-dimensional multi-focal patterns produced via holographic projection combined with two-photon photolysis of caged compounds can provide for highly localized release of neurotransmitters within each diffraction-limited focus, and in this way emulate simultaneous synaptic inputs to the neuron. However, this technique so far cannot achieve time-dependent stimulation patterns due to fundamental limitations of the hologram-encoding device and other factors that affect the consistency of controlled synaptic stimulation. Here, we report an advanced technique that enables the design and application of arbitrary spatio-temporal photostimulation patterns that resemble physiological synaptic inputs. By combining holographic projection with a programmable high-speed light-switching array, we have overcome temporal limitations with holographic projection, allowing us to mimic distributed activation of synaptic inputs leading to action potential generation. Our experiments uniquely demonstrate multi-site two-photon glutamate uncaging in three dimensions with submillisecond temporal resolution. Implementing this approach opens up new prospects for studying neuronal synaptic integration in four dimensions.

  10. Calcium microdomains at presynaptic active zones of vertebrate hair cells unmasked by stochastic deconvolution.

    Science.gov (United States)

    Bortolozzi, Mario; Lelli, Andrea; Mammano, Fabio

    2008-08-01

    Signal transduction by auditory and vestibular hair cells involves an impressive ensemble of finely tuned control mechanisms, strictly dependent on the local intracellular Ca(2+) concentration ([Ca(2+)](i)). The study of Ca(2+) dynamics in hair cells typically combines Ca(2+)-sensitive fluorescent indicators (dyes), patch clamp and optical microscopy to produce images of the patterns of fluorescence of a Ca(2+) indicator following various stimulation protocols. Here we describe a novel method that combines electrophysiological recordings, fluorescence imaging and numerical simulations to effectively deconvolve Ca(2+) signals within cytoplasmic microdomains that would otherwise remain inaccessible to direct observation. The method relies on the comparison of experimental data with virtual signals derived from a Monte Carlo reaction-diffusion model based on a realistic reconstruction of the relevant cell boundaries in three dimensions. The model comprises Ca(2+) entry at individual presynaptic active zones followed by diffusion, buffering, extrusion and release of Ca(2+). Our results indicate that changes of the hair cell [Ca(2+)](i) during synaptic transmission are primarily controlled by the Ca(2+) endogenous buffers both at short (hair cell endogenous Ca(2+) buffers and Ca(2+)-ATPases. We finally show that experimental fluorescence data collected during Ca(2+) influx are not interpreted correctly if the [Ca(2+)](i) is estimated by assuming that Ca(2+) equilibrates instantly with its reactants. In our opinion, this approach is of potentially general interest as it can be easily adapted to the study of Ca(2+) dynamics in diverse biological systems.

  11. Unique presynaptic alpha 2-receptor selectivity and specificity of the antihypertensive agent moxonidine.

    Science.gov (United States)

    Armah, B I

    1988-10-01

    The characteristics of the alpha-receptor activating property of the new antihypertensive agent moxonidine (4-chloro-N-(4, 5-dihydro-1H-imidazol-2-yl)-6-methyl-2-methyl-5-pyrimidinamine, BDF 5895) was studied using peripheral vasculature and brain membranes of various animals. Moxonidine exerted a full agonist effect in elevating diastolic blood pressure in the pithed rat. Activation of postsynaptic alpha 1- and alpha 2-receptors contribute to the vasoconstrictory effect in rats. In the vasculature of the rabbit, moxonidine was a full agonist at presynaptic alpha 2-receptors in inhibiting transmitter release induced by electrical stimulation of pulmonary artery strips. At postsynaptic sites, exogenously applied moxonidine was a full agonist at alpha 1-receptors in the isolated aorta, pulmonary artery and vena cava of the rabbit. Selectivity for alpha 2-receptors in the pulmonary artery was 106-fold. In rat brain membranes, moxonidine showed 288-fold greater selectivity for alpha 2-receptors, when the displacement of [3H]-rauwolscine was compared with the displacement of [3H]-prazosin. On the whole, clonidine exhibited greater potency than moxonidine on both alpha-receptor subtypes, but moxonidine consistently showed greater alpha 2-receptor selectivity than clonidine. In the guinea pig myocardium, moxonidine caused neither bradycardia nor tachycardia in the isolated right atrium and produced a negligible positive inotropic effect at 100 mumol/l in the isolated papillary muscle.

  12. The molecular basis of memory. Part 3: tagging with "emotive" neurotransmitters.

    Science.gov (United States)

    Marx, Gerard; Gilon, Chaim

    2014-01-01

    Many neurons of all animals that exhibit memory (snails, worms, flies, vertebrae) present arborized shapes with many varicosities and boutons. These neurons, release neurotransmitters and contain ionotropic receptors that produce and sense electrical signals (ephaptic transmission). The extended shapes maximize neural contact with the surrounding neutrix [defined as: neural extracellular matrix (nECM) + diffusible (neurometals and neurotransmitters)] as well as with other neurons. We propose a tripartite mechanism of animal memory based on the dynamic interactions of splayed neurons with the "neutrix." Their interactions form cognitive units of information (cuinfo), metal-centered complexes within the nECM around the neuron. Emotive content is provided by NTs, which embody molecular links between physiologic (body) responses and psychic feelings. We propose that neurotransmitters form mixed complexes with cuinfo used for tagging emotive memory. Thus, NTs provide encoding option not available to a Turing, binary-based, device. The neurons employ combinatorially diverse options, with >10 NMs and >90 NTs for encoding ("flavoring") cuinfo with emotive tags. The neural network efficiently encodes, decodes and consolidates related (entangled) sets of cuinfo into a coherent pattern, the basis for emotionally imbued memory, critical for determining a behavioral choice aimed at survival. The tripartite mechanism with tagging of NTs permits of a causal connection between physiology and psychology.

  13. The molecular basis of memory. Part 3: tagging with “emotive” neurotransmitters

    Science.gov (United States)

    Marx, Gerard; Gilon, Chaim

    2014-01-01

    Many neurons of all animals that exhibit memory (snails, worms, flies, vertebrae) present arborized shapes with many varicosities and boutons. These neurons, release neurotransmitters and contain ionotropic receptors that produce and sense electrical signals (ephaptic transmission). The extended shapes maximize neural contact with the surrounding neutrix [defined as: neural extracellular matrix (nECM) + diffusible (neurometals and neurotransmitters)] as well as with other neurons. We propose a tripartite mechanism of animal memory based on the dynamic interactions of splayed neurons with the “neutrix.” Their interactions form cognitive units of information (cuinfo), metal-centered complexes within the nECM around the neuron. Emotive content is provided by NTs, which embody molecular links between physiologic (body) responses and psychic feelings. We propose that neurotransmitters form mixed complexes with cuinfo used for tagging emotive memory. Thus, NTs provide encoding option not available to a Turing, binary-based, device. The neurons employ combinatorially diverse options, with >10 NMs and >90 NTs for encoding (“flavoring”) cuinfo with emotive tags. The neural network efficiently encodes, decodes and consolidates related (entangled) sets of cuinfo into a coherent pattern, the basis for emotionally imbued memory, critical for determining a behavioral choice aimed at survival. The tripartite mechanism with tagging of NTs permits of a causal connection between physiology and psychology. PMID:24778616

  14. The Molecular Basis of Memory. Part 3: Tagging with emotive neurotransmitters.

    Directory of Open Access Journals (Sweden)

    Gerard eMarx

    2014-04-01

    Full Text Available Many neurons of all animals that exhibit memory (snails, worms, flies, vertebrae present arborized shapes with many varicosities and boutons. These neurons, release neurotransmitters and contain ionotropic receptors that produce and sense electrical signals (ephaptic transmission. The extended shapes maximize neural contact with the surrounding neutrix (neural extracellular matrix (nECM+ diffusible (neurometals and neurotransmitters as well as with other neurons. We propose a tripartite mechanism of animal memory based on the dynamic interactions of splayed neurons with the neutrix. Their interactions form cognitive units of information (cuinfo, metal-centered complexes within the nECM around the neuron. Emotive content is provided by NTs, which embody molecular links between physiologic (body responses and psychic feelings. We propose that neurotransmitters form mixed complexes with cuinfo used for tagging emotive memory.Thus, NTs provide encoding option not available to a Turing, binary-based, device.The neurons employ combinatorially diverse options, with > 10 NMs and > 90 NTs for encoding (flavoring cuinfo with emotive tags. The neural network efficiently encodes, decodes and consolidates related (entangled sets of cuinfo into a coherent pattern, the basis for emotionally imbued memory, critical for determining a behavioral choice aimed at survival. The tripartite mechanism with tagging of NTs permits of a causal connection between physiology and psychology.

  15. Challenges and recent advances in mass spectrometric imaging of neurotransmitters

    Science.gov (United States)

    Gemperline, Erin; Chen, Bingming; Li, Lingjun

    2014-01-01

    Mass spectrometric imaging (MSI) is a powerful tool that grants the ability to investigate a broad mass range of molecules, from small molecules to large proteins, by creating detailed distribution maps of selected compounds. To date, MSI has demonstrated its versatility in the study of neurotransmitters and neuropeptides of different classes toward investigation of neurobiological functions and diseases. These studies have provided significant insight in neurobiology over the years and current technical advances are facilitating further improvements in this field. neurotransmitters, focusing specifically on the challenges and recent Herein, we advances of MSI of neurotransmitters. PMID:24568355

  16. Presynaptic pH and vesicle fusion in Drosophila larvae neurones.

    Science.gov (United States)

    Caldwell, Lesley; Harries, Peter; Sydlik, Sebastian; Schwiening, Christof J

    2013-11-01

    Both intracellular pH (pHi) and synaptic cleft pH change during neuronal activity yet little is known about how these pH shifts might affect synaptic transmission by influencing vesicle fusion. To address this we imaged pH- and Ca(2+) -sensitive fluorescent indicators (HPTS, Oregon green) in boutons at neuromuscular junctions. Electrical stimulation of motor nerves evoked presynaptic Ca(2+) i rises and pHi falls (∼0.1 pH units) followed by recovery of both Ca(2+) i and pHi. The plasma-membrane calcium ATPase (PMCA) inhibitor, 5(6)-carboxyeosin diacetate, slowed both the calcium recovery and the acidification. To investigate a possible calcium-independent role for the pHi shifts in modulating vesicle fusion we recorded post-synaptic miniature end-plate potential (mEPP) and current (mEPC) frequency in Ca(2+) -free solution. Acidification by propionate superfusion, NH(4)(+) withdrawal, or the inhibition of acid extrusion on the Na(+)/H(+) exchanger (NHE) induced a rise in miniature frequency. Furthermore, the inhibition of acid extrusion enhanced the rise induced by propionate addition and NH(4)(+) removal. In the presence of NH(4)(+), 10 out of 23 cells showed, after a delay, one or more rises in miniature frequency. These findings suggest that Ca(2+) -dependent pHi shifts, caused by the PMCA and regulated by NHE, may stimulate vesicle release. Furthermore, in the presence of membrane permeant buffers, exocytosed acid or its equivalents may enhance release through positive feedback. This hitherto neglected pH signalling, and the potential feedback role of vesicular acid, could explain some important neuronal excitability changes associated with altered pH and its buffering. Copyright © 2013 Wiley Periodicals, Inc.

  17. Reactive oxygen species contribute to the presynaptic action of extracellular ATP at the frog neuromuscular junction

    Science.gov (United States)

    Giniatullin, AR; Grishin, SN; Sharifullina, ER; Petrov, AM; Zefirov, AL; Giniatullin, RA

    2005-01-01

    During normal cell metabolism the production of intracellular ATP is associated with the generation of reactive oxygen species (ROS), which appear to be important signalling molecules. Both ATP and ROS can be released extracellularly by skeletal muscle during intense activity. Using voltage clamp recording combined with imaging and biochemical assay of ROS, we tested the hypothesis that at the neuromuscular junction extracellular ATP generates ROS to inhibit transmitter release from motor nerve endings. We found that ATP produced the presynaptic inhibitory action on multiquantal end-plate currents. The inhibitory action of ATP (but not that of adenosine) was significantly reduced by several antioxidants or extracellular catalase, which breaks down H2O2. Consistent with these data, the depressant effect of ATP was dramatically potentiated by the pro-oxidant Fe2+. Exogenous H2O2 reproduced the depressant effects of ATP and showed similar sensitivity to anti- and pro-oxidants. While NO also inhibited synaptic transmission, inhibitors of the NO-producing cascade did not prevent the depressant action of ATP. The ferrous oxidation in xylenol orange assay showed the increase of ROS production by ATP and 2-MeSADP but not by adenosine. Suramin, a non-selective antagonist of P2 receptors, and pertussis toxin prevented the action of ATP on ROS production. Likewise, imaging with the ROS-sensitive dye carboxy-2′,7′-dichlorodihydrofluorescein revealed increased production of ROS in the muscle treated with ATP or ADP while UTP or adenosine had no effect. Thus, generation of ROS contributed to the ATP-mediated negative feedback mechanism controlling quantal secretion of ACh from the motor nerve endings. PMID:15774519

  18. Effects of focal brain cooling on extracellular concentrations of neurotransmitters in patients with epilepsy.

    Science.gov (United States)

    Nomura, Sadahiro; Inoue, Takao; Imoto, Hirochika; Suehiro, Eiichi; Maruta, Yuichi; Hirayama, Yuya; Suzuki, Michiyasu

    2017-04-01

    Brain hypothermia controls epileptic discharge and reduces extracellular concentrations of glutamate (Glu), an excitatory neurotransmitter. We aimed to determine the effects of focal brain cooling (FBC) on levels of γ-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter. The relationship between Glu or GABA concentrations and the severity of epileptic symptoms was also analyzed. Patients with intractable epilepsy underwent FBC at lesionectomized (n = 11) or hippocampectomized (n = 8) regions at 15°C for 30 min using custom-made cooling devices. Concentrations of Glu (n = 18) and GABA (n = 12) were measured in extracellular fluid obtained through microdialysis using high-performance liquid chromatography (HPLC). The reduction rate of neurotransmitter levels and its relationship with electrocorticography (ECoG) signal changes in response to FBC were measured. We found no relationship between the concentrations of Glu or GABA and seizure severity. There was a significant decrease in the concentration of Glu to 66.3% of control levels during the cooling period (p = 0.001). This rate of reduction correlated with ECoG power (r 2 = 0.68). Cortical and hippocampal GABA levels significantly (p = 0.02) and nonsignificantly decreased to 47.7% and 32.4% of control levels, respectively. However, the rate of this reduction did not correlate with ECoG (r 2 = 0.11). Although the decrease in hippocampal GABA levels was not significant due to wide variations in its concentration, the levels of cortical GABA and Glu were decreased following FBC. FBC suppresses epileptic discharge and the release of both excitatory and inhibitory neurotransmitters. The reduction in Glu levels further contributes to the reduction in epileptic discharge. However, the reduction in the levels of GABA has no impact on ECoG. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  19. Endocannabinoids control vesicle release mode at midbrain periaqueductal grey inhibitory synapses.

    Science.gov (United States)

    Aubrey, Karin R; Drew, Geoffrey M; Jeong, Hyo-Jin; Lau, Benjamin K; Vaughan, Christopher W

    2017-01-01

    The midbrain periaqueductal grey (PAG) forms part of an endogenous analgesic system which is tightly regulated by the neurotransmitter GABA. The role of endocannabinoids in regulating GABAergic control of this system was examined in rat PAG slices. Under basal conditions GABAergic neurotransmission onto PAG output neurons was multivesicular. Activation of the endocannabinoid system reduced GABAergic inhibition by reducing the probability of release and by shifting release to a univesicular mode. Blockade of endocannabinoid system unmasked a tonic control over the probability and mode of GABA release. These findings provides a mechanistic foundation for the control of the PAG analgesic system by disinhibition. The midbrain periaqueductal grey (PAG) has a crucial role in coordinating endogenous analgesic responses to physiological and psychological stressors. Endocannabinoids are thought to mediate a form of stress-induced analgesia within the PAG by relieving GABAergic inhibition of output neurons, a process known as disinhibition. This disinhibition is thought to be achieved by a presynaptic reduction in GABA release probability. We examined whether other mechanisms have a role in endocannabinoid modulation of GABAergic synaptic transmission within the rat PAG. The group I mGluR agonist DHPG ((R,S)-3,5-dihydroxyphenylglycine) inhibited evoked IPSCs and increased their paired pulse ratio in normal external Ca 2+ , and when release probability was reduced by lowering Ca 2+ . However, the effect of DHPG on the coefficient of variation and kinetics of evoked IPSCs differed between normal and low Ca 2+ . Lowering external Ca 2+ had a similar effect on evoked IPSCs to that observed for DHPG in normal external Ca 2+ . The low affinity GABA A receptor antagonist TPMPA ((1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid) inhibited evoked IPSCs to a greater extent in low than in normal Ca 2+ . Together these findings indicate that the normal mode of GABA release is

  20. Effect of purines on calcium-independent acetylcholine release at the mouse neuromuscular junction.

    Science.gov (United States)

    Veggetti, M; Muchnik, S; Losavio, A

    2008-07-17

    At the mouse neuromuscular junction, activation of adenosine A(1) and P2Y receptors inhibits acetylcholine release by an effect on voltage dependent calcium channels related to spontaneous and evoked secretion. However, an effect of purines upon the neurotransmitter-releasing machinery downstream of Ca(2+) influx cannot be ruled out. An excellent tool to study neurotransmitter exocytosis in a Ca(2+)-independent step is the hypertonic response. Intracellular recordings were performed on diaphragm fibers of CF1 mice to determine the action of the specific adenosine A(1) receptor agonist 2-chloro-N(6)-cyclopentyl-adenosine (CCPA) and the P2Y(12-13) agonist 2-methylthio-adenosine 5'-diphosphate (2-MeSADP) on the hypertonic response. Both purines significantly decreased such response (peak and area under the curve), and their effect was prevented by specific antagonists of A(1) and P2Y(12-13) receptors, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) and N-[2-(methylthioethyl)]-2-[3,3,3-trifluoropropyl]thio-5'-adenylic acid, monoanhydride with dichloromethylenebiphosphonic acid, tetrasodium salt (AR-C69931MX), respectively. Moreover, incubation of preparations only with the antagonists induced a higher response compared with controls, suggesting that endogenous ATP/ADP and adenosine are able to modulate the hypertonic response by activating their specific receptors. To search for the intracellular pathways involved in this effect, we studied the action of CCPA and 2-MeSADP in hypertonicity in the presence of inhibitors of several pathways. We found that the effect of CPPA was prevented by the calmodulin antagonist N-(6-aminohexil)-5-chloro-1-naphthalenesulfonamide hydrochloride (W-7) while that of 2-MeSADP was occluded by the protein kinase C antagonist chelerythrine and W-7. On the other hand, the inhibitors of protein kinase A (N-(2[pbromocinnamylamino]-ethyl)-5-isoquinolinesulfonamide, H-89) and phosphoinositide-3 kinase (PI3K) (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran

  1. Presynaptic localization of histamine H3-receptors in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, K.; Mizuguchi, H.; Fukui, H.; Wada, H. (Osaka Univ. (Japan))

    1991-06-28

    The localization of histamine H3-receptors in subcellular fractions from the rat brain was examined in a (3H) (R) alpha-methylhistamine binding assay and compared with those of histamine H1- and adrenaline alpha 1- and alpha 2-receptors. Major (3H)(R) alpha-methylhistamine binding sites with increased specific activities ((3H)ligand binding vs. protein amount) were recovered from the P2 fraction by differential centrifugation. Minor (3H)(R)alpha-methylhistamine binding sites with increased specific activities were also detected in the P3 fraction. Further subfractionation of the P2 fraction by discontinuous sucrose density gradient centrifugation showed major recoveries of (3H)(R)alpha-methylhistamine binding in myelin (MYE) and synaptic plasma membrane (SPM) fractions. A further increase in specific activity was observed in the MYE fraction, but the SPM fraction showed no significant increase in specific activity. Adrenaline alpha 2-receptors, the pre-synaptic autoreceptors, in a (3H) yohimbine binding assay showed distribution patterns similar to histamine H3-receptors. On the other hand, post-synaptic histamine H1- and adrenaline alpha 1-receptors were closely localized and distributed mainly in the SPM fraction with increased specific activity. Only a negligible amount was recovered in the MYE fraction, unlike the histamine H3- and adrenaline alpha 2-receptors.

  2. Dishevelled proteins are associated with olfactory sensory neuron presynaptic terminals.

    Directory of Open Access Journals (Sweden)

    Diego J Rodriguez-Gil

    Full Text Available Olfactory sensory neurons (OSNs project their axons from the olfactory epithelium toward the olfactory bulb (OB in a heterogeneous and unsorted arrangement. However, as the axons approach the glomerular layer of the OB, axons from OSNs expressing the same odorant receptor (OR sort and converge to form molecularly homogeneous glomeruli. Axon guidance cues, cell adhesion molecules, and OR induced activity have been implicated in the final targeting of OSN axons to specific glomeruli. Less understood, and often controversial, are the mechanisms used by OSN axons to initially navigate from the OE toward the OB. We previously demonstrated a role for Wnt and Frizzled (Fz molecules in OSN axon extension and organization within the olfactory nerve. Building on that we now turned our attention to the downstream signaling cascades from Wnt-Fz interactions. Dishevelled (Dvl is a key molecule downstream of Fz receptors. Three isoforms of Dvl with specific as well as overlapping functions are found in mammals. Here, we show that Dvl-1 expression is restricted to OSNs in the dorsal recess of the nasal cavity, and labels a unique subpopulation of glomeruli. Dvl-2 and Dvl-3 have a widespread distribution in both the OE and OB. Both Dvl-1 and Dvl-2 are associated with intra-glomerular pre-synaptic OSN terminals, suggesting a role in synapse formation/stabilization. Moreover, because Dvl proteins were observed in all OSN axons, we hypothesize that they are important determinants of OSN cell differentiation and axon extension.

  3. The presynaptic machinery at the synapse of C. elegans.

    Science.gov (United States)

    Calahorro, Fernando; Izquierdo, Patricia G

    2018-03-12

    Synapses are specialized contact sites that mediate information flow between neurons and their targets. Important physical interactions across the synapse are mediated by synaptic adhesion molecules. These adhesions regulate formation of synapses during development and play a role during mature synaptic function. Importantly, genes regulating synaptogenesis and axon regeneration are conserved across the animal phyla. Genetic screens in the nematode Caenorhabditis elegans have identified a number of molecules required for synapse patterning and assembly. C. elegans is able to survive even with its neuronal function severely compromised. This is in comparison with Drosophila and mice where increased complexity makes them less tolerant to impaired function. Although this fact may reflect differences in the function of the homologous proteins in the synapses between these organisms, the most likely interpretation is that many of these components are equally important, but not absolutely essential, for synaptic transmission to support the relatively undemanding life style of laboratory maintained C. elegans. Here, we review research on the major group of synaptic proteins, involved in the presynaptic machinery in C. elegans, showing a strong conservation between higher organisms and highlight how C. elegans can be used as an informative tool for dissecting synaptic components, based on a simple nervous system organization.

  4. Presynaptic localization of histamine H3-receptors in rat brain

    International Nuclear Information System (INIS)

    Fujimoto, K.; Mizuguchi, H.; Fukui, H.; Wada, H.

    1991-01-01

    The localization of histamine H3-receptors in subcellular fractions from the rat brain was examined in a [3H] (R) alpha-methylhistamine binding assay and compared with those of histamine H1- and adrenaline alpha 1- and alpha 2-receptors. Major [3H](R) alpha-methylhistamine binding sites with increased specific activities ([3H]ligand binding vs. protein amount) were recovered from the P2 fraction by differential centrifugation. Minor [3H](R)alpha-methylhistamine binding sites with increased specific activities were also detected in the P3 fraction. Further subfractionation of the P2 fraction by discontinuous sucrose density gradient centrifugation showed major recoveries of [3H](R)alpha-methylhistamine binding in myelin (MYE) and synaptic plasma membrane (SPM) fractions. A further increase in specific activity was observed in the MYE fraction, but the SPM fraction showed no significant increase in specific activity. Adrenaline alpha 2-receptors, the pre-synaptic autoreceptors, in a [3H] yohimbine binding assay showed distribution patterns similar to histamine H3-receptors. On the other hand, post-synaptic histamine H1- and adrenaline alpha 1-receptors were closely localized and distributed mainly in the SPM fraction with increased specific activity. Only a negligible amount was recovered in the MYE fraction, unlike the histamine H3- and adrenaline alpha 2-receptors

  5. Availability of neurotransmitter glutamate is diminished when beta-hydroxybutyrate replaces glucose in cultured neurons

    DEFF Research Database (Denmark)

    Lund, Trine Meldgaard; Risa, Øystein; Sonnewald, Ursula

    2009-01-01

    ,4-(13)C]beta-hydroxybutyrate to that of [1,6-(13)C]glucose in cultured glutamatergic neurons and investigated the effect of neuronal activity focusing on the aspartate-glutamate homeostasis, an essential component of the excitatory activity in the brain. The amount of (13)C incorporation and cellular...... reduced malate-aspartate shuttle activity in neurons using beta-hydroxybutyrate. In the presence of glucose, the glutamate content decreased significantly upon activation of neurotransmitter release, whereas in the presence of only beta-hydroxybutyrate, no decrease in the glutamate content was observed...

  6. Therapeutics of Neurotransmitters in Alzheimer’s Disease

    Science.gov (United States)

    Kandimalla, Ramesh; Reddy, P. Hemachandra

    2018-01-01

    Alzheimer’s disease (AD) is a progressive neurodegenerative disease, characterized by the loss of memory, multiple cognitive impairments and changes in the personality and behavior. Several decades of intense research have revealed that multiple cellular changes are involved in disease process, including synaptic damage, mitochondrial abnormalities and inflammatory responses, in addition to formation and accumulation of amyloid-β (Aβ) and phosphorylated tau. Although tremendous progress has been made in understanding the impact of neurotransmitters in the progression and pathogenesis of AD, we still do not have a drug molecule associated with neurotransmitter(s) that can delay disease process in elderly individuals and/or restore cognitive functions in AD patients. The purpose of our article is to assess the latest developments in neurotransmitters research using cell and mouse models of AD. We also updated the current status of clinical trials using neurotransmitters’ agonists/antagonists in AD. PMID:28211810

  7. Proton electrochemical gradient: Driving and regulating neurotransmitter uptake.

    Science.gov (United States)

    Farsi, Zohreh; Jahn, Reinhard; Woehler, Andrew

    2017-05-01

    Accumulation of neurotransmitters in the lumen of synaptic vesicles (SVs) relies on the activity of the vacuolar-type H + -ATPase. This pump drives protons into the lumen, generating a proton electrochemical gradient (Δμ H+ ) across the membrane. Recent work has demonstrated that the balance between the chemical (ΔpH) and electrical (ΔΨ) components of Δμ H+ is regulated differently by some distinct vesicle types. As different neurotransmitter transporters use ΔpH and ΔΨ with different relative efficiencies, regulation of this gradient balance has the potential to influence neurotransmitter uptake. Nevertheless, the underlying mechanisms responsible for this regulation remain poorly understood. In this review, we provide an overview of current neurotransmitter uptake models, with a particular emphasis on the distinct roles of the electrical and chemical gradients and current hypotheses for regulatory mechanisms. © 2017 WILEY Periodicals, Inc.

  8. Brain neurotransmitters in fatigue and overtraining.

    Science.gov (United States)

    Meeusen, Romain; Watson, Philip; Hasegawa, Hiroshi; Roelands, Bart; Piacentini, Maria F

    2007-10-01

    Since the publication of the serotonin hypothesis, numerous theories involving the accumulation or depletion of different substances in the brain have been proposed to explain central fatigue. Although the theoretical rationale for the "serotonin-fatigue hypothesis" is clear, several seemingly well-conducted studies have failed to support a significant role for 5-hydroxytryptamine in the development of fatigue. As brain function appears to be dependent upon the interaction of a number of systems, it is unlikely that a single neurotransmitter system is responsible for central fatigue. Several other mechanisms are involved, with evidence supporting a role for the brain catecholamines. Fatigue is therefore probably an integrated phenomenon, with complex interaction among central and peripheral factors. When prolonged and excessive training happens, concurrent with other stressors and insufficient recovery, performance decrements can result in chronic maladaptations that can lead to the overtraining syndrome (OTS). The mechanism of the OTS could be difficult to examine in detail, perhaps because the stress caused by excessive training load, in combination with other stressors, might trigger different "defence mechanisms" such as the immunological, neuroendocrine, and other physiological systems that all interact and probably therefore cannot be pinpointed as the "sole" cause of the OTS. It might be that, as in other syndromes, the psychoneuroimmunology (study of brain-behavior-immune interrelationships) might shed a light on the possible mechanisms of the OTS, but until there is a definite diagnostic tool, it is of utmost importance to standardize measures that are now thought to provide a good inventory of the training status of the athlete. It is very important to emphasize the need to distinguish the OTS from overreaching and other potential causes of temporary underperformance such as anemia, acute infection, muscle damage, and insufficient carbohydrate intake.

  9. Levodopa and pramipexole effects on presynaptic dopamine PET markers and estimated dopamine release

    Energy Technology Data Exchange (ETDEWEB)

    Sossi, Vesna; Fuente-Fernandez, Raul de la [University of British Columbia, Vancouver (Canada); Department of Physics and Astronomy, Vancouver, BC (Canada); Dinelle, Katherine; Doudet, Doris J. [University of British Columbia, Vancouver (Canada); Schulzer, Michael; Mak, Edwin [Department of Physics and Astronomy, Vancouver, BC (Canada)

    2010-12-15

    Levodopa and dopamine (DA) agonist therapy are two common treatments for Parkinson's disease (PD). There is controversy about the effects of these treatments on disease progression and imaging markers. Here we used multi-tracer positron emission tomography imaging and a unilateral 6-hydroxydopamine (6-OHDA) rat model of PD to evaluate in vivo the effects of chronic levodopa and pramipexole treatments on measurements of vesicular monoamine transporter type 2 (VMAT2), dopamine transporter (DAT) levels, and on levodopa-induced changes in synaptic DA levels [{delta}(DA)]. Twenty-three unilaterally 6-OHDA lesioned rats underwent an {sup 11}C-dihydrotetrabenazine (DTBZ, VMAT2 marker), an {sup 11}C-methylphenidate (MP, DAT marker), and a double {sup 11}C-raclopride (RAC, D{sub 2}-type receptor marker) scan. They were assigned to three treatment groups: saline (N = 7), pramipexole (N = 8), and levodopa (N = 8). After 4 weeks of treatment, imaging was repeated. Results showed (1) a significant treatment effect on DTBZ, with pramipexole decreasing DTBZ binding compared to levodopa, (2) significant side and treatment-striatal side interaction effects for MP, indicating that levodopa tends to decrease MP binding compared to pramipexole, and (3) no treatment effect on {delta}(DA). These data indicate that while chronic dopaminergic pharmacological treatment affects DTBZ and MP binding, it does not affect levodopa-induced changes in synaptic DA level. (orig.)

  10. New Treatments for Drug-Resistant Epilepsy that Target Presynaptic Transmitter Release

    Science.gov (United States)

    2015-07-01

    Pharmacol 2004; 4: 18-22. [75] Flor PJ, Battaglia G, Nicoletti F, Gasparini F, Bruno V. Neuroprotective activity of metabotropic glutamate receptor ligands...slices by multiphoton excitation of the styryl FM 1-43. Biotechniques. 2006 Mar ;40(3):343-51. [111] Zakharenko SS, Zablow L, Siegelbaum SA. Altered

  11. Monoamine neurotransmitter disorders--clinical advances and future perspectives.

    Science.gov (United States)

    Ng, Joanne; Papandreou, Apostolos; Heales, Simon J; Kurian, Manju A

    2015-10-01

    The monoamine neurotransmitter disorders are important genetic syndromes that cause disturbances in catecholamine (dopamine, noradrenaline and adrenaline) and serotonin homeostasis. These disorders result in aberrant monoamine synthesis, metabolism and transport. The clinical phenotypes are predominantly neurological, and symptoms resemble other childhood neurological disorders, such as dystonic or dyskinetic cerebral palsy, hypoxic ischaemic encephalopathy and movement disorders. As a consequence, monoamine neurotransmitter disorders are under-recognized and often misdiagnosed. The diagnosis of monoamine neurotransmitter disorders requires detailed clinical assessment, cerebrospinal fluid neurotransmitter analysis and further supportive diagnostic investigations. Prompt and accurate diagnosis of neurotransmitter disorders is paramount, as many are responsive to treatment. The treatment is usually mechanism-based, with the aim to reverse disturbances of monoamine synthesis and/or metabolism. Therapeutic intervention can lead to complete resolution of motor symptoms in some conditions, and considerably improve quality of life in others. In this Review, we discuss the clinical features, diagnosis and management of monoamine neurotransmitter disorders, and consider novel concepts, the latest advances in research and future prospects for therapy.

  12. Inter-channel scaffolding of presynaptic CaV2.2 via the C terminal PDZ ligand domain

    Directory of Open Access Journals (Sweden)

    Sabiha R. Gardezi

    2013-04-01

    Calcium entry through CaV2.2 calcium channels clustered at the active zone (AZ of the presynaptic nerve terminal gates synaptic vesicle (SV fusion and the discharge of neurotransmitters, but the mechanism of channel scaffolding remains poorly understood. Recent studies have implicated the binding of a PDZ ligand domain (PDZ-LD at the tip of the channel C terminal to a partner PDZ domain on RIM1/2, a synaptic vesicle-associated protein. To explore CaV2.2 scaffolding, we created intracellular region fusion proteins and used these to test for binding by ‘fishing’ for native CaV2.2 channels from cell lysates. Fusion proteins mimicking the distal half of the channel C terminal (C3strep reliably captured CaV2.2 from whole brain crude membrane or purified synaptosome membrane lysates, whereas channel I–II loop or the distal half of the II–III loop proteins were negative. This capture could be replicated in a non-synaptic environment using CaV2.2 expressed in a cell line. The distal tip PDZ-LD, DDWC-COOH, was confirmed as the critical binding site by block of pull-down with mimetic peptides. Pull-down experiments using brain crude membrane lysates confirmed that RIM1/2 can bind to the DDWC PDZ-LD. However, robust CaV2.2 capture was observed from synaptosome membrane or in the cell line expression system with little or no RIM1/2 co-capture. Thus, we conclude that CaV2.2 channels can scaffold to each other via an interaction that involves the PDZ-LD by an inter-channel linkage bridged by an unknown protein.

  13. Whereas Short-Term Facilitation Is Presynaptic, Intermediate-Term Facilitation Involves Both Presynaptic and Postsynaptic Protein Kinases and Protein Synthesis

    Science.gov (United States)

    Jin, Iksung; Kandel, Eric R.; Hawkins, Robert D.

    2011-01-01

    Whereas short-term plasticity involves covalent modifications that are generally restricted to either presynaptic or postsynaptic structures, long-term plasticity involves the growth of new synapses, which by its nature involves both pre- and postsynaptic alterations. In addition, an intermediate-term stage of plasticity has been identified that…

  14. Brain neurotransmitters and hippocampal proteome in pigs under stress and environmental enrichment

    Directory of Open Access Journals (Sweden)

    Laura Arroyo

    2017-06-01

    Full Text Available Stress and wellbeing are psychological conditions that are mediated by the central nervous system. In the brain, stress is mediated mainly by the hypothalamus, which will activate the hypothalamic-pituitary-adrenal (HPA axis, leading to the secretion of cortisol, the paradigmatic stress hormone. Other brain areas as the amygdala, the hippocampus or the prefrontal cortex (PFC are involved in emotions such as happiness, anxiety and fear. Communication between brain areas is achieved by chemical neurotransmitters (NTs, which are secreted by presynaptic neurons to reach postsynaptic neurons, where they will cause a variation in membrane polarization and other cell signaling actions, leading to physiological responses. Amongst these NTs, catecholamines (noradrenaline and dopamine and serotonin play an important role. On the other hand, the adverse effects of stress may be counteracted by housing the individuals under environmental enrichment conditions. This long-term situation should have an effect, not only on NTs, but also on the brain proteome. Under the hypothesis that different stress situations will lead to changes in NT composition that will be specific for crucial brain areas, we have tested the effects of transport stress, handling stress at the slaughterhouse, and the stress-susceptible genotype (Ryr1 on the amine NT concentration in amygdala, hippocampus, PFC and hypothalamus of pigs. The effects of living under environmentally enriched or control conditions on the NT concentration in several brain regions and on the hippocampus proteome has been also analyzed. In conclusion, genetic factors as well as management conditions related to housing, transport and slaughterhouse alter in different degree the catecholaminergic and the serotoninergic neurotransmission in the brain, and give clues about how different individual types are able to react to external challenges. Likewise, environmental enrichment leads to changes in the proteome

  15. Interplay between presynaptic and postsynaptic activities is required for dendritic plasticity and synaptogenesis in the supraoptic nucleus.

    Science.gov (United States)

    Chevaleyre, Vivien; Moos, Francoise C; Desarménien, Michel G

    2002-01-01

    Developing oxytocin and vasopressin (OT/AVP) supraoptic nucleus (SON) neurons positively autocontrol their electrical activity via dendritic release of their respective peptide. The effects of this autocontrol are maximum during the second postnatal week (PW2), when the dendritic arbor transiently increases and glutamatergic postsynaptic potentials appear. Here, we studied the role and interaction of dendritic OT/AVP release and glutamate release in dendritic plasticity and synaptogenesis in SON. In vivo treatment with the peptides antagonists or with an NMDA antagonist suppressed the transient increase in dendritic arbor of SON neurons at the beginning of PW2. Incubation of acute slices with these compounds decreased the dendritic arbor on a short time scale (3-8 hr) in slices of postnatal day 7 (P7) to P9 rats. Conversely, application of OT/AVP or NMDA increased dendritic branches in slices of P3-P6 rats. Their effects were inhibited by blockade of electrical activity, voltage-gated Ca2+ channels, or intracellular Ca2+ mobilization. They were also interdependent because both OT/AVP and NMDA (but not AMPA) receptor activation were required for increasing the dendritic arbor. Part of this interdependence probably results from a retrograde action of the peptides facilitating glutamate release. Finally, blocking OT/AVP receptors by in vivo treatment with the peptides antagonists during development decreased spontaneous glutamatergic synaptic activity recorded in young adults. These results show that an interplay between postsynaptic dendritic peptide release and presynaptic glutamate release is involved in the transient increase in dendritic arbor of SON neurons and indicate that OT/AVP are required for normal synaptogenesis of glutamatergic inputs in SON.

  16. Tuning Selectivity of Fluorescent Carbon Nanotube-Based Neurotransmitter Sensors.

    Science.gov (United States)

    Mann, Florian A; Herrmann, Niklas; Meyer, Daniel; Kruss, Sebastian

    2017-06-28

    Detection of neurotransmitters is an analytical challenge and essential to understand neuronal networks in the brain and associated diseases. However, most methods do not provide sufficient spatial, temporal, or chemical resolution. Near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) have been used as building blocks for sensors/probes that detect catecholamine neurotransmitters, including dopamine. This approach provides a high spatial and temporal resolution, but it is not understood if these sensors are able to distinguish dopamine from similar catecholamine neurotransmitters, such as epinephrine or norepinephrine. In this work, the organic phase (DNA sequence) around SWCNTs was varied to create sensors with different selectivity and sensitivity for catecholamine neurotransmitters. Most DNA-functionalized SWCNTs responded to catecholamine neurotransmitters, but both dissociation constants ( K d ) and limits of detection were highly dependent on functionalization (sequence). K d values span a range of 2.3 nM (SWCNT-(GC) 15 + norepinephrine) to 9.4 μM (SWCNT-(AT) 15 + dopamine) and limits of detection are mostly in the single-digit nM regime. Additionally, sensors of different SWCNT chirality show different fluorescence increases. Moreover, certain sensors (e.g., SWCNT-(GT) 10 ) distinguish between different catecholamines, such as dopamine and norepinephrine at low concentrations (50 nM). These results show that SWCNTs functionalized with certain DNA sequences are able to discriminate between catecholamine neurotransmitters or to detect them in the presence of interfering substances of similar structure. Such sensors will be useful to measure and study neurotransmitter signaling in complex biological settings.

  17. Altered Expression of Genes Encoding Neurotransmitter Receptors in GnRH Neurons of Proestrous Mice.

    Science.gov (United States)

    Vastagh, Csaba; Rodolosse, Annie; Solymosi, Norbert; Liposits, Zsolt

    2016-01-01

    Gonadotropin-releasing hormone (GnRH) neurons play a key role in the central regulation of reproduction. In proestrous female mice, estradiol triggers the pre-ovulatory GnRH surge, however, its impact on the expression of neurotransmitter receptor genes in GnRH neurons has not been explored yet. We hypothesized that proestrus is accompanied by substantial changes in the expression profile of genes coding for neurotransmitter receptors in GnRH neurons. We compared the transcriptome of GnRH neurons obtained from intact, proestrous, and metestrous female GnRH-GFP transgenic mice, respectively. About 1500 individual GnRH neurons were sampled from both groups and their transcriptome was analyzed using microarray hybridization and real-time PCR. In this study, changes in mRNA expression of genes involved in neurotransmitter signaling were investigated. Differential gene expression was most apparent in GABA-ergic ( Gabbr1, Gabra3, Gabrb3, Gabrb2, Gabrg2 ), glutamatergic ( Gria1, Gria2, Grin1, Grin3a, Grm1, Slc17a6 ), cholinergic ( Chrnb2, Chrm4 ) and dopaminergic ( Drd3, Drd4 ), adrenergic ( Adra1b, Adra2a, Adra2c ), adenosinergic ( Adora2a, Adora2b ), glycinergic ( Glra ), purinergic ( P2rx7 ), and serotonergic ( Htr1b ) receptors. In concert with these events, expression of genes in the signaling pathways downstream to the receptors, i.e., G-proteins ( Gnai1, Gnai2, Gnas ), adenylate-cyclases ( Adcy3, Adcy5 ), protein kinase A ( Prkaca, Prkacb ) protein kinase C ( Prkca ) and certain transporters ( Slc1a4, Slc17a6, Slc6a17 ) were also changed. The marked differences found in the expression of genes involved in neurotransmitter signaling of GnRH neurons at pro- and metestrous stages of the ovarian cycle indicate the differential contribution of these neurotransmitter systems to the induction of the pre-ovulatory GnRH surge, the known prerequisite of the subsequent hormonal cascade inducing ovulation.

  18. Altered expression of genes encoding neurotransmitter receptors in GnRH neurons of proestrous mice

    Directory of Open Access Journals (Sweden)

    Csaba Vastagh

    2016-10-01

    Full Text Available Gonadotropin-releasing hormone (GnRH neurons play a key role in the central regulation of reproduction. In proestrous female mice, estradiol triggers the pre-ovulatory GnRH surge, however, its impact on the expression of neurotransmitter receptor genes in GnRH neurons has not been explored yet. We hypothesized that proestrus is accompanied by substantial changes in the expression profile of genes coding for neurotransmitter receptors in GnRH neurons. We compared the transcriptome of GnRH neurons obtained from intact, proestrous and metestrous female GnRH-GFP transgenic mice, respectively. About 1500 individual GnRH neurons were sampled from both groups and their transcriptome was analyzed using microarray hybridization and real-time PCR. In this study, changes in mRNA expression of genes involved in neurotransmitter signaling were investigated. Differential gene expression was most apparent in GABA-ergic (Gabbr1, Gabra3, Gabrb3, Gabrb2, Gabrg2, glutamatergic (Gria1, Gria2, Grin1, Grin3a, Grm1, Slc17a6, cholinergic (Chrnb2, Chrm4 and dopaminergic (Drd3, Drd4, adrenergic (Adra1b, Adra2a, Adra2c, adenosinergic (Adora2a, Adora2b, glycinergic (Glra, purinergic (P2rx7 and serotonergic (Htr1b receptors. In concert with these events, expression of genes in the signaling pathways downstream to the receptors, i.e. G-proteins (Gnai1, Gnai2, Gnas, adenylate-cyclases (Adcy3, Adcy5, protein kinase A (Prkaca, Prkacb protein kinase C (Prkca and certain transporters (Slc1a4, Slc17a6, Slc6a17 were also changed. The marked differences found in the expression of genes involved in neurotransmitter signaling of GnRH neurons at pro- and metestrous stages of the ovarian cycle indicate the differential contribution of these neurotransmitter systems to the induction of the pre-ovulatory GnRH surge, the known prerequisite of the subsequent hormonal cascade inducing ovulation.

  19. Presynaptic plasticity as a hallmark of rat stress susceptibility and antidepressant response.

    Directory of Open Access Journals (Sweden)

    Jose Luis Nieto-Gonzalez

    Full Text Available Two main questions are important for understanding and treating affective disorders: why are certain individuals susceptible or resilient to stress, and what are the features of treatment response and resistance? To address these questions, we used a chronic mild stress (CMS rat model of depression. When exposed to stress, a fraction of rats develops anhedonic-like behavior, a core symptom of major depression, while another subgroup of rats is resilient to CMS. Furthermore, the anhedonic-like state is reversed in about half the animals in response to chronic escitalopram treatment (responders, while the remaining animals are resistant (non-responder animals. Electrophysiology in hippocampal brain slices was used to identify a synaptic hallmark characterizing these groups of animals. Presynaptic properties were investigated at GABAergic synapses onto single dentate gyrus granule cells. Stress-susceptible rats displayed a reduced probability of GABA release judged by an altered paired-pulse ratio of evoked inhibitory postsynaptic currents (IPSCs (1.48 ± 0.25 compared with control (0.81 ± 0.05 and stress-resilient rats (0.78 ± 0.03. Spontaneous IPSCs (sIPSCs occurred less frequently in stress-susceptible rats compared with control and resilient rats. Finally, a subset of stress-susceptible rats responding to selective serotonin reuptake inhibitor (SSRI treatment showed a normalization of the paired-pulse ratio (0.73 ± 0.06 whereas non-responder rats showed no normalization (1.2 ± 0.2. No changes in the number of parvalbumin-positive interneurons were observed. Thus, we provide evidence for a distinct GABAergic synaptopathy which associates closely with stress-susceptibility and treatment-resistance in an animal model of depression.

  20. `Full fusion' is not ineluctable during vesicular exocytosis of neurotransmitters by endocrine cells

    Science.gov (United States)

    Oleinick, Alexander; Svir, Irina; Amatore, Christian

    2017-01-01

    Vesicular exocytosis is an essential and ubiquitous process in neurons and endocrine cells by which neurotransmitters are released in synaptic clefts or extracellular fluids. It involves the fusion of a vesicle loaded with chemical messengers with the cell membrane through a nanometric fusion pore. In endocrine cells, unless it closes after some flickering (`Kiss-and-Run' events), this initial pore is supposed to expand exponentially, leading to a full integration of the vesicle membrane into the cell membrane-a stage called `full fusion'. We report here a compact analytical formulation that allows precise measurements of the fusion pore expansion extent and rate to be extracted from individual amperometric spike time courses. These data definitively establish that, during release of catecholamines, fusion pores enlarge at most to approximately one-fifth of the radius of their parent vesicle, hence ruling out the ineluctability of `full fusion'.

  1. Synthesis of symmetrical and non-symmetrical bivalent neurotransmitter ligands

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Andersen, Jacob; Thygesen, Mikkel Boas

    2016-01-01

    A novel procedure for synthesis of bivalent neurotransmitter ligands was developed by reacting O-benzyl protected N-nosylated dopamine and serotonin with alkyl- or PEG-linked diols under Fukuyama-Mitsunobu conditions in the presence of DIAD/PPh3 generating three different bivalent neurotransmitter...... ligands in a one-pot reaction. The methodol. establishes a facile route towards bivalent neurotransmitter ligands, and libraries of in total 40 sym. and non-sym. bivalent and monovalent dopamine and serotonin compds. linked through alkyl or PEG spacers of varying length were prepd. Interestingly......, attempted synthesis of an O-tert-Bu analog of the N-nosylated serotonin precursor resulted in unexpected tert-butylations at the 1-, 2- and 6-positions of the indole skeleton. We found that upscaling of selected bivalent serotonin ligands was most efficiently performed via N,O-bis-nosyl-serotonin since...

  2. Pharmacological approaches for Alzheimer's disease: neurotransmitter as drug targets.

    Science.gov (United States)

    Prakash, Atish; Kalra, Jaspreet; Mani, Vasudevan; Ramasamy, Kalavathy; Majeed, Abu Bakar Abdul

    2015-01-01

    Alzheimer's disease (AD) is the most common CNS disorder occurring worldwide. There is neither proven effective prevention for AD nor a cure for patients with this disorder. Hence, there is an urgent need to develop safer and more efficacious drugs to help combat the tremendous increase in disease progression. The present review is an attempt at discussing the treatment strategies and drugs under clinical trials governing the modulation of neurotransmitter. Therefore, looking at neurotransmitter abnormalities, there is an urge for developing the pharmacological approaches aimed at correcting those abnormalities and dysfunctioning. In addition, this review also discusses the drugs that are in Phase III trials for the treatment of AD. Despite advances in treatment strategies aimed at correcting neurotransmitter abnormalities, there exists a need for the development of drug therapies focusing on the attempts to remove the pathogenomic protein deposits, thus combating the disease progression.

  3. NEUROTRANSMITTER ABNORMALITIES AND RESPONSE TO SUPPLEMENTATION IN SPG11

    Science.gov (United States)

    Vanderver, Adeline; Tonduti, Davide; Auerbach, Sarah; Schmidt, Johanna L.; Parikh, Sumit; Gowans, Gordon C.; Jackson, Kelly E.; Brock, Pamela L.; Patterson, Marc; Nehrebecky, Michelle; Godfrey, Rena; Zein, Wadih M.; Gahl, William; Toro, Camilo

    2012-01-01

    Objective To report the detection of secondary neurotransmitter abnormalities in a group of SPG11 patients and describe treatment with L-dopa/carbidopa and sapropterin. Design Case reports Setting National Institutes of Health in the context of the Undiagnosed Disease Program; Children’s National Medical Center in the context of Myelin Disorders Bioregistry Program Patients Four SPG11 patients with a clinical picture of progressive spastic paraparesis complicated by extrapyramidal symptoms and maculopathy Interventions L-dopa/carbidopa and sapropterin Results 3/4 patients presented secondary neurotransmitter abnormalities; 4/4 partially responded to L-dopa as well as sapropterin Conclusions In the SPG11 patient with extrapyramidal symptoms, a trial of L-dopa/carbidopa and sapropterin and/or evaluation of cerebrospinal fluid neurotransmitters should be considered. PMID:22749184

  4. Muscle Contraction Regulates BDNF/TrkB Signaling to Modulate Synaptic Function through Presynaptic cPKCα and cPKCβI

    Directory of Open Access Journals (Sweden)

    Erica Hurtado

    2017-05-01

    Full Text Available The neurotrophin brain-derived neurotrophic factor (BDNF acts via tropomyosin-related kinase B receptor (TrkB to regulate synapse maintenance and function in the neuromuscular system. The potentiation of acetylcholine (ACh release by BDNF requires TrkB phosphorylation and Protein Kinase C (PKC activation. BDNF is secreted in an activity-dependent manner but it is not known if pre- and/or postsynaptic activities enhance BDNF expression in vivo at the neuromuscular junction (NMJ. Here, we investigated whether nerve and muscle cell activities regulate presynaptic conventional PKC (cPKCα and βI via BDNF/TrkB signaling to modulate synaptic strength at the NMJ. To differentiate the effects of presynaptic activity from that of muscle contraction, we stimulated the phrenic nerve of rat diaphragms (1 Hz, 30 min with or without contraction (abolished by μ-conotoxin GIIIB. Then, we performed ELISA, Western blotting, qRT-PCR, immunofluorescence and electrophysiological techniques. We found that nerve-induced muscle contraction: (1 increases the levels of mature BDNF protein without affecting pro-BDNF protein or BDNF mRNA levels; (2 downregulates TrkB.T1 without affecting TrkB.FL or p75 neurotrophin receptor (p75 levels; (3 increases presynaptic cPKCα and cPKCβI protein level through TrkB signaling; and (4 enhances phosphorylation of cPKCα and cPKCβI. Furthermore, we demonstrate that cPKCβI, which is exclusively located in the motor nerve terminals, increases activity-induced acetylcholine release. Together, these results show that nerve-induced muscle contraction is a key regulator of BDNF/TrkB signaling pathway, retrogradely activating presynaptic cPKC isoforms (in particular cPKCβI to modulate synaptic function. These results indicate that a decrease in neuromuscular activity, as occurs in several neuromuscular disorders, could affect the BDNF/TrkB/PKC pathway that links pre- and postsynaptic activity to maintain neuromuscular function.

  5. Benzodiazepine receptor and neurotransmitter studies in the brain of suicides

    Energy Technology Data Exchange (ETDEWEB)

    Manchon, M.; Kopp, N.; Rouzioux, J.J.; Lecestre, D.; Deluermoz, S.; Miachon, S.

    1987-12-14

    The characteristics of benzodiazepine binding sites were studied on frozen sections of hippocampus of 7 suicides and 5 controls subjects, using biochemical and autoradiographic techniques. /sup 3/H flunitrazepam was used as ligand, clonazepam and CL 218,872 as displacing agents. Some neurotransmitters or their derivatives were evaluated quantitatively in parallel in the hippocampal tissue by liquid chromatography. The authors observed mainly an increase in the Ki of CL 218,872 subtype I binding sites in suicides, and an increase in % of type I binding sites. Among neurotransmitters, only norepinephrine differed significantly between controls and suicides. 36 references, 3 figures, 1 table.

  6. Benzodiazepine receptor and neurotransmitter studies in the brain of suicides

    International Nuclear Information System (INIS)

    Manchon, M.; Kopp, N.; Rouzioux, J.J.; Lecestre, D.; Deluermoz, S.; Miachon, S.

    1987-01-01

    The characteristics of benzodiazepine binding sites were studied on frozen sections of hippocampus of 7 suicides and 5 controls subjects, using biochemical and autoradiographic techniques. 3 H flunitrazepam was used as ligand, clonazepam and CL 218,872 as displacing agents. Some neurotransmitters or their derivatives were evaluated quantitatively in parallel in the hippocampal tissue by liquid chromatography. The authors observed mainly an increase in the Ki of CL 218,872 subtype I binding sites in suicides, and an increase in % of type I binding sites. Among neurotransmitters, only norepinephrine differed significantly between controls and suicides. 36 references, 3 figures, 1 table

  7. Expression of presynaptic markers in a neurodevelopmental animal model with relevance to schizophrenia

    DEFF Research Database (Denmark)

    Karlsen, Anna S; Kaalund, Sanne Simone; Møller, Morten

    2013-01-01

    Administration of N-methyl-D-aspartate receptor antagonist phencyclidine (PCP) to rat pups at postnatal day (PND) 7, 9, and 11 [neonatal PCP (neoPCP) model] induces cognitive deficits similar to those observed in schizophrenia. Expression of presynaptic SNARE protein, synaptosomal......-associated protein of 25 kDa (Snap25), has been shown to be downregulated in postmortem brains from patients with schizophrenia. The present study was designed to investigate the long-term effects of neoPCP administration on expression of presynaptic markers altered in schizophrenia. Using radioactive in...

  8. Axonal and presynaptic protein synthesis: new insights into the biology of the neuron.

    Science.gov (United States)

    Giuditta, Antonio; Kaplan, Barry B; van Minnen, Jan; Alvarez, Jaime; Koenig, Edward

    2002-08-01

    The presence of a local mRNA translation system in axons and terminals was proposed almost 40 years ago. Over the ensuing period, an impressive body of evidence has grown to support this proposal -- yet the nerve cell body is still considered to be the only source of axonal and presynaptic proteins. To dispel this lingering neglect, we now present the wealth of recent observations bearing on this central idea, and consider their impact on our understanding of the biology of the neuron. We demonstrate that extrasomatic translation sites, which are now well recognized in dendrites, are also present in axonal and presynaptic compartments.

  9. Peptides and neurotransmitters that affect renin secretion

    Science.gov (United States)

    Ganong, W. F.; Porter, J. P.; Bahnson, T. D.; Said, S. I.

    1984-01-01

    Substance P inhibits renin secretion. This polypeptide is a transmitter in primary afferent neurons and is released from the peripheral as well as the central portions of these neurons. It is present in afferent nerves from the kidneys. Neuropeptide Y, which is a cotransmitter with norepinephrine and epinephrine, is found in sympathetic neurons that are closely associated with and presumably innervate the juxtagolmerular cells. Its effect on renin secretion is unknown, but it produces renal vasoconstriction and natriuresis. Vasoactive intestinal polypeptide (VIP) is a cotransmitter with acetylocholine in cholinergic neurons, and this polypeptide stimulates renin secretion. We cannot find any evidence for its occurence in neurons in the kidneys, but various stimuli increase plasma VIP to levels comparable to those produced by doses of exogenous VIP which stimulated renin secretion. Neostigmine increases plasma VIP and plasma renin activity, and the VIP appears to be responsible for the increase in renin secretion, since the increase is not blocked by renal denervation or propranolol. Stimulation of various areas in the brain produces sympathetically mediated increases in plasma renin activity associated with increases in blood pressure. However, there is pharmacological evidence that the renin response can be separated from the blood pressure response. In anaesthetized dogs, drugs that increase central serotonergic discharge increase renin secretion without increasing blood pressure. In rats, activation of sertonergic neurons in the dorsal raphe nucleus increases renin secretion by a pathway that projects from this nucleus to the ventral hypothalamus, and from there to the kidneys via the sympathetic nervous system. The serotonin releasing drug parachloramphetamine also increases plasma VIP, but VIP does not appear to be the primary mediator of the renin response. There is preliminary evidence that the serotonergic neurons in the dorsal raphe nucleus are part of the

  10. High dose sapropterin dihydrochloride therapy improves monoamine neurotransmitter turnover in murine phenylketonuria (PKU)

    Science.gov (United States)

    Winn, Shelley R; Scherer, Tanya; Thöny, Beat; Harding, Cary O

    2015-01-01

    Central nervous system (CNS) deficiencies of the monoamine neurotransmitters, dopamine and serotonin, have been implicated in the pathophysiology of neuropsychiatric dysfunction in phenylketonuria (PKU). Increased brain phenylalanine concentration likely competitively inhibits the activities of tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), the rate limiting steps in dopamine and serotonin synthesis respectively. Tetrahydrobiopterin (BH4) is a required cofactor for TH and TPH activity. Our hypothesis was that treatment of hyperphenylalaninemic Pahenu2/enu2 mice, a model of human PKU, with sapropterin dihydrochloride, a synthetic form of BH4, would stimulate TH and TPH activities leading to improved dopamine and serotonin synthesis despite persistently elevated brain phenylalanine. Sapropterin (20, 40, or 100 mg/kg body weight in 1% ascorbic acid) was administered daily for 4 days by oral gavage to Pahenu2/enu2 mice followed by measurement of brain biopterin, phenylalanine, tyrosine, tryptophan and monoamine neurotransmitter content. A significant increase in brain biopterin content was detected only in mice that had received the highest sapropterin dose, 100 mg/kg. Blood and brain phenylalanine concentrations were unchanged by sapropterin therapy. Sapropterin therapy also did not alter the absolute amounts of dopamine and serotonin in brain but was associated with increased homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), dopamine and serotonin metabolites respectively, in both wild type and Pahenu2/enu2 mice. Oral sapropterin therapy likely does not directly affect central nervous system monoamine synthesis in either wild type or hyperphenylalaninemic mice but may stimulate synaptic neurotransmitter release and subsequent metabolism. PMID:26653793

  11. Secondary neurotransmitter deficiencies in epilepsy caused by voltage-gated sodium channelopathies: A potential treatment target?

    Science.gov (United States)

    Horvath, Gabriella A; Demos, Michelle; Shyr, Casper; Matthews, Allison; Zhang, Linhua; Race, Simone; Stockler-Ipsiroglu, Sylvia; Van Allen, Margot I; Mancarci, Ogan; Toker, Lilah; Pavlidis, Paul; Ross, Colin J; Wasserman, Wyeth W; Trump, Natalie; Heales, Simon; Pope, Simon; Cross, J Helen; van Karnebeek, Clara D M

    2016-01-01

    We describe neurotransmitter abnormalities in two patients with drug-resistant epilepsy resulting from deleterious de novo mutations in sodium channel genes. Whole exome sequencing identified a de novo SCN2A splice-site mutation (c.2379+1G>A, p.Glu717Gly.fs*30) resulting in deletion of exon 14, in a 10-year old male with early onset global developmental delay, intermittent ataxia, autism, hypotonia, epileptic encephalopathy and cerebral/cerebellar atrophy. In the cerebrospinal fluid both homovanillic acid and 5-hydroxyindoleacetic acid were significantly decreased; extensive biochemical and genetic investigations ruled out primary neurotransmitter deficiencies and other known inborn errors of metabolism. In an 8-year old female with an early onset intractable epileptic encephalopathy, developmental regression, and progressive cerebellar atrophy, a previously unreported de novo missense mutation was identified in SCN8A (c.5615G>A; p.Arg1872Gln), affecting a highly conserved residue located in the C-terminal of the Nav1.6 protein. Aside from decreased homovanillic acid and 5-hydroxyindoleacetic acid, 5-methyltetrahydrofolate was also found to be low. We hypothesize that these channelopathies cause abnormal synaptic mono-amine metabolite secretion/uptake via impaired vesicular release and imbalance in electrochemical ion gradients, which in turn aggravate the seizures. Treatment with oral 5-hydroxytryptophan, l-Dopa/Carbidopa, and a dopa agonist resulted in mild improvement of seizure control in the male case, most likely via dopamine and serotonin receptor activated signal transduction and modulation of glutamatergic, GABA-ergic and glycinergic neurotransmission. Neurotransmitter analysis in other sodium channelopathy patients will help validate our findings, potentially yielding novel treatment opportunities. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. SELF ADMINISTRATION OF OXYCODONE BY ADOLESCENT AND ADULT MICE AFFECTS STRIATAL NEUROTRANSMITTER RECEPTOR GENE EXPRESSION

    Science.gov (United States)

    Mayer-Blackwell, B.; Schlussman, S. D.; Butelman, E. R.; Ho, A.; Ott, J.; Kreek, M. J.; Zhang, Y.

    2014-01-01

    Illicit use of prescription opioid analgesics (e.g., oxycodone) in adolescence is a pressing public health issue. Our goal was to determine whether oxycodone self administration differentially affects striatal neurotransmitter receptor gene expression in the dorsal striatum of adolescent compared to adult C57BL/6J mice. Groups of adolescent mice (4 weeks old, n= 12) and of adult mice (11 weeks old, n= 11) underwent surgery during which a catheter was implanted into their jugular veins. After recovering from surgery, mice self administered oxycodone (0.25 mg/kg/infusion) 2 h/day for 14 consecutive days or served as yoked saline controls. Mice were sacrificed within 1 h after the last self-administration session and the dorsal striatum was isolated for mRNA analysis. Gene expression was analyzed with real time PCR using a commercially available neurotransmitter receptor PCR array containing 84 genes. We found that adolescent mice self administered less oxycodone than adult mice over the 14 days. Monoamine oxidase A (Maoa) and neuropeptide Y receptor 5 mRNA levels were lower in adolescent mice than in adult mice without oxycodone exposure. Oxycodone self administration increased Maoa mRNA levels compared to controls in both age groups. There was a positive correlation of the amount of oxycodone self administered in the last session or across 14 sessions with Maoa mRNA levels. Gastrin-releasing peptide receptor mRNA showed a significant Drug × Age interaction, with point-wise significance. More genes in the dorsal striatum of adolescents (19) changed in response to oxycodone self administration compared to controls than in adult (4) mice. Overall, this study demonstrates that repeated oxycodone self administration alters neurotransmitter receptors gene expression in the dorsal striatum of adolescent and adult mice. PMID:24220688

  13. High dose sapropterin dihydrochloride therapy improves monoamine neurotransmitter turnover in murine phenylketonuria (PKU).

    Science.gov (United States)

    Winn, Shelley R; Scherer, Tanja; Thöny, Beat; Harding, Cary O

    2016-01-01

    Central nervous system (CNS) deficiencies of the monoamine neurotransmitters, dopamine and serotonin, have been implicated in the pathophysiology of neuropsychiatric dysfunction in phenylketonuria (PKU). Increased brain phenylalanine concentration likely competitively inhibits the activities of tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), the rate limiting steps in dopamine and serotonin synthesis respectively. Tetrahydrobiopterin (BH4) is a required cofactor for TH and TPH activity. Our hypothesis was that treatment of hyperphenylalaninemic Pah(enu2/enu2) mice, a model of human PKU, with sapropterin dihydrochloride, a synthetic form of BH4, would stimulate TH and TPH activities leading to improved dopamine and serotonin synthesis despite persistently elevated brain phenylalanine. Sapropterin (20, 40, or 100mg/kg body weight in 1% ascorbic acid) was administered daily for 4 days by oral gavage to Pah(enu2/enu2) mice followed by measurement of brain biopterin, phenylalanine, tyrosine, tryptophan and monoamine neurotransmitter content. A significant increase in brain biopterin content was detected only in mice that had received the highest sapropterin dose, 100mg/kg. Blood and brain phenylalanine concentrations were unchanged by sapropterin therapy. Sapropterin therapy also did not alter the absolute amounts of dopamine and serotonin in brain but was associated with increased homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), dopamine and serotonin metabolites respectively, in both wild type and Pah(enu2/enu2) mice. Oral sapropterin therapy likely does not directly affect central nervous system monoamine synthesis in either wild type or hyperphenylalaninemic mice but may stimulate synaptic neurotransmitter release and subsequent metabolism. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. A Critical Assessment of Research on Neurotransmitters in Alzheimer’s Disease

    Science.gov (United States)

    Reddy, P. Hemachandra

    2018-01-01

    The purpose of this mini-forum, “Neurotransmitters and Alzheimer’s Disease”, is to critically assess the current status of neurotransmitters in Alzheimer’s disease. Neurotransmitters are essential neurochemicals that maintain synaptic and cognitive functions in mammals, including humans, by sending signals across pre- to post-synaptic neurons. Authorities in the fields of synapses and neurotransmitters of Alzheimer’s disease summarize the current status of basic biology of synapses and neurotransmitters, and also update the current status of clinical trials of neurotransmitters in Alzheimer’s disease. This article discusses the prevalence, economic impact, and stages of Alzheimer’s dementia in humans. PMID:28409748

  15. What is the role of neurotransmitter systems in cortical seizures?

    Czech Academy of Sciences Publication Activity Database

    Mareš, Pavel; Kubová, Hana

    2008-01-01

    Roč. 57, Suppl.3 (2008), S111-S120 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LC554 Institutional research plan: CEZ:AV0Z50110509 Keywords : neurotransmitters * cerebral cortex * seizures Subject RIV: FH - Neurology Impact factor: 1.653, year: 2008

  16. Glucagon-related peptide 1 (GLP-1): hormone and neurotransmitter

    DEFF Research Database (Denmark)

    Larsen, Philip J; Holst, Jens Juul

    2005-01-01

    normal and pathophysiological role of GLP-1 have been published over the last two decades and our understanding of GLP-1 action has widened considerably. In the present review, we have tried to cover our current understanding of GLP-1 actions both as a peripheral hormone and as a central neurotransmitter...

  17. Inherited disorders of brain neurotransmitters: pathogenesis and diagnostic approach.

    Science.gov (United States)

    Szymańska, Krystyna; Kuśmierska, Katarzyna; Demkow, Urszula

    2015-01-01

    Neurotransmitters (NTs) play a central role in the efficient communication between neurons necessary for normal functioning of the nervous system. NTs can be divided into two groups: small molecule NTs and larger neuropeptide NTs. Inherited disorders of NTs result from a primary disturbance of NTs metabolism or transport. This group of disorders requires sophisticated diagnostic procedures. In this review we discuss disturbances in the metabolism of tetrahydrobiopterin, biogenic amines, γ-aminobutyric acid, foliate, pyridoxine-dependent enzymes, and also the glycine-dependent encephalopathy. We point to pathologic alterations of proteins involved in synaptic neurotransmission that may cause neurological and psychiatric symptoms. We postulate that synaptic receptors and transporter proteins for neurotransmitters should be investigated in unresolved cases. Patients with inherited neurotransmitters disorders present various clinical presentations such as mental retardation, refractory seizures, pyramidal and extrapyramidal syndromes, impaired locomotor patterns, and progressive encephalopathy. Every patient with suspected inherited neurotransmitter disorder should undergo a structured interview and a careful examination including neurological, biochemical, and imaging.

  18. Table S1 Basic characteristics of 32 SNPs of neurotransmitter ...

    Indian Academy of Sciences (India)

    微软用户

    Table 1. Basic characteristics of 32 SNPs in neurotransmitter-related genes. Gene. SNP ID. Allele variants. Chromosome. Genomic position (bp). Intermarker distances (bp). Genic position .... (head to back of shoulder), Middle (back of shoulder to hind-quarters), Hind-quarters, and Legs (from the accessory digit upwards).

  19. Impact of aspartame consumption on neurotransmitters in rat brain ...

    African Journals Online (AJOL)

    Background: Aspartame (APM), a common artificial sweetener, has been used for diabetic subjects and body weight control for a long time. The goal of the present study was to evaluate the impact of APM consumption on neurotransmitters and oxidative stress in rat's brain. Materials and Methods: Four groups of male ...

  20. The Top 5 Neurotransmitters from a Clinical Neurologist's Perspective

    DEFF Research Database (Denmark)

    Kondziella, Daniel

    2017-01-01

    that we routinely prescribe. Most of us can hardly come up with more than a handful of relevant neurochemicals. From our point of view the most important neurotransmitters are, in alphabetical order, acetylcholine (associated with Alzheimer's disease and myasthenia gravis), dopamine (Parkinson's disease...

  1. Detection and monitoring of neurotransmitters--a spectroscopic analysis.

    Science.gov (United States)

    Manciu, Felicia S; Lee, Kendall H; Durrer, William G; Bennet, Kevin E

    2013-01-01

    We demonstrate that confocal Raman mapping spectroscopy provides rapid, detailed, and accurate neurotransmitter analysis, enabling millisecond time resolution monitoring of biochemical dynamics. As a prototypical demonstration of the power of the method, we present real-time in vitro serotonin, adenosine, and dopamine detection, and dopamine diffusion in an inhomogeneous organic gel, which was used as a substitute for neurologic tissue.  Dopamine, adenosine, and serotonin were used to prepare neurotransmitter solutions in distilled water. The solutions were applied to the surfaces of glass slides, where they interdiffused. Raman mapping was achieved by detecting nonoverlapping spectral signatures characteristic of the neurotransmitters with an alpha 300 WITec confocal Raman system, using 532 nm neodymium-doped yttrium aluminum garnet laser excitation. Every local Raman spectrum was recorded in milliseconds and complete Raman mapping in a few seconds.  Without damage, dyeing, or preferential sample preparation, confocal Raman mapping provided positive detection of each neurotransmitter, allowing association of the high-resolution spectra with specific microscale image regions. Such information is particularly important for complex, heterogeneous samples, where changes in composition can influence neurotransmission processes. We also report an estimated dopamine diffusion coefficient two orders of magnitude smaller than that calculated by the flow-injection method.  Accurate nondestructive characterization for real-time detection of neurotransmitters in inhomogeneous environments without the requirement of sample labeling is a key issue in neuroscience. Our work demonstrates the capabilities of Raman spectroscopy in biological applications, possibly providing a new tool for elucidating the mechanism and kinetics of deep brain stimulation. © 2012 International Neuromodulation Society.

  2. Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides

    Directory of Open Access Journals (Sweden)

    Jean-Luc eDo-Rego

    2012-01-01

    Full Text Available The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7-hydroxypregnenolone (7-OH-5P, while prolactin produced by the adenohypophysis enhances the formation of 7-OH-5P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABAA receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocine, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation

  3. Axonal and presynaptic protein synthesis: new insights into the biology of the neuron

    NARCIS (Netherlands)

    Giuditta, A.; Kaplan, B.B.; van Minnen, J.; Alvarez, J.; Koenig, E.

    2002-01-01

    The presence of a local mRNA translation system in axons and terminals was proposed almost 40 years ago. Over the ensuing period, an impressive body of evidence has grown to support this proposal - yet the nerve cell body is still considered to be the only source of axonal and presynaptic proteins.

  4. Neto Auxiliary Subunits Regulate Interneuron Somatodendritic and Presynaptic Kainate Receptors to Control Network Inhibition

    Directory of Open Access Journals (Sweden)

    Megan S. Wyeth

    2017-08-01

    Full Text Available Although Netos are considered auxiliary subunits critical for kainate receptor (KAR function, direct evidence for their regulation of native KARs is limited. Because Neto KAR regulation is GluK subunit/Neto isoform specific, such regulation must be determined in cell-type-specific contexts. We demonstrate Neto1/2 expression in somatostatin (SOM-, cholecystokinin/cannabinoid receptor 1 (CCK/CB1-, and parvalbumin (PV-containing interneurons. KAR-mediated excitation of these interneurons is contingent upon Neto1 because kainate yields comparable effects in Neto2 knockouts and wild-types but fails to excite interneurons or recruit inhibition in Neto1 knockouts. In contrast, presynaptic KARs in CCK/CB1 interneurons are dually regulated by both Neto1 and Neto2. Neto association promotes tonic presynaptic KAR activation, dampening CCK/CB1 interneuron output, and loss of this brake in Neto mutants profoundly increases CCK/CB1 interneuron-mediated inhibition. Our results confirm that Neto1 regulates endogenous somatodendritic KARs in diverse interneurons and demonstrate Neto regulation of presynaptic KARs in mature inhibitory presynaptic terminals.

  5. The use of LeuT as a model in elucidating binding sites for substrates and inhibitors in neurotransmitter transporters

    DEFF Research Database (Denmark)

    Løland, Claus Juul

    2015-01-01

    Background: The mammalian neurotransmitter transporters are complex proteins playing a central role in synaptic transmission between neurons by rapid reuptake of neurotransmitters. The proteins which transport dopamine, noradrenaline and serotonin belong to the Neurotransmitter:Sodium Symporters...

  6. Intersession reliability of Hoffmann reflex gain and presynaptic inhibition in the human soleus muscle.

    Science.gov (United States)

    Hayes, Bradley T; Hicks-Little, Charlie A; Harter, Rod A; Widrick, Jeffrey J; Hoffman, Mark A

    2009-12-01

    Hayes BT, Hicks-Little CA, Harter RA, Widrick JJ, Hoffman MA. Intersession reliability of Hoffmann reflex gain and presynaptic inhibition in the human soleus muscle. To determine the day-to-day reliability of Hoffmann reflex (H-reflex) gain and presynaptic inhibition of spinal reflexes in the human soleus muscle. Controlled trial. Research laboratory. Volunteers (N=30; mean +/- SD age, 23.4+/-3.9y; height, 175.64+/-10.87cm; mass, 84.50+/-24.18kg) with no history of lower extremity pathology and/or injury participated. Subjects lay prone with the head, shoulders, arms, and hips supported in a static position by a massage body pillow and the ankle positioned at 90 degrees . Recording electrodes were placed over the soleus and tibialis anterior muscle bellies, and the stimulating electrodes were positioned over the tibial nerve in the popliteal space and the common peroneal nerve near the fibular head. The H-reflex and motor wave recruitment curves were then measured and recorded. Presynaptic inhibition was also assessed in the soleus muscle, and a conditioning stimulation of the common peroneal nerve (1 x motor threshold = motor threshold) was used prior to soleus H-reflex measurement. Two testing sessions took place between 2 and 7 days, and each session occurred at the same time of day. Assessments of H-reflex gain and presynaptic inhibition yielded test-retest reliability of R equal to . 95 and .91, respectively. Measures of presynaptic inhibition and H-reflex gain (H slope/M slope) in the human soleus muscle are consistent and reliable day to day.

  7. The presynaptic microtubule cytoskeleton in physiological and pathological conditions: lessons from Fragile X Syndrome and Hereditary Spastic Paraplegias

    Directory of Open Access Journals (Sweden)

    Felipe Bodaleo

    2016-07-01

    Full Text Available The capacity of the nervous system to generate neuronal networks relies on the establishment and maintenance of synaptic contacts. Synapses are composed of functionally different presynaptic and postsynaptic compartments. An appropriate synaptic architecture is required to provide the structural basis that supports synaptic transmission, a process involving changes in cytoskeletal dynamics. Actin microfilaments are the main cytoskeletal components present at both presynaptic and postsynaptic terminals in glutamatergic synapses. However, in the last few years it has been demonstrated that microtubules (MTs transiently invade dendritic spines, promoting their maturation. Nevertheless, the presence and functions of MTs at the presynaptic site are still a matter of debate. Early electron microscopy (EM studies revealed that MTs are present in the presynaptic terminals of the central nervous system (CNS where they interact with synaptic vesicles (SVs and reach the active zone. These observations have been reproduced by several EM protocols; however, there is empirical heterogeneity in detecting presynaptic MTs, since they appear to be both labile and unstable. Moreover, increasing evidence derived from studies in the fruit fly neuromuscular junction proposes different roles for MTs in regulating presynaptic function in physiological and pathological conditions. In this review, we summarize the main findings that support the presence and roles of MTs at presynaptic terminals, integrating descriptive and biochemical analyses, and studies performed in invertebrate genetic models.

  8. Evidence for an inhibitory presynaptic component of neuroleptic drug action.

    OpenAIRE

    de Belleroche, J. S.; Bradford, H. F.

    1981-01-01

    1 The action of five neuroleptic drugs (haloperidol, cis-flupenthixol, chlorpromazine, fluphenazine and thioridazine) was studied on the synthesis and release of dopamine from rat striatal synaptosomes. 2. In vitro application of the drugs induced an inhibition of synthesis of [14C]-dopamine from L-[U-14C]-tyrosine and a decrease in the tissue content of [14-C]-dopamine, with IC50 values for the latter effect ranging from 3.6 x 10(-7) to 5.9 x 10(-5) M. The rank of their potency was similar t...

  9. Spectroscopic Analysis of Neurotransmitters: A Theoretical and Experimental Raman Study

    Science.gov (United States)

    Alonzo, Matthew

    Surface-enhanced Raman spectroscopy (SERS) was applied to investigate the feasibility in the detection and monitoring of the dopamine (DA) neurotransmitter adsorbed onto silver nanoparticles (Ag NPs) at 10-11 molar, a concentration far below physiological levels. In addition, density functional theory (DFT) calculations were obtained with the Gaussian-09 analytical suite software to generate the theoretical molecular configuration of DA in its neutral, cationic, anionic, and dopaminequinone states for the conversion of computer-simulated Raman spectra. Comparison of theoretical and experimental results show good agreement and imply the presence of dopamine in all of its molecular forms in the experimental setting. The dominant dopamine Raman bands at 750 cm-1 and 795 cm-1 suggest the adsorption of dopaminequinone onto the silver nanoparticle surface. The results of this experiment give good insight into the applicability of using Raman spectroscopy for the biodetection of neurotransmitters.

  10. Affinity of four polar neurotransmitters for lipid bilayer membranes

    DEFF Research Database (Denmark)

    Wang, Chunhua; Ye, Fengbin; Valardez, Gustavo F.

    2011-01-01

    (dimyristoyl phosphatidylglycerol, DMPG, or dimyristoyl phosphatidylserine, DMPS), or 1:1 mixtures of dipalmitoyl phosphatidylcholine (DPPC) and dilauroyl phosphatidylcholine (DLPC). The results showed a remarkable variability among the investigated systems. For example, the chloride salt of acetylcholine......-mediated modulation of nerve transmission seems to be fulfilled. However, the strong variability in interaction strengths also shows that this attraction is not an inherent property of all neurotransmitters. © 2010 American Chemical Society....

  11. Regulation of Neurosteroid Biosynthesis by Neurotransmitters and Neuropeptides

    OpenAIRE

    Do Rego, Jean Luc; Seong, Jae Young; Burel, Delphine; Leprince, Jerôme; Vaudry, David; Luu-The, Van; Tonon, Marie-Christine; Tsutsui, Kazuyoshi; Pelletier, Georges; Vaudry, Hubert

    2012-01-01

    The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones, and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out...

  12. Nanomaterial-based electrochemical sensing of neurological drugs and neurotransmitters

    International Nuclear Information System (INIS)

    Sanghavi, Bankim J.; Swami, Nathan S.; Wolfbeis, Otto S.; Hirsch, Thomas

    2015-01-01

    Nanomaterial-modified detection systems represent a chief driver towards the adoption of electrochemical methods, since nanomaterials enable functional tunability, ability to self-assemble, and novel electrical, optical and catalytic properties that emerge at this scale. This results in tremendous gains in terms of sensitivity, selectivity and versatility. We review the electrochemical methods and mechanisms that may be applied to the detection of neurological drugs. We focus on understanding how specific nano-sized modifiers may be applied to influence the electron transfer event to result in gains in sensitivity, selectivity and versatility of the detection system. This critical review is structured on the basis of the Anatomical Therapeutic Chemical (ATC) Classification System, specifically ATC Code N (neurotransmitters). Specific sections are dedicated to the widely used electrodes based on the carbon materials, supporting electrolytes, and on electrochemical detection paradigms for neurological drugs and neurotransmitters within the groups referred to as ATC codes N01 to N07. We finally discuss emerging trends and future challenges such as the development of strategies for simultaneous detection of multiple targets with high spatial and temporal resolutions, the integration of microfluidic strategies for selective and localized analyte pre-concentration, the real-time monitoring of neurotransmitter secretions from active cell cultures under electro- and chemotactic cues, aptamer-based biosensors, and the miniaturization of the sensing system for detection in small sample volumes and for enabling cost savings due to manufacturing scale-up. The Electronic Supporting Material (ESM) includes review articles dealing with the review topic in last 40 years, as well as key properties of the analytes, viz., pK a values, half-life of drugs and their electrochemical mechanisms. The ESM also defines analytical figures of merit of the drugs and neurotransmitters. The

  13. How LeuT shapes our understanding of the mechanisms of sodium-coupled neurotransmitter transporters.

    Science.gov (United States)

    Penmatsa, Aravind; Gouaux, Eric

    2014-03-01

    Neurotransmitter transporters are ion-coupled symporters that drive the uptake of neurotransmitters from neural synapses. In the past decade, the structure of a bacterial amino acid transporter, leucine transporter (LeuT), has given valuable insights into the understanding of architecture and mechanism of mammalian neurotransmitter transporters. Different conformations of LeuT, including a substrate-free state, inward-open state, and competitive and non-competitive inhibitor-bound states, have revealed a mechanistic framework for the transport and transport inhibition of neurotransmitters. The current review integrates our understanding of the mechanistic and pharmacological properties of eukaryotic neurotransmitter transporters obtained through structural snapshots of LeuT.

  14. Electrochemical Techniques for Subsecond Neurotransmitter Detection in Live Rodents

    Science.gov (United States)

    Hascup, Kevin N; Hascup, Erin R

    2014-01-01

    Alterations in neurotransmission have been implicated in numerous neurodegenerative and neuropsychiatric disorders, including Alzheimer disease, Parkinson disease, epilepsy, and schizophrenia. Unfortunately, few techniques support the measurement of real-time changes in neurotransmitter levels over multiple days, as is essential for ethologic and pharmacodynamic testing. Microdialysis is commonly used for these research paradigms, but its poor temporal and spatial resolution make this technique inadequate for measuring the rapid dynamics (milliseconds to seconds) of fast signaling neurotransmitters, such as glutamate and acetylcholine. Enzymatic microelectrode arrays (biosensors) coupled with electrochemical recording techniques have demonstrated fast temporal resolution (less than 1 s), excellent spatial resolution (micron-scale), low detection limits (≤200 nM), and minimal damage (50 to 100 µm) to surrounding brain tissue. Here we discuss the benefits, methods, and animal welfare considerations of using platinum microelectrodes on a ceramic substrate for enzyme-based electrochemical recording techniques for real-time in vivo neurotransmitter recordings in both anesthetized and awake, freely moving rodents. PMID:25296011

  15. Peripheral Nerve Fibers and Their Neurotransmitters in Osteoarthritis Pathology.

    Science.gov (United States)

    Grässel, Susanne; Muschter, Dominique

    2017-04-28

    The importance of the nociceptive nervous system for maintaining tissue homeostasis has been known for some time, and it has also been suggested that organogenesis and tissue repair are under neuronal control. Changes in peripheral joint innervation are supposed to be partly responsible for degenerative alterations in joint tissues which contribute to development of osteoarthritis. Various resident cell types of the musculoskeletal system express receptors for sensory and sympathetic neurotransmitters, allowing response to peripheral neuronal stimuli. Among them are mesenchymal stem cells, synovial fibroblasts, bone cells and chondrocytes of different origin, which express distinct subtypes of adrenoceptors (AR), receptors for vasoactive intestinal peptide (VIP), substance P (SP) and calcitonin gene-related peptide (CGRP). Some of these cell types synthesize and secrete neuropeptides such as SP, and they are positive for tyrosine-hydroxylase (TH), the rate limiting enzyme for biosynthesis of catecholamines. Sensory and sympathetic neurotransmitters are involved in the pathology of inflammatory diseases such as rheumatoid arthritis (RA) which manifests mainly in the joints. In addition, they seem to play a role in pathogenesis of priori degenerative joint disorders such as osteoarthritis (OA). Altogether it is evident that sensory and sympathetic neurotransmitters have crucial trophic effects which are critical for joint tissue and bone homeostasis. They modulate articular cartilage, subchondral bone and synovial tissue properties in physiological and pathophysiological conditions, in addition to their classical neurological features.

  16. [Preliminary research on multi-neurotransmitters' change regulation in 120 depression patients' brains].

    Science.gov (United States)

    Chi, Ming; Qing, Xue-Mei; Pan, Yan-Shu; Xu, Feng-Quan; Liu, Chao; Zhang, Cheng; Xu, Zhen-Hua

    2014-04-01

    In view of the effective traditional Chinese medicine (TCM) in the treatment of clinical depression, the mechanism is not clear, this study attempts to research the cause of depression in a complex situation to lay the foundation for the next step of TCM curative effect evaluation. Based on the brain wave of 120 depression patients and 40 ordinary person, the change regulation of acetylcholine, dopamine, norepinephrine, depression neurotransmitters and excited neurotransmitters in the whole and various encephalic regions' multi-neurotransmitters of depression patients-serotonin are analysed by search of encephalo-telex (SET) system, which lays the foundation for the diagnosis of depression. The result showed that: contrased with the normal person group, the mean value of the six neurotransmitters in depression patients group are: (1) in the whole encephalic region of depression patients group the dopamine fall (P neurotransmitters and neurotransmitters: (1) the three antagonizing pairs of neurotransmitters-serotonin and dopamine, acetylcholine and norepinephrine, depression neurotransmitters and excited neurotransmitters, in ordinary person group and depression patients group are characterizeed by middle or strong negative correlation. Serotonin and dopamine, which are characterized by weak negative correlation in the right rear temporal region of ordinary person group, are characterized by strong negative correlation in the other encephalic regions and the whole encephalic (ordinary person group except the right rear temporal region: the range of [r] is [0.82, 0.92], P neurotransmitters and excited neurotransmitters are characterized by middle strong negative correlation (ordinary person group: the range of [r] is [0.57, 0.80], P neurotransmitters which are not antagonizing pairs of neurotransmitters, serotonin and excited neurotransmitters, or acetylcholine and depression neurotra-nsmitters, or dopamine and depression neurotransmitters in the various encephalic

  17. Effects of presynaptic mutations on a postsynaptic Cacna1s calcium channel colocalized with mGluR6 at mouse photoreceptor ribbon synapses.

    Science.gov (United States)

    Specht, Dana; Wu, Shu-Biao; Turner, Paul; Dearden, Peter; Koentgen, Frank; Wolfrum, Uwe; Maw, Marion; Brandstätter, Johann Helmut; tom Dieck, Susanne

    2009-02-01

    Photoreceptor ribbon synapses translate light-dependent changes of membrane potential into graded transmitter release via L-type voltage-dependent calcium channel (VDCC) activity. Functional abnormalities (e.g., a reduced electroretinogram b-wave), arising from mutations of presynaptic proteins, such as Bassoon and the VDCCalpha1 subunit Cacna1f, have been shown to altered transmitter release. L-type VDCCalpha1 subtype expression in wild-type and mutant mice was examined, to investigate the underlying pathologic mechanism. Two antisera against Cacna1f, and a Cacna1f mouse mutant (Cacna1fDeltaEx14-17) were generated. Immunocytochemistry for L-type VDCCalpha1 subunits and additional synaptic marker proteins was performed in wild-type, BassoonDeltaEx4-5 and Cacna1fDeltaEx14-17 mice. Active zone staining at photoreceptor ribbon synapses with a panalpha1 antibody colocalized with staining for Cacna1f in wild-type mouse retina. Similarly, in the BassoonDeltaEx4-5 mouse, residual mislocalized staining for panalpha1 and Cacna1f showed colocalization. Unlike the presynaptic location of Cacna1f and panalpha1 antibody staining, the skeletal muscle VDCCalpha1 subunit Cacna1s was present postsynaptically at ON-bipolar cell dendrites, where it colocalized with metabotropic glutamate receptor 6 (mGluR6). Surprisingly, Cacna1s labeling was severely downregulated in the BassoonDeltaEx4-5 and Cacna1fDeltaEx14-17 mutants. Subsequent analyses revealed severely reduced ON-bipolar cell dendritic expression of the sarcoplasmic reticulum Ca(2+) ATPase Serca2 in both mouse mutants and of mGluR6 in the Cacna1fDeltaEx14-17 mutant. Presynaptic mutations leading to reduced photoreceptor-to-bipolar cell signaling are associated with disturbances in protein expression within postsynaptic dendrites. Moreover, detection of Cacna1s and Serca2 in ON-bipolar cell dendrites in wild-type animals suggests a putative role in regulation of postsynaptic Ca(2+) flux.

  18. Immobilization induces changes in presynaptic control of group Ia afferents in healthy humans

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Nielsen, Jens Bo

    2008-01-01

    Neural plasticity occurs throughout adult life in response to maturation, use and disuse. Recent studies have documented that H-reflex amplitudes increase following a period of immobilization. To elucidate the mechanisms contributing to the increase in H-reflex size following immobilization we...... immobilized the left foot and ankle joint for 2 weeks in 12 able-bodied subjects. Disynaptic reciprocal inhibition of soleus (SOL) motoneurones and presynaptic control of SOL group Ia afferents was measured before and after the immobilization as well as following 2 weeks of recovery. Following immobilization...... inhibition of SOL Ia afferents and taken together suggest that GABAergic presynaptic inhibition of the SOL Ia afferents is decreased following 2 weeks of immobilization. The depression of the SOL H-reflex when evoked at intervals shorter than 10 s (homosynaptic post-activation depression) also decreased...

  19. Presynaptic CaV2.1 calcium channels carrying familial hemiplegic migraine mutation R192Q allow faster recovery from synaptic depression in mouse calyx of Held.

    Science.gov (United States)

    Inchauspe, Carlota González; Urbano, Francisco J; Di Guilmi, Mariano N; Ferrari, Michel D; van den Maagdenberg, Arn M J M; Forsythe, Ian D; Uchitel, Osvaldo D

    2012-12-01

    Ca(V)2.1 Ca(2+) channels have a dominant and specific role in initiating fast synaptic transmission at central excitatory synapses, through a close association between release sites and calcium sensors. Familial hemiplegic migraine type 1 (FHM-1) is an autosomal-dominant subtype of migraine with aura, caused by missense mutations in the CACNA1A gene that encodes the α(1A) pore-forming subunit of Ca(V)2.1 channel. We used knock-in (KI) transgenic mice harboring the FHM-1 mutation R192Q to study the consequences of this mutation in neurotransmission at the giant synapse of the auditory system formed by the presynaptic calyx of Held terminal and the postsynaptic neurons of the medial nucleus of the trapezoid body (MNTB). Although synaptic transmission seems unaffected by low-frequency stimulation in physiological Ca(2+) concentration, we observed that with low Ca(2+) concentrations (transmitter release. In addition, when EPSCs were evoked by broadened presynaptic action potentials (achieved by inhibition of K(+) channels) via Ca(v)2.1-triggered exocytosis, R192Q KI mice exhibited further enhancement of EPSC amplitude and charge compared with WT mice. Repetitive stimulation of afferent axons to the MNTB at different frequencies caused short-term depression of EPSCs that recovered significantly faster in R192Q KI mice than in WT mice. Faster recovery in R192Q KI mice was prevented by the calcium chelator EGTA-AM, pointing to enlarged residual calcium as a key factor in accelerating the replenishment of synaptic vesicles.

  20. 123-I ioflupane (Datscan) presynaptic nigrostriatal imaging in patients with movement disorders

    International Nuclear Information System (INIS)

    Soriano Castrejon, Angel; Garcia Vicente, Ana Maria; Cortes Romera, Montserrat; Rodado Marina, Sonia; Poblete Garcia, Victor Manuel; Ruiz Solis, Sebastian Ruiz; Talavera Rubio, Maria del Prado; Vaamonde Cano, Julia

    2005-01-01

    123-I Ioflupane (Datscan) presynaptic imaging has been shown to have a significant utility in the assessment of patients with movement disorders 123 I Ioflupane SPECT is able to distinguish between Parkinson's disease (PD) and other forms of parkinsonism without degeneration of the nigrostriatal pathway, including a common movement disorder such as essential tremor, and to assess disease progression in PD and other neuro degenerative disorders involving the substantia nigra. (author)

  1. No consistent bioenergetic defects in presynaptic nerve terminals isolated from mouse models of Alzheimer’s disease

    OpenAIRE

    Choi, Sung W.; Gerencser, Akos A.; Ng, Ryan; Flynn, James M.; Melov, Simon; Danielson, Steven R.; Gibson, Bradford W.; Nicholls, David G.; Bredesen, Dale E.; Brand, Martin D.

    2012-01-01

    Depressed cortical energy supply and impaired synaptic function are predominant associations of Alzheimer’s disease (AD). To test the hypothesis that presynaptic bioenergetic deficits are associated with the progression of AD pathogenesis, we compared bioenergetic variables of cortical and hippocampal presynaptic nerve terminals (synaptosomes) from commonly used mouse models with AD-like phenotypes (J20 age 6 months, Tg2576 age 16 months and APP/PS age 9 and 14 months) to ag...

  2. Local synthesis of axonal and presynaptic RNA in squid model systems.

    Science.gov (United States)

    Eyman, Maria; Cefaliello, Carolina; Ferrara, Eugenia; De Stefano, Rosanna; Lavina, Zeno Scotto; Crispino, Marianna; Squillace, Angela; van Minnen, Jan; Kaplan, Barry B; Giuditta, Antonio

    2007-01-01

    The presence of active systems of protein synthesis in axons and nerve endings raises the question of the cellular origin of the corresponding RNAs. Our present experiments demonstrate that, besides a possible derivation from neuronal cell bodies, axoplasmic RNAs originate in periaxonal glial cells and presynaptic RNAs derive from nearby cells, presumably glial cells. Indeed, in perfused squid giant axons, delivery of newly synthesized RNA to the axon perfusate is strongly stimulated by axonal depolarization or agonists of glial glutamate and acetylcholine receptors. Likewise, incubation of squid optic lobe slices with [3H]uridine leads to a marked accumulation of [3H]RNA in the large synaptosomes derived from the nerve terminals of retinal photoreceptor neurons. As the cell bodies of these neurons lie outside the optic lobe, the data demonstrate that presynaptic RNA is locally synthesized, presumably by perisynaptic glial cells. Overall, our results support the view that axons and presynaptic regions are endowed with local systems of gene expression which may prove essential for the maintenance and plasticity of these extrasomatic neuronal domains.

  3. Protein synthesizing units in presynaptic and postsynaptic domains of squid neurons.

    Science.gov (United States)

    Martin, R; Vaida, B; Bleher, R; Crispino, M; Giuditta, A

    1998-11-01

    Putative protein synthesizing domains, called plaques, are characterized in the squid giant synapse and axon and in terminals of squid photoreceptor neurons. Plaques are oval-shaped formations of about 1 microm in size, which (1) generate signals that have spectroscopic electron energy loss characteristics of ribosomes, (2) exhibit ribonuclease-sensitive binding of YOYO-1, a fluorescent RNA/DNA dye, and (3) in part hybridize with a poly(dT) oligonucleotide. In the giant synapse plaques are abundant in the postsynaptic area, but are absent in the presynaptic terminal. In the cortical layer of the optic lobes, plaques are localized in the large carrot-shaped presynaptic terminals of photoreceptor neurons, where they are surrounded by synaptic vesicles and mitochondria. Biochemical and autoradiographic data have documented that the protein synthetic activity of squid optic lobe synaptosomes is largely due to the presynaptic terminals of the photoreceptor neurons. The identification of ribosomes and poly(A+)-mRNA in the plaques indicates that these structures are sites of local protein synthesis in synaptic domains.

  4. No consistent bioenergetic defects in presynaptic nerve terminals isolated from mouse models of Alzheimer's disease.

    Science.gov (United States)

    Choi, Sung W; Gerencser, Akos A; Ng, Ryan; Flynn, James M; Melov, Simon; Danielson, Steven R; Gibson, Bradford W; Nicholls, David G; Bredesen, Dale E; Brand, Martin D

    2012-11-21

    Depressed cortical energy supply and impaired synaptic function are predominant associations of Alzheimer's disease (AD). To test the hypothesis that presynaptic bioenergetic deficits are associated with the progression of AD pathogenesis, we compared bioenergetic variables of cortical and hippocampal presynaptic nerve terminals (synaptosomes) from commonly used mouse models with AD-like phenotypes (J20 age 6 months, Tg2576 age 16 months, and APP/PS age 9 and 14 months) to age-matched controls. No consistent bioenergetic deficiencies were detected in synaptosomes from the three models; only APP/PS cortical synaptosomes from 14-month-old mice showed an increase in respiration associated with proton leak. J20 mice were chosen for a highly stringent investigation of mitochondrial function and content. There were no significant differences in the quality of the synaptosomal preparations or the mitochondrial volume fraction. Furthermore, respiratory variables, calcium handling, and membrane potentials of synaptosomes from symptomatic J20 mice under calcium-imposed stress were not consistently impaired. The recovery of marker proteins during synaptosome preparation was the same, ruling out the possibility that the lack of functional bioenergetic defects in synaptosomes from J20 mice was due to the selective loss of damaged synaptosomes during sample preparation. Our results support the conclusion that the intrinsic bioenergetic capacities of presynaptic nerve terminals are maintained in these symptomatic AD mouse models.

  5. Three Gaseous Neurotransmitters, Nitric oxide, Carbon Monoxide, and Hydrogen Sulfide, Are Involved in the Neurogenic Relaxation Responses of the Porcine Internal Anal Sphincter.

    Science.gov (United States)

    Folasire, Oladayo; Mills, Kylie A; Sellers, Donna J; Chess-Williams, Russ

    2016-01-31

    The internal anal sphincter (IAS) plays an important role in maintaining continence and a number of neurotransmitters are known to regulate IAS tone. The aim of this study was to determine the relative importance of the neurotransmitters involved in the relaxant and contractile responses of the porcine IAS. Responses of isolated strips of IAS to electrical field stimulation (EFS) were obtained in the absence and presence of inhibitors of neurotransmitter systems. Contractile responses of the sphincter to EFS were unaffected by the muscarinic receptor antagonist, atropine (1 μM), but were almost completely abolished by the adrenergic neuron blocker guanethidine (10 μM). Contractile responses were also reduced (by 45% at 5 Hz, P synthesis (40-50% reduction), zinc protoprophyrin IX (10 μM), an inhibitor of carbon monoxide synthesis (20-40% reduction), and also propargylglycine (30 μM) and aminooxyacetic acid (30 μM), inhibitors of hydrogen sulphide synthesis (15-20% reduction). Stimulation of IAS efferent nerves releases excitatory and inhibitory neurotransmitters: noradrenaline is the predominant contractile transmitter with a smaller component from ATP, whilst 3 gases mediate relaxation responses to EFS, with the combined contributions being nitric oxide > carbon monoxide > hydrogen sulfide.

  6. Expression of neurotransmitters and neurotrophins in neurogenic inflammation of the rat retina

    Directory of Open Access Journals (Sweden)

    E Bronzetti

    2009-08-01

    Full Text Available Antidromic stimulation of the rat trigeminal ganglion triggers the release of substance P (SP and calcitonin gene-related peptide (CGRP from sensory nerve terminals of the capsaicin sensitive C-fibers. These pro-inflammatory neuropeptides produce a marked hyperemia in the anterior segment of the eye, accompanied by increased intraocular pressure, breakdown of the blood-aqueous barrier and myosis. To assess the effects of neurogenic inflammation on the retina, specifically on the immunostaining of neurotransmitters and neurotrophins, as well as on the expression of neurotrophin receptors in the retina. RT-PCR was also accomplished in control and stimulated animals to confirm the immunohistochemical results. In the electrically stimulated eyes, immunostaining for SP, CGRP, VIP and nNOS demonstrated a marked increase in the RPE/POS (Retinal Pigment Epithelium/Photoreceptor Outer Segments, in the inner and outer granular layers and in the ganglion cells in comparison to the control eyes. CGRP and SP were found increased in stimulated animals and this result has been confirmed by RT- PCR. Changes in neurotrophin immunostaining and in receptor expression were also observed after electric stimulation of trigeminal ganglia. Decrease of BDNF and NT4 in the outer and inner layers and in ganglion cells was particularly marked. In stimulated rat retinas immunostaining and RT-PCR showed a NGF expression increase. Neurotrophin receptors remained substantially unchanged. These studies demonstrated, for the first time, that antidromic stimulation of the trigeminal ganglion and subsequent neurogenic inflammation affect immunostaining of retinal cell neurotransmitter/ neuropeptides and neurotrophins as well as the expression of neurotrophin receptors.

  7. Brain neurotransmitters in an animal model with postpartum depressive-like behavior.

    Science.gov (United States)

    Avraham, Y; Hants, Y; Vorobeiv, L; Staum, M; Abu Ahmad, Wiessam; Mankuta, D; Galun, E; Arbel-Alon, S

    2017-05-30

    Post-Partum Depression (PPD) occurs in 15% of pregnancies and its patho-physiology is not known. We studied female BALB/c ("depressive") and C57BL/6 (control) mice as a model for PPD and assessed their behavior and correlates with brain neurotransmitters (NTs) - norepinephrine, dopamine, serotonin and intermediates, during the pre-pregnancy (PREP), pregnancy (PREG) and post-partum (PP) periods. Depressive-like behavior was evaluated by the Open Field (OFT), Tail Suspension (TST) and Forced Swim (FST) tests. Neurotransmitters (NTs) were determined in the striatum (care-giving), hippocampus (cognitive function) and hypothalamus (maternal care & eating behavior). In the BALB/c mice, while their performance in all behavioral tests was significantly reduced during pregnancy and P-P indicative of the development of depressive-like responses, no changes were observed in the C57BL/6 mice. Changes in NTs in BALB/C were as follows: PREP, all NTs in the three brain areas were decreased, although an increase in dopamine release was observed in the hippocampus. PREG: No changes were observed in the NTs except for a decrease in 5-HT in the striatum. P-P: striatum, low 5-HT, NE and dopamine; Hippocampus: low 5-HT, NE and high Dopamine; hypothalamus: all NTs increased, especially NE. Following pregnancy and delivery, the BALB/c mice developed depressive-like behavior associated with a significant decrease in 5-HT, dopamine and NE in the striatum and 5-HT and NE in the hippocampus. Dopamine increased in the latter together with a significant increase in all NTs in the hypothalamus. These findings suggest that the development of PPD may be associated with NT changes. Normalization of these alterations may have a role in the treatment of PPD. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate

    Science.gov (United States)

    Molina, Anthony J A; Verzi, Michael P; Birnbaum, Andrea D; Yamoah, Ebenezer N; Hammar, Katherine; Smith, Peter J S; Malchow, Robert Paul

    2004-01-01

    Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neurones. PMID:15272044

  9. Long-term plasticity determines the postsynaptic response to correlated afferents with multivesicular short-term synaptic depression

    Directory of Open Access Journals (Sweden)

    Alexander David Bird

    2014-01-01

    Full Text Available Synchrony in a presynaptic population leads to correlations in vesicle occupancy at the active sites for neurotransmitter release. The number of independent release sites per presynaptic neuron, a synaptic parameter recently shown to be modifed during long-term plasticity, will modulate these correlations and therefore have a significant effect on the firing rate of the postsynaptic neuron. To understand how correlations from synaptic dynamics and from presynaptic synchrony shape the postsynaptic response, we study a model of multiple release site short-term plasticity and derive exact results for the crosscorrelation function of vesicle occupancy and neurotransmitter release, as well as the postsynaptic voltage variance. Using approximate forms for the postsynaptic firing rate in the limits of low and high correlations, we demonstrate that short-term depression leads to a maximum response for an intermediate number of presynaptic release sites, and that this leads to a tuning-curve response peaked at an optimal presynaptic synchrony setby the number of neurotransmitter release sites per presynaptic neuron. These effects arise because, above a certain level of correlation, activity in the presynaptic population is overly strong resulting in wastage of the pool of releasable neurotransmitter. As the nervous system operates under constraints of efficient metabolism it is likely that this phenomenon provides an activity-dependent constraint on network architecture.

  10. Name that neurotransmitter: using music to teach psychopharmacology concepts.

    Science.gov (United States)

    Hermanns, Melinda; Lilly, Mary LuAnne; Wilson, Kathy; Russell, Nathan Andrew

    2012-09-01

    The purpose of this article is to discuss the use of music (i.e., two original songs, "Neurotransmitter Twitter" and "Parkinson's Shuffle") to teach aspects of psychopharmacology to students in the course Psychiatric/Mental Health Nursing. Songs were incorporated in both the clinical and classroom settings. This innovative teaching method allowed students the opportunity to revisit the information through multiple exposures of the content for reinforcement and enhancement of student learning in a fun, creative approach. Brain-based research will be discussed, along with the process of development. Copyright 2012, SLACK Incorporated.

  11. Neurotransmitter receptors as signaling platforms in anterior pituitary cells

    Czech Academy of Sciences Publication Activity Database

    Zemková, Hana; Stojilkovic, S. S.

    2018-01-01

    Roč. 463, C (2018), s. 49-64 ISSN 0303-7207 R&D Projects: GA ČR(CZ) GA16-12695S; GA ČR(CZ) GBP304/12/G069; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : pituitary * ligand-gated receptor channels * G protein-coupled receptors * neurotransmitters * action potentials * calcium signaling * hormone secretion Subject RIV: FH - Neurology OBOR OECD: Neurosciences (including psychophysiology Impact factor: 3.754, year: 2016

  12. Carbon Nanotube-based microelectrodes for enhanced detection of neurotransmitters

    Science.gov (United States)

    Jacobs, Christopher B.

    Fast-scan cyclic voltammetry (FSCV) is one of the common techniques used for rapid measurement of neurotransmitters in vivo. Carbon-fiber microelectrodes (CFMEs) are typically used for neurotransmitter detection because of sub-second measurement capabilities, ability to measure changes in neurotransmitter concentration during neurotransmission, and the small size electrode diameter, which limits the amount of damage caused to tissue. Cylinder CFMEs, typically 50 -- 100 microm long, are commonly used for in vivo experiments because the electrode sensitivity is directly related to the electrode surface area. However the length of the electrode can limit the spatial resolution of neurotransmitter detection, which can restrict experiments in Drosophila and other small model systems. In addition, the electrode sensitivity toward dopamine and serotonin detection drops significantly for measurements at rates faster than 10 Hz, limiting the temporal resolution of CFMEs. While the use of FSCV at carbon-fiber microelectrodes has led to substantial strides in our understanding of neurotransmission, techniques that expand the capabilities of CFMEs are crucial to fully maximize the potential uses of FSCV. This dissertation introduces new methods to integrate carbon nanotubes (CNT) into microelectrodes and discusses the electrochemical enhancements of these CNT-microelectrodes. The electrodes are specifically designed with simple fabrication procedures so that highly specialized equipment is not necessary, and they utilize commercially available materials so that the electrodes could be easily integrated into existing systems. The electrochemical properties of CNT modified CFMEs are characterized using FSCV and the effect of CNT functionalization on these properties is explored in Chapter 2. For example, CFME modification using carboxylic acid functionalized CNTs yield about a 6-fold increase in dopamine oxidation current, but modification with octadecylamine CNTs results in a

  13. Kinetics of neurotransmitter release in neuromuscular synapses of newborn and adult rats

    Czech Academy of Sciences Publication Activity Database

    Khuzakhmetova, V.; Samigullin, D.; Nurullin, L.; Vyskočil, František; Nikolsky, E.; Bukharaeva, E.

    2014-01-01

    Roč. 34, MAY (2014), s. 9-18 ISSN 0736-5748 R&D Projects: GA AV ČR(CZ) IAA500110905 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : ryanodine receptor * synaptic latency Subject RIV: ED - Physiology Impact factor: 2.580, year: 2014

  14. Modeling of quantal neurotransmitter release kinetics in the presence of fixed and mobile calcium buffers

    Czech Academy of Sciences Publication Activity Database

    Gilmanov, I.R.; Samigullin, D. V.; Vyskočil, František; Nikolsky, E. E.; Bukharaeva, E. A.

    2008-01-01

    Roč. 25, č. 2 (2008), s. 296-307 ISSN 0929-5313 R&D Projects: GA AV ČR(CZ) IAA5011411; GA ČR GA305/02/1333 Institutional research plan: CEZ:AV0Z50110509 Keywords : neuromuscular junction Subject RIV: ED - Physiology Impact factor: 2.750, year: 2008

  15. MRI sensing of neurotransmitters with a crown ether appended Gd(3+) complex.

    Science.gov (United States)

    Oukhatar, Fatima; Même, Sandra; Même, William; Szeremeta, Frédéric; Logothetis, Nikos K; Angelovski, Goran; Tóth, Éva

    2015-02-18

    Molecular magnetic resonance imaging (MRI) approaches that detect biomarkers associated with neural activity would allow more direct observation of brain function than current functional MRI based on blood-oxygen-level-dependent contrast. Our objective was to create a synthetic molecular platform with appropriate recognition moieties for zwitterionic neurotransmitters that generate an MR signal change upon neurotransmitter binding. The gadolinium complex (GdL) we report offers ditopic binding for zwitterionic amino acid neurotransmitters, via interactions (i) between the positively charged and coordinatively unsaturated metal center and the carboxylate function and (ii) between a triazacrown ether and the amine group of the neurotransmitters. GdL discriminates zwitterionic neurotransmitters from monoamines. Neurotransmitter binding leads to a remarkable relaxivity change, related to a decrease in hydration number. GdL was successfully used to monitor neural activity in ex vivo mouse brain slices by MRI.

  16. Functional imaging of neurotransmitter systems in movement disorders

    International Nuclear Information System (INIS)

    Ilgin, N.

    1998-01-01

    PET and SPECT enable the direct measurement of components of the dopaminergic and other systems in the living human brain and offer unique opportunity for the in vivo quantification on the dopaminergic function in PD and other movement disorders. The need to establish the early and differential diagnosis of PD is increasingly important given the recent evidence that early pharmacologic intervention may slow progression of this progressive degenerative disease. Accordingly, imaging with PET and SPECT using specific neuro markers has been increasingly important to biochemically identify the loss of specific neurotransmitters, their synthesizing enzymes and their receptors in movement disorders. Through the parallel development of new radiotracers, kinetic models and better instruments, PET and SPECT technology is enabling investigation of increasingly more complex aspects of the human brain neurotransmitter systems. This paper summarizes the results of different PET-SPECT studies used to evaluate the various elements of the dopamine system in the human brain with PET and intends to introduce the newly emerging specific tracers and their applications to clinical research in movement disorders

  17. [Developmental changes of neurotransmitter properties in sympathetic neurons].

    Science.gov (United States)

    Masliukov, P M; Emanuilov, A I; Nozdrachev, A D

    2016-01-01

    Sympathetic ganglia consist of neurochemically and functionally distinct populations of neurons, characterized by a specific projection pattern and a set of neutransmitters including classical mediators (catecholamines and acetylcholine), neuropeptides and small molecules such as NO, H2S, CO. The majority of the principal ganglionic sympathetic neurons is noradrenergic and expresses tyrosine hydroxylase (TH), i.e., a key enzyme in catecholamine synthesis. In mammals, two third of catecholaminergic neurons also co-localizes neuropeptide Y. A small number of ganglionic sympathetic neurons contains enzyme of acetylcholine synthesis and some neuropeptides, such as somatostatin, vasoactive intestinal (poly)peptide (VIP), calcitonin gene-related peptide (CGRP). Acetylcholine-containing sympathetic neurons in most cases colocalize VIP and/or CGRP. Phenotype of autonomic neurons is regulated by both target-independent and target-dependent mechanisms. The most of transmitters are expressed during embryogenesis. TH appears during embryonic development and the percentage of TH-positive neurons remains virtually identical during ontogenesis. After birth, cholinergic neurons exhibit a noradrenergic phenotype. Expression of different neuropeptides changes in pre- and postnatal development. Neurotransmitter expression in sympathetic neurons is influenced by growth factor signaling via innervated target tissues. Multiple growth factors including bone morphogenetic proteins, neurotrophins, glial cell line-derived neurotrophic factor family ligands and neuropoietic cytokines play instructive role at different stages of neurotransmitter development.

  18. Identification of catecholamine neurotransmitters using fluorescence sensor array

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi, Forough [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Hormozi-Nezhad, M. Reza, E-mail: hormozi@sharif.edu [Department of Chemistry, Sharif University of Technology, Tehran 11155-9516 (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Mahmoudi, Morteza, E-mail: mahmoudi@stanford.edu [Department of Nanotechnology and Nanotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 13169-43551 (Iran, Islamic Republic of); Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA 94305-5101 (United States)

    2016-04-21

    A nano-based sensor array has been developed for identification and discrimination of catecholamine neurotransmitters based on optical properties of their oxidation products under alkaline conditions. To produce distinct fluorescence response patterns for individual catecholamine, quenching of thioglycolic acid functionalized cadmium telluride (CdTe) quantum dots, by oxidation products, were employed along with the variation of fluorescence spectra of oxidation products. The spectral changes were analyzed with hierarchical cluster analysis (HCA) and principal component analysis (PCA) to identify catecholamine patterns. The proposed sensor could efficiently discriminate the individual catecholamine (i.e., dopamine, norepinephrine, and L-DOPA) and their mixtures in the concentration range of 0.25–30 μmol L{sup −1}. Finally, we found that the sensor had capability to identify the various catecholamines in urine sample. - Highlights: • We have proposed a fluorescence sensor array to detect catecholamine neurotransmitters. • Visual differentiation of catecholamines is provided by fluorescence array fingerprints. • Discrimination of catecholamines from each other, and from their mixture is obtained on a PCA plot. • Proposed sensor array can be used for detection of catecholamines in urine samples.

  19. Detection and Monitoring of Neurotransmitters - a Spectroscopic Analysis

    Science.gov (United States)

    Manciu, Felicia; Lee, Kendall; Durrer, William; Bennet, Kevin

    2012-10-01

    In this work we demonstrate the capability of confocal Raman mapping spectroscopy for simultaneously and locally detecting important compounds in neuroscience such as dopamine, serotonin, and adenosine. The Raman results show shifting of the characteristic vibrations of the compounds, observations consistent with previous spectroscopic studies. Although some vibrations are common in these neurotransmitters, Raman mapping was achieved by detecting non-overlapping characteristic spectral signatures of the compounds, as follows: for dopamine the vibration attributed to C-O stretching, for serotonin the indole ring stretching vibration, and for adenosine the adenine ring vibrations. Without damage, dyeing, or preferential sample preparation, confocal Raman mapping provided positive detection of each neurotransmitter, allowing association of the high-resolution spectra with specific micro-scale image regions. Such information is particularly important for complex, heterogeneous samples, where modification of the chemical or physical composition can influence the neurotransmission processes. We also report an estimated dopamine diffusion coefficient two orders of magnitude smaller than that calculated by the flow-injection method.

  20. "Stiff neonate" with mitochondrial DNA depletion and secondary neurotransmitter defects.

    LENUS (Irish Health Repository)

    Moran, Margaret M

    2011-12-01

    Mitochondrial disorders comprise a heterogenous group. A neonate who presented with episodes of severe truncal hypertonia and apnea progressed to a hypokinetic rigid syndrome characterized by hypokinesia, tremulousness, profound head lag, absent suck and gag reflexes, brisk deep tendon reflexes, ankle and jaw clonus, and evidence of autonomic dysfunction. Analysis of cerebrospinal fluid neurotransmitters from age 7 weeks demonstrated low levels of amine metabolites (homovanillic acid and 5-hydroxyindoleacetic acid), tetrahydrobiopterin, and pyridoxal phosphate. Mitochondrial DNA quantitative studies on muscle homogenate demonstrated a mitochondrial DNA depletion disorder. Respiratory chain enzymology demonstrated decreased complex IV activity. Screening for mitochondrial DNA rearrangement disorders and sequencing relevant mitochondrial genes produced negative results. No clinical or biochemical response to treatment with pyridoxal phosphate, tetrahydrobiopterin, or l-dopa occurred. The clinical course was progressive, and the patient died at age 19 months. Mitochondrial disorders causing secondary neurotransmitter diseases are usually severe, but are rarely reported. This diagnosis should be considered in neonates or infants who present with hypertonia, hypokinesia rigidity, and progressive neurodegeneration.

  1. Excitatory neurotransmitters in brain regions in interictal migraine patients

    Directory of Open Access Journals (Sweden)

    Jensen Eric

    2009-06-01

    Full Text Available Abstract Objective To examine biochemical differences in the anterior cingulate cortex (ACC and insula during the interictal phase of migraine patients. We hypothesized that there may be differences in levels of excitatory amino acid neurotransmitters and/or their derivatives in migraine group based on their increased sensitivity to pain. Methods 2D J-resolved proton magnetic resonance spectroscopy (1H-MRS data were acquired at 4.0 Tesla (T from the ACC and insula in 10 migraine patients (7 women, 3 men, age 43 ± 11 years and 8 age gender matched controls (7 women, 3 men, age 41 ± 9 years. Results Standard statistical analyses including analysis of variance (ANOVA showed no significant metabolite differences between the two subject cohorts in the ACC nor the insula. However, linear discriminant analysis (LDA introduced a clear separation between subject cohorts based on N-acetyl aspartylglutamate (NAAG and glutamine (Gln in the ACC and insula. Conclusion These results are consistent with glutamatergic abnormalities in the ACC and insula in migraine patients during their interictal period compared to healthy controls. An alteration in excitatory amino acid neurotransmitters and their derivatives may be a contributing factor for migraineurs for a decrease in sensitivity for migraine or a consequence of the chronic migraine state. Such findings, if extrapolated to other regions of the brain would offer new opportunities to modulate central system as interictal or preemptive medications in these patients.

  2. Modelling vesicular release at hippocampal synapses.

    Directory of Open Access Journals (Sweden)

    Suhita Nadkarni

    2010-11-01

    Full Text Available We study local calcium dynamics leading to a vesicle fusion in a stochastic, and spatially explicit, biophysical model of the CA3-CA1 presynaptic bouton. The kinetic model for vesicle release has two calcium sensors, a sensor for fast synchronous release that lasts a few tens of milliseconds and a separate sensor for slow asynchronous release that lasts a few hundred milliseconds. A wide range of data can be accounted for consistently only when a refractory period lasting a few milliseconds between releases is included. The inclusion of a second sensor for asynchronous release with a slow unbinding site, and thereby a long memory, affects short-term plasticity by facilitating release. Our simulations also reveal a third time scale of vesicle release that is correlated with the stimulus and is distinct from the fast and the slow releases. In these detailed Monte Carlo simulations all three time scales of vesicle release are insensitive to the spatial details of the synaptic ultrastructure. Furthermore, our simulations allow us to identify features of synaptic transmission that are universal and those that are modulated by structure.

  3. Serotonin, dopamine and noradrenaline adjust actions of myelinated afferents via modulation of presynaptic inhibition in the mouse spinal cord.

    Science.gov (United States)

    García-Ramírez, David L; Calvo, Jorge R; Hochman, Shawn; Quevedo, Jorge N

    2014-01-01

    Gain control of primary afferent neurotransmission at their intraspinal terminals occurs by several mechanisms including primary afferent depolarization (PAD). PAD produces presynaptic inhibition via a reduction in transmitter release. While it is known that descending monoaminergic pathways complexly regulate sensory processing, the extent these actions include modulation of afferent-evoked PAD remains uncertain. We investigated the effects of serotonin (5HT), dopamine (DA) and noradrenaline (NA) on afferent transmission and PAD. Responses were evoked by stimulation of myelinated hindlimb cutaneous and muscle afferents in the isolated neonatal mouse spinal cord. Monosynaptic responses were examined in the deep dorsal horn either as population excitatory synaptic responses (recorded as extracellular field potentials; EFPs) or intracellular excitatory postsynaptic currents (EPSCs). The magnitude of PAD generated intraspinally was estimated from electrotonically back-propagating dorsal root potentials (DRPs) recorded on lumbar dorsal roots. 5HT depressed the DRP by 76%. Monosynaptic actions were similarly depressed by 5HT (EFPs 54%; EPSCs 75%) but with a slower time course. This suggests that depression of monosynaptic EFPs and DRPs occurs by independent mechanisms. DA and NA had similar depressant actions on DRPs but weaker effects on EFPs. IC50 values for DRP depression were 0.6, 0.8 and 1.0 µM for 5HT, DA and NA, respectively. Depression of DRPs by monoamines was nearly-identical in both muscle and cutaneous afferent-evoked responses, supporting a global modulation of the multimodal afferents stimulated. 5HT, DA and NA produced no change in the compound antidromic potentials evoked by intraspinal microstimulation indicating that depression of the DRP is unrelated to direct changes in the excitability of intraspinal afferent fibers, but due to metabotropic receptor activation. In summary, both myelinated afferent-evoked DRPs and monosynaptic transmission in the

  4. Serotonin, dopamine and noradrenaline adjust actions of myelinated afferents via modulation of presynaptic inhibition in the mouse spinal cord.

    Directory of Open Access Journals (Sweden)

    David L García-Ramírez

    Full Text Available Gain control of primary afferent neurotransmission at their intraspinal terminals occurs by several mechanisms including primary afferent depolarization (PAD. PAD produces presynaptic inhibition via a reduction in transmitter release. While it is known that descending monoaminergic pathways complexly regulate sensory processing, the extent these actions include modulation of afferent-evoked PAD remains uncertain. We investigated the effects of serotonin (5HT, dopamine (DA and noradrenaline (NA on afferent transmission and PAD. Responses were evoked by stimulation of myelinated hindlimb cutaneous and muscle afferents in the isolated neonatal mouse spinal cord. Monosynaptic responses were examined in the deep dorsal horn either as population excitatory synaptic responses (recorded as extracellular field potentials; EFPs or intracellular excitatory postsynaptic currents (EPSCs. The magnitude of PAD generated intraspinally was estimated from electrotonically back-propagating dorsal root potentials (DRPs recorded on lumbar dorsal roots. 5HT depressed the DRP by 76%. Monosynaptic actions were similarly depressed by 5HT (EFPs 54%; EPSCs 75% but with a slower time course. This suggests that depression of monosynaptic EFPs and DRPs occurs by independent mechanisms. DA and NA had similar depressant actions on DRPs but weaker effects on EFPs. IC50 values for DRP depression were 0.6, 0.8 and 1.0 µM for 5HT, DA and NA, respectively. Depression of DRPs by monoamines was nearly-identical in both muscle and cutaneous afferent-evoked responses, supporting a global modulation of the multimodal afferents stimulated. 5HT, DA and NA produced no change in the compound antidromic potentials evoked by intraspinal microstimulation indicating that depression of the DRP is unrelated to direct changes in the excitability of intraspinal afferent fibers, but due to metabotropic receptor activation. In summary, both myelinated afferent-evoked DRPs and monosynaptic

  5. Acute and sustained effects of methylphenidate on cognition and presynaptic dopamine metabolism: an [18F]FDOPA PET study.

    Science.gov (United States)

    Schabram, Ina; Henkel, Karsten; Mohammadkhani Shali, Siamak; Dietrich, Claudia; Schmaljohann, Jörn; Winz, Oliver; Prinz, Susanne; Rademacher, Lena; Neumaier, Bernd; Felzen, Marc; Kumakura, Yoshitaka; Cumming, Paul; Mottaghy, Felix M; Gründer, Gerhard; Vernaleken, Ingo

    2014-10-29

    Methylphenidate (MPH) inhibits the reuptake of dopamine and noradrenaline. PET studies with MPH challenge show increased competition at postsynaptic D2/3-receptors, thus indirectly revealing presynaptic dopamine release. We used [(18)F]fluorodopamine ([(18)F]FDOPA)-PET in conjunction with the inlet-outlet model (IOM) of Kumakura et al. (2007) to investigate acute and long-term changes in dopamine synthesis capacity and turnover in nigrostriatal fibers of healthy subjects with MPH challenge. Twenty healthy human females underwent two dynamic [(18)F]FDOPA PET scans (124 min; slow bolus-injection; arterial blood sampling), with one scan in untreated baseline condition and the other after MPH administration (0.5 mg/kg, p.o.), in randomized order. Subjects underwent cognitive testing at each PET session. Time activity curves were obtained for ventral putamen and caudate and were analyzed according to the IOM to obtain the regional net-uptake of [(18)F]FDOPA (K; dopamine synthesis capacity) as well as the [(18)F]fluorodopamine washout rate (kloss, index of dopamine turnover). MPH substantially decreased kloss in putamen (-22%; p = 0.003). In the reversed treatment order group (MPH/no drug), K was increased by 18% at no drug follow-up. The magnitude of K at the no drug baseline correlated with cognitive parameters. Furthermore, individual kloss changes correlated with altered cognitive performance under MPH. [(18)F]FDOPA PET in combination with the IOM detects an MPH-evoked decrease in striatal dopamine turnover, in accordance with the known acute pharmacodynamics of MPH. Furthermore, the scan-ordering effect on K suggested that a single MPH challenge persistently increased striatal dopamine synthesis capacity. Attenuation of dopamine turnover by MPH is linked to enhanced cognitive performance in healthy females. Copyright © 2014 the authors 0270-6474/14/3414769-08$15.00/0.

  6. Histamine H3 receptors mediate inhibition of noradrenaline release from intestinal sympathetic nerves

    OpenAIRE

    Blandizzi, Corrado; Tognetti, Martina; Colucci, Rocchina; Tacca, Mario Del

    2000-01-01

    The present study investigates whether presynaptic histamine receptors regulate noradrenaline release from intestinal sympathetic nerves. The experiments were performed on longitudinal muscle-myenteric plexus preparations of guinea-pig ileum, preincubated with [3H]-noradrenaline.In the presence of rauwolscine, electrically-induced [3H]-noradrenaline release was inhibited by histamine or R-α-methylhistamine, whereas it was unaffected by pyridylethylamine, impromidine, pyrilamine, cimetidine, t...

  7. Local synthesis of nuclear-encoded mitochondrial proteins in the presynaptic nerve terminal.

    Science.gov (United States)

    Gioio, A E; Eyman, M; Zhang, H; Lavina, Z S; Giuditta, A; Kaplan, B B

    2001-06-01

    One of the central tenets in neuroscience has been that the protein constituents of distal compartments of the neuron (e.g., the axon and nerve terminal) are synthesized in the nerve cell body and are subsequently transported to their ultimate sites of function. In contrast to this postulate, we have established previously that a heterogeneous population of mRNAs and biologically active polyribosomes exist in the giant axon and presynaptic nerve terminals of the photoreceptor neurons in squid. We report that these mRNA populations contain mRNAs for nuclear-encoded mitochondrial proteins to include: cytochrome oxidase subunit 17, propionyl-CoA carboxylase (EC 6.4.1.3), dihydrolipoamide dehydrogenase (EC 1.8.1.4), and coenzyme Q subunit 7. The mRNA for heat shock protein 70, a chaperone protein known to be involved in the import of proteins into mitochondria, has also been identified. Electrophoretic gel analysis of newly synthesized proteins in the synaptosomal fraction isolated from the squid optic lobe revealed that the large presynaptic terminals of the photoreceptor neuron contain a cytoplasmic protein synthetic system. Importantly, a significant amount of the cycloheximide resistant proteins locally synthesized in the terminal becomes associated with mitochondria. PCR analysis of RNA from synaptosomal polysomes establishes that COX17 and CoQ7 mRNAs are being actively translated. Taken together, these findings indicate that proteins required for the maintenance of mitochondrial function are synthesized locally in the presynaptic nerve terminal, and call attention to the intimacy of the relationship between the terminal and its energy generating system. J. Neurosci. Res. 64:447-453, 2001. Published 2001 Wiley-Liss, Inc.

  8. Control of autophagosome axonal retrograde flux by presynaptic activity unveiled using botulinum neurotoxin type a.

    Science.gov (United States)

    Wang, Tong; Martin, Sally; Papadopulos, Andreas; Harper, Callista B; Mavlyutov, Timur A; Niranjan, Dhevahi; Glass, Nick R; Cooper-White, Justin J; Sibarita, Jean-Baptiste; Choquet, Daniel; Davletov, Bazbek; Meunier, Frédéric A

    2015-04-15

    Botulinum neurotoxin type A (BoNT/A) is a highly potent neurotoxin that elicits flaccid paralysis by enzymatic cleavage of the exocytic machinery component SNAP25 in motor nerve terminals. However, recent evidence suggests that the neurotoxic activity of BoNT/A is not restricted to the periphery, but also reaches the CNS after retrograde axonal transport. Because BoNT/A is internalized in recycling synaptic vesicles, it is unclear which compartment facilitates this transport. Using live-cell confocal and single-molecule imaging of rat hippocampal neurons cultured in microfluidic devices, we show that the activity-dependent uptake of the binding domain of the BoNT/A heavy chain (BoNT/A-Hc) is followed by a delayed increase in retrograde axonal transport of BoNT/A-Hc carriers. Consistent with a role of presynaptic activity in initiating transport of the active toxin, activity-dependent uptake of BoNT/A in the terminal led to a significant increase in SNAP25 cleavage detected in the soma chamber compared with nonstimulated neurons. Surprisingly, most endocytosed BoNT/A-Hc was incorporated into LC3-positive autophagosomes generated in the nerve terminals, which then underwent retrograde transport to the cell soma, where they fused with lysosomes both in vitro and in vivo. Blocking autophagosome formation or acidification with wortmannin or bafilomycin A1, respectively, inhibited the activity-dependent retrograde trafficking of BoNT/A-Hc. Our data demonstrate that both the presynaptic formation of autophagosomes and the initiation of their retrograde trafficking are tightly regulated by presynaptic activity. Copyright © 2015 the authors 0270-6474/15/356179-16$15.00/0.

  9. Pancreatic and snake venom presynaptically active phospholipases A2 inhibit nicotinic acetylcholine receptors.

    Science.gov (United States)

    Vulfius, Catherine A; Kasheverov, Igor E; Kryukova, Elena V; Spirova, Ekaterina N; Shelukhina, Irina V; Starkov, Vladislav G; Andreeva, Tatyana V; Faure, Grazyna; Zouridakis, Marios; Tsetlin, Victor I; Utkin, Yuri N

    2017-01-01

    Phospholipases A2 (PLA2s) are enzymes found throughout the animal kingdom. They hydrolyze phospholipids in the sn-2 position producing lysophospholipids and unsaturated fatty acids, agents that can damage membranes. PLA2s from snake venoms have numerous toxic effects, not all of which can be explained by phospholipid hydrolysis, and each enzyme has a specific effect. We have earlier demonstrated the capability of several snake venom PLA2s with different enzymatic, cytotoxic, anticoagulant and antiproliferative properties, to decrease acetylcholine-induced currents in Lymnaea stagnalis neurons, and to compete with α-bungarotoxin for binding to nicotinic acetylcholine receptors (nAChRs) and acetylcholine binding protein. Since nAChRs are implicated in postsynaptic and presynaptic activities, in this work we probe those PLA2s known to have strong presynaptic effects, namely β-bungarotoxin from Bungarus multicinctus and crotoxin from Crotalus durissus terrificus. We also wished to explore whether mammalian PLA2s interact with nAChRs, and have examined non-toxic PLA2 from porcine pancreas. It was found that porcine pancreatic PLA2 and presynaptic β-bungarotoxin blocked currents mediated by nAChRs in Lymnaea neurons with IC50s of 2.5 and 4.8 μM, respectively. Crotoxin competed with radioactive α-bungarotoxin for binding to Torpedo and human α7 nAChRs and to the acetylcholine binding protein. Pancreatic PLA2 interacted similarly with these targets; moreover, it inhibited radioactive α-bungarotoxin binding to the water-soluble extracellular domain of human α9 nAChR, and blocked acetylcholine induced currents in human α9α10 nAChRs heterologously expressed in Xenopus oocytes. These and our earlier results show that all snake PLA2s, including presynaptically active crotoxin and β-bungarotoxin, as well as mammalian pancreatic PLA2, interact with nAChRs. The data obtained suggest that this interaction may be a general property of all PLA2s, which should be proved by

  10. Pancreatic and snake venom presynaptically active phospholipases A2 inhibit nicotinic acetylcholine receptors.

    Directory of Open Access Journals (Sweden)

    Catherine A Vulfius

    Full Text Available Phospholipases A2 (PLA2s are enzymes found throughout the animal kingdom. They hydrolyze phospholipids in the sn-2 position producing lysophospholipids and unsaturated fatty acids, agents that can damage membranes. PLA2s from snake venoms have numerous toxic effects, not all of which can be explained by phospholipid hydrolysis, and each enzyme has a specific effect. We have earlier demonstrated the capability of several snake venom PLA2s with different enzymatic, cytotoxic, anticoagulant and antiproliferative properties, to decrease acetylcholine-induced currents in Lymnaea stagnalis neurons, and to compete with α-bungarotoxin for binding to nicotinic acetylcholine receptors (nAChRs and acetylcholine binding protein. Since nAChRs are implicated in postsynaptic and presynaptic activities, in this work we probe those PLA2s known to have strong presynaptic effects, namely β-bungarotoxin from Bungarus multicinctus and crotoxin from Crotalus durissus terrificus. We also wished to explore whether mammalian PLA2s interact with nAChRs, and have examined non-toxic PLA2 from porcine pancreas. It was found that porcine pancreatic PLA2 and presynaptic β-bungarotoxin blocked currents mediated by nAChRs in Lymnaea neurons with IC50s of 2.5 and 4.8 μM, respectively. Crotoxin competed with radioactive α-bungarotoxin for binding to Torpedo and human α7 nAChRs and to the acetylcholine binding protein. Pancreatic PLA2 interacted similarly with these targets; moreover, it inhibited radioactive α-bungarotoxin binding to the water-soluble extracellular domain of human α9 nAChR, and blocked acetylcholine induced currents in human α9α10 nAChRs heterologously expressed in Xenopus oocytes. These and our earlier results show that all snake PLA2s, including presynaptically active crotoxin and β-bungarotoxin, as well as mammalian pancreatic PLA2, interact with nAChRs. The data obtained suggest that this interaction may be a general property of all PLA2s, which

  11. Extracellular Osmotic Stress Reduces the Vesicle Size while Keeping a Constant Neurotransmitter Concentration.

    Science.gov (United States)

    Fathali, Hoda; Dunevall, Johan; Majdi, Soodabeh; Cans, Ann-Sofie

    2017-02-15

    Secretory cells respond to hypertonic stress by cell shrinking, which causes a reduction in exocytosis activity and the amount of signaling molecules released from single exocytosis events. These changes in exocytosis have been suggested to result from alterations in biophysical properties of cell cytoplasm and plasma membrane, based on the assumption that osmotic stress does not affect the secretory vesicle content and size prior to exocytosis. To further investigate whether vesicles in secretory cells are affected by the osmolality of the extracellular environment, we used intracellular electrochemical cytometry together with transmission electron microscopy imaging to quantify and determine the catecholamine concentration of dense core vesicles in situ before and after cell exposure to osmotic stress. In addition, single cell amperometry recordings of exocytosis at chromaffin cells were used to monitor the effect on exocytosis activity and quantal release when cells were exposed to osmotic stress. Here we show that hypertonic stress hampers exocytosis secretion after the first pool of readily releasable vesicles have been fused and that extracellular osmotic stress causes catecholamine filled vesicles to shrink, mainly by reducing the volume of the halo solution surrounding the protein matrix in dense core vesicles. In addition, the vesicles demonstrate the ability to perform adjustments in neurotransmitter content during shrinking, and intracellular amperometry measurements in situ suggest that vesicles reduce the catecholamine content to maintain a constant concentration within the vesicle compartment. Hence, the secretory vesicles in the cell cytoplasm are highly affected and respond to extracellular osmotic stress, which gives a new perspective to the cause of reduction in quantal size by these vesicles when undergoing exocytosis.

  12. Mechanism of the Association between Na+ Binding and Conformations at the Intracellular Gate in Neurotransmitter:Sodium Symporters

    DEFF Research Database (Denmark)

    Stolzenberg, Sebastian; Quick, Matthias; Zhao, Chunfeng

    2015-01-01

    Neurotransmitter:sodium symporters (NSSs) terminate neurotransmission by Na+-dependent reuptake of released neurotransmitters. Previous studies suggested that Na+-binding reconfigures dynamically coupled structural elements in an allosteric interaction network (AIN) responsible for function...... in both LeuT and human dopamine transporter (hDAT), we apply the novel method to identify the composition and the dynamic properties of their conserved AIN. In LeuT, two different perturbations disrupting Na+ binding and transport (i.e. replacing Na+ with Li+ or the Y268A mutation at the intracellular...... gate) affect the AIN in strikingly similar ways. In contrast, other mutations that affect the intracellular gate (i.e. R5A and D369A) do not significantly impair Na+ cooperativity and transport. Our analysis shows these perturbations to have much lesser effects on the AIN, underscoring the sensitivity...

  13. Identification of catecholamine neurotransmitters using fluorescence sensor array.

    Science.gov (United States)

    Ghasemi, Forough; Hormozi-Nezhad, M Reza; Mahmoudi, Morteza

    2016-04-21

    A nano-based sensor array has been developed for identification and discrimination of catecholamine neurotransmitters based on optical properties of their oxidation products under alkaline conditions. To produce distinct fluorescence response patterns for individual catecholamine, quenching of thioglycolic acid functionalized cadmium telluride (CdTe) quantum dots, by oxidation products, were employed along with the variation of fluorescence spectra of oxidation products. The spectral changes were analyzed with hierarchical cluster analysis (HCA) and principal component analysis (PCA) to identify catecholamine patterns. The proposed sensor could efficiently discriminate the individual catecholamine (i.e., dopamine, norepinephrine, and l-DOPA) and their mixtures in the concentration range of 0.25-30 μmol L(-1). Finally, we found that the sensor had capability to identify the various catecholamines in urine sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Key modulatory role of presynaptic adenosine A2A receptors in cortical neurotransmission to the striatal direct pathway.

    Science.gov (United States)

    Quiroz, César; Luján, Rafael; Uchigashima, Motokazu; Simoes, Ana Patrícia; Lerner, Talia N; Borycz, Janusz; Kachroo, Anil; Canas, Paula M; Orru, Marco; Schwarzschild, Michael A; Rosin, Diane L; Kreitzer, Anatol C; Cunha, Rodrigo A; Watanabe, Masahiko; Ferré, Sergi

    2009-11-18

    Basal ganglia processing results from a balanced activation of direct and indirect striatal efferent pathways, which are controlled by dopamine D1 and D2 receptors, respectively. Adenosine A2A receptors are considered novel antiparkinsonian targets, based on their selective postsynaptic localization in the indirect pathway, where they modulate D2 receptor function. The present study provides evidence for the existence of an additional, functionally significant, segregation of A2A receptors at the presynaptic level. Using integrated anatomical, electrophysiological, and biochemical approaches, we demonstrate that presynaptic A2A receptors are preferentially localized in cortical glutamatergic terminals that contact striatal neurons of the direct pathway, where they exert a selective modulation of corticostriatal neurotransmission. Presynaptic striatal A2A receptors could provide a new target for the treatment of neuropsychiatric disorders.

  15. Key Modulatory Role of Presynaptic Adenosine A2A Receptors in Cortical Neurotransmission to the Striatal Direct Pathway

    Directory of Open Access Journals (Sweden)

    César Quiroz

    2009-01-01

    Full Text Available Basal ganglia processing results from a balanced activation of direct and indirect striatal efferent pathways, which are controlled by dopamine D1 and D2 receptors, respectively. Adenosine A2A receptors are considered novel antiparkinsonian targets, based on their selective postsynaptic localization in the indirect pathway, where they modulate D2 receptor function. The present study provides evidence for the existence of an additional, functionally significant, segregation of A2A receptors at the presynaptic level. Using integrated anatomical, electrophysiological, and biochemical approaches, we demonstrate that presynaptic A2A receptors are preferentially localized in cortical glutamatergic terminals that contact striatal neurons of the direct pathway, where they exert a selective modulation of corticostriatal neurotransmission. Presynaptic striatal A2A receptors could provide a new target for the treatment of neuropsychiatric disorders.

  16. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    Directory of Open Access Journals (Sweden)

    Dmitry eSamigullin

    2015-01-01

    Full Text Available At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 рА and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 µM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  17. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes.

    Science.gov (United States)

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

    2014-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers-which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal-has hitherto been technically impossible. With the aim of quantifying both Ca(2+) currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 pA and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 μM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity.

  18. Protein synthesis in presynaptic endings from squid brain: modulation by calcium ions.

    Science.gov (United States)

    Benech, J C; Crispino, M; Kaplan, B B; Giuditta, A

    1999-03-15

    Previous biochemical, autoradiographic, and ultrastructural data have shown that, in the synaptosomal fraction of the squid optic lobe, protein synthesis is largely due to the presynaptic terminals of the retinal photoreceptor neurons (Crispino et al. [1993a] Mol. Cell. Neurosci. 4:366-374; Crispino et al. [1993b] J. Neurochem. 61:1144-1146; Crispino et al. [1997] J. Neurosci. 17:7694-7702). We now report that this process is close to its maximum at the basal concentration of cytosolic Ca++, and is markedly inhibited when the concentration of this ion is either decreased or increased. This conclusion is supported by the results of experiments with: 1) compounds known to increase the level of cytosolic Ca++, such as A23187, ionomycin, thapsigargin, and caffeine; 2) compounds sequestering cytosolic calcium ions such as BAPTA-AM; and 3) agents that block the role of Ca++ as second messenger, such as TFP and W7, which inhibit calmodulin, and calphostin, which inhibits protein kinase C. We conclude that variations in the level of cytosolic Ca++ induced in presynaptic terminals by neuronal activity may contribute to the modulation of the local synthesis of protein.

  19. Presynaptic serotonin 2A receptors modulate thalamocortical plasticity and associative learning

    Science.gov (United States)

    Barre, Alexander; Berthoux, Coralie; De Bundel, Dimitri; Valjent, Emmanuel; Bockaert, Joël; Marin, Philippe; Bécamel, Carine

    2016-01-01

    Higher-level cognitive processes strongly depend on a complex interplay between mediodorsal thalamus nuclei and the prefrontal cortex (PFC). Alteration of thalamofrontal connectivity has been involved in cognitive deficits of schizophrenia. Prefrontal serotonin (5-HT)2A receptors play an essential role in cortical network activity, but the mechanism underlying their modulation of glutamatergic transmission and plasticity at thalamocortical synapses remains largely unexplored. Here, we show that 5-HT2A receptor activation enhances NMDA transmission and gates the induction of temporal-dependent plasticity mediated by NMDA receptors at thalamocortical synapses in acute PFC slices. Expressing 5-HT2A receptors in the mediodorsal thalamus (presynaptic site) of 5-HT2A receptor-deficient mice, but not in the PFC (postsynaptic site), using a viral gene-delivery approach, rescued the otherwise absent potentiation of NMDA transmission, induction of temporal plasticity, and deficit in associative memory. These results provide, to our knowledge, the first physiological evidence of a role of presynaptic 5-HT2A receptors located at thalamocortical synapses in the control of thalamofrontal connectivity and the associated cognitive functions. PMID:26903620

  20. Pre-synaptic control of remote fear extinction in the neocortex

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    Gisella eVetere

    2012-06-01

    Full Text Available Consolidation of remote memory enhances immediate early genes induction (IEGs, augments the expression of the presynaptic growth associated protein 43 (GAP-43, and increases the density and size of dendritic spines in anterior cingulate (aCC and infra-limbic (ILC cortices. Remote memory extinction, however, does not uniformly alter consolidation-induced structural changes. In the aCC, the density, but not the size, of spines is reset to pseudo-conditioning levels while novel thin spines are formed in the ILC. Whether IEGs and GAP-43 also undergo region-specific changes upon remote memory extinction is undetermined. Here we confirm in the same batch of mice that c-Fos induction and GAP-43 expression are increased in both the aCC and the ILC 36 days after contextual fear conditioning. We then show that, in both regions, remote memory extinction is associated with decrease of c-Fos induction but no change in GAP-43 expression thus revealing similar, although protein-specific, pre-synaptic adaptations in aCC and ILC neurons. These observations, in addition to our previous report of region-specific post-synaptic structural changes, disclose a complex pattern of extinction-driven neocortical alterations suitable to support erasure or reinstatement of fear according to the environment demand.

  1. Proton MR Spectroscopy—Detectable Major Neurotransmitters of the Brain: Biology and Possible Clinical Applications

    Science.gov (United States)

    Agarwal, N.; Renshaw, P.F.

    2015-01-01

    SUMMARY Neurotransmitters are chemical substances that, by definition, allow communication between neurons and permit most neuronal-glial interactions in the CNS. Approximately 80% of all neurons use glutamate, and almost all interneurons use GABA. A third neurotransmitter, NAAG, modulates glutamatergic neurotransmission. Concentration changes in these molecules due to defective synthetic machinery, receptor expression, or errors in their degradation and metabolism are accepted causes of several neurologic disorders. Knowledge of changes in neurotransmitter concentrations in the brain can add useful information in making a diagnosis, helping to pick the right drug of treatment, and monitoring patient response to drugs in a more objective manner. Recent advances in 1H-MR spectroscopy hold promise in providing a more reliable in vivo detection of these neurotransmitters. In this article, we summarize the essential biology of 3 major neurotransmitters: glutamate, GABA, and NAAG. Finally we illustrate possible applications of 1H-MR spectroscopy in neuroscience research. PMID:22207303

  2. Effect of Gonadal Hormones on Neurotransmitters Implicated in the Pathophysiology of Obsessive-Compulsive Disorder: A Critical Review.

    Science.gov (United States)

    Karpinski, Marta; Mattina, Gabriella Francesca; Steiner, Meir

    2017-01-01

    Obsessive-compulsive disorder (OCD) is a relatively common neuropsychiatric disorder affecting between 1.6 and 3.2% of the population. A number of studies have previously reported increased incidence of OCD, or exacerbation of preexisting symptoms in females during reproductive events. Since these periods are known to involve fluctuating levels of gonadal hormones, these steroids have been suggested to be involved in modulating the course of the disorder. However, to date, only a few studies have measured hormone levels and obsessive-compulsive (OC) symptoms concurrently; thus, direct evidence for this relationship is limited. In turn, investigations into neurotransmission in OC individuals have been more extensive, and have implicated the serotonergic, dopaminergic, and glutamatergic neurotransmitter systems in OCD pathology. There is evidence suggesting that reproductive hormones estrogens and progesterone can modulate neurotransmission in the aforementioned signaling pathways by regulating the expression of receptors and channels, as well as the synthesis and release of the neurotransmitter itself. Overall, estrogen and progesterone appear to enhance serotonin signaling, which has been associated with improved OC symptoms. The effect of the gonadal hormones in dopaminergic and glutamatergic signaling is much more variable, highlighting the need for further research in this field. The existing evidence shows that gonadal hormones can have profound impacts on neurotransmission in the brain, leading to the conclusion that the hormonal fluctuations during reproductive events are a plausible factor contributing to the change in OCD course during these times. © 2016 S. Karger AG, Basel.

  3. Xanomeline wash-resistantly bound to presynaptic M2 and M4 muscarinic receptors decreases the evoked release of acetylcholine

    Czech Academy of Sciences Publication Activity Database

    Machová, Eva; Jakubík, Jan; El-Fakahany, E. E.; Doležal, Vladimír

    2007-01-01

    Roč. 101, Suppl.1 (2007), s. 52-53 ISSN 0022-3042. [ESN - meeting /17./ - Conference on Advances in Molecular Mechanims and Disorders /3./. 19.05.2007-22.05.2007, Salamanca] R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA305/05/0452 Grant - others:NIH(US) NS25732 Institutional research plan: CEZ:AV0Z50110509 Keywords : cpo1 * xanomeline * muscarinic receptor Subject RIV: FH - Neurology

  4. NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.

    Science.gov (United States)

    Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

    2015-01-21

    A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 Gαq and egl-8 PLCβ) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 Gαq and egl-8 PLCβ and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. Copyright © 2015 the authors 0270-6474/15/351038-05$15.00/0.

  5. Multivesicular release underlies short term synaptic potentiation independent of release probability change in the supraoptic nucleus.

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    Michelle E Quinlan

    Full Text Available Magnocellular neurons of the supraoptic nucleus receive glutamatergic excitatory inputs that regulate the firing activity and hormone release from these neurons. A strong, brief activation of these excitatory inputs induces a lingering barrage of tetrodotoxin-resistant miniature EPSCs (mEPSCs that lasts for tens of minutes. This is known to accompany an immediate increase in large amplitude mEPSCs. However, it remains unknown how long this amplitude increase can last and whether it is simply a byproduct of greater release probability. Using in vitro patch clamp recording on acute rat brain slices, we found that a brief, high frequency stimulation (HFS of afferents induced a potentiation of mEPSC amplitude lasting up to 20 min. This amplitude potentiation did not correlate with changes in mEPSC frequency, suggesting that it does not reflect changes in presynaptic release probability. Nonetheless, neither postsynaptic calcium chelator nor the NMDA receptor antagonist blocked the potentiation. Together with the known calcium dependency of HFS-induced potentiation of mEPSCs, our results imply that mEPSC amplitude increase requires presynaptic calcium. Further analysis showed multimodal distribution of mEPSC amplitude, suggesting that large mEPSCs were due to multivesicular glutamate release, even at late post-HFS when the frequency is no longer elevated. In conclusion, high frequency activation of excitatory synapses induces lasting multivesicular release in the SON, which is independent of changes in release probability. This represents a novel form of synaptic plasticity that may contribute to prolonged excitatory tone necessary for generation of burst firing of magnocellular neurons.

  6. Changes in Neurotransmitter Profiles during Early Zebrafish (Danio rerio) Development and after Pesticide Exposure.

    Science.gov (United States)

    Tufi, Sara; Leonards, Pim; Lamoree, Marja; de Boer, Jacob; Legler, Juliette; Legradi, Jessica

    2016-03-15

    During early development, neurotransmitters are important stimulants for the development of the central nervous system. Although the development of different neuronal cell types during early zebrafish (Danio rerio) development is well-studied, little is known of the levels of neurotransmitters, their precursors and metabolites during development, and how these levels are affected by exposure to environmental contaminants. A method based on hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry has been applied for the first time to zebrafish embryos and larvae to study five neurotransmitter systems in parallel, including the dopaminergic-andrenergic, glutaminergic-GABAnergic, serotoninergic, histaminergic, and cholinergic systems. Our method enables the quantification of neurotransmitters and their precursors and metabolites in whole zebrafish from the period of zygote to free-swimming larvae 6 days postfertilization (dpf). We observed a developmental stage-dependent pattern with clear differences between the first 2 days of development and the following days. Whereas the neurotransmitter levels steadily increased, the precursors showed a peak at 3 dpf. After exposure to several pesticides, significant differences in concentrations of neurotransmitters and precursors were observed. Our study revealed new insights about neurotransmitter systems during early zebrafish development and showed the usefulness of our approach for environmental neurotoxicity studies.

  7. Does chronic nicotine alter neurotransmitter receptors involved in Parkinson's disease?

    International Nuclear Information System (INIS)

    Reilly, M.A.; Lapin, E.P.; Lajtha, A.; Maker, H.S.

    1986-01-01

    Cigarette smokers are fewer in number among Parkinson's Disease (PD) patients than among groups of persons who do not have PD. Several hypotheses have been proposed to explain this observation. One which must be tested is the possibility that some pharmacologic agent present in cigarette smoke may interact with some central nervous system component involved in PD. To this end, they have investigated the effect of chronic nicotine administration on receptors for some of the neurotransmitters that are affected in PD. Rats were injected for six weeks with saline or nicotine 0.8 mg/kg S.C., then killed and brains removed and dissected. The binding of ( 3 H)-ketanserin to serotonin receptors in frontal cortex and of ( 3 H)-domperidone to dopamine receptors in caudate was not affected. However, the binding of ( 3 H)-domperidone in nucleus accumbens was altered: the K/sub d/ increased from 0.16 +/- 0.02 nM to 0.61 +/- 0.07 nM, and the B/sub max/ increased from 507 +/- 47 fmol/mg protein to 910 +/- 43 fmol/mg (p < 0.001 for both comparisons). These values are based on three ligand concentrations. Additional studies are in progress to substantiate the data. It is concluded that chronic nicotine administration may alter dopamine receptors in nucleus accumbens

  8. Potential Antidepressant Role of Neurotransmitter CART: Implications for Mental Disorders

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    Peizhong Mao

    2011-01-01

    Full Text Available Depression is one of the most prevalent and debilitating public health concerns. Although no single cause of depression has been identified, it appears that interaction among genetic, epigenetic, biochemical, environmental, and psychosocial factors may explain its etiology. Further, only a fraction of depressed patients show full remission while using current antidepressants. Therefore, identifying common pathways of the disorder and using that knowledge to develop more effective pharmacological treatments are two primary targets of research in this field. Brain-enriched neurotransmitter CART (cocaine- and amphetamine-regulated transcript has multiple functions related to emotions. It is a potential neurotrophic factor and is involved in the regulation of hypothalamic-pituitary-adrenal axis and stress response as well as in energy homeostasis. CART is also highly expressed in limbic system, which is considered to have an important role in regulating mood. Notably, adolescents carrying a missense mutation in the CART gene exhibit increased depression and anxiety. Hence, CART peptide may be a novel promising antidepressant agent. In this paper, we summarize recent progress in depression and CART. In particular, we emphasize a new antidepressant function for CART.

  9. Less means more: The magnitude of synaptic plasticity along the hippocampal dorso-ventral axis is inversely related to the expression levels of plasticity-related neurotransmitter receptors.

    Science.gov (United States)

    Dubovyk, Valentyna; Manahan-Vaughan, Denise

    2018-02-01

    The dorsoventral axis of the hippocampus exhibits functional differentiations with regard to (spatial Vs emotional) learning and information retention (rapid encoding Vs long-term storage), as well as its sensitivity to neuromodulation and information received from extrahippocampal structures. The mechanisms that underlie these differentiations remain unclear. Here, we explored neurotransmitter receptor expression along the dorsoventral hippocampal axis and compared hippocampal synaptic plasticity in the CA1 region of the dorsal (DH), intermediate (IH) and ventral hippocampi (VH). We observed a very distinct gradient of expression of the N-methyl-D-aspartate receptor GluN2B subunit in the Stratum radiatum (DH IH > VH). Neurotransmitter release probability was lowest in DH. Surprisingly, identical afferent stimulation conditions resulted in hippocampal synaptic plasticity that was the most robust in the DH, compared with IH and VH. These data suggest that differences in hippocampal information processing and synaptic plasticity along the dorsoventral axis may relate to specific differences in the expression of plasticity-related neurotransmitter receptors. This gradient may support the fine-tuning and specificity of hippocampal synaptic encoding. © 2017 The Authors. Hippocampus Published by Wiley Periodicals, Inc.

  10. Ethylbenzene-induced hearing loss, neurobehavioral function, and neurotransmitter alterations in petrochemical workers.

    Science.gov (United States)

    Zhang, Ming; Wang, Yanrang; Wang, Qian; Yang, Deyi; Zhang, Jingshu; Wang, Fengshan; Gu, Qing

    2013-09-01

    To estimate hearing loss, neurobehavioral function, and neurotransmitter alteration induced by ethylbenzene in petrochemical workers. From two petrochemical plants, 246 and 307 workers exposed to both ethylbenzene and noise were recruited-290 workers exposed to noise only from a power station plant and 327 office personnel as control group, respectively. Hearing and neurobehavioral functions were evaluated. Serum neurotransmitters were also determined. The prevalence of hearing loss was much higher in petrochemical groups than that in power station and control groups (P workers (P hearing loss, neurobehavioral function impairment, and imbalance of neurotransmitters.

  11. Learning and retrieval behavior in recurrent neural networks with pre-synaptic dependent homeostatic plasticity

    Science.gov (United States)

    Mizusaki, Beatriz E. P.; Agnes, Everton J.; Erichsen, Rubem; Brunnet, Leonardo G.

    2017-08-01

    The plastic character of brain synapses is considered to be one of the foundations for the formation of memories. There are numerous kinds of such phenomenon currently described in the literature, but their role in the development of information pathways in neural networks with recurrent architectures is still not completely clear. In this paper we study the role of an activity-based process, called pre-synaptic dependent homeostatic scaling, in the organization of networks that yield precise-timed spiking patterns. It encodes spatio-temporal information in the synaptic weights as it associates a learned input with a specific response. We introduce a correlation measure to evaluate the precision of the spiking patterns and explore the effects of different inhibitory interactions and learning parameters. We find that large learning periods are important in order to improve the network learning capacity and discuss this ability in the presence of distinct inhibitory currents.

  12. Electrical receptive fields of retinal ganglion cells: Influence of presynaptic neurons.

    Science.gov (United States)

    Maturana, Matias I; Apollo, Nicholas V; Garrett, David J; Kameneva, Tatiana; Cloherty, Shaun L; Grayden, David B; Burkitt, Anthony N; Ibbotson, Michael R; Meffin, Hamish

    2018-02-01

    Implantable retinal stimulators activate surviving neurons to restore a sense of vision in people who have lost their photoreceptors through degenerative diseases. Complex spatial and temporal interactions occur in the retina during multi-electrode stimulation. Due to these complexities, most existing implants activate only a few electrodes at a time, limiting the repertoire of available stimulation patterns. Measuring the spatiotemporal interactions between electrodes and retinal cells, and incorporating them into a model may lead to improved stimulation algorithms that exploit the interactions. Here, we present a computational model that accurately predicts both the spatial and temporal nonlinear interactions of multi-electrode stimulation of rat retinal ganglion cells (RGCs). The model was verified using in vitro recordings of ON, OFF, and ON-OFF RGCs in response to subretinal multi-electrode stimulation with biphasic pulses at three stimulation frequencies (10, 20, 30 Hz). The model gives an estimate of each cell's spatiotemporal electrical receptive fields (ERFs); i.e., the pattern of stimulation leading to excitation or suppression in the neuron. All cells had excitatory ERFs and many also had suppressive sub-regions of their ERFs. We show that the nonlinearities in observed responses arise largely from activation of presynaptic interneurons. When synaptic transmission was blocked, the number of sub-regions of the ERF was reduced, usually to a single excitatory ERF. This suggests that direct cell activation can be modeled accurately by a one-dimensional model with linear interactions between electrodes, whereas indirect stimulation due to summated presynaptic responses is nonlinear.

  13. Presynaptic inhibition of GABAergic synaptic transmission by adenosine in mouse hypothalamic hypocretin neurons.

    Science.gov (United States)

    Xia, J X; Xiong, J X; Wang, H K; Duan, S M; Ye, J N; Hu, Z A

    2012-01-10

    Hypocretin neurons in the lateral hypothalamus, a new wakefulness-promoting center, have been recently regarded as an important target involved in endogenous adenosine-regulating sleep homeostasis. The GABAergic synaptic transmissions are the main inhibitory afferents to hypocretin neurons, which play an important role in the regulation of excitability of these neurons. The inhibitory effect of adenosine, a homeostatic sleep-promoting factor, on the excitatory glutamatergic synaptic transmissions in hypocretin neurons has been well documented, whether adenosine also modulates these inhibitory GABAergic synaptic transmissions in these neurons has not been investigated. In this study, the effect of adenosine on inhibitory postsynaptic currents (IPSCs) in hypocretin neurons was examined by using perforated patch-clamp recordings in the acute hypothalamic slices. The findings demonstrated that adenosine suppressed the amplitude of evoked IPSCs in a dose-dependent manner, which was completely abolished by 8-cyclopentyltheophylline (CPT), a selective antagonist of adenosine A1 receptor but not adenosine A2 receptor antagonist 3,7-dimethyl-1-(2-propynyl) xanthine. A presynaptic origin was suggested as following: adenosine increased paired-pulse ratio as well as reduced GABAergic miniature IPSC frequency without affecting the miniature IPSC amplitude. Further findings demonstrated that when the frequency of electrical stimulation was raised to 10 Hz, but not 1 Hz, a time-dependent depression of evoked IPSC amplitude was detected in hypocretin neurons, which could be partially blocked by CPT. However, under a higher frequency at 100 Hz stimulation, CPT had no action on the depressed GABAergic synaptic transmission induced by such tetanic stimulation in these hypocretin neurons. These results suggest that endogenous adenosine generated under certain stronger activities of synaptic transmissions exerts an inhibitory effect on GABAergic synaptic transmission in hypocretin

  14. Presynaptic selectivity of a ligand for serotonin 1A receptors revealed by in vivo PET assays of rat brain.

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    Takeaki Saijo

    Full Text Available A novel investigational antidepressant with high affinity for the serotonin transporter and the serotonin 1A (5-HT(1A receptor, called Wf-516 (structural formula: (2S-1-[4-(3,4-dichlorophenylpiperidin-1-yl]-3-[2-(5-methyl-1,3,4-oxadiazol-2-ylbenzo[b]furan-4-yloxy]propan-2-ol monohydrochloride, has been found to exert a rapid therapeutic effect, although the mechanistic basis for this potential advantage remains undetermined. We comparatively investigated the pharmacokinetics and pharmacodynamics of Wf-516 and pindolol by positron emission tomographic (PET and autoradiographic assays of rat brains in order to elucidate their molecular interactions with presynaptic and postsynaptic 5-HT(1A receptors. In contrast to the full receptor occupancy by pindolol in PET measurements, the binding of Wf-516 to 5-HT(1A receptors displayed limited capacity, with relatively high receptor occupancy being achieved in regions predominantly containing presynaptic receptors. This selectivity was further proven by PET scans of neurotoxicant-treated rats deficient in presynaptic 5-HT(1A receptors. In addition, [(35S]guanosine 5'-O-[γ-thio]triphosphate autoradiography indicated a partial agonistic ability of Wf-516 for 5-HT(1A receptors. This finding has lent support to reports that diverse partial agonists for 5-HT(1A receptors exert high sensitivity for presynaptic components. Thus, the present PET data suggest a relatively high capacity of presynaptic binding sites for partial agonists. Since our in vitro and ex vivo autoradiographies failed to illustrate these distinct features of Wf-516, in vivo PET imaging is considered to be, thus far, the sole method capable of pharmacokinetically demonstrating the unique actions of Wf-516 and similar new-generation antidepressants.

  15. Super-resolution microscopy reveals presynaptic localization of the ALS / FTD related protein FUS in hippocampal neurons

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    Michael eSchoen

    2016-01-01

    Full Text Available Fused in Sarcoma (FUS is a multifunctional RNA- / DNA-binding protein, which is involved in the pathogenesis of the neurodegenerative disorders amyotrophic lateral sclerosis (ALS and frontotemporal dementia (FTD. A common hallmark of these disorders is the abnormal accumulation of mutated FUS protein in the cytoplasm. Under normal conditions FUS is confined to the nuclear compartment, in neurons however, additional somatodendritic localization can be observed. In this study, we carefully analyzed the subcellular localization of endogenous FUS at synaptic sites of hippocampal neurons which are among the most affected cell types in frontotemporal dementia with FUS pathology. We could confirm a strong nuclear localization of FUS as well as its prominent and widespread neuronal expression throughout the adult and developing rat brain, particularly in the hippocampus, the cerebellum and the outer layers of the cortex. Intriguingly, FUS was also consistently observed at synaptic sites as detected by neuronal subcellular fractionation as well as by immunolabeling. To define a pre- and / or postsynaptic localization of FUS, we employed super-resolution fluorescence localization microscopy. FUS was found to be localized within the axon terminal in close proximity to the presynaptic vesicle protein Synaptophysin1 and adjacent to the active zone protein Bassoon, but well separated from the postsynaptic protein PSD-95. Having shown the presynaptic localization of FUS in the nervous system, a novel extranuclear role of FUS at neuronal contact sites has to be considered. Since there is growing evidence that local presynaptic translation might also be an important mechanism for plasticity, FUS - like the fragile X mental retardation protein FMRP - might act as one of the presynaptic RNA-binding proteins regulating this machinery. Our observation of presynaptic FUS should foster further investigations to determine its role in neurodegenerative diseases such as

  16. Neurotransmitter signaling pathways required for normal development in Xenopus laevis embryos: a pharmacological survey screen.

    Science.gov (United States)

    Sullivan, Kelly G; Levin, Michael

    2016-10-01

    Neurotransmitters are not only involved in brain function but are also important signaling molecules for many diverse cell types. Neurotransmitters are widely conserved, from evolutionarily ancient organisms lacking nervous systems through man. Here, results are reported from a loss- and gain-of-function survey, using pharmacological modulators of several neurotransmitter pathways to examine possible roles for these pathways in normal embryogenesis. Applying reagents targeting the glutamatergic, adrenergic and dopaminergic pathways to embryos of Xenopus laevis from gastrulation to organogenesis stages, we observed and quantified numerous malformations, including craniofacial defects, hyperpigmentation, muscle mispatterning and miscoiling of the gut. These data implicate several key neurotransmitters in new embryonic patterning roles, reveal novel earlier stages for processes involved in eye development, suggest new targets for subsequent molecular-genetic investigation, and highlight the necessity for in-depth toxicology studies of psychoactive compounds to which human embryos might be exposed during pregnancy. © 2016 Anatomical Society.

  17. Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA

    OpenAIRE

    Schousboe, Arne; Bak, Lasse K.; Waagepetersen, Helle S.

    2013-01-01

    Glutamate and GABA are the quantitatively major neurotransmitters in the brain mediating excitatory and inhibitory signaling, respectively. These amino acids are metabolically interrelated and at the same time they are tightly coupled to the intermediary metabolism including energy homeostasis. Astrocytes play a pivotal role in the maintenance of the neurotransmitter pools of glutamate and GABA since only these cells express pyruvate carboxylase, the enzyme required for de novo synthesis of t...

  18. Characterization of taurine binding, uptake, and release in the rat hypothalamus

    International Nuclear Information System (INIS)

    Hanretta, A.T.

    1985-01-01

    The neurotransmitter criteria of specific receptors, inactivation, and release were experimentally examined for taurine in the hypothalamus. Specific membrane binding and synaptosomal uptake of taurine both displayed high affinity and low affinity systems. The neurotransmitter criterion of release was studied in superfused synaptosomes. Exposure of synaptosomes which had been preloaded with a concentration of [ 3 H]taurine in the high affinity uptake range (1.5 μM) to either 56 mM K + or 100 μM veratridine evoked a Ca 2+ -independent release. Exposure of synaptosomes which had been preloaded with a concentration of [ 3 H]taurine in the low affinity uptake range (2 mM) to 56 mM K + induced a Ca 2+ -independent release, whereas 100 + M veratridine did not, either in the presence or absence of Ca 2+ . Based on these results, as well as other observations, a model is proposed in which the high affinity uptake system is located on neuronal membranes and the low affinity uptake system is located on glial membranes. The mechanisms of binding, uptake, and release in relation to the cellular location of each are discussed. We conclude that the neurotransmitter criterion of activation by re-uptake is satisfied for taurine in the hypothalamus. However, the failure to demonstrate both a specific taurine receptor site and a Ca 2+ -dependent evoked release, necessitates that we conclude that taurine appears not to function as a hypothalamic neurotransmitter, at least not in the classical sense

  19. Transcriptomic responses in mouse brain exposed to chronic excess of the neurotransmitter glutamate

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    Pal Ranu

    2010-06-01

    Full Text Available Abstract Background Increases during aging in extracellular levels of glutamate (Glu, the major excitatory neurotransmitter in the brain, may be linked to chronic neurodegenerative diseases. Little is known about the molecular responses of neurons to chronic, moderate increases in Glu levels. Genome-wide gene expression in brain hippocampus was examined in a unique transgenic (Tg mouse model that exhibits moderate Glu hyperactivity throughout the lifespan, the neuronal Glutamate dehydrogenase (Glud1 mouse, and littermate 9 month-old wild type mice. Results Integrated bioinformatic analyses on transcriptomic data were used to identify bio-functions, pathways and gene networks underlying neuronal responses to increased Glu synaptic release. Bio-functions and pathways up-regulated in Tg mice were those associated with oxidative stress, cell injury, inflammation, nervous system development, neuronal growth, and synaptic transmission. Increased gene expression in these functions and pathways indicated apparent compensatory responses offering protection against stress, promoting growth of neuronal processes (neurites and re-establishment of synapses. The transcription of a key gene in the neurite growth network, the kinase Ptk2b, was significantly up-regulated in Tg mice as was the activated (phosphorylated form of the protein. In addition to genes related to neurite growth and synaptic development, those associated with neuronal vesicle trafficking in the Huntington's disease signalling pathway, were also up-regulated. Conclusions This is the first study attempting to define neuronal gene expression patterns in response to chronic, endogenous Glu hyperactivity at brain synapses. The patterns observed were characterized by a combination of responses to stress and stimulation of nerve growth, intracellular transport and recovery.

  20. Electrochemical sensors and biosensors for determination of catecholamine neurotransmitters: A review.

    Science.gov (United States)

    Ribeiro, José A; Fernandes, Paula M V; Pereira, Carlos M; Silva, F

    2016-11-01

    This work describes the state of the art of electrochemical devices for the detection of an important class of neurotransmitters: the catecholamines. This class of biogenic amines includes dopamine, noradrenaline (also called norepinephrine) and adrenaline (also called epinephrine). Researchers have focused on the role of catecholamine molecules within the human body because they are involved in many important biological functions and are commonly associated with several diseases, such as Alzheimer's and Parkinson. Furthermore, the release of catecholamines as a consequence of induced stimulus is an important indicator of reward-related behaviors, such as food, drink, sex and drug addiction. Thus, the development of simple, fast and sensitive electroanalytical methodologies for the determination of catecholamines is currently needed in clinical and biomedical fields, as they have the potential to serve as clinically relevant biomarkers for specific disease states or to monitor treatment efficacy. Currently, three main strategies have used by researchers to detect catecholamine molecules, namely: the use electrochemical materials in combination with, for example, HPLC or FIA, the incorporation of new materials/layers on the sensor surfaces (Tables 1-7) and in vivo detection, manly by using FSCV at CFMEs (Section 10). The developed methodologies were able not only to accurately detect catecholamines at relevant concentration levels, but to do so in the presence of co-existing interferences in samples detected (ascorbate, for example). This review examines the progress made in electrochemical sensors for the selective detection of catecholamines in the last 15 years, with special focus on highly innovative features introduced by nanotechnology. As the literature in rather extensive, we try to simplify this work by summarizing and grouping electrochemical sensors according to the manner their substrates were chemically modified. We also discuss the current and future

  1. Marine omega-3 polyunsaturated fatty acids induce sex-specific changes in reinforcer-controlled behaviour and neurotransmitter metabolism in a spontaneously hypertensive rat model of ADHD

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    Dervola Kine S

    2012-12-01

    Full Text Available Abstract Background Previous reports suggest that omega-3 (n-3 polyunsaturated fatty acids (PUFA supplements may reduce ADHD-like behaviour. Our aim was to investigate potential effects of n-3 PUFA supplementation in an animal model of ADHD. Methods We used spontaneously hypertensive rats (SHR. SHR dams were given n-3 PUFA (EPA and DHA-enriched feed (n-6/n-3 of 1:2.7 during pregnancy, with their offspring continuing on this diet until sacrificed. The SHR controls and Wistar Kyoto (WKY control rats were given control-feed (n-6/n-3 of 7:1. During postnatal days (PND 25–50, offspring were tested for reinforcement-dependent attention, impulsivity and hyperactivity as well as spontaneous locomotion. The animals were then sacrificed at PND 55–60 and their neostriata were analysed for monoamine and amino acid neurotransmitters with high performance liquid chromatography. Results n-3 PUFA supplementation significantly enhanced reinforcement-controlled attention and reduced lever-directed hyperactivity and impulsiveness in SHR males whereas the opposite or no effects were observed in females. Analysis of neostriata from the same animals showed significantly enhanced dopamine and serotonin turnover ratios in the male SHRs, whereas female SHRs showed no change, except for an intermediate increase in serotonin catabolism. In contrast, both male and female SHRs showed n-3 PUFA-induced reduction in non-reinforced spontaneous locomotion, and sex-independent changes in glycine levels and glutamate turnover. Conclusions Feeding n-3 PUFAs to the ADHD model rats induced sex-specific changes in reinforcement-motivated behaviour and a sex-independent change in non-reinforcement-associated behaviour, which correlated with changes in presynaptic striatal monoamine and amino acid signalling, respectively. Thus, dietary n-3 PUFAs may partly ameliorate ADHD-like behaviour by reinforcement-induced mechanisms in males and partly via reinforcement-insensitive mechanisms

  2. Dopamine in the Auditory Brainstem and Midbrain: Co-localization with Amino Acid Neurotransmitters and Gene Expression following Cochlear Trauma

    Directory of Open Access Journals (Sweden)

    Avril Genene eHolt

    2015-07-01

    Full Text Available Dopamine (DA modulates the effects of amino acid neurotransmitters, including GABA and glutamate, in motor, visual, olfactory and reward systems (Hnasko et al., 2010; Stuber et al., 2010; Hnasko and Edwards, 2012. The results suggest that DA may play a similar modulatory role in the auditory pathways. Previous studies have shown that deafness results in decreased GABA release, changes in excitatory neurotransmitter levels, and increased spontaneous neuronal activity within brainstem regions related to auditory function. Modulation of the expression and localization of tyrosine hydroxylase (TH; the rate limiting enzyme in the production of DA in the IC following cochlear trauma has been previously reported (Tong et al., 2005. In the current study the possibility of co-localization of TH with amino acid neurotransmitters (AANs was examined. Changes in the gene expression of TH were compared with changes in the gene expression of markers for AANs in the cochlear nucleus (CN and IC to determine whether those deafness related changes occur concurrently. The results indicate that bilateral cochlear ablation significantly reduced TH gene expression in the CN after two months while in the IC the reduction in TH was observed at both three days and two months following ablation. Furthermore, in the CN, glycine transporter 2 (GlyT2 and the GABA transporter (GABAtp were also significantly reduced only after two months. However, in the IC, DA receptor 1 (DRDA1, vesicular glutamate transporters 2 and 3 (vGluT2, vGluT3, GABAtp and GAD67 were reduced in expression both at the three day and two month time points. A close relationship between the distribution of TH and several of the AANs was determined in both the CN and the IC. In addition, GlyT2 and vGluT3 each co-localized with TH within IC somata and dendrites. Therefore, the results of the current study suggest that DA is spatially well positioned to influence the effects of AANs on auditory neurons.

  3. APP Homodimers Transduce an Amyloid-β-Mediated Increase in Release Probability at Excitatory Synapses

    Directory of Open Access Journals (Sweden)

    Hilla Fogel

    2014-06-01

    Full Text Available Accumulation of amyloid-β peptides (Aβ, the proteolytic products of the amyloid precursor protein (APP, induces a variety of synaptic dysfunctions ranging from hyperactivity to depression that are thought to cause cognitive decline in Alzheimer’s disease. While depression of synaptic transmission has been extensively studied, the mechanisms underlying synaptic hyperactivity remain unknown. Here, we show that Aβ40 monomers and dimers augment release probability through local fine-tuning of APP-APP interactions at excitatory hippocampal boutons. Aβ40 binds to the APP, increases the APP homodimer fraction at the plasma membrane, and promotes APP-APP interactions. The APP activation induces structural rearrangements in the APP/Gi/o-protein complex, boosting presynaptic calcium flux and vesicle release. The APP growth-factor-like domain (GFLD mediates APP-APP conformational changes and presynaptic enhancement. Thus, the APP homodimer constitutes a presynaptic receptor that transduces signal from Aβ40 to glutamate release. Excessive APP activation may initiate a positive feedback loop, contributing to hippocampal hyperactivity in Alzheimer’s disease.

  4. Molecular machines regulating the release probability of synaptic vesicles at the active zone.

    Directory of Open Access Journals (Sweden)

    Christoph eKoerber

    2016-03-01

    Full Text Available The fusion of synaptic vesicles (SVs with the plasma membrane of the active zone (AZ upon arrival of an action potential (AP at the presynaptic compartment is a tightly regulated probabil-istic process crucial for information transfer. The probability of a SV to release its transmitter content in response to an AP, termed release probability (Pr, is highly diverse both at the level of entire synapses and individual SVs at a given synapse. Differences in Pr exist between different types of synapses, between synapses of the same type, synapses originating from the same axon and even between different SV subpopulations within the same presynaptic terminal. The Pr of SVs at the AZ is set by a complex interplay of different presynaptic properties including the availability of release-ready SVs, the location of the SVs relative to the voltage-gated calcium channels (VGCCs at the AZ, the magnitude of calcium influx upon arrival of the AP, the buffer-ing of calcium ions as well as the identity and sensitivity of the calcium sensor. These properties are not only interconnected, but can also be regulated dynamically to match the requirements of activity patterns mediated by the synapse. Here, we review recent advances in identifying mole-cules and molecular machines taking part in the determination of vesicular Pr at the AZ.

  5. Presynaptic control of group Ia afferents in relation to acquisition of a visuo-motor skill in healthy humans

    DEFF Research Database (Denmark)

    Perez, Monica A.; Lungholt, Bjarke K.S.; Nielsen, Jens Bo

    2005-01-01

    Sensory information continuously converges on the spinal cord during a variety of motor behaviours. Here, we examined presynaptic control of group Ia afferents in relation to acquisition of a novel motor skill. We tested whether repetition of two motor tasks with different degrees of difficulty...... of the monosynaptic Ia facilitation of the soleus H-reflex evoked by femoral nerve stimulation. The D1 inhibition was increased and the femoral nerve facilitation was decreased following the visuo-motor skill task, suggesting an increase in presynaptic inhibition of Ia afferents. No changes were observed...... in the disynaptic reciprocal Ia inhibition. Somatosensory evoked potentials (SEPs) evoked by stimulation of the tibial nerve (TN) were also unchanged, suggesting that transmission in ascending pathways was unaltered following the visuo-motor skill task. Together these observations suggest that a selective...

  6. Neurotransmitter measures in the cerebrospinal fluid of patients with Alzheimer's disease: a review.

    Science.gov (United States)

    Strac, Dubravka Svob; Muck-Seler, Dorotea; Pivac, Nela

    2015-03-01

    Alzheimer's disease (AD) is a severe neurodegenerative disorder characterized by progressive cognitive and functional decline, as well as by a variety of neuropsychiatric and psychological symptoms and behavioral dysfunctions. Various studies proposed the role of different neurotransmitter systems not only in AD-related cognitive, but also psychotic symptoms and behavioral and emotional deficits. Due to the close proximity, pathological neurochemical changes in brain occurring in AD are likely to be reflected in the cerebrospinal fluid (CSF). The purpose of this review is to provide a summary of the CSF neurotransmitter correlates of AD in order to get further insights into the potential role of altered neurotransmitters in the pathophysiology of AD and to offer novel AD biomarkers. PubMed and MEDLINE data bases were searched for English-language articles by using "Alzheimer's disease", "CSF" and "neurotransmitter" as primary terms. No time or article type constraints were applied. Moreover, the lists of references were searched manually for additional articles. Changes in various correlates of cholinergic, monoaminergic and amino acid neurotransmitter systems, as well as neuropeptides, have been observed in CSF of AD patients. However, as the results of these studies have been controversial, the importance of CSF neurotransmitter parameters as potential biomarkers in AD remains quite unclear. The observed discrepancies could be bypassed by implementation of new sensitive methods, such as novel proteomics approaches that include protein separation techniques, mass spectroscopy and targeted multiplex panels of specific analytes. Although no individual CSF neurotransmitter correlate was demonstrated as suitable biomarker of AD, a combined profile of several CSF neurochemical parameters might show enhanced sensitivity and specificity and thus contribute to earlier and more accurate diagnosis of AD, crucial for application of effective treatments.

  7. Intra-Amniotic LPS Induced Region-Specific Changes in Presynaptic Bouton Densities in the Ovine Fetal Brain

    Directory of Open Access Journals (Sweden)

    Eveline Strackx

    2015-01-01

    Full Text Available Rationale. Chorioamnionitis has been associated with increased risk for fetal brain damage. Although, it is now accepted that synaptic dysfunction might be responsible for functional deficits, synaptic densities/numbers after a fetal inflammatory challenge have not been studied in different regions yet. Therefore, we tested in this study the hypothesis that LPS-induced chorioamnionitis caused profound changes in synaptic densities in different regions of the fetal sheep brain. Material and Methods. Chorioamnionitis was induced by a 10 mg intra-amniotic LPS injection at two different exposure intervals. The fetal brain was studied at 125 days of gestation (term = 150 days either 2 (LPS2D group or 14 days (LPS14D group after LPS or saline injection (control group. Synaptophysin immunohistochemistry was used to quantify the presynaptic density in layers 2-3 and 5-6 of the motor cortex, somatosensory cortex, entorhinal cortex, and piriforme cortex, in the nucleus caudatus and putamen and in CA1/2, CA3, and dentate gyrus of the hippocampus. Results. There was a significant reduction in presynaptic bouton densities in layers 2-3 and 5-6 of the motor cortex and in layers 2-3 of the entorhinal and the somatosensory cortex, in the nucleus caudate and putamen and the CA1/2 and CA3 of the hippocampus in the LPS2D compared to control animals. Only in the motor cortex and putamen, the presynaptic density was significantly decreased in the LPS14 D compared to the control group. No changes were found in the dentate gyrus of the hippocampus and the piriforme cortex. Conclusion. We demonstrated that LPS-induced chorioamnionitis caused a decreased density in presynaptic boutons in different areas in the fetal brain. These synaptic changes seemed to be region-specific, with some regions being more affected than others, and seemed to be transient in some regions.

  8. 123-I ioflupane (Datscan® presynaptic nigrostriatal imaging in patients with movement disorders

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    Angel Soriano Castrejón

    2005-10-01

    Full Text Available 123-I Ioflupane (Datscan® presynaptic imaging has been shown to have a significant utility in the assessment of patients with movement disorders 123-I Ioflupane SPECT is able to distinguish between Parkinson’s disease (PD and other forms of parkinsonism without degeneration of the nigrostriatal pathway, including a common movement disorder such as essential tremor, and to assess disease progression in PD and other neurodegenerative disorders involving the substantia nigra.A imagem pré-sináptica através de 123-I Ioflupane (Datscan® tem mostrado um papel significante na avaliação de pacientes com distúrbios do movimento. 123-I Ioflupane SPECT é capaz de distinguir entre Mal de Parkinson (MP e outras formas de parkinsonismo sem degenerações da via nigroestriatal incluindo um distúrbio comum de movimento parecido com o tremor essencial e para medir a evolução da doença no Mal de Parkinson e outros distúrbios neurodegenerativos envolvendo a substantia nigra.

  9. A postsynaptic PI3K-cII dependent signaling controller for presynaptic homeostatic plasticity

    Science.gov (United States)

    Hauswirth, Anna G; Ford, Kevin J; Wang, Tingting; Fetter, Richard D; Tong, Amy

    2018-01-01

    Presynaptic homeostatic plasticity stabilizes information transfer at synaptic connections in organisms ranging from insect to human. By analogy with principles of engineering and control theory, the molecular implementation of PHP is thought to require postsynaptic signaling modules that encode homeostatic sensors, a set point, and a controller that regulates transsynaptic negative feedback. The molecular basis for these postsynaptic, homeostatic signaling elements remains unknown. Here, an electrophysiology-based screen of the Drosophila kinome and phosphatome defines a postsynaptic signaling platform that includes a required function for PI3K-cII, PI3K-cIII and the small GTPase Rab11 during the rapid and sustained expression of PHP. We present evidence that PI3K-cII localizes to Golgi-derived, clathrin-positive vesicles and is necessary to generate an endosomal pool of PI(3)P that recruits Rab11 to recycling endosomal membranes. A morphologically distinct subdivision of this platform concentrates postsynaptically where we propose it functions as a homeostatic controller for retrograde, trans-synaptic signaling. PMID:29303480

  10. Sensory transduction channel subunits, tax-4 and tax-2, modify presynaptic molecular architecture in C. elegans.

    Science.gov (United States)

    Hellman, Andrew B; Shen, Kang

    2011-01-01

    During development, neural activity is important for forming proper connections in neural networks. The effect of activity on the gross morphology and synaptic strength of neurons has been well documented, but little is known about how activity affects different molecular components during development. Here, we examine the localization of four fluorescently-tagged presynaptic proteins, RAB-3, SNG-1/synaptogyrin, SYD-2/Liprin-α, and SAD-1/SAD kinase, in the C. elegans thermosensory neuron AFD. We show that tax-4 and tax-2, two genes that encode the cyclic nucleotide-gated channel necessary for sensory transduction in AFD, disrupt the localization of all four proteins. In wild-type animals, the synaptic vesicle (SV) markers RAB-3 and SNG-1 and the active zone markers SYD-2 and SAD-1 localize in a stereotyped, punctate pattern in the AFD axon. In tax-4 and tax-2 mutants, SV and SYD-2 puncta are more numerous and less intense. Interestingly, SAD-1 puncta are also less intense but do not increase in number. The change in puncta number can be rescued cell-autonomously in AFD. These results suggest that sensory transduction genes tax-4 and tax-2 are necessary for the proper assembly of presynapses.

  11. Sensory transduction channel subunits, tax-4 and tax-2, modify presynaptic molecular architecture in C. elegans.

    Directory of Open Access Journals (Sweden)

    Andrew B Hellman

    Full Text Available During development, neural activity is important for forming proper connections in neural networks. The effect of activity on the gross morphology and synaptic strength of neurons has been well documented, but little is known about how activity affects different molecular components during development. Here, we examine the localization of four fluorescently-tagged presynaptic proteins, RAB-3, SNG-1/synaptogyrin, SYD-2/Liprin-α, and SAD-1/SAD kinase, in the C. elegans thermosensory neuron AFD. We show that tax-4 and tax-2, two genes that encode the cyclic nucleotide-gated channel necessary for sensory transduction in AFD, disrupt the localization of all four proteins. In wild-type animals, the synaptic vesicle (SV markers RAB-3 and SNG-1 and the active zone markers SYD-2 and SAD-1 localize in a stereotyped, punctate pattern in the AFD axon. In tax-4 and tax-2 mutants, SV and SYD-2 puncta are more numerous and less intense. Interestingly, SAD-1 puncta are also less intense but do not increase in number. The change in puncta number can be rescued cell-autonomously in AFD. These results suggest that sensory transduction genes tax-4 and tax-2 are necessary for the proper assembly of presynapses.

  12. Phagocytic clearance of presynaptic dystrophies by reactive astrocytes in Alzheimer's disease.

    Science.gov (United States)

    Gomez-Arboledas, Angela; Davila, Jose C; Sanchez-Mejias, Elisabeth; Navarro, Victoria; Nuñez-Diaz, Cristina; Sanchez-Varo, Raquel; Sanchez-Mico, Maria Virtudes; Trujillo-Estrada, Laura; Fernandez-Valenzuela, Juan Jose; Vizuete, Marisa; Comella, Joan X; Galea, Elena; Vitorica, Javier; Gutierrez, Antonia

    2018-03-01

    Reactive astrogliosis, a complex process characterized by cell hypertrophy and upregulation of components of intermediate filaments, is a common feature in brains of Alzheimer's patients. Reactive astrocytes are found in close association with neuritic plaques; however, the precise role of these glial cells in disease pathogenesis is unknown. In this study, using immunohistochemical techniques and light and electron microscopy, we report that plaque-associated reactive astrocytes enwrap, engulf and may digest presynaptic dystrophies in the hippocampus of amyloid precursor protein/presenilin-1 (APP/PS1) mice. Microglia, the brain phagocytic population, was apparently not engaged in this clearance. Phagocytic reactive astrocytes were present in 35% and 67% of amyloid plaques at 6 and 12 months of age, respectively. The proportion of engulfed dystrophic neurites was low, around 7% of total dystrophies around plaques at both ages. This fact, along with the accumulation of dystrophic neurites during disease course, suggests that the efficiency of the astrocyte phagocytic process might be limited or impaired. Reactive astrocytes surrounding and engulfing dystrophic neurites were also detected in the hippocampus of Alzheimer's patients by confocal and ultrastructural analysis. We posit that the phagocytic activity of reactive astrocytes might contribute to clear dysfunctional synapses or synaptic debris, thereby restoring impaired neural circuits and reducing the inflammatory impact of damaged neuronal parts and/or limiting the amyloid pathology. Therefore, potentiation of the phagocytic properties of reactive astrocytes may represent a potential therapy in Alzheimer's disease. © 2017 The Authors GLIA Published by Wiley Periodicals, Inc.

  13. Muscarinic receptor modulation of acetylcholine release from rat cerebral cortex and hippocampus.

    Science.gov (United States)

    Vannucchi, M G; Pepeu, G

    1995-04-28

    An attempt to identify the muscarinic receptor subtypes involved in presynaptic modulation of acetylcholine (ACh) release from cortical and hippocampal slices was made by means of several muscarinic antagonists. Cortical and hippocampal slices prepared from adult rats were superfused with Krebs solution containing physostigmine; ACh content of the superfusate at rest and after electrical stimulation (1 Hz) was quantified by high performance liquid chromatography. The antagonists were added to the Krebs at the concentration of 1 microM. ACh release at rest was enhanced only in the cortex by (+/-)-5,11-dihydro-11-([(2-[2-[(dipropylamino)methyl]-1- piperidinyl)ethyl)amino]carbonyl)-6H-pyrido[2,3-b](1,4)- benzodiazepine-6-one (AFDX384), an M2/M4 selective antagonist. The evoked ACh release from the cerebral cortex was significantly increased by AFDX384, methoctramine, pirenzepine, M2/M4, M2 and M1 selective antagonists, respectively, and scopolamine. This finding suggests that M1, M2 and M4 presynaptic receptor subtypes could regulate evoked ACh release in the cortex. In hippocampal slices, the evoked ACh release was enhanced by AFDX384, pirenzepine and scopolamine but not by methoctramine. In this region ACh release seems therefore regulated only by M1 and M4 receptor subtypes. The M3 antagonist (+/-)-p-fluorohexahydro-sila-difenidol hydrochloride did not affect ACh release.

  14. Temperature dependence of electrical properties of mixture of exogenous neurotransmitters dopamine and epinephrine

    Science.gov (United States)

    Patki, Mugdha; Patil, Vidya

    2016-05-01

    Neurotransmitters are chemical messengers that support the communication between the neurons. In vitro study of exogenous neurotransmitters Dopamine and Epinephrine and their mixture, carried out to learn about their electrical properties being dielectric constant and conductivity amongst others. Dielectric constant and conductivity of the selected neurotransmitters are found to increase with temperature. As a result, the time constant of the system increases with temperature. This change leads to increase in the time taken by the synapse to transport the action potential. The correlation between physical properties of exogenous neurotransmitters and psychological and physiological behaviour of human being may be understood with the help of current study. The response time of Epinephrine is in microseconds whereas response time of Dopamine is in milliseconds. The response time for both the neurotransmitters and their mixture is found to be increasing with temperature indicating the symptoms such as depression, apathy, chronic fatigue and low physical energy with no desire to exercise the body, which are observed during the fever.

  15. Urinary Neurotransmitters Are Selectively Altered in Children With Obstructive Sleep Apnea and Predict Cognitive Morbidity

    Science.gov (United States)

    Kheirandish-Gozal, Leila; McManus, Corena J. T.; Kellermann, Gottfried H.; Samiei, Arash

    2013-01-01

    Background: Pediatric obstructive sleep apnea (OSA) is associated with cognitive dysfunction, suggesting altered neurotransmitter function. We explored overnight changes in neurotransmitters in the urine of children with and without OSA. Methods: Urine samples were collected from children with OSA and from control subjects before and after sleep studies. A neurocognitive battery assessing general cognitive ability (GCA) was administered to a subset of children with OSA. Samples were subjected to multiple enzyme-linked immunosorbent assays for 12 neurotransmitters, and adjusted for creatinine concentrations. Results: The study comprised 50 children with OSA and 20 control subjects. Of the children with OSA, 20 had normal GCA score (mean ± SD) (101.2 ± 14.5) and 16 had a reduced GCA score (87.3 ± 13.9; P neurotransmitters enabled prediction of OSA (area under the curve [AUC]: 0.923; P neurotransmitters in urine may not only predict OSA but also the presence of cognitive deficits. Larger cohort studies appear warranted to confirm these findings. PMID:23306904

  16. Recent progress and challenges in nanotechnology for biomedical applications: an insight into the analysis of neurotransmitters.

    Science.gov (United States)

    Shankaran, Dhesingh Ravi; Miura, Norio

    2007-01-01

    Nanotechnology offers exciting opportunities and unprecedented compatibilities in manipulating chemical and biological materials at the atomic or molecular scale for the development of novel functional materials with enhanced capabilities. It plays a central role in the recent technological advances in biomedical technology, especially in the areas of disease diagnosis, drug design and drug delivery. In this review, we present the recent trend and challenges in the development of nanomaterials for biomedical applications with a special emphasis on the analysis of neurotransmitters. Neurotransmitters are the chemical messengers which transform information and signals all over the body. They play prime role in functioning of the central nervous system (CNS) and governs most of the metabolic functions including movement, pleasure, pain, mood, emotion, thinking, digestion, sleep, addiction, fear, anxiety and depression. Thus, development of high-performance and user-friendly analytical methods for ultra-sensitive detection of neurotransmitters remain a major challenge in modern biomedical analysis. Nanostructured materials are emerging as a powerful mean for diagnosis of CNS disorders because of their unique optical, size and surface characteristics. This review provides a brief outline on the basic concepts and recent advancements of nanotechnology for biomedical applications, especially in the analysis of neurotransmitters. A brief introduction to the nanomaterials, bionanotechnology and neurotransmitters is also included along with discussions on most of the patents published in these areas.

  17. Insertion of Neurotransmitters into a Lipid Bilayer Membrane and Its Implication on Membrane Stability: A Molecular Dynamics Study.

    Science.gov (United States)

    Shen, Chun; Xue, Minmin; Qiu, Hu; Guo, Wanlin

    2017-03-17

    The signaling molecules in neurons, called neurotransmitters, play an essential role in the transportation of neural signals, during which the neurotransmitters interact with not only specific receptors, but also cytomembranes, such as synaptic vesicle membranes and postsynaptic membranes. Through extensive molecular dynamics simulations, the atomic-scale insertion dynamics of typical neurotransmitters, including methionine enkephalin (ME), leucine enkephalin (LE), dopamine (DA), acetylcholine (ACh), and aspartic acid (ASP), into lipid bilayers is investigated. The results show that the first three neurotransmitters (ME, LE, and DA) are able to diffuse freely into both 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) membranes, and are guided by the aromatic residues Tyr and Phe. Only a limited number of these neurotransmitters are allowed to penetrate into the membrane, which suggests an intrinsic mechanism by which the membrane is protected from being destroyed by excessive inserted neurotransmitters. After spontaneous insertion, the neurotransmitters disturb the surrounding phospholipids in the membrane, as indicated by the altered distribution of components in lipid leaflets and the disordered lipid tails. In contrast, the last two neurotransmitters (ACh and ASP) cannot enter the membrane, but instead always diffuse freely in solution. These findings provide an understanding at the atomic level of how neurotransmitters interact with the surrounding cytomembrane, as well as their impact on membrane behavior. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Inhibition of transmitter release and attenuation of anti-retroviral-associated and tibial nerve injury-related painful peripheral neuropathy by novel synthetic Ca2+ channel peptides.

    Science.gov (United States)

    Wilson, Sarah M; Schmutzler, Brian S; Brittain, Joel M; Dustrude, Erik T; Ripsch, Matthew S; Pellman, Jessica J; Yeum, Tae-Sung; Hurley, Joyce H; Hingtgen, Cynthia M; White, Fletcher A; Khanna, Rajesh

    2012-10-12

    N-type Ca(2+) channels (CaV2.2) are a nidus for neurotransmitter release and nociceptive transmission. However, the use of CaV2.2 blockers in pain therapeutics is limited by side effects resulting from inhibition of the physiological functions of CaV2.2 within the CNS. We identified an anti-nociceptive peptide (Brittain, J. M., Duarte, D. B., Wilson, S. M., Zhu, W., Ballard, C., Johnson, P. L., Liu, N., Xiong, W., Ripsch, M. S., Wang, Y., Fehrenbacher, J. C., Fitz, S. D., Khanna, M., Park, C. K., Schmutzler, B. S., Cheon, B. M., Due, M. R., Brustovetsky, T., Ashpole, N. M., Hudmon, A., Meroueh, S. O., Hingtgen, C. M., Brustovetsky, N., Ji, R. R., Hurley, J. H., Jin, X., Shekhar, A., Xu, X. M., Oxford, G. S., Vasko, M. R., White, F. A., and Khanna, R. (2011) Suppression of inflammatory and neuropathic pain by uncoupling CRMP2 from the presynaptic Ca(2+) channel complex. Nat. Med. 17, 822-829) derived from the axonal collapsin response mediator protein 2 (CRMP2), a protein known to bind and enhance CaV2.2 activity. Using a peptide tiling array, we identified novel peptides within the first intracellular loop (CaV2.2(388-402), "L1") and the distal C terminus (CaV1.2(2014-2028) "Ct-dis") that bound CRMP2. Microscale thermophoresis demonstrated micromolar and nanomolar binding affinities between recombinant CRMP2 and synthetic L1 and Ct-dis peptides, respectively. Co-immunoprecipitation experiments showed that CRMP2 association with CaV2.2 was inhibited by L1 and Ct-dis peptides. L1 and Ct-dis, rendered cell-penetrant by fusion with the protein transduction domain of the human immunodeficiency virus TAT protein, were tested in in vitro and in vivo experiments. Depolarization-induced calcium influx in dorsal root ganglion (DRG) neurons was inhibited by both peptides. Ct-dis, but not L1, peptide inhibited depolarization-stimulated release of the neuropeptide transmitter calcitonin gene-related peptide in mouse DRG neurons. Similar results were obtained in DRGs from mice

  19. Multi-metal, Multi-wavelength Surface-Enhanced Raman Spectroscopy Detection of Neurotransmitters.

    Science.gov (United States)

    Moody, Amber S; Sharma, Bhavya

    2018-04-05

    The development of a sensor for the rapid and sensitive detection of neurotransmitters could provide a pathway for the diagnosis of neurological diseases, leading to the discovery of more effective treatment methods. We investigate the use of surface enhanced Raman spectroscopy (SERS) based sensors for the rapid detection of melatonin, serotonin, glutamate, dopamine, GABA, norepinephrine, and epinephrine. Previous studies have demonstrated SERS detection of neurotransmitters; however, there has been no comprehensive study on the effect of the metal used as the SERS substrate or the excitation wavelength used for detection. Here, we present the detection of 7 neurotransmitters using both silver and gold nanoparticles at excitation wavelengths of 532, 633, and 785 nm. Over the range of wavelengths investigated, the SERS enhancement on the silver and gold nanoparticles varies, with an average enhancement factor of 10 5 -10 6 . The maximum SERS enhancement occurs at an excitation wavelength of 785 nm for the gold nanoparticles and at 633 nm for the silver nanoparticles.

  20. Neurotransmitter Specific, Cellular-Resolution Functional Brain Mapping Using Receptor Coated Nanoparticles: Assessment of the Possibility

    Science.gov (United States)

    Forati, Ebrahim; Sabouni, Abas; Ray, Supriyo; Head, Brian; Schoen, Christian; Sievenpiper, Dan

    2015-01-01

    Receptor coated resonant nanoparticles and quantum dots are proposed to provide a cellular-level resolution image of neural activities inside the brain. The functionalized nanoparticles and quantum dots in this approach will selectively bind to different neurotransmitters in the extra-synaptic regions of neurons. This allows us to detect neural activities in real time by monitoring the nanoparticles and quantum dots optically. Gold nanoparticles (GNPs) with two different geometries (sphere and rod) and quantum dots (QDs) with different sizes were studied along with three different neurotransmitters: dopamine, gamma-Aminobutyric acid (GABA), and glycine. The absorption/emission spectra of GNPs and QDs before and after binding of neurotransmitters and their corresponding receptors are reported. The results using QDs and nanorods with diameter 25nm and aspect rations larger than three were promising for the development of the proposed functional brain mapping approach. PMID:26717196

  1. Measuring endogenous 5-HT release by emission tomography: promises and pitfalls

    Science.gov (United States)

    Paterson, Louise M; Tyacke, Robin J; Nutt, David J; Knudsen, Gitte M

    2010-01-01

    Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron emission tomography, but has not yet been adequately extended to other neurotransmitter systems. This review focuses on how the technique has been applied to the study of the 5-hydroxytryptamine (5-HT) system. The principles behind visualising fluctuations in neurotransmitters are introduced, with reference to the dopaminergic system. Studies that aim to image acute, endogenous 5-HT release or depletion at 5-HT receptor targets are summarised, with particular attention to studies in humans. Radiotracers targeting the 5-HT1A, 5-HT2A, and 5-HT4 receptors and the serotonin reuptake transporter have been explored for their sensitivity to 5-HT fluctuations, but with mixed outcomes; tracers for these targets cannot reliably image endogenous 5-HT in humans. Shortcomings in our basic knowledge of the mechanisms underlying changes in binding potential are addressed, and suggestions are made as to how the selection of targets, radiotracers, challenge paradigms, and experimental design might be optimised to improve our chances of successfully imaging endogenous neurotransmitters in the future. PMID:20664611

  2. Dopamine D2/3 receptor availability and amphetamine-induced dopamine release in obesity

    NARCIS (Netherlands)

    van de Giessen, Elsmarieke; Celik, Funda; Schweitzer, Dave H.; van den Brink, Wim; Booij, Jan

    2014-01-01

    The neurotransmitter dopamine is important in the regulation of food intake. It is hypothesised that obese people experience less reward from food due to lower striatal dopamine release, which consequently leads to overeating. This study is the first to assess whether obese subjects have blunted

  3. A practical guide to the synthesis of dinitroindolinyl-caged neurotransmitters.

    Science.gov (United States)

    Ellis-Davies, Graham C R

    2011-03-01

    This protocol describes a method for efficient chemical synthesis of dinitroindolinyl derivatives of glutamate and γ-aminobutyric acid. These caged neurotransmitters are currently the most chemically and photochemically efficient probes for two-photon photolysis in living brain slices. The protocol only requires basic organic synthesis equipment, and no silica gel column chromatography or NMR spectroscopy is needed at any stage. HPLC is used to purify the caged transmitters at the end of the syntheses. Thus, the synthesis of dinitroindolinyl-caged neurotransmitters is within the scope of a modestly equipped chemistry laboratory.

  4. Transition metal ion FRET uncovers K(+) regulation of a neurotransmitter/sodium symporter

    DEFF Research Database (Denmark)

    Billesbølle, Christian B; Mortensen, Jonas S; Sohail, Azmat

    2016-01-01

    Neurotransmitter/sodium symporters (NSSs) are responsible for Na(+)-dependent reuptake of neurotransmitters and represent key targets for antidepressants and psychostimulants. LeuT, a prokaryotic NSS protein, constitutes a primary structural model for these transporters. Here we show that K(+) in......(+)-effect. The K(+)-effect depended on an intact Na1 site and mutating the Na2 site potentiated K(+) binding by facilitating transition to the inward-facing state. The data reveal an unrecognized ability of K(+) to regulate the LeuT transport cycle....

  5. Presynaptic Inputs to Any CNS Projection Neuron Identified by Dual Recombinant Virus Infection.

    Science.gov (United States)

    Bráz, João M; Wang, Fan; Basbaum, Allan I

    2015-01-01

    Although neuroanatomical tracing studies have defined the origin and targets of major projection neurons (PN) of the central nervous system (CNS), there is much less information about the circuits that influence these neurons. Recently, genetic approaches that use Cre recombinase-dependent viral vectors have greatly facilitated such circuit analysis, but these tracing approaches are limited by the availability of Cre-expressing mouse lines and the difficulty in restricting Cre expression to discrete regions of the CNS. Here, we illustrate an alternative approach to drive Cre expression specifically in defined subsets of CNS projection neurons, so as to map both direct and indirect presynaptic inputs to these cells. The method involves a combination of Cre-dependent transneuronal viral tracers that can be used in the adult and that does not require genetically modified mice. To trigger Cre-expression we inject a Cre-expressing adenovirus that is retrogradely transported to the projection neurons of interest. The region containing the retrogradely labeled projection neurons is next injected with Cre-dependent pseudorabies or rabies vectors, which results in labeling of poly- and monosynaptic neuronal inputs, respectively. In proof-of-concept experiments, we used this novel tracing system to study the circuits that engage projection neurons of the superficial dorsal horn of the spinal cord and trigeminal nucleus caudalis, neurons of the parabrachial nucleus of the dorsolateral pons that project to the amygdala and cortically-projecting neurons of the lateral geniculate nucleus. Importantly, because this dual viral tracing method does not require genetically derived Cre-expressing mouse lines, inputs to almost any projection system can be studied and the analysis can be performed in larger animals, such as the rat.

  6. Presynaptic Inputs to Any CNS Projection Neuron Identified by Dual Recombinant Virus Infection.

    Directory of Open Access Journals (Sweden)

    João M Bráz

    Full Text Available Although neuroanatomical tracing studies have defined the origin and targets of major projection neurons (PN of the central nervous system (CNS, there is much less information about the circuits that influence these neurons. Recently, genetic approaches that use Cre recombinase-dependent viral vectors have greatly facilitated such circuit analysis, but these tracing approaches are limited by the availability of Cre-expressing mouse lines and the difficulty in restricting Cre expression to discrete regions of the CNS. Here, we illustrate an alternative approach to drive Cre expression specifically in defined subsets of CNS projection neurons, so as to map both direct and indirect presynaptic inputs to these cells. The method involves a combination of Cre-dependent transneuronal viral tracers that can be used in the adult and that does not require genetically modified mice. To trigger Cre-expression we inject a Cre-expressing adenovirus that is retrogradely transported to the projection neurons of interest. The region containing the retrogradely labeled projection neurons is next injected with Cre-dependent pseudorabies or rabies vectors, which results in labeling of poly- and monosynaptic neuronal inputs, respectively. In proof-of-concept experiments, we used this novel tracing system to study the circuits that engage projection neurons of the superficial dorsal horn of the spinal cord and trigeminal nucleus caudalis, neurons of the parabrachial nucleus of the dorsolateral pons that project to the amygdala and cortically-projecting neurons of the lateral geniculate nucleus. Importantly, because this dual viral tracing method does not require genetically derived Cre-expressing mouse lines, inputs to almost any projection system can be studied and the analysis can be performed in larger animals, such as the rat.

  7. Active polysomes are present in the large presynaptic endings of the synaptosomal fraction from squid brain.

    Science.gov (United States)

    Crispino, M; Kaplan, B B; Martin, R; Alvarez, J; Chun, J T; Benech, J C; Giuditta, A

    1997-10-15

    Previous data have suggested that the large nerve terminals present in the synaptosomal fraction from squid optic lobe are capable of protein synthesis (Crispino et al., 1993a,b). We have further examined this issue by comparing the translation products of synaptosomal and microsomal polysomes. Both preparations programmed an active process of translation, which was completely abolished by their previous treatment with EDTA. After immunoabsorption of the newly synthesized neurofilament (NF) proteins, the labeling ratio of the 60 and 70 kDa NF proteins was found to differ, in agreement with comparable differences obtained with intact synaptosomes. These observations indicate that the set of mRNAs translated by synaptosomes differs from that translated by nerve cell bodies. Hence, because NF proteins are neuron-specific, they support the view that the active synaptosomal polysomes are mostly localized in the large nerve terminals that represent the most abundant neuronal component of the fraction. This hypothesis was confirmed (1) by electron spectroscopic data demonstrating the presence of ribosomes and polysomes within the large nerve endings of the synaptosomal fraction, as well as in the carrot-like nerve endings of the retinal photoreceptors that constitute the only large terminals in the optic lobe, and (2) by light and high resolution autoradiography of synaptosomal samples incubated with [3H]leucine, showing that most labeled proteins are associated with the large nerve endings. This response was abolished by cycloheximide. Taken together, the data provide the first unequivocal demonstration that presynaptic nerve terminals are capable of protein synthesis.

  8. Lambert-Eaton myasthenic syndrome (LEMS): a rare autoimmune presynaptic disorder often associated with cancer.

    Science.gov (United States)

    Schoser, Benedikt; Eymard, Bruno; Datt, Joe; Mantegazza, Renato

    2017-09-01

    Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune neuromuscular junction disorder that is related to the loss of functional P/Q-type voltage-gated calcium channels (VGCCs) on presynaptic nerve terminals. Up to 60% of cases occur as a paraneoplastic disorder (SCLC-LEMS), most commonly in association with small cell lung cancer. The remaining cases have an idiopathic non-tumor etiology but are associated with underlying autoimmune disease (NT-LEMS). Patients with LEMS invariably experience progressive proximal muscle weakness, often accompanied by general fatigue and autonomic symptoms. Some LEMS clinical symptoms overlap with those of other myasthenic syndromes, most commonly myasthenia gravis, which can contribute to misdiagnosis or delayed diagnosis. Prognosis is related to the presence of cancer or autoimmune disease and the severity/distribution of muscle weakness. Cause of death in patients with SCLC-LEMS is typically tumor progression, whereas NT-LEMS does not reduce life expectancy. LEMS diagnosis is supported by a threefold approach: clinical features, electromyography, and anti-VGCC antibody serology. LEMS is a clinically important early indicator of possible cancer; therefore, a LEMS diagnosis should immediately prompt rigorous oncological screening and surveillance. Symptomatic treatment of LEMS typically involves medications that improve neurotransmission (e.g., the potassium channel blocker amifampridine [3,4-diaminopyridine]), with addition of immunosuppressants/modulators (e.g., prednisone plus azathioprine) in individuals with persistent symptoms. Where a tumor is identified, oncological treatment should take priority. It should be remembered, however, that LEMS has a significant impact on a patient's quality of life and ability to perform daily activities, and therefore warrants timely diagnosis and appropriate treatment in and of itself.

  9. Presynaptic [Ca2+] and GCAPs: aspects on the structure and function of photoreceptor ribbon synapses

    Directory of Open Access Journals (Sweden)

    Frank eSchmitz

    2014-02-01

    Full Text Available Changes in intracellular calcium ions [Ca2+] play important roles in photoreceptor signalling. Consequently, intracellular [Ca2+] levels need to be tightly controlled. In the light-sensitive outer segments (OS of photoreceptors, Ca2+ regulates the activity of retinal guanylate cyclases (ret-GCs thus playing a central role in phototransduction and light-adaptation by restoring light-induced decreases in cGMP. In the synaptic terminals, changes of intracellular Ca2+ trigger various aspects of neurotransmission. Photoreceptors employ tonically active ribbon synapses that encode light-induced, graded changes of membrane potential into different rates of synaptic vesicle exocytosis. The active zones of ribbon synapses contain large electron-dense structures, synaptic ribbons, that are associated with large numbers of synaptic vesicles. Synaptic coding at ribbon synapses differs from synaptic coding at conventional (phasic synapses. Recent studies revealed new insights how synaptic ribbons are involved in this process. This review focuses on the regulation of [Ca2+] in presynaptic photoreceptor terminals and on the function of a particular Ca2+-regulated protein, the neuronal calcium sensor protein GCAP2 (guanylate cyclase-activating protein-2 in the photoreceptor ribbon synapse. GCAP2, an EF hand-containing protein plays multiple roles in the OS and in the photoreceptor synapse. In the OS, GCAP2 works as a Ca2+-sensor within a Ca2+-regulated feedback loop that adjusts cGMP levels. In the photoreceptor synapse, GCAP2 binds to RIBEYE, a component of synaptic ribbons, and mediates Ca2+-dependent plasticity at that site. Possible mechanisms are discussed.

  10. APP Is a Context-Sensitive Regulator of the Hippocampal Presynaptic Active Zone.

    Directory of Open Access Journals (Sweden)

    Melanie Laßek

    2016-04-01

    Full Text Available The hallmarks of Alzheimer's disease (AD are characterized by cognitive decline and behavioral changes. The most prominent brain region affected by the progression of AD is the hippocampal formation. The pathogenesis involves a successive loss of hippocampal neurons accompanied by a decline in learning and memory consolidation mainly attributed to an accumulation of senile plaques. The amyloid precursor protein (APP has been identified as precursor of Aβ-peptides, the main constituents of senile plaques. Until now, little is known about the physiological function of APP within the central nervous system. The allocation of APP to the proteome of the highly dynamic presynaptic active zone (PAZ highlights APP as a yet unknown player in neuronal communication and signaling. In this study, we analyze the impact of APP deletion on the hippocampal PAZ proteome. The native hippocampal PAZ derived from APP mouse mutants (APP-KOs and NexCreAPP/APLP2-cDKOs was isolated by subcellular fractionation and immunopurification. Subsequently, an isobaric labeling was performed using TMT6 for protein identification and quantification by high-resolution mass spectrometry. We combine bioinformatics tools and biochemical approaches to address the proteomics dataset and to understand the role of individual proteins. The impact of APP deletion on the hippocampal PAZ proteome was visualized by creating protein-protein interaction (PPI networks that incorporated APP into the synaptic vesicle cycle, cytoskeletal organization, and calcium-homeostasis. The combination of subcellular fractionation, immunopurification, proteomic analysis, and bioinformatics allowed us to identify APP as structural and functional regulator in a context-sensitive manner within the hippocampal active zone network.

  11. Deep brain stimulation results in local glutamate and adenosine release: investigation into the role of astrocytes.

    Science.gov (United States)

    Tawfik, Vivianne L; Chang, Su-Youne; Hitti, Frederick L; Roberts, David W; Leiter, James C; Jovanovic, Svetlana; Lee, Kendall H

    2010-08-01

    Several neurological disorders are treated with deep brain stimulation; however, the mechanism underlying its ability to abolish oscillatory phenomena associated with diseases as diverse as Parkinson's disease and epilepsy remain largely unknown. To investigate the role of specific neurotransmitters in deep brain stimulation and determine the role of non-neuronal cells in its mechanism of action. We used the ferret thalamic slice preparation in vitro, which exhibits spontaneous spindle oscillations, to determine the effect of high-frequency stimulation on neurotransmitter release. We then performed experiments using an in vitro astrocyte culture to investigate the role of glial transmitter release in high-frequency stimulation-mediated abolishment of spindle oscillations. In this series of experiments, we demonstrated that glutamate and adenosine release in ferret slices was able to abolish spontaneous spindle oscillations. The glutamate release was still evoked in the presence of the Na channel blocker tetrodotoxin, but was eliminated with the vesicular H-ATPase inhibitor bafilomycin and the calcium chelator 2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester. Furthermore, electrical stimulation of purified primary astrocytic cultures was able to evoke intracellular calcium transients and glutamate release, and bath application of 2-bis (2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis acetoxymethyl ester inhibited glutamate release in this setting. Vesicular astrocytic neurotransmitter release may be an important mechanism by which deep brain stimulation is able to achieve clinical benefits.

  12. All roads lead to presynaptic calcium channel inhibition by the ghrelin receptor: Separate agonist-dependent and -independent signaling pathways

    Czech Academy of Sciences Publication Activity Database

    Weiss, Norbert; Zamponi, G. W.

    2015-01-01

    Roč. 146, č. 3 (2015), s. 201-204 ISSN 0022-1295 R&D Projects: GA ČR GA15-13556S; GA MŠk 7AMB15FR015 Institutional support: RVO:61388963 Keywords : heterotrimeric G protein * neurotransmitters decrease * hypothalamic neurons Subject RIV: ED - Physiology Impact factor: 4.511, year: 2015

  13. N-Ethylmaleimide Dissociates α7 ACh Receptor from a Complex with NSF and Promotes Its Delivery to the Presynaptic Membrane.

    Science.gov (United States)

    Nishizaki, Tomoyuki

    2016-08-01

    N-Ethylmaleimide (NEM)-sensitive factor (NSF) associates with soluble NSF attachment protein (SNAP), that binds to SNAP receptors (SNAREs) including syntaxin, SNAP25, and synaptobrevin. The complex of NSF/SNAP/SNAREs plays a critical role in the regulation of vesicular traffic. The present study investigated NEM-regulated α7 ACh receptor translocation. NSF associated with β-SNAP and the SNAREs syntaxin 1 and synaptobrevin 2 in the rat hippocampus. NSF also associated with the α7 ACh receptor subunit, the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA1 and GluA2, and the γ-aminobutyric acid A (GABAA) receptor γ2 subunit. NEM, an inhibitor of NSF, significantly dissociated the α7 ACh receptor subunit from a complex with NSF and increased cell surface localization of the receptor subunit, but such effect was not obtained with the GluA1, GluA2 or γ2 subunits. NEM, alternatively, dissociated synaptobrevin 2 from an assembly of NSF/β-SNAP/syntaxin 1/synaptobrevin 2. NEM significantly increased the rate of nicotine-triggered AMPA receptor-mediated miniature excitatory postsynaptic currents, without affecting the amplitude, in rat hippocampal slices. The results of the present study indicate that NEM releases the α7 ACh receptor subunit and synaptobrevin 2 from an assembly of α7 ACh receptor subunit/NSF/β-SNAP/syntaxin 1/synaptobrevin 2, thereby promoting delivery of the α7 ACh receptor subunit to presynaptic membrane.

  14. The determination of presynaptic pA2 values of yohimbine and phentolamine on the perfused rat heart under conditions of negligible autoinhibition.

    Science.gov (United States)

    Fuder, H.; Muscholl, E.; Spemann, R.

    1983-01-01

    1 Rat isolated perfused hearts with the right sympathetic nerves attached were loaded with [3H]-(-)-noradrenaline. The nerves were stimulated with up to 40 trains of 10 pulses every min at 1 Hz, and the evoked increases of [3H-]noradrenaline overflow into the perfusate, of right atrial tension development and ventricular beating frequency were measured. 2 Oxymetazoline inhibited the evoked transmitter overflow (IC50: 10 nM) and decreased the postsynaptic responses in a concentration-dependent manner. It behaved as a full against in abolishing the evoked transmitter overflow. 3 Yohimbine up to 1 microM neither enhanced the evoked [3H]-noradrenaline overflow nor the postsynaptic parameters. Phentolamine (1 microM) caused a transient, minor (less than 30%) increase in [3H]-noradrenaline overflow. 4 Yohimbine (0.03-1.0 microM) and phentolamine (0.1-5.0 microM) shifted to the right the concentration-response curve of oxymetazoline for the inhibition of [3H]-noradrenaline overflow in response to nerve stimulation without depressing the maxima. The pA2 values were 7.82 and 7.52, respectively. 5 Yohimbine (0.1 microM) also antagonized the decrease induced by oxymetazoline in the postsynaptic responses to nerve stimulation. 6 The results confirm the existence of presynaptic inhibitory alpha 2-adrenoceptors at the adrenergic nerve fibres of the rat heart in vitro. Under the stimulation and perfusion conditions selected, the released endogenous transmitter apparently does not activate a negative feedback mechanism, thus permitting the determination of pA2 values. PMID:6307450

  15. New mechanisms of the TCM spleen-based treatment of immune thrombocytopenia purpura from the perspective of blood neurotransmitters

    Directory of Open Access Journals (Sweden)

    Ke Chen

    2017-04-01

    Conclusions: The JYS prescription may regulate the expression levels of blood neurotransmitters via the brain-gut axis in patients with “spleen deficiency” ITP and thus activate hemostatic mechanisms to promote hemostasis. β-EP and VIP are key neurotransmitters of the JYS-induced functional regulation.

  16. Direct assessment of substrate binding to the Neurotransmitter:Sodium Symporter LeuT by solid state NMR

    DEFF Research Database (Denmark)

    Erlendsson, Simon; Gotfryd, Kamil; Larsen, Flemming Hofmann

    2017-01-01

    The Neurotransmitter:Sodium Symporters (NSSs) represent an important class of proteins mediating sodium-dependent uptake of neurotransmitters from the extracellular space. The substrate binding stoichiometry of the bacterial NSS protein, LeuT, and thus the principal transport mechanism, has been...

  17. Glucose is necessary to maintain neurotransmitter homeostasis during synaptic activity in cultured glutamatergic neurons

    DEFF Research Database (Denmark)

    Bak, Lasse K; Schousboe, Arne; Sonnewald, Ursula

    2006-01-01

    Glucose is the primary energy substrate for the adult mammalian brain. However, lactate produced within the brain might be able to serve this purpose in neurons. In the present study, the relative significance of glucose and lactate as substrates to maintain neurotransmitter homeostasis was inves...

  18. Altered neurotransmitter expression profile in the ganglionic bowel in Hirschsprung's disease.

    Science.gov (United States)

    Coyle, David; O'Donnell, Anne Marie; Gillick, John; Puri, Prem

    2016-05-01

    Despite having optimal pull-through (PT) surgery for Hirschsprung's disease (HSCR), many patients experience persistent bowel symptoms with no mechanical/histopathological cause. Murine models of HSCR suggest that expression of key neurotransmitters is unbalanced proximal to the aganglionic colonic segment. We aimed to investigate expression of key enteric neurotransmitters in the colon of children with HSCR. Full-length PT specimens were collected fresh from children with HSCR (n=10). Control specimens were collected at colostomy closure from children with anorectal malformation (n=8). The distributions of neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), vasoactive intestinal peptide (VIP), and substance P (SP) were evaluated using immunofluorescence and confocal microscopy. Neurotransmitter quantification was with Western blot analysis. ChAT expression was high in aganglionic bowel and transition zone but reduced in ganglionic bowel in HSCR relative to controls. Conversely, nNOS expression was markedly reduced in aganglionic bowel but high in ganglionic bowel in HSCR relative to controls. VIP expression was similar in ganglionic HSCR and control colon. SP expression was similar in all tissue types. Imbalance of key excitatory and inhibitory neurotransmitters in the ganglionic bowel in HSCR may explain the basis of bowel dysmotility after an optimal pull-through operation in some patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Aging rather than aneuploidy affects monoamine neurotransmitters in brain regions of Down syndrome mouse models

    NARCIS (Netherlands)

    Dekker, Alain D; Vermeiren, Yannick; Albac, Christelle; Lana-Elola, Eva; Watson-Scales, Sheona; Gibbins, Dorota; Aerts, Tony; Van Dam, Debby; Fisher, Elizabeth M C; Tybulewicz, Victor L J; Potier, Marie-Claude; De Deyn, Peter P

    Altered concentrations of monoamine neurotransmitters and metabolites have been repeatedly found in people with Down syndrome (DS, trisomy 21). Because of the limited availability of human post-mortem tissue, DS mouse models are of great interest to study these changes and the underlying

  20. The molecular mechanism for overcoming the rate-limiting step in monoamine neurotransmitter transport

    DEFF Research Database (Denmark)

    Sinning, Steffen; Said, Saida; Malinauskaite, Lina

    and are targets for drugs of abuse such as cocaine, amphetamine and ecstasy as well as anxiolytics and antidepressants. The transporters undergo a series of concerted conformational changes in order to harness the driving force of co-transported cations to translocate the neurotransmitter across the neuronal...

  1. Spinal cord regeneration by modulating bone marrow with neurotransmitters and Citicholine: Analysis at micromolecular level

    Directory of Open Access Journals (Sweden)

    Cheramadathukudiyil Skaria Paulose

    2017-04-01

    Conclusion: Thus our results suggest that the neurotransmitters combination along with bone marrow or Citicholine with bone marrow can reverse the muscarinic receptor alterations in the spinal cord of spinal cord injured rats, which is a promising step towards a better therapeutic intervention for spinal cord injury because of the positive role of cholinergic system in regulation of both locomotor activity and synaptic plasticity.

  2. Simultaneous quantification of seven hippocampal neurotransmitters in depression mice by LC-MS/MS.

    Science.gov (United States)

    Huang, Fei; Li, Jia; Shi, Hai-Lian; Wang, Ting-ting; Muhtar, Wahaf; Du, Min; Zhang, Bei-bei; Wu, Hui; Yang, Li; Hu, Zhi-bi; Wu, Xiao-jun

    2014-05-30

    There is no method available to simultaneously detect GABA, Glu, Epi, NE, DA, 5-HT and 5-HIAA in mouse hippocampus. A rapid and sensitive LC-MS/MS method has been developed for simultaneously measuring seven neurotransmitters in mouse hippocampus. The analytes were detected in positive mode with multiple reaction monitoring (MRM) and the procedure was completed in less than 9min. This method exhibited excellent linearity for all of the analytes with regression coefficients higher than 0.99, and showed good intra- and inter-day precisions (RSDneurotransmitters in a mouse depression model induced by successive methylprednisolone injections. The results indicated that this depression model was closely associated with the decreased level of Epi (p=0.002) and elevated ratio of 5-HIAA/5-HT (p=0.01), which has never been reported elsewhere. Compared with previous methods, current approach is more convenient without any pre-column derivatization of the analytes but enhances detectability with incremental neurotransmitter profile and shortens detection time. This work represents the first accurate simultaneous determination of seven neurotransmitters in the mouse depression model induced by methylprednisolone. The reliable method will benefit the research of neurological diseases with the altered neurotransmitter profile in brain. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Quantitative-profiling of neurotransmitter abnormalities in the disease progression of experimental diabetic encephalopathy rat.

    Science.gov (United States)

    Zhou, Xueyan; Zhu, Qiuxiang; Han, Xiaowen; Chen, Renguo; Liu, Yaowu; Fan, Hongbin; Yin, Xiaoxing

    2015-11-01

    Diabetic encephalopathy (DE) is one of the most prevalent chronic complications of diabetes mellitus (DM), with neither effective prevention nor proven therapeutic regimen. This study aims to uncover the potential dysregulation pattern of the neurotransmitters in a rat model of streptozotocin (STZ)-induced experimental DE. For that purpose, male Sprague-Dawley (SD) rats were treated with a single intraperitoneal injection of STZ. Cognitive performance was detected with the Morris water maze (MWM) test. Serum, cerebrospinal fluid (CSF), and brain tissues were collected to measure the levels of neurotransmitters. Compared with the control rats, the acetylcholine (ACh) levels in serum, CSF, hippocampus, and cortex were all significantly down-regulated as early as 6 weeks in the STZ treatment group. In contrast, the glutamate (Glu) levels were decreased in CSF and the hippocampus, but unaffected in the serum and cortex of STZ-treated rats. As for γ-aminobutyric acid (GABA), it was down-regulated in serum, but up-regulated in CSF, hippocampus, and the cortex in the STZ-treated group. The mRNA expressions of neurotransmitter-related rate limiting enzymes (including AChE, GAD1, and GAD2) and pro-inflammatory cytokines (including IL-1β and TNF-α) were all increased in the DE rats. Our data suggest that DM induces isoform-dependent and tissue-specific neurotransmitter abnormalities, and that neuroinflammation may underlay the nervous system dysfunction observed in the progression of DE.

  4. Selective Detection of Neurotransmitters by Fluorescence and Chemiluminescence Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ziqiang Wang; Edward S. Yeung

    2001-08-06

    In recent years, luminescence imaging has been widely employed in neurochemical analysis. It has a number of advantages for the study of neuronal and other biological cells: (1) a particular molecular species or cellular constituent can be selectively visualized in the presence of a large excess of other species in a heterogeneous environment; (2) low concentration detection limits can be achieved because of the inherent sensitivity associated with fluorescence and chemiluminescence; (3) low excitation intensities can be used so that long-term observation can be realized while the viability of the specimen is preserved; and (4) excellent spatial resolution can be obtained with the light microscope so subcellular compartments can be identified. With good sensitivity, temporal and spatial resolution, the flux of ions and molecules and the distribution and dynamics of intracellular species can be measured in real time with specific luminescence probes, substrates, or with native fluorescence. A noninvasive detection scheme based on glutamate dehydrogenase (GDH) enzymatic assay combined with microscopy was developed to measure the glutamate release in cultured cells from the central nervous system (CNS). The enzyme reaction is very specific and sensitive. The detection limit with CCD imaging is down to {micro}M levels of glutamate with reasonable response time. They also found that chemiluminescence associated with the ATP-dependent reaction between luciferase and luciferin can be used to image ATP at levels down to 10 nM in the millisecond time scale. Similar imaging experiments should be feasible in a broad spectrum of biological systems.

  5. Role for voltage gated calcium channels in calcitonin gene-related peptide release in the rat trigeminovascular system

    DEFF Research Database (Denmark)

    Amrutkar, D V; Ploug, K B; Olesen, J

    2011-01-01

    Clinical and genetic studies have suggested a role for voltage gated calcium channels (VGCCs) in the pathogenesis of migraine. Release of calcitonin gene-related peptide (CGRP) from trigeminal neurons has also been implicated in migraine. The VGCCs are located presynaptically on neurons and are i......Clinical and genetic studies have suggested a role for voltage gated calcium channels (VGCCs) in the pathogenesis of migraine. Release of calcitonin gene-related peptide (CGRP) from trigeminal neurons has also been implicated in migraine. The VGCCs are located presynaptically on neurons...... and are involved in the release of these peptides to different stimuli. We have examined the presence and importance of VGCCs in controlling the CGRP release from rat dura mater, freshly isolated trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC). Each of the four VGCCs, P/Q-, N-, and L- and T...... the potassium induced CGRP release. In the absence of calcium ions (Ca2+) and in the presence of a cocktail of blockers, the stimulated CGRP release from dura mater was reduced almost to the same level as basal CGRP release. In the TG ¿-conotoxin GVIA inhibited the potassium induced CGRP release significantly...

  6. Role for voltage gated calcium channels in calcitonin gene-related peptide release in the rat trigeminovascular system

    DEFF Research Database (Denmark)

    Amrutkar, D V; Ploug, K B; Olesen, J

    2011-01-01

    Clinical and genetic studies have suggested a role for voltage gated calcium channels (VGCCs) in the pathogenesis of migraine. Release of calcitonin gene-related peptide (CGRP) from trigeminal neurons has also been implicated in migraine. The VGCCs are located presynaptically on neurons and are i......Clinical and genetic studies have suggested a role for voltage gated calcium channels (VGCCs) in the pathogenesis of migraine. Release of calcitonin gene-related peptide (CGRP) from trigeminal neurons has also been implicated in migraine. The VGCCs are located presynaptically on neurons...... and are involved in the release of these peptides to different stimuli. We have examined the presence and importance of VGCCs in controlling the CGRP release from rat dura mater, freshly isolated trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC). Each of the four VGCCs, P/Q-, N-, and L- and T...... the potassium induced CGRP release. In the absence of calcium ions (Ca2+) and in the presence of a cocktail of blockers, the stimulated CGRP release from dura mater was reduced almost to the same level as basal CGRP release. In the TG ω-conotoxin GVIA inhibited the potassium induced CGRP release significantly...

  7. Glutamate released spontaneously from astrocytes sets the threshold for synaptic plasticity.

    Science.gov (United States)

    Bonansco, Christian; Couve, Alejandro; Perea, Gertrudis; Ferradas, Carla Á; Roncagliolo, Manuel; Fuenzalida, Marco

    2011-04-01

    Astrocytes exhibit spontaneous calcium oscillations that could induce the release of glutamate as gliotransmitter in rat hippocampal slices. However, it is unknown whether this spontaneous release of astrocytic glutamate may contribute to determining the basal neurotransmitter release probability in central synapses. Using whole-cell recordings and Ca(2+) imaging, we investigated the effects of the spontaneous astrocytic activity on neurotransmission and synaptic plasticity at CA3-CA1 hippocampal synapses. We show here that the metabolic gliotoxin fluorocitrate (FC) reduces the amplitude of evoked excitatory postsynaptic currents and increases the paired-pulse facilitation, mainly due to the reduction of the neurotransmitter release probability and the synaptic potency. FC also decreased intracellular Ca(2+) signalling and Ca(2+) -dependent glutamate release from astrocytes. The addition of glutamine rescued the effects of FC over the synaptic potency; however, the probability of neurotransmitter release remained diminished. The blockage of group I metabotropic glutamate receptors mimicked the effects of FC on the frequency of miniature synaptic responses. In the presence of FC, the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N ',N '-tetra-acetate or group I metabotropic glutamate receptor antagonists, the excitatory postsynaptic current potentiation induced by the spike-timing-dependent plasticity protocol was blocked, and it was rescued by delivering a stronger spike-timing-dependent plasticity protocol. Taken together, these results suggest that spontaneous glutamate release from astrocytes contributes to setting the basal probability of neurotransmitter release via metabotropic glutamate receptor activation, which could be operating as a gain control mechanism that regulates the threshold of long-term potentiation. Therefore, endogenous astrocyte activity provides a novel non-neuronal mechanism that could be critical for transferring information in

  8. The Role of Cysteine String Protein α Phosphorylation at Serine 10 and 34 by Protein Kinase Cγ for Presynaptic Maintenance.

    Science.gov (United States)

    Shirafuji, Toshihiko; Ueyama, Takehiko; Adachi, Naoko; Yoshino, Ken-Ichi; Sotomaru, Yusuke; Uwada, Junsuke; Kaneoka, Azumi; Ueda, Taro; Tanaka, Shigeru; Hide, Izumi; Saito, Naoaki; Sakai, Norio

    2018-01-10

    Protein kinase Cγ (PKCγ) knock-out (KO) animals exhibit symptoms of Parkinson's disease (PD), including dopaminergic neuronal loss in the substantia nigra. However, the PKCγ substrates responsible for the survival of dopaminergic neurons in vivo have not yet been elucidated. Previously, we found 10 potent substrates in the striatum of PKCγ-KO mice. Here, we focused on cysteine string protein α (CSPα), a protein from the heat shock protein (HSP) 40 cochaperone families localized on synaptic vesicles. We found that in cultured cells, PKCγ phosphorylates CSPα at serine (Ser) 10 and Ser34. Additionally, apoptosis was found to have been enhanced by the overexpression of a phosphorylation-null mutant of CSPα, CSPα(S10A/S34A). Compared with wild-type (WT) CSPα, the CSPα(S10A/S34A) mutant had a weaker interaction with HSP70. However, in sharp contrast, a phosphomimetic CSPα(S10D/S34D) mutant, compared with WT CSPα, had a stronger interaction with HSP70. In addition, total levels of synaptosomal-associated protein (SNAP) 25, a main downstream target of the HSC70/HSP70 chaperone complex, were found to have decreased by the CSPα(S10A/S34A) mutant through increased ubiquitination of SNAP25 in PC12 cells. In the striatum of 2-year-old male PKCγ-KO mice, decreased phosphorylation levels of CSPα and decreased SNAP25 protein levels were observed. These findings indicate the phosphorylation of CSPα by PKCγ may protect the presynaptic terminal from neurodegeneration. The PKCγ-CSPα-HSC70/HSP70-SNAP25 axis, because of its role in protecting the presynaptic terminal, may provide a new therapeutic target for the treatment of PD. SIGNIFICANCE STATEMENT Cysteine string protein α (CSPα) is a protein belonging to the heat shock protein (HSP) 40 cochaperone families localized on synaptic vesicles, which maintain the presynaptic terminal. However, the function of CSPα phosphorylation by protein kinase C (PKC) for neuronal cell survival remains unclear. The experiments

  9. Effect of Low Level Laser Irradiation at Wavelengths 488 and 515 nm on Glutamate Neurotransmitter in Mitochondria of Visual Brain Cortex in Albino Rat

    International Nuclear Information System (INIS)

    Omran, M.F.; El-Ahdal, M.A.; El-Kady, M.H.; Yousri, R.M.

    2004-01-01

    The presence of glutamate in the visual cortex and mitochondria could be used as a measure for the argon laser effect having wavelengths 488 and 515 nm, on the mitochondria. A comparative response for the bound and free glutamate was found. Irradiation with different energies 0.2, 0.5 and 1.0 J for both wavelengths were accomplished. This study makes us to recommend the advantage of using argon laser having wavelength 515 nm to enhance the blocking of glutamate and hence the reduction of brain toxicity. Most of the energy required for cellular functions comes from mitochondria (Shepherd, 1994). Glutamate, which is present in central nervous system at very high level is essential for brain intermediary metabolism (Frazer et al., 1994; Meldrum et al., 2000 and Blumcke et al., 2000). Glutamate is enriched in synaptic vesicles, the subcellular organelles, which are associated with the storage and release of neurotransmitters. Also, biochemical evidence for glutamate as neurotransmitter in fibers from the visual cortex to the subcortical visual relay nuclei has been indicated (Fose and Fonnum, 1987 and George, 1998)

  10. Role of brain cytochrome P450 (CYP2D) in the metabolism of monoaminergic neurotransmitters.

    Science.gov (United States)

    Anna Haduch, Anna; Bromek, Ewa; Daniel, Władysława A

    2013-01-01

    This article focuses on recent research on the cytochrome P450 2D (CYP2D) catalyzed synthesis of the monoaminergic neurotransmitters dopamine and serotonin in the brain and on the influence of psychotropic drugs on the activity of brain CYP2D. Recent in vitro and in vivo studies performed in rodents indicate that dopamine and serotonin may be formed in the brain via alternative CYP2D-mediated pathways, i.e., tyramine hydroxylation and 5-methoxytryptamine O-demethylation, respectively. The contribution of these alternative pathways to the total synthesis of brain neurotransmitters may be higher in humans and may be significantly increased under specific conditions, such as tyrosine hydroxylase and amino acid decarboxylase or tryptophan hydroxylase deficiency. These alternative pathways of neurotransmitter synthesis may also become more efficient when the CYP2D enzyme is mutated or activated by inducers (e.g., alcohol, nicotine, psychotropics), which may be of importance in some neurodegenerative or psychiatric diseases. In addition to the previously observed influence of antidepressants and neuroleptics on CYP2D in the liver, the investigated drugs also produce an effect on CYP2D in the brain. However, their effect on brain CYP2D is different than that in the liver and is structure-dependent. The observed psychotropic drug-brain CYP2D interactions may be important for the metabolism of endogenous neuroactive substrates (e.g., monoaminergic neurotransmitters, neurosteroids) and for the local biotransformation of drugs. The results are discussed with regard to the contribution of CYP2D to the total synthesis of neurotransmitters in the brain in vivo as well as the possible significance of these alternative pathways in specific physiological and pathological conditions and in the pharmacological actions of psychotropic drugs.

  11. Multiple metal exposures and their correlation with monoamine neurotransmitter metabolism in Chinese electroplating workers.

    Science.gov (United States)

    Wu, Lin-Lin; Gong, Wei; Shen, Si-Peng; Wang, Zhong-He; Yao, Jia-Xi; Wang, Jun; Yu, Jing; Gao, Rong; Wu, Gang

    2017-09-01

    Excessive metal exposure has been recognized as one of the detrimental factors for brain damage. However, the potential adverse effects induced by heavy metals on monoamine neurotransmitter pathways remains poorly understood. Our study aimed to investigate the possible association between metal exposure and neurotransmitter metabolism. By a cross-sectional investigation, 224 electroplating workers and 213 non-electroplating exposure workers were recruited in the exposure and control groups. Metal exposure levels were analyzed using inductively-coupled plasma mass spectrometry and monoamine neurotransmitter pathway metabolites were measured by ultra-performance liquid chromatography tandem mass spectrometry in human urine samples. Multivariate linear regression model was used to assess the dose-response relationships of urinary metals and neurotransmitter pathway metabolites. Significant dose-dependent trends of urinary vanadium quartiles with all metabolites were observed, and the trends demonstrated significance after multiple testing correction. It also showed that urinary chromium levels were significantly associated with decreased serotonin level and cadmium was positively associated with norepinephrine and epinephrine. In addition, arsenic was positively associated with tryptophan, serotonin, dopamine and norepinephrine. Iron was positively associated with increased homovanillic acid (HVA) and epinephrine while nickel was negatively associated with increased epinephrine levels. Zinc was positively related to tryptophan, kynurenin (KYN), 5-hydroxyindole acetic acid (5-HIAA), dopamine, HVA and norepinephrine. There was no significant association between urinary copper with any other metabolites after adjusting of multiple metal models. Metal exposure may be associated with neurotransmitter metabolism disturbances. The present work is expected to provide some support in the prevention and management of metal-associated neurological diseases. Copyright © 2017

  12. Expression Profiles of Neuropeptides, Neurotransmitters, and Their Receptors in Human Keratocytes In Vitro and In Situ.

    Science.gov (United States)

    Słoniecka, Marta; Le Roux, Sandrine; Boman, Peter; Byström, Berit; Zhou, Qingjun; Danielson, Patrik

    2015-01-01

    Keratocytes, the quiescent cells of the corneal stroma, play a crucial role in corneal wound healing. Neuropeptides and neurotransmitters are usually associated with neuronal signaling, but have recently been shown to be produced also by non-neuronal cells and to be involved in many cellular processes. The aim of this study was to assess the endogenous intracellular and secreted levels of the neuropeptides substance P (SP) and neurokinin A (NKA), and of the neurotransmitters acetylcholine (ACh), catecholamines (adrenaline, noradrenaline and dopamine), and glutamate, as well as the expression profiles of their receptors, in human primary keratocytes in vitro and in keratocytes of human corneal tissue sections in situ. Cultured keratocytes expressed genes encoding for SP and NKA, and for catecholamine and glutamate synthesizing enzymes, as well as genes for neuropeptide, adrenergic and ACh (muscarinic) receptors. Keratocytes in culture produced SP, NKA, catecholamines, ACh, and glutamate, and expressed neurokinin-1 and -2 receptors (NK-1R and NK-2R), dopamine receptor D2, muscarinic ACh receptors, and NDMAR1 glutamate receptor. Human corneal sections expressed SP, NKA, NK-1R, NK-2R, receptor D2, choline acetyl transferase (ChAT), M3, M4 and M5 muscarinic ACh receptors, glutamate, and NMDAR1, but not catecholamine synthesizing enzyme or the α1 and β2 adrenoreceptors, nor M1 receptor. In addition, expression profiles assumed significant differences between keratocytes from the peripheral cornea as compared to those from the central cornea, as well as differences between keratocytes cultured under various serum concentrations. In conclusion, human keratocytes express an array of neuropeptides and neurotransmitters. The cells furthermore express receptors for neuropeptides/neurotransmitters, which suggests that they are susceptible to stimulation by these substances in the cornea, whether of neuronal or non-neuronal origin. As it has been shown that neuropeptides/neurotransmitters

  13. Ménage à trois: the role of neurotransmitters in the energy metabolism of astrocytes, glutamatergic, and GABAergic neurons.

    Science.gov (United States)

    Calvetti, Daniela; Somersalo, Erkki

    2012-08-01

    This work is a computational study based on a new detailed metabolic network model comprising well-mixed compartments representing separate cytosol and mitochondria of astrocytes, glutamatergic and gamma aminobutyric acid (GABA)ergic neurons, communicating through an extracellular space compartment and fed by arterial blood flow. Our steady-state analysis assumes statistical mass balance of both carbons and amino groups. The study is based on Bayesian flux balance analysis, which uses Markov chain Monte Carlo sampling techniques and provides a quantitative description of steady states when the two exchangers aspartate-glutamate carrier (AGC1) and oxoglutarate carrier (OGC) in the malate-aspartate shuttle in astrocyte are not in equilibrium, as recent studies suggest. It also highlights the importance of anaplerotic reactions, pyruvate carboxylase in astrocyte and malic enzyme in neurons, for neurotransmitter synthesis and recycling. The model is unbiased with respect to the glucose partitioning between cell types, and shows that determining the partitioning cannot be done by stoichiometric constraints alone. Furthermore, the intercellular lactate trafficking is found to depend directly on glucose partitioning, suggesting that a steady state may support different scenarios. At inhibitory steady state, characterized by high rate of GABA release, there is elevated oxidative activity in astrocyte, not in response to specific energetic needs.

  14. Evidence for evoked release of adenosine and glutamate from cultured cerebellar granule cells

    International Nuclear Information System (INIS)

    Schousboe, A.; Frandsen, A.; Drejer, J.

    1989-01-01

    Evoked release of [ 3 H]-D-aspartate which labels the neurotransmitter glutamate pool in cultured cerebellar granule cells was compared with evoked release of adenosine from similar cultures. It was found that both adenosine and [3H]-D-aspartate could be released from the neurons in a calcium dependent manner after depolarization of the cells with either 10-100 microM glutamate or 50 mM KCl. Cultures of cerebellar granule cells treated with 50 microM kainate to eliminate GABAergic neurons behaved in the same way. This together with the observation that cultured astrocytes did not exhibit a calcium dependent, potassium stimulated adenosine release strongly suggest that cerebellar granule cells release adenosine in a neurotransmitter-like fashion together with glutamate which is the classical neurotransmitter of these neurons. Studies of the metabolism of adenosine showed that in the granule cells adenosine is rapidly metabolized to ATP, ADP, and AMP, but in spite of this, adenosine was found to be released preferential to ATP

  15. Nicotine stimulates pancreatic cancer xenografts by systemic increase in stress neurotransmitters and suppression of the inhibitory neurotransmitter gamma-aminobutyric acid.

    Science.gov (United States)

    Al-Wadei, Hussein A N; Plummer, Howard K; Schuller, Hildegard M

    2009-03-01

    Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality in Western countries. We have shown previously that four representative human PDAC cell lines were regulated by beta-adrenoreceptors via cyclic adenosine 3',5'-monophosphate (cAMP)-dependent signaling. In the current study, we have tested the hypothesis that nicotine stimulates the growth of PDAC xenografts in nude mice by increasing the systemic levels of the stress neurotransmitters adrenaline and noradrenaline, which are the physiological agonists for beta-adrenoreceptors and that inhibition by gamma-aminobutyric acid (GABA) of the adenylyl cyclase-dependent pathway downstream of adrenoreceptors blocks this effect. The size of xenografts from PDAC cell line Panc-1 was determined 30 days after inoculation of the cancer cells. Stress neurotransmitters in serum as well as cAMP in the cellular fraction of blood and in tumor tissue were assessed by immunoassays. Levels of GABA, its synthesizing enzymes GAD65 and GAD67 and beta-adrenergic signaling proteins in the tumor tissue were determined by western blotting. Nicotine significantly increased the systemic levels of adrenaline, noradrenaline and cAMP while increasing xenograft size and protein levels of cAMP, cyclic AMP response element-binding protein and p-extracellular signal-regulated kinase 1/2 in the tumor tissue. Nicotine additionally reduced the protein levels of both GAD isozymes and GABA in tumor tissue. Treatment with GABA abolished these responses to nicotine and blocked the development of xenografts in mice not exposed to nicotine. These findings suggest that the development and progression of PDAC is subject to significant modulation by stimulatory stress neurotransmitters and inhibitory GABA and that treatment with GABA may be useful for marker-guided cancer intervention of PDAC.

  16. Hexabromocyclododecane inhibits depolarization-induced increase in intracellular calcium levels and neurotransmitter release in PC12 cells.

    NARCIS (Netherlands)

    Dingemans, M.M.L.; Heusinkveld, H.J.; de Groot, A.; Bergman, A.; van den Berg, M.; Westerink, R.H.S.

    2009-01-01

    Environmental levels of the brominated flame retardant (BFR) hexabromocyclododecane (HBCD) have been increasing. HBCD has been shown to cause adverse effects on learning and behavior in mice, as well as on dopamine uptake in rat synaptosomes and synaptic vesicles. For other BFRs, alterations in the

  17. Protective Effects of Testosterone on Presynaptic Terminals against Oligomeric β-Amyloid Peptide in Primary Culture of Hippocampal Neurons

    Directory of Open Access Journals (Sweden)

    Chi-Fai Lau

    2014-01-01

    Full Text Available Increasing lines of evidence support that testosterone may have neuroprotective effects. While observational studies reported an association between higher bioavailable testosterone or brain testosterone levels and reduced risk of Alzheimer’s disease (AD, there is limited understanding of the underlying neuroprotective mechanisms. Previous studies demonstrated that testosterone could alleviate neurotoxicity induced by β-amyloid (Aβ, but these findings mainly focused on neuronal apoptosis. Since synaptic dysfunction and degeneration are early events during the pathogenesis of AD, we aim to investigate the effects of testosterone on oligomeric Aβ-induced synaptic changes. Our data suggested that exposure of primary cultured hippocampal neurons to oligomeric Aβ could reduce the length of neurites and decrease the expression of presynaptic proteins including synaptophysin, synaptotagmin, and synapsin-1. Aβ also disrupted synaptic vesicle recycling and protein folding machinery. Testosterone preserved the integrity of neurites and the expression of presynaptic proteins. It also attenuated Aβ-induced impairment of synaptic exocytosis. By using letrozole as an aromatase antagonist, we further demonstrated that the effects of testosterone on exocytosis were unlikely to be mediated through the estrogen receptor pathway. Furthermore, we showed that testosterone could attenuate Aβ-induced reduction of HSP70, which suggests a novel mechanism that links testosterone and its protective function on Aβ-induced synaptic damage. Taken together, our data provide further evidence on the beneficial effects of testosterone, which may be useful for future drug development for AD.

  18. The clinical benefit of imaging striatal dopamine transporters with [123I]FP-CIT SPET in differentiating patients with presynaptic parkinsonism from those with other forms of parkinsonism

    International Nuclear Information System (INIS)

    Booij, J.; Speelman, J.DE.; Horstink, M. W.I.M.; Wolters, E.C.

    2001-01-01

    [ 123 I]FP-CIT (N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane) has been developed successfully as a radioligand for single-photon emission tomography (SPET) imaging of dopamine transporters, which are situated in the membrane of dopaminergic neurons. Imaging of these transporters has shown promise as a clinical tool to detect degeneration of the dopaminergic nigrostriatal pathway. Several ''presynaptic parkinsonian'' syndromes, such as Parkinson's disease or multiple system atrophy, are characterised by degeneration of the nigrostriatal pathway. [ 123 I]FP-CIT SPET imaging studies have shown the ability to detect loss of striatal dopamine transporters in such syndromes. However, in clinical practice it is sometimes difficult, but important, to discriminate patients with ''presynaptic parkinsonism'' from those with other forms of parkinsonism not characterised by loss of presynaptic dopaminergic cells (e.g. psychogenic parkinsonism or drug-induced postsynaptic parkinsonism). In these inconclusive cases, it may be of value to confirm or exclude the existence of degeneration of nigrostriatal dopaminergic cells by using imaging techniques such as [ 123 I]FP-CIT SPET. Using [ 123 I]FP-CIT SPET, we have imaged the striatal dopamine transporters in a group of patients with inconclusive forms of parkinsonism, and, moreover, have been able to perform clinical follow-up of these patients 2-4 years after imaging. In 33 inconclusive cases, ratios of specific to non-specific binding were calculated for the caudate nucleus and putamen following [ 123 I]FP-CIT SPET imaging and compared with ratios obtained in healthy controls. In nine of the patients, degeneration of the nigrostriatal pathway was found scintigraphically and in all these cases, presynaptic parkinsonism was confirmed by clinical follow-up. In the other 24 subjects no degeneration was found scintigraphically. Forms of parkinsonism other than the presynaptic were confirmed at follow-up in 19 cases

  19. Effect of canagliflozin and metformin on cortical neurotransmitters in a diabetic rat model.

    Science.gov (United States)

    Arafa, Nadia M S; Marie, Mohamed-Assem S; AlAzimi, Sara Abdullah Mubarak

    2016-10-25

    The rapid economic development in the Arabian Gulf has resulted in lifestyle changes that have increased the prevalence of obesity and type 2 diabetes, with the greatest increases observed in Kuwait. Dyslipidemia and diabetes are risk factors for disruptions in cortical neurotransmitter homeostasis. This study investigated the effect of the antidiabetic medications canagliflozin (CAN) and metformin (MET) on the levels of cortical neurotransmitters in a diabetic rat model. The rats were assigned to the control (C) group, the diabetic group that did not receive treatment (D) or the diabetic group treated with either CAN (10 mg/kg) or MET (100 mg/kg) for 2 or 4 weeks. Blood and urine glucose levels and cortical acetylcholinesterase (AChE) activity were assayed, and amino acid and monoamine levels were measured using HPLC. The diabetic group exhibited a significant increase in AChE activity and a decrease in monoamine and amino acid neurotransmitter levels. In the CAN group, AChE was significantly lower than that in the D and D + MET groups after 2 weeks of treatment. In addition, a significant increase in some cortical monoamines and amino acids was observed in the D + MET and D + CAN groups compared with the D group. Histopathological analysis revealed the presence of severe focal hemorrhage, neuronal degeneration, and cerebral blood vessel congestion, with gliosis in the cerebrum of rats in the D group. The CAN-treated group exhibited severe cerebral blood vessel congestion after 2 weeks of treatment and focal gliosis in the cerebrum after 4 weeks of treatment. Focal gliosis in the cerebrum of rats in the MET-treated group was observed after 2 and 4 weeks of treatment. We conclude that the effect of CAN and MET on neurotransmitters is potentially mediated by their antihyperglycemic and antihyperlipidemic effects. In addition, the effects of CAN on neurotransmitters might be associated with its receptor activity, and the effect of MET on neurotransmitters

  20. Analysis of neurotransmitter tissue content of Drosophila melanogaster in different life stages.

    Science.gov (United States)

    Denno, Madelaine E; Privman, Eve; Venton, B Jill

    2015-01-21

    Drosophila melanogaster is a widely used model organism for studying neurological diseases with similar neurotransmission to mammals. While both larva and adult Drosophila have central nervous systems, not much is known about how neurotransmitter tissue content changes through development. In this study, we quantified tyramine, serotonin, octopamine, and dopamine in larval, pupal, and adult fly brains using capillary electrophoresis coupled to fast-scan cyclic voltammetry. Tyramine and octopamine content varied between life stages, with almost no octopamine being present in the pupa, while tyramine levels in the pupa were very high. Adult females had significantly higher dopamine content than males, but no other neurotransmitters were dependent on sex in the adult. Understanding the tissue content of different life stages will be beneficial for future work comparing the effects of diseases on tissue content throughout development.

  1. Effects of the Bee Venom Herbal Acupuncture on the Neurotransmitters of the Rat Brain Cortex

    Directory of Open Access Journals (Sweden)

    Hyoung-Seok Yun

    2001-02-01

    Full Text Available In order to study the effects of bee venom Herbal Acupuncture on neurotransmitters in the rat brain cortex, herbal acupuncture with bee venom group and normal saline group was performed at LI4 bilaterally of the rat. the average optical density of neurotransmitters from the cerebral cortex was analysed 30 minutes after the herbal aqupuncture, by the immunohistochemistry. The results were as follows: 1. The density of NADPH-diaphorase in bee venom group was increased significantly at the motor cortex, visual cortex, auditory cortex, cingulate cortex, retrosplenial cortex and perirhinal cortex compared to the normal saline group. 2. The average optical density of vasoactive intestinal peptide in bee venom group had significant changes at the insular cortex, retrosplenial cortex and perirhinal cortex, compared to the normal saline group. 3. The average optical density of neuropeptide-Y in bee venom group increased significantly at the visual cortex and cingulate cortex, compared to the normal saline group.

  2. Use of neurotransmitter regulators in functional gastrointestinal disorders based on symptom analysis.

    Science.gov (United States)

    Luo, Qing Qing; Chen, Sheng Liang

    2017-04-01

    It has been a great challenge for gastroenterologists to cope with functional gastrointestinal disorders (FGIDs) in clinical practice due to the contemporary increase in stressful events. A growing body of evidence has shown that neuroregulators such as anti-anxiety agents and antidepressants function well on FGIDs, particularly in cases that are refractory to classical gastrointestinal (GI) medications. Among these central-acting agents, small individualized doses of tricyclic antidepressants and selective serotonin reuptake inhibitors are usually recommended as a complement to routine GI management. When these drugs are chosen to treat FGIDs, both their central effects and the modulation of peripheral neurotransmitters should be taken into consideration. In this article we recommend strategies for choosing drugs based on an analysis of psychosomatic GI symptoms. The variety and dosage of the neurotransmitter regulators are also discussed. © 2017 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  3. Identification of neurotransmitters and co-localization of transmitters in brainstem respiratory neurons

    Science.gov (United States)

    R.L., Stornetta

    2008-01-01

    Identifying the major ionotropic neurotransmitter in a respiratory neuron is of critical importance in determining how the neuron fits into the respiratory system, whether in producing or modifying respiratory drive and rhythm. There are now several groups of respiratory neurons whose major neurotransmitters have been identified and in some of these cases, more than one transmitter have been identified in particular neurons. This review will describe the physiologically identified neurons in major respiratory areas that have been phenotyped for major ionotropic transmitters as well as those where more than one transmitter has been identified. Although the purpose of the additional transmitter has not been elucidated for any of the respiratory neurons, some examples from other systems will be discussed. PMID:18722563

  4. Microfluidic in-channel multi-electrode platform for neurotransmitter sensing

    Science.gov (United States)

    Kara, A.; Mathault, J.; Reitz, A.; Boisvert, M.; Tessier, F.; Greener, J.; Miled, A.

    2016-03-01

    In this project we present a microfluidic platform with in-channel micro-electrodes for in situ screening of bio/chemical samples through a lab-on-chip system. We used a novel method to incorporate electrochemical sensors array (16x20) connected to a PCB, which opens the way for imaging applications. A 200 μm height microfluidic channel was bonded to electrochemical sensors. The micro-channel contains 3 inlets used to introduce phosphate buffer saline (PBS), ferrocynide and neurotransmitters. The flow rate was controlled through automated micro-pumps. A multiplexer was used to scan electrodes and perform individual cyclic voltammograms by a custom potentiostat. The behavior of the system was linear in terms of variation of current versus concentration. It was used to detect the neurotransmitters serotonin, dopamine and glutamate.

  5. New Trends and Perspectives in the Evolution of Neurotransmitters in Microbial, Plant, and Animal Cells.

    Science.gov (United States)

    Roshchina, Victoria V

    2016-01-01

    The evolutionary perspective on the universal roles of compounds known as neurotransmitters may help in the analysis of relations between all organisms in biocenosis-from microorganisms to plant and animals. This phenomenon, significant for chemosignaling and cellular endocrinology, has been important in human health and the ability to cause disease or immunity, because the "living environment" influences every organism in a biocenosis relationship (microorganism-microorganism, microorganism-plant, microorganism-animal, plant-animal, plant-plant and animal-animal). Non-nervous functions of neurotransmitters (rather "biomediators" on a cellular level) are considered in this review and ample consideration is given to similarities and differences that unite, as well as distinguish, taxonomical kingdoms.

  6. Behavioural, Neurotransmitters and Hematological Studies on Rats Exposed to Time Varying Magnetic Field

    International Nuclear Information System (INIS)

    EI-Ahiad, N.M.; Lotfi, S.A.; Marzook, E.A.

    2008-01-01

    Today everyone in the society is exposed to different levels of electromagnetic radiations produced by most electric devices used in our daily life. Effects of 5 times exposure per week to 10 μT magnetic field (MF) 15,30 and 45 minutes for six weeks on behavioural changes, neurotransmitters and hematological parameter s were studied. The behavioural changes of rats, induced by exposure to MF,appeared as fast movement, aggressive response, more activity and less feeding. Long exposure time to MF leads to a significant decrease in body weight, epinephrine, Hb values and RBCs and WBCs counts. On the other hand, MF exposure results in insignificant changes in serum testosterone, platelets level and nor epinephrine. It could be concluded that exposure to magnetic fields may affect the brain neurotransmitters levels and some blood parameters

  7. Climbing fiber-evoked endocannabinoid signaling heterosynaptically suppresses presynaptic cerebellar long-term potentiation

    NARCIS (Netherlands)

    B.J. van Beugen (Boeke); R.Y. Nagaraja (Raghavendra); C.R.W. Hansel (Christian)

    2006-01-01

    textabstractEndocannabinoid signaling has been demonstrated to mediate depolarization-induced suppression of excitation at climbing fiber (CF) and parallel fiber (PF) synapses onto cerebellar Purkinje cells. Here, we show that CF-evoked release of cannabinoids (CBs) additionally suppresses a

  8. IL-4 Inhibits IL-1β-Induced Depressive-Like Behavior and Central Neurotransmitter Alterations

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Park

    2015-01-01

    Full Text Available It has been known that activation of the central innate immune system or exposure to stress can disrupt balance of anti-/proinflammatory cytokines. The aim of the present study was to investigate the role of pro- and anti-inflammatory cytokines in the modulation of depressive-like behaviors, the hormonal and neurotransmitter systems in rats. We investigated whether centrally administered IL-1β is associated with activation of CNS inflammatory pathways and behavioral changes and whether treatment with IL-4 could modulate IL-1β-induced depressive-like behaviors and central neurotransmitter systems. Infusion of IL-4 significantly decreased IL-1β-induced anhedonic responses and increased social exploration and total activity. Treatment with IL-4 markedly blocked IL-1β-induced increase in PGE2 and CORT levels. Also, IL-4 reduced IL-1β-induced 5-HT levels by inhibiting tryptophan hydroxylase (TPH mRNA and activating serotonin transporter (SERT in the hippocampus, and levels of NE were increased by activating tyrosine hydroxylase (TH mRNA expression. These results demonstrate that IL-4 may locally contribute to the regulation of noradrenergic and serotonergic neurotransmission and may inhibit IL-1β-induced behavioral and immunological changes. The present results suggest that IL-4 modulates IL-1β-induced depressive behavior by inhibiting IL-1β-induced central glial activation and neurotransmitter alterations. IL-4 reduced central and systemic mediatory inflammatory activation, as well as reversing the IL-1β-induced alterations in neurotransmitter levels. The present findings contribute a biochemical pathway regulated by IL-4 that may have therapeutic utility for treatment of IL-1β-induced depressive behavior and neuroinflammation which warrants further study.

  9. A practical guide to the synthesis of dinitroindolinyl-caged neurotransmitters

    OpenAIRE

    Ellis-Davies, Graham C R

    2011-01-01

    This protocol describes a method for efficient chemical synthesis of dinitroindolinyl derivatives of glutamate and gamma-aminobutyric acid. these caged neurotransmitters are currently the most chemically and photochemically efficient probes for two-photon photolysis in living brain slices. the protocol only requires basic organic synthesis equipment, and no silica gel column chromatography or NMR spectroscopy is needed at any stage. Hplc is used to purify the caged transmitters at the end of ...

  10. Brain regions and monoaminergic neurotransmitters that are involved in mouse ambulatory activity promoted by bupropion

    Directory of Open Access Journals (Sweden)

    Toyoshi Umezu

    2016-01-01

    Full Text Available Bupropion (BUP, a substituted phenyl-ethylamine, has been utilized for the treatment of depression and for smoking cessation, however, one concern is that BUP may increase a risk of psychosis similar to other substituted phenyl-ethylamine amphetamine (AMPH and methamphetamine (MetAMPH. BUP promotes ambulation in mice and causes behavioral sensitization on the ambulation-promoting effect when repeatedly administered as well as AMPH and MetAMPH. The present study aimed to elucidate brain regions and monoaminergic neurotransmitters that are involved in the ambulation-promoting effect of BUP. c-Fos-like immunoreactivity (c-Fos-IR mapping in brain in combination with measuring ambulatory activity was conducted to determine brain region(s that is involved in the ambulatory effect of BUP. Three kinds of statistical analyses for c-Fos-IR in 24 brain regions consistently showed that c-Fos-IR in the Caudate putamen (CPu is positively correlated with the ambulatory response to BUP. In addition, multiple regression analysis indicated that the ambulatory response is a function of c-Fos-IR not only in the CPu but also in the lateral septum nucleus (LS, median raphe nucleus (MnR, lateral globus pallidus (LGP, medial globus pallidus (MGP, locus coeruleus (LC and ventral hypothalamic nucleus (VMH. Effects of BUP on monoaminergic neurotransmitters in the CPu were examined using in vivo microdialysis method, as the pharmacological experiments indicated that monoaminergic neurotransmitters, dopamine (DA in particular, mediate the ambulatory response to BUP. Response of DA in the CPu to BUP was parallel to the ambulatory response, showing that DA in the CPu is involved in the ambulatory response to BUP. The present study also suggests that other brain regions such as the LC, the origin nucleus of norepinephrine (NE neurons, and another neurotransmitter NE may also play some roles for the ambulatory response to BUP, however, further studies are needed to elucidate

  11. Regulation of nonsmall-cell lung cancer stem cell like cells by neurotransmitters and opioid peptides.

    Science.gov (United States)

    Banerjee, Jheelam; Papu John, Arokya M S; Schuller, Hildegard M

    2015-12-15

    Nonsmall-cell lung cancer (NSCLC) is the leading type of lung cancer and has a poor prognosis. We have shown that chronic stress promoted NSCLC xenografts in mice via stress neurotransmitter-activated cAMP signaling downstream of beta-adrenergic receptors and incidental beta-blocker therapy was reported to improve clinical outcomes in NSCLC patients. These findings suggest that psychological stress promotes NSCLC whereas pharmacologically or psychologically induced decreases in cAMP may inhibit NSCLC. Cancer stem cells are thought to drive the development, progression and resistance to therapy of NSCLC. However, their potential regulation by stress neurotransmitters has not been investigated. In the current study, epinephrine increased the number of cancer stem cell like cells (CSCs) from three NSCLC cell lines in spheroid formation assays while enhancing intracellular cAMP and the stem cell markers sonic hedgehog (SHH), aldehyde dehydrogenase-1 (ALDH-1) and Gli1, effects reversed by GABA or dynorphin B via Gαi -mediated inhibition of cAMP formation. The growth of NSCLC xenografts in a mouse model of stress reduction was significantly reduced as compared with mice maintained under standard conditions. Stress reduction reduced serum levels of corticosterone, norepinephrine and epinephrine while the inhibitory neurotransmitter γ-aminobutyric acid (GABA) and opioid peptides increased. Stress reduction significantly reduced cAMP, VEGF, p-ERK, p-AKT, p-CREB, p-SRc, SHH, ALDH-1 and Gli1 in xenograft tissues whereas cleaved caspase-3 and p53 were induced. We conclude that stress neurotransmitters activate CSCs in NSCLC via multiple cAMP-mediated pathways and that pharmacologically or psychologically induced decreases in cAMP signaling may improve clinical outcomes in NSCLC patients. © 2015 UICC.

  12. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    DEFF Research Database (Denmark)

    Kreft, Marko; Bak, Lasse Kristoffer; Waagepetersen, Helle S

    2012-01-01

    Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pat......-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation....

  13. Effect of paroxetine combined with climen on hormone levels and neurotransmitters in patients with perimenopausal depression

    Directory of Open Access Journals (Sweden)

    Wei-Ling Huang

    2016-03-01

    Full Text Available Objective: To analyze the effect of paroxetine combined with climen on hormone levels and neurotransmitters in patients with perimenopausal depression. Methods: A total of 96 cases of perimenopausal women who met the diagnosis of depression and were treated in our hospital from July 2012 to March 2015 were selected as research subjects and randomly divided into observation group and control group, each group with 48 cases. Control group received paroxetine therapy alone, observation group received paroxetine combined with climen therapy, serum hormone and neurotransmitter levels of two groups were compared, and severity of menopause and depression was detected after treatment. Results: E2 level of observation group after treatment was higher than that of control group, and levels of FSH and LH were lower than those of control group; serum NE, 5-HT, DA, Glu and Asp values of observation group after treatment were higher than those of control group, and values of GABA and Gly were lower than those of control group; KI, MRS and HAMD scores of observation group after treatment were lower than those of control group. Conclusion: Paroxetine combined with climen therapy for patients with perimenopausal depression can effectively optimize the levels of hormones and neurotransmitters in patients and reduce the symptom severity of menopause and depression.

  14. Spinal cord regeneration by modulating bone marrow with neurotransmitters and Citicholine: Analysis at micromolecular level.

    Science.gov (United States)

    Paulose, Cheramadathukudiyil Skaria; John, Ponnezhathu Sebastian; Chinthu, Romeo; Akhilraj, Puthenveetil Raju; Anju, Thoppil Raveendran

    2017-04-01

    Spinal cord injury results in disruption of brain-spinal cord fibre connectivity, leading to progressive tissue damage at the site of injury and resultant paralysis of varying degrees. The current study investigated the role of autologous bone marrow modulated with neurotransmitters and neurotransmitter stimulating agent, Citicholine, in spinal cord of spinal cord injured rats. Radioreceptor assay using [3H] ligand was carried out to quantify muscarinic receptor. Gene expression studies were done using Real Time PCR analysis. Scatchard analysis of muscarinic M1 receptor showed significantly decreased B max (p spinal cord injury treated with 5HT and GABA, and spinal cord injury treated with Citicholine). Muscarinic M1 receptor gene expression in spinal cord injured group showed significant down regulation (p spinal cord injured group. The confocal microscopic study using specific antibody of muscarinic M1 confirmed the gene expression studies. Thus our results suggest that the neurotransmitters combination along with bone marrow or Citicholine with bone marrow can reverse the muscarinic receptor alterations in the spinal cord of spinal cord injured rats, which is a promising step towards a better therapeutic intervention for spinal cord injury because of the positive role of cholinergic system in regulation of both locomotor activity and synaptic plasticity. Copyright © 2017 Chang Gung University. Published by Elsevier B.V. All rights reserved.

  15. Neuromodulating mice and men: Are there functional species differences in neurotransmitter concentration?

    Science.gov (United States)

    Fitzgerald, Paul J

    2009-07-01

    I examine evidence that the concentration of certain modulatory neurotransmitters varies across species, including differences between rodents and primates. Microdialysis studies indicate that the baseline concentration of serotonin, norepinephrine, dopamine, and acetylcholine, as measured in the prefrontal cortex of awake animals, may differ between rats and macaque monkeys. These differences may extend to mice and humans, as well. If there are differences in the tonic concentration of these neurotransmitters, this may affect the functioning of these transmitter systems in multiple ways, including potential effects on neuropsychiatric conditions such as the various mental illnesses and modeling of them in animals. Species differences in transmitter concentration may also have neuropharmacological implications, and may be relevant to the phenomenon of differences in speed of drug response between humans and rodents. This paper is divided into three sections that address related questions about the potential concentration differences: (1) Are there species differences in baseline neurotransmitter concentration? (2) Are the putative differences functional? (3) What might the functional differences be? Consideration of the existing evidence indicates that there may indeed be functional species differences in the modulatory transmitter systems.

  16. Individual differences in visual motion perception and neurotransmitter concentrations in the human brain.

    Science.gov (United States)

    Takeuchi, Tatsuto; Yoshimoto, Sanae; Shimada, Yasuhiro; Kochiyama, Takanori; Kondo, Hirohito M

    2017-02-19

    Recent studies have shown that interindividual variability can be a rich source of information regarding the mechanism of human visual perception. In this study, we examined the mechanisms underlying interindividual variability in the perception of visual motion, one of the fundamental components of visual scene analysis, by measuring neurotransmitter concentrations using magnetic resonance spectroscopy. First, by psychophysically examining two types of motion phenomena-motion assimilation and contrast-we found that, following the presentation of the same stimulus, some participants perceived motion assimilation, while others perceived motion contrast. Furthermore, we found that the concentration of the excitatory neurotransmitter glutamate-glutamine (Glx) in the dorsolateral prefrontal cortex (Brodmann area 46) was positively correlated with the participant's tendency to motion assimilation over motion contrast; however, this effect was not observed in the visual areas. The concentration of the inhibitory neurotransmitter γ-aminobutyric acid had only a weak effect compared with that of Glx. We conclude that excitatory process in the suprasensory area is important for an individual's tendency to determine antagonistically perceived visual motion phenomena.This article is part of the themed issue 'Auditory and visual scene analysis'. © 2017 The Author(s).

  17. Detection of amino acid neurotransmitters by surface enhanced Raman scattering and hollow core photonic crystal fiber

    Science.gov (United States)

    Tiwari, Vidhu S.; Khetani, Altaf; Monfared, Ali Momenpour T.; Smith, Brett; Anis, Hanan; Trudeau, Vance L.

    2012-03-01

    The present work explores the feasibility of using surface enhanced Raman scattering (SERS) for detecting the neurotransmitters such as glutamate (GLU) and gamma-amino butyric acid (GABA). These amino acid neurotransmitters that respectively mediate fast excitatory and inhibitory neurotransmission in the brain, are important for neuroendocrine control, and upsets in their synthesis are also linked to epilepsy. Our SERS-based detection scheme enabled the detection of low amounts of GLU (10-7 M) and GABA (10-4 M). It may complement existing techniques for characterizing such kinds of neurotransmitters that include high-performance liquid chromatography (HPLC) or mass spectrography (MS). This is mainly because SERS has other advantages such as ease of sample preparation, molecular specificity and sensitivity, thus making it potentially applicable to characterization of experimental brain extracts or clinical diagnostic samples of cerebrospinal fluid and saliva. Using hollow core photonic crystal fiber (HC-PCF) further enhanced the Raman signal relative to that in a standard cuvette providing sensitive detection of GLU and GABA in micro-litre volume of aqueous solutions.

  18. The Dynamics of Autism Spectrum Disorders: How Neurotoxic Compounds and Neurotransmitters Interact

    Directory of Open Access Journals (Sweden)

    Margot Van de Bor

    2013-08-01

    Full Text Available In recent years concern has risen about the increasing prevalence of Autism Spectrum Disorders (ASD. Accumulating evidence shows that exposure to neurotoxic compounds is related to ASD. Neurotransmitters might play a key role, as research has indicated a connection between neurotoxic compounds, neurotransmitters and ASD. In the current review a literature overview with respect to neurotoxic exposure and the effects on neurotransmitter systems is presented. The aim was to identify mechanisms and related factors which together might result in ASD. The literature reported in the current review supports the hypothesis that exposure to neurotoxic compounds can lead to alterations in the GABAergic, glutamatergic, serotonergic and dopaminergic system which have been related to ASD in previous work. However, in several studies findings were reported that are not supportive of this hypothesis. Other factors also might be related, possibly altering the mechanisms at work, such as time and length of exposure as well as dose of the compound. Future research should focus on identifying the pathway through which these factors interact with exposure to neurotoxic compounds making use of human studies.

  19. Sympathetic Neurotransmitters Modulate Osteoclastogenesis and Osteoclast Activity in the Context of Collagen-Induced Arthritis

    Science.gov (United States)

    Muschter, Dominique; Schäfer, Nicole; Stangl, Hubert; Straub, Rainer H.; Grässel, Susanne

    2015-01-01

    Excessive synovial osteoclastogenesis is a hallmark of rheumatoid arthritis (RA). Concomitantly, local synovial changes comprise neuronal components of the peripheral sympathetic nervous system. Here, we wanted to analyze if collagen-induced arthritis (CIA) alters bone marrow-derived macrophage (BMM) osteoclastogenesis and osteoclast activity, and how sympathetic neurotransmitters participate in this process. Therefore, BMMs from Dark Agouti rats at different CIA stages were differentiated into osteoclasts in vitro and osteoclast number, cathepsin K activity, matrix resorption and apoptosis were analyzed in the presence of acetylcholine (ACh), noradrenaline (NA) vasoactive intestinal peptide (VIP) and assay-dependent, adenylyl cyclase activator NKH477. We observed modulation of neurotransmitter receptor mRNA expression in CIA osteoclasts without affecting protein level. CIA stage-dependently altered marker gene expression associated with osteoclast differentiation and activity without affecting osteoclast number or activity. Neurotransmitter stimulation modulated osteoclast differentiation, apoptosis and activity. VIP, NA and adenylyl cyclase activator NKH477 inhibited cathepsin K activity and osteoclastogenesis (NKH477, 10-6M NA) whereas ACh mostly acted pro-osteoclastogenic. We conclude that CIA alone does not affect metabolism of in vitro generated osteoclasts whereas stimulation with NA, VIP plus specific activation of adenylyl cyclase induced anti-resorptive effects probably mediated via cAMP signaling. Contrary, we suggest pro-osteoclastogenic and pro-resorptive properties of ACh mediated via muscarinic receptors. PMID:26431344

  20. Simultaneous analysis of multiple neurotransmitters by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Tufi, Sara; Lamoree, Marja; de Boer, Jacob; Leonards, Pim

    2015-05-22

    Neurotransmitters are endogenous metabolites that allow the signal transmission across neuronal synapses. Their biological role is crucial for many physiological functions and their levels can be changed by several diseases. Because of their high polarity, hydrophilic interaction liquid chromatography (HILIC) is a promising tool for neurotransmitter analysis. Due to the large number of HILIC stationary phases available, an evaluation of the column performances and retention behaviors has been performed on five different commercial HILIC packing materials (silica, amino, amide and two zwitterionic stationary phases). Several parameters like the linear correlation between retention and the distribution coefficient (logD), the separation factor k and the column resolution Rs have been investigated and the column performances have been visualized with a heat map and hierarchical clustering analysis. An optimized and validated HILIC-MS/MS method based on the ZIC-cHILIC column is proposed for the simultaneous detection and quantification of twenty compounds consisting of neurotransmitters, precursors and metabolites: 3-methoxytyramine (3-MT), 5-hydroxyindoleacetic acid (5-HIAA), 5-hydroxy-L-tripthophan, acetylcholine, choline, L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine, epinephrine, γ-aminobutyric acid (GABA), glutamate, glutamine, histamine, histidine, L-tryptophan, L-tyrosine, norepinephrine, normetanephrine, phenylalanine, serotonin and tyramine. The method was applied to neuronal metabolite profiling of the central nervous system of the freshwater snail Lymnaea stagnalis. This method is suitable to explore neuronal metabolism and its alteration in different biological matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Monitoring the electrochemical responses of neurotransmitters through localized surface plasmon resonance using nanohole array.

    Science.gov (United States)

    Li, Nantao; Lu, Yanli; Li, Shuang; Zhang, Qian; Wu, Jiajia; Jiang, Jing; Liu, Gang Logan; Liu, Qingjun

    2017-07-15

    In this study, a novel spectroelectrochemical method was proposed for neurotransmitters detection. The central sensing device was a hybrid structure of nanohole array and gold nanoparticles, which demonstrated good conductivity and high localized surface plasmon resonance (LSPR) sensitivity. By utilizing such specially-designed nanoplasmonic sensor as working electrode, both electrical and spectral responses on the surface of the sensor could be simultaneously detected during the electrochemical process. Cyclic voltammetry was implemented to activate the oxidation and recovery of dopamine and serotonin, while transmission spectrum measurement was carried out to synchronously record to LSPR responses of the nanoplasmonic sensor. Coupling with electrochemistry, LSPR results indicated good integrity and linearity, along with promising accuracy in qualitative and quantitative detection even for mixed solution and in brain tissue homogenates. Also, the detection results of other negatively-charged neurotransmitters like acetylcholine demonstrated the selectivity of our detection method for transmitters with positive charge. When compared with traditional electrochemical signals, LSPR signals provided better signal-to-noise ratio and lower detection limits, along with immunity against interference factors like ascorbic acid. Taking the advantages of such robustness, the coupled detection method was proved to be a promising platform for point-of-care testing for neurotransmitters. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Sex and intrauterine growth restriction modify brain neurotransmitters profile of newborn piglets.

    Science.gov (United States)

    Vázquez-Gómez, M; Valent, D; García-Contreras, C; Arroyo, L; Óvilo, C; Isabel, B; Bassols, A; González-Bulnes, A

    2016-12-01

    The current study aimed to determine, using a swine model of intrauterine growth restriction (IUGR), whether short- and long-term neurological deficiencies and interactive dysfunctions of Low Birth-Weight (LBW) offspring might be related to altered pattern of neurotransmitters. Hence, we compared the quantities of different neurotransmitters (catecholamines and indoleamines), which were determined by HPLC, at brain structures related to the limbic system (hippocampus and amygdala) in 14 LBW and 10 Normal Body-Weight (NBW) newborn piglets. The results showed, firstly, significant effects of sex on the NBW newborns, with females having higher dopamine (DA) concentrations than males. The IUGR processes affected DA metabolism, with LBW piglets having lower concentrations of noradrenaline at the hippocampus and higher concentrations of the DA metabolites, homovanillic acid (HVA), at both the hippocampus and the amygdala than NBW neonates. The effects of IUGR were modulated by sex; there were no significant differences between LBW and NBW females, but LBW males had higher HVA concentration at the amygdala and higher concentration of 5-hydroxyindoleacetic acid, the serotonin metabolite, at the hippocampus than NBW males. In conclusion, the present study shows that IUGR is mainly related to changes, modulated by sex, in the concentrations of catecholamine neurotransmitters, which are related to adaptation to physical activity and to essential cognitive functions such as learning, memory, reward-motivated behavior and stress. Copyright © 2016 ISDN. Published by Elsevier Ltd. All rights reserved.

  3. [Single and combining effects of Calculus Bovis and zolpidem on inhibitive neurotransmitter of rat striatum corpora].

    Science.gov (United States)

    Liu, Ping; He, Xinrong; Guo, Mei

    2010-04-01

    To investigate the correlation effects between single or combined administration of Calculus Bovis or zolpidem and changes of inhibitive neurotransmitter in rat striatum corpora. Sampling from rat striatum corpora was carried out through microdialysis. The content of two inhibitive neurotransmitters in rat corpus striatum- glycine (Gly) and gama aminobutyric acid (GABA), was determined by HPLC, which involved pre-column derivation with orthophthaladehyde, reversed-phase gradient elution and fluorescence detection. GABA content of rat striatum corpora in Calculus Bovis group was significantly increased compared with saline group (P Calculus Boris plus zolpidem group were increased largely compared with saline group as well (P Calculus Bovis group was higher than combination group (P Calculus Bovis or zolpidem group was markedly increased compared with saline group or combination group (P Calculus Bovis group, zolpidem group and combination group. The magnitude of increase was lower in combination group than in Calculus Bovis group and Zolpidem group, suggesting that Calculus Bovis promoted encephalon inhibition is more powerful than zolpidem. The increase in two inhibitive neurotransmitters did not show reinforcing effect in combination group, suggesting that Calculus Bovis and zolpidem may compete the same receptors. Therefore, combination of Calculus Bovis containing drugs and zolpidem has no clinical significance. Calculus Bovis shouldn't as an aperture-opening drugs be used for resuscitation therapy.

  4. The effect of nucleotides and adenosine on stimulus-evoked glutamate release from rat brain cortical slices

    OpenAIRE

    Bennett, Gillian C; Boarder, Michael R

    2000-01-01

    Evidence has previously been presented that P1 receptors for adenosine, and P2 receptors for nucleotides such as ATP, regulate stimulus-evoked release of biogenic amines from nerve terminals in the brain. Here we investigated whether adenosine and nucleotides exert presynaptic control over depolarisation-elicited glutamate release.Slices of rat brain cortex were perfused and stimulated with pulses of 46 mM K+ in the presence of the glutamate uptake inhibitor L-trans-pyrrolidine-2,4-dicarboxyl...

  5. Nitric oxide donors enhance the frequency dependence of dopamine release in nucleus accumbens.

    Science.gov (United States)

    Hartung, Henrike; Threlfell, Sarah; Cragg, Stephanie J

    2011-08-01

    Dopamine (DA) neurotransmission in the nucleus accumbens (NAc) is critically involved in normal as well as maladaptive motivated behaviors including drug addiction. Whether the striatal neuromodulator nitric oxide (NO) influences DA release in NAc is unknown. We investigated whether exogenous NO modulates DA transmission in NAc core and how this interaction varies depending on the frequency of presynaptic activation. We detected DA with cyclic voltammetry at carbon-fiber microelectrodes in mouse NAc in slices following stimuli spanning a full range of DA neuron firing frequencies (1-100 Hz). NO donors 3-morpholinosydnonimine hydrochloride (SIN-1) or z-1-[N-(3-ammoniopropyl)-N-(n-propyl)amino]diazen-1-ium-1,2-diolate (PAPA/NONOate) enhanced DA release with increasing stimulus frequency. This NO-mediated enhancement of frequency sensitivity of DA release was not prevented by inhibition of soluble guanylyl cyclase (sGC), DA transporters, or large conductance Ca(2+)-activated K(+) channels, and did not require glutamatergic or GABAergic input. However, experiments to identify whether frequency-dependent NO effects were mediated via changes in powerful acetylcholine-DA interactions revealed multiple components to NO modulation of DA release. In the presence of a nicotinic receptor antagonist (dihydro-β-erythroidine), NO donors increased DA release in a frequency-independent manner. These data suggest that NO in the NAc can modulate DA release through multiple GC-independent neuronal mechanisms whose net outcome varies depending on the activity in DA neurons and accumbal cholinergic interneurons. In the presence of accumbal acetylcholine, NO promotes the sensitivity of DA release to presynaptic activation, but with reduced acetylcholine input, NO will promote DA release in an activity-independent manner through a direct action on dopaminergic terminals.

  6. Synaptophysin 1 Clears Synaptobrevin 2 from the Presynaptic Active Zone to Prevent Short-Term Depression

    Directory of Open Access Journals (Sweden)

    Rajit Rajappa

    2016-02-01

    Full Text Available Release site clearance is an important process during synaptic vesicle (SV recycling. However, little is known about its molecular mechanism. Here we identify self-assembly of exocytosed Synaptobrevin 2 (Syb2 and Synaptophysin 1 (Syp1 by homo- and hetero-oligomerization into clusters as key mechanisms mediating release site clearance for preventing cis-SNARE complex formation at the active zone (AZ. In hippocampal neurons from Syp1 knockout mice, neurons expressing a monomeric Syb2 mutant, or after acute block of the ATPase N-ethylmaleimide-sensitive factor (NSF, responsible for cis-SNARE complex disassembly, we found strong frequency-dependent short-term depression (STD, whereas retrieval of Syb2 by compensatory endocytosis was only affected weakly. Defects in Syb2 endocytosis were stimulus- and frequency-dependent, indicating that Syp1 is not essential for Syb2 retrieval, but for its efficient clearance upstream of endocytosis. Our findings identify an SV protein as a release site clearance factor.

  7. Bortezomib induces neuropathic pain through protein kinase C-mediated activation of presynaptic NMDA receptors in the spinal cord.

    Science.gov (United States)

    Xie, Jing-Dun; Chen, Shao-Rui; Chen, Hong; Pan, Hui-Lin

    2017-09-01

    Chemotherapeutic drugs, including bortezomib, often cause painful peripheral neuropathy, which is a severe dose-limiting adverse effect experienced by many cancer patients. The glutamate N-methyl-d-aspartate receptors (NMDARs) at the spinal cord level are critically involved in the synaptic plasticity associated with neuropathic pain. In this study, we determined whether treatment with bortezomib, a proteasome inhibitor, affects the NMDAR activity of spinal dorsal horn neurons. Systemic treatment with bortezomib in rats did not significantly affect postsynaptic NMDAR currents elicited by puff application of NMDA directly to dorsal horn neurons. Bortezomib treatment markedly increased the baseline frequency of miniature excitatory postsynaptic currents (EPSCs), which was completely normalized by the NMDAR antagonist 2-amino-5-phosphonopentanoic acid (AP5). AP5 also reduced the amplitude of monosynaptic EPSCs evoked by dorsal root stimulation in bortezomib-treated, but not vehicle-treated, rats. Furthermore, inhibition of protein kinase C (PKC) with chelerythrine fully reversed the increased frequency of miniature EPSCs and the amplitude of evoked EPSCs in bortezomib-treated rats. Intrathecal injection of AP5 and chelerythrine both profoundly attenuated mechanical allodynia and hyperalgesia induced by systemic treatment with bortezomib. In addition, treatment with bortezomib induced striking membrane translocation of PKC-βII, PKC-δ, and PKC-ε in the dorsal root ganglion. Our findings indicate that bortezomib treatment potentiates nociceptive input from primary afferent nerves via PKC-mediated tonic activation of presynaptic NMDARs. Targeting presynaptic NMDARs and PKC at the spinal cord level may be an effective strategy for treating chemotherapy-induced neuropathic pain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Regulation of presynaptic Ca2+, synaptic plasticity and contextual fear conditioning by a N-terminal β-amyloid fragment.

    Science.gov (United States)

    Lawrence, James L M; Tong, Mei; Alfulaij, Naghum; Sherrin, Tessi; Contarino, Mark; White, Michael M; Bellinger, Frederick P; Todorovic, Cedomir; Nichols, Robert A

    2014-10-22

    Soluble β-amyloid has been shown to regulate presynaptic Ca(2+) and synaptic plasticity. In particular, picomolar β-amyloid was found to have an agonist-like action on presynaptic nicotinic receptors and to augment long-term potentiation (LTP) in a manner dependent upon nicotinic receptors. Here, we report that a functional N-terminal domain exists within β-amyloid for its agonist-like activity. This sequence corresponds to a N-terminal fragment generated by the combined action of α- and β-secretases, and resident carboxypeptidase. The N-terminal β-amyloid fragment is present in the brains and CSF of healthy adults as well as in Alzheimer's patients. Unlike full-length β-amyloid, the N-terminal β-amyloid fragment is monomeric and nontoxic. In Ca(2+) imaging studies using a model reconstituted rodent neuroblastoma cell line and isolated mouse nerve terminals, the N-terminal β-amyloid fragment proved to be highly potent and more effective than full-length β-amyloid in its agonist-like action on nicotinic receptors. In addition, the N-terminal β-amyloid fragment augmented theta burst-induced post-tetanic potentiation and LTP in mouse hippocampal slices. The N-terminal fragment also rescued LTP inhibited by elevated levels of full-length β-amyloid. Contextual fear conditioning was also strongly augmented following bilateral injection of N-terminal β-amyloid fragment into the dorsal hippocampi of intact mice. The fragment-induced augmentation of fear conditioning was attenuated by coadministration of nicotinic antagonist. The activity of the N-terminal β-amyloid fragment appears to reside largely in a sequence surrounding a putative metal binding site, YEVHHQ. These findings suggest that the N-terminal β-amyloid fragment may serve as a potent and effective endogenous neuromodulator. Copyright © 2014 the authors 0270-6474/14/3414210-09$15.00/0.

  9. Presynaptic localization of Smn and hnRNP R in axon terminals of embryonic and postnatal mouse motoneurons.

    Directory of Open Access Journals (Sweden)

    Benjamin Dombert

    Full Text Available Spinal muscular atrophy (SMA is caused by deficiency of the ubiquitously expressed survival motoneuron (SMN protein. SMN is crucial component of a complex for the assembly of spliceosomal small nuclear ribonucleoprotein (snRNP particles. Other cellular functions of SMN are less characterized so far. SMA predominantly affects lower motoneurons, but the cellular basis for this relative specificity is still unknown. In contrast to nonneuronal cells where the protein is mainly localized in perinuclear regions and the nucleus, Smn is also present in dendrites, axons and axonal growth cones of isolated motoneurons in vitro. However, this distribution has not been shown in vivo and it is not clear whether Smn and hnRNP R are also present in presynaptic axon terminals of motoneurons in postnatal mice. Smn also associates with components not included in the classical SMN complex like RNA-binding proteins FUS, TDP43, HuD and hnRNP R which are involved in RNA processing, subcellular localization and translation. We show here that Smn and hnRNP R are present in presynaptic compartments at neuromuscular endplates of embryonic and postnatal mice. Smn and hnRNP R are localized in close proximity to each other in axons and axon terminals both in vitro and in vivo. We also provide new evidence for a direct interaction of Smn and hnRNP R in vitro and in vivo, particularly in the cytosol of motoneurons. These data point to functions of SMN beyond snRNP assembly which could be crucial for recruitment and transport of RNA particles into axons and axon terminals, a mechanism which may contribute to SMA pathogenesis.

  10. Isolation and characterization of a presynaptic neurotoxin, P-elapitoxin-Bf1a from Malaysian Bungarus fasciatus venom.

    Science.gov (United States)

    Rusmili, Muhamad Rusdi Ahmad; Yee, Tee Ting; Mustafa, Mohd Rais; Hodgson, Wayne C; Othman, Iekhsan

    2014-10-01

    Presynaptic neurotoxins are one of the major components in Bungarus venom. Unlike other Bungarus species that have been studied, β-bungarotoxin has never been isolated from Bungarus fasciatus venom. It was hypothesized that the absence of β-bungarotoxin in this species was due to divergence during evolution prior to evolution of β-bungarotoxin. In this study, we have isolated a β-bungarotoxin isoform we named P-elapitoxin-Bf1a by using gel filtration, cation-exchange and reverse-phase chromatography from Malaysian B. fasciatus venom. The toxin consists of two heterogeneous subunits, subunit A and subunit B. LCMS/MS data showed that subunit A was homologous to acidic phospholipase A2 subunit A3 from Bungarus candidus and B. multicinctus venoms, whereas subunit B was homologous with subunit B1 from B. fasciatus venom that was previously detected by cDNA cloning. The toxin showed concentration- and time-dependent reduction of indirect-twitches without affecting contractile responses to ACh, CCh or KCl at the end of experiment in the chick biventer preparation. Toxin modification with 4-BPB inhibited the neurotoxic effect suggesting the importance of His-48. Tissue pre-incubation with monovalent B. fasciatus (BFAV) or neuro-polyvalent antivenom (NPV), at the recommended titer, was unable to inhibit the twitch reduction induced by the toxin. This study indicates that Malaysian B. fasciatus venom has a unique β-bungarotoxin isoform which was not neutralized by antivenoms. This suggests that there might be other presynaptic neurotoxins present in the venom and there is a variation in the enzymatic neurotoxin composition in venoms from different localities. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Depolarization by K+ and glutamate activates different neurotransmitter release mechanisms in GABAergic neurons: vesicular versus non-vesicular release of GABA

    DEFF Research Database (Denmark)

    Belhage, B; Hansen, G H; Schousboe, A

    1993-01-01

    was also reduced by organic (verapamil) and inorganic (Co++) Ca++ channel blockers but was insensitive to the GABA transport inhibitor SKF 89976A. In contrast, the second phase was less sensitive to nocodazole and Ca++ channel antagonists but could be inhibited by SKF 89976A. The glutamate-induced [3H...

  12. Neurotransmitter matters

    DEFF Research Database (Denmark)

    Gerlach, Christian

    2004-01-01

    It weighs like half a bag of flour and has more holes than a sponge, but if we look closely, we find that the brain is also a complex and vibrant part of our body, one that undergoes physical changes as we learn. Join neuroscience for a brief sojourn into the realm of memory ? a world of neurons...

  13. Potentiation of transmitter release by ciliary neurotrophic factor requires somatic signaling.

    Science.gov (United States)

    Stoop, R; Poo, M M

    1995-02-03

    Neurotrophic factors participate in the development and maintenance of the nervous system. Application of ciliary neurotrophic factor (CNTF), a protein that promotes survival of motor neurons, resulted in an immediate potentiation of spontaneous and impulse-evoked transmitter release at developing neuromuscular synapses in Xenopus cell cultures. When CNTF was applied at the synapse, the onset of the potentiation was slower than that produced by application at the cell body of the presynaptic neuron. The potentiation effect was abolished when the neurite shaft was severed from the cell body. Thus, transmitter secretion from the nerve terminals is under immediate somatic control and can be regulated by CNTF.

  14. Differential Release of β-Amyloid from Dendrite- Versus Axon-Targeted APP

    Science.gov (United States)

    DeBoer, Scott R.; Dolios, Georgia; Wang, Rong

    2014-01-01

    The β-amyloid precursor protein (APP) plays a central role in the pathogenesis of Alzheimer's disease. APP is processed in neurons, but little is known about the relative contributions of presynaptic or postsynaptic compartments to the release of Aβ peptides. To address this issue, we transduced primary neurons from Sprague-Dawley rats or APP−/− mice (B6.129S7-Apptm1Dbo/J) with lentiviral constructs expressing APP chimeras harboring targeting motifs from low-density lipoprotein receptor or neuron-glia cell-adhesion molecule to polarize expression to either dendritic or axonal membranes, respectively. Using imaging and quantitative biochemical approaches, we now report that APP selectively targeted to either axons or dendrites leads to the secretion of full-length Aβ peptides with significantly elevated release from dendritic compartments. These findings reveal that the enzymatic machinery required for production of Aβ peptides are operative both in presynaptic and postsynaptic compartments of primary neurons, leading to the suggestion that Aβ-mediated impairments in glutamatergic neurotransmission is the result of Aβ release from both local and distal neuronal compartments. PMID:25209273

  15. The molecular mechanism for overcoming the rate-limiting step in monoamine neurotransmitter transport

    DEFF Research Database (Denmark)

    Sinning, Steffen; Said, Saida; Malinauskaite, Lina

    and are targets for drugs of abuse such as cocaine, amphetamine and ecstasy as well as anxiolytics and antidepressants. The transporters undergo a series of concerted conformational changes in order to harness the driving force of co-transported cations to translocate the neurotransmitter across the neuronal...... structures of the bacterial homolog, LeuT, captured in a new conformation without substrate or sodium bound shows a dramatic rotation of an absolutely conserved leucine into the substrate site. Molecular dynamics simulations combined with functional studies on SERT support that this leucine must act...

  16. Exploration of inclusion complexes of neurotransmitters with β-cyclodextrin by physicochemical techniques

    Science.gov (United States)

    Roy, Mahendra Nath; Saha, Subhadeep; Kundu, Mitali; Saha, Binoy Chandra; Barman, Siti

    2016-07-01

    Molecular assemblies of β-cyclodextrin with few of the most important neurotransmitters, viz., dopamine hydrochloride, tyramine hydrochloride and (±)-epinephrine hydrochloride in aqueous medium have been explored by reliable spectroscopic and physicochemical techniques as potential drug delivery systems. Job plots confirm the 1:1 host-guest inclusion complexes, while surface tension and conductivity studies illustrate the inclusion process. The inclusion complexes were characterized by 1H NMR spectroscopy and association constants have been calculated by using Benesi-Hildebrand method. Thermodynamic parameters for the formation of inclusion complexes have been derived by van't Hoff equation, which demonstrate that the overall inclusion processes are thermodynamically favorable.

  17. Noncovalent Complexation of Monoamine Neurotransmitters and Related Ammonium Ions by Tetramethoxy Tetraglucosylcalix[4]arene

    Science.gov (United States)

    Torvinen, Mika; Kalenius, Elina; Sansone, Francesco; Casnati, Alessandro; Jänis, Janne

    2012-02-01

    The noncovalent complexation of monoamine neurotransmitters and related ammonium and quaternary ammonium ions by a conformationally flexible tetramethoxy glucosylcalix[4]arene was studied by electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. The glucosylcalixarene exhibited highest binding affinity towards serotonin, norepinephrine, epinephrine, and dopamine. Structural properties of the guests, such as the number, location, and type of hydrogen bonding groups, length of the alkyl spacer between the ammonium head-group and the aromatic ring structure, and the degree of nitrogen substitution affected the complexation. Competition experiments and guest-exchange reactions indicated that the hydroxyl groups of guests participate in intermolecular hydrogen bonding with the glucocalixarene.

  18. Astrocytic control of biosynthesis and turnover of the neurotransmitters glutamate and GABA

    DEFF Research Database (Denmark)

    Schousboe, Arne; Bak, Lasse Kristoffer; Waagepetersen, Helle S

    2013-01-01

    . Astrocytes play a pivotal role in the maintenance of the neurotransmitter pools of glutamate and GABA since only these cells express pyruvate carboxylase, the enzyme required for de novo synthesis of the two amino acids. Such de novo synthesis is obligatory to compensate for catabolism of glutamate and GABA...... that GS is exclusively expressed in astrocytes. It should be kept in mind that the operation of the cycle is associated with movement of ammonia nitrogen between the two cell types and different mechanisms which can mediate this have been proposed. This review is intended to delineate the above mentioned...

  19. Measuring endogenous 5-HT release by emission tomography: promises and pitfalls

    DEFF Research Database (Denmark)

    Paterson, Louise M; Tyacke, Robin J; Nutt, David J

    2010-01-01

    Molecular in vivo neuroimaging techniques can be used to measure regional changes in endogenous neurotransmitters, evoked by challenges that alter synaptic neurotransmitter concentration. This technique has most successfully been applied to the study of endogenous dopamine release using positron......, with reference to the dopaminergic system. Studies that aim to image acute, endogenous 5-HT release or depletion at 5-HT receptor targets are summarised, with particular attention to studies in humans. Radiotracers targeting the 5-HT(1A), 5-HT(2A), and 5-HT(4) receptors and the serotonin reuptake transporter...... have been explored for their sensitivity to 5-HT fluctuations, but with mixed outcomes; tracers for these targets cannot reliably image endogenous 5-HT in humans. Shortcomings in our basic knowledge of the mechanisms underlying changes in binding potential are addressed, and suggestions are made...

  20. Wash-Resistantly Bound Xanomeline Inhibits Acetylcholine Release by Persistent Activation of Presynaptic M2 and M4 Muscarinic Receptors in Rat Brain

    Czech Academy of Sciences Publication Activity Database

    Machová, Eva; Jakubík, Jan; El-Fakahany, E. E.; Doležal, Vladimír

    2007-01-01

    Roč. 322, č. 1 (2007), s. 316-323 ISSN 0022-3565 R&D Projects: GA ČR(CZ) GA305/05/0452; GA MŠk(CZ) LC554 Grant - others:-(US) NS25743 Institutional research plan: CEZ:AV0Z50110509 Keywords : acetylcholine * xanomeline * muscarinic receptor Subject RIV: ED - Physiology Impact factor: 4.003, year: 2007

  1. Glutamate and dopamine transmission from midbrain dopamine neurons share similar release properties but are differentially affected by cocaine.

    Science.gov (United States)

    Adrover, Martín F; Shin, Jung Hoon; Alvarez, Veronica A

    2014-02-26

    Synaptic transmission between ventral tegmental area and nucleus accumbens (NAc) is critically involved in reward-motivated behaviors and thought to be altered in addiction. In addition to dopamine (DA), glutamate is packaged and released by a subset of mesolimbic DA neurons, eliciting EPSCs onto medium spiny neurons in NAc. Little is known about the properties and modulation of glutamate release from DA midbrain terminals and the effect of cocaine. Using an optogenetic approach to selectively activate midbrain DA fibers, we compared the properties and modulation of DA transients and EPSCs measured using fast-scan cyclic voltammetry and whole-cell recordings in mouse brain slices. DA transients and EPSCs were inhibited by DA receptor D2R agonist and showed a marked paired-pulse depression that required 2 min for full recovery. Cocaine depressed EPSCs amplitude by 50% but enhanced the overall DA transmission from midbrain DA neurons. AMPA and NMDA receptor-mediated EPSCs were equally inhibited by cocaine, suggesting a presynaptic mechanism of action. Pharmacological blockage and genetic deletion of D2R in DA neurons prevented the cocaine-induced inhibition of EPSCs and caused a larger increase in DA transient peak, confirming the involvement of presynaptic D2R. These findings demonstrate that acute cocaine inhibits DA and glutamate release from midbrain DA neurons via presynaptic D2R but has differential overall effects on their transmissions in the NAc. We postulate that cocaine, by blocking DA reuptake, prolongs DA transients and facilitates the feedback inhibition of DA and glutamate release from these terminals.

  2. Three Gaseous Neurotransmitters, Nitric oxide, Carbon Monoxide, and Hydrogen Sulfide, Are Involved in the Neurogenic Relaxation Responses of the Porcine Internal Anal Sphincter

    OpenAIRE

    Folasire, Oladayo; Mills, Kylie A; Sellers, Donna J; Chess-Williams, Russ

    2016-01-01

    Background/Aims The internal anal sphincter (IAS) plays an important role in maintaining continence and a number of neurotransmitters are known to regulate IAS tone. The aim of this study was to determine the relative importance of the neurotransmitters involved in the relaxant and contractile responses of the porcine IAS. Methods Responses of isolated strips of IAS to electrical field stimulation (EFS) were obtained in the absence and presence of inhibitors of neurotransmitter systems. Resul...

  3. Probing interactions of neurotransmitters with twin tailed anionic surfactant: A detailed physicochemical study.

    Science.gov (United States)

    Kaur, Rajwinder; Sanan, Reshu; Mahajan, Rakesh Kumar

    2016-05-01

    Keeping in view the role of neurotransmitters (NTs) in central nervous system diseases and in controlling various physiological processes, present study is aimed to study the binding of neurotransmitters (NTs) such as norepinephrine hydrochloride (NE) and serotonin hydrochloride (5-HT) with twin tailed surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT). Spectroscopic and electrochemical measurements combined with microcalorimetric measurements were used to characterize the interactions between AOT and NTs. Meteoric modifications to emission profile and absorption spectra of NTs upon addition of AOT are indicative of the binding of NTs with AOT. Distinct interactional states such as formation of ion-pairs, induced and regular micelles with adsorbed NTs molecules have been observed in different concentration regimes of AOT. The formation of ion-pairs from oppositely charged NTs and AOT is confirmed by the reduced absorbance, quenched fluorescence intensity and decrease in peak current (ipa) as well as shifts in peak potential (Epa) values. The stoichiometry and formation of the NTs-AOT complexes has been judged and the extent of interactions is quantitatively discussed in terms of binding constant (K) and free energy of binding (ΔG°). The enthalpy (ΔH°mic) and free energy of micellization (ΔG°mic) for AOT in presence and absence of NTs are determined from the enthalpy curves. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Immunohistochemical profile of various neurotransmitters, neurotrophins and MIB-1 in cholesteatomas of the petrous bone.

    Science.gov (United States)

    Artico, Marco; Bronzetti, Elena; Lo Vasco, Vincenza Rita; Ionta, Brunella; Alicino, Valentina; D'Ambrosio, Anna; Magliulo, Giuseppe

    2008-01-01

    Compared to the normal epidermal epithelium, cholesteatomas have altered growth properties characterized by the excessive growth of keratinocytes leading to mucosal destruction. Either congenital or acquired, these lesions, which grow in the middle ear space, the petrous apex or the mastoid of temporal bones, are mostly considered benign skin tumoral lesions. However, many questions remain concerning their pathophysiology. Numerous studies have been proposed to identify those cholesteatoma lesions at risk of recurrence, a possible event that may cause hearing loss. We examined patients with petrous apex or mastoid cholesteatoma in order to analyze the expression of various neurotransmitters, neurotrophins and their receptors and the Ki-67 antigen for identification of a possible relationship between clinical outcome and histopathological behaviour in terms of the proliferative activity of cholesteatomas. Expression of the analyzed molecules was studied using immunohistochemical methods in seven adult patients with petrous apex cholesteatoma who underwent surgical removal of the lesion. Our results, in accordance with published data, confirm that Molecular Immunology Borstel-1 (MIB-1) and certain neurotransmitters could be useful in the prognostic evaluation of the risk of recurrence of aggressive forms of cholesteatoma.

  5. Neuromodulatory neurotransmitters influence LTP-like plasticity in human cortex: a pharmaco-TMS study.

    Science.gov (United States)

    Korchounov, Alexei; Ziemann, Ulf

    2011-08-01

    Long-term potentiation (LTP) of synaptic efficacy is considered a fundamental mechanism of learning and memory. At the cellular level a large body of evidence demonstrated that the major neuromodulatory neurotransmitters dopamine (DA), norepinephrine (NE), and acetylcholine (ACh) influence LTP magnitude. Noninvasive brain stimulation protocols provide the opportunity to study LTP-like plasticity at the systems level of human cortex. Here we applied paired associative stimulation (PAS) to induce LTP-like plasticity in the primary motor cortex of eight healthy subjects. In a double-blind, randomized, placebo-controlled, crossover design, the acute effects of a single oral dose of the neuromodulatory drugs cabergoline (DA agonist), haloperidol (DA antagonist), methylphenidate (indirect NE agonist), prazosine (NE antagonist), tacrine (ACh agonist), and biperiden (ACh antagonist) on PAS-induced LTP-like plasticity were examined. The antagonists haloperidol, prazosine, and biperiden depressed significantly the PAS-induced LTP-like plasticity observed under placebo, whereas the agonists cabergoline, methylphenidate, and tacrine had no effect. Findings demonstrate that antagonists in major neuromodulatory neurotransmitter systems suppress LTP-like plasticity at the systems level of human cortex, in accord with evidence of their modulating action of LTP at the cellular level. This provides further supportive evidence for the known detrimental effects of these drugs on LTP-dependent mechanisms such as learning and memory.

  6. Brain structures and neurotransmitters regulating aggression in cats: implications for human aggression.

    Science.gov (United States)

    Gregg, T R; Siegel, A

    2001-01-01

    1. Violence and aggression are major public health problems. 2. The authors have used techniques of electrical brain stimulation, anatomical-immunohistochemical techniques, and behavioral pharmacology to investigate the neural systems and circuits underlying aggressive behavior in the cat. 3. The medial hypothalamus and midbrain periaqueductal gray are the most important structures mediating defensive rage behavior, and the perifornical lateral hypothalamus clearly mediates predatory attack behavior. The hippocampus, amygdala, bed nucleus of the stria terminalis, septal area, cingulate gyrus, and prefrontal cortex project to these structures directly or indirectly and thus can modulate the intensity of attack and rage. 4. Evidence suggests that several neurotransmitters facilitate defensive rage within the PAG and medial hypothalamus, including glutamate, Substance P, and cholecystokinin, and that opioid peptides suppress it; these effects usually depend on the subtype of receptor that is activated. 5. A key recent discovery was a GABAergic projection that may underlie the often-observed reciprocally inhibitory relationship between these two forms of aggression. 6. Recently, Substance P has come under scrutiny as a possible key neurotransmitter involved in defensive rage, and the mechanism by which it plays a role in aggression and rage is under investigation. 7. It is hoped that this line of research will provide a better understanding of the neural mechanisms and substrates regulating aggression and rage and thus establish a rational basis for treatment of disorders associated with these forms of aggression.

  7. Modulation of stress consequences by hippocampal monoaminergic, glutamatergic and nitrergic neurotransmitter systems.

    Science.gov (United States)

    Joca, Sâmia Regiane Lourenço; Ferreira, Frederico Rogério; Guimarães, Francisco Silveira

    2007-08-01

    Several findings relate the hippocampal formation to the behavioural consequences of stress. It contains a high concentration of corticoid receptors and undergoes plastic modifications, including decreased neurogenesis and cellular remodelling, following stress exposure. Various major neurotransmitter systems in the hippocampus are involved in these effects. Serotonin (5-HT) seems to exert a protective role in the hippocampus and attenuates the behavioural consequences of stress by activating 5-HT1A receptors in this structure. These effects may mediate the therapeutic actions of several antidepressants. The role of noradrenaline is less clear and possibly depends on the specific hippocampal region (dorsal vs. ventral). The deleterious modifications induced in the hippocampus by stress might involve a decrease in neurotrophic factors such as brain derived neurotrophic factor (BDNF) following glutamate N-methyl-D-aspartate (NMDA) receptor activation. In addition to glutamate, nitric oxide (NO) could also be related to these effects. Systemic and intra-hippocampal administration of nitric oxide synthase (NOS) inhibitors attenuates stress-induced behavioural consequences. The challenge for the future will be to integrate results related to these different neurotransmitter systems in a unifying theory about the role of the hippocampus in mood regulation, depressive disorder and antidepressant effects.

  8. Deletion of mouse FXR gene disturbs multiple neurotransmitter systems and alters neurobehavior

    Directory of Open Access Journals (Sweden)

    Fei eHuang

    2015-03-01

    Full Text Available Farnesoid X receptor (FXR is a nuclear hormone receptor involved in bile acid synthesis and homeostasis. Dysfunction of FXR is involved in cholestasis and atherosclerosis. FXR is prevalent in liver, gallbladder, and intestine, but it is not yet clear whether it modulates neurobehavior. In the current study, we tested the hypothesis that mouse FXR deficiency affects a specific subset of neurotransmitters and results in a unique behavioral phenotype. The FXR knockout mice showed less depressive-like and anxiety-related behavior, but increased motor activity. They had impaired memory and reduced motor coordination. There were changes of glutamatergic, GABAergic, serotoninergic and norepinephrinergic neurotransmission in either hippocampus or cerebellum. FXR deletion decreased the amount of the GABA synthesis enzyme GAD65 in hippocampus but increased GABA transporter GAT1 in cerebral cortex. FXR deletion increased serum concentrations of many bile acids, including taurodehydrocholic acid, taurocholic acid, deoxycholic acid, glycocholic acid, tauro-α-muricholic acid, tauro-ω-muricholic acid, and hyodeoxycholic acid. There were also changes in brain concentrations of taurocholic acid, taurodehydrocholic acid, tauro-ω-muricholic acid, tauro-β-muricholic acid, deoxycholic acid, and lithocholic acid. Taken together, the results from studies with FXR knockout mice suggest that FXR contributes to the homeostasis of multiple neurotransmitter systems in different brain regions and modulates neurobehavior. The effect appears to be at least partially mediated by bile acids that are known to cross the blood-brain barrier inducing potential neurotoxicity.

  9. Fine-tuning of defensive behaviors in the dorsal periaqueductal gray by atypical neurotransmitters

    Directory of Open Access Journals (Sweden)

    M.V. Fogaça

    2012-04-01

    Full Text Available This paper presents an up-to-date review of the evidence indicating that atypical neurotransmitters such as nitric oxide (NO and endocannabinoids (eCBs play an important role in the regulation of aversive responses in the periaqueductal gray (PAG. Among the results supporting this role, several studies have shown that inhibitors of neuronal NO synthase or cannabinoid receptor type 1 (CB1 receptor agonists cause clear anxiolytic responses when injected into this region. The nitrergic and eCB systems can regulate the activity of classical neurotransmitters such as glutamate and γ-aminobutyric acid (GABA that control PAG activity. We propose that they exert a ‘fine-tuning’ regulatory control of defensive responses in this area. This control, however, is probably complex, which may explain the usually bell-shaped dose-response curves observed with drugs that act on NO- or CB1-mediated neurotransmission. Even if the mechanisms responsible for this complex interaction are still poorly understood, they are beginning to be recognized. For example, activation of transient receptor potential vanilloid type-1 channel (TRPV1 receptors by anandamide seems to counteract the anxiolytic effects induced by CB1 receptor activation caused by this compound. Further studies, however, are needed to identify other mechanisms responsible for this fine-tuning effect.

  10. Near-future carbon dioxide levels alter fish behaviour by interfering with neurotransmitter function

    Science.gov (United States)

    Nilsson, Göran E.; Dixson, Danielle L.; Domenici, Paolo; McCormick, Mark I.; Sørensen, Christina; Watson, Sue-Ann; Munday, Philip L.

    2012-03-01

    Predicted future CO2 levels have been found to alter sensory responses and behaviour of marine fishes. Changes include increased boldness and activity, loss of behavioural lateralization, altered auditory preferences and impaired olfactory function. Impaired olfactory function makes larval fish attracted to odours they normally avoid, including ones from predators and unfavourable habitats. These behavioural alterations have significant effects on mortality that may have far-reaching implications for population replenishment, community structure and ecosystem function. However, the underlying mechanism linking high CO2 to these diverse responses has been unknown. Here we show that abnormal olfactory preferences and loss of behavioural lateralization exhibited by two species of larval coral reef fish exposed to high CO2 can be rapidly and effectively reversed by treatment with an antagonist of the GABA-A receptor. GABA-A is a major neurotransmitter receptor in the vertebrate brain. Thus, our results indicate that high CO2 interferes with neurotransmitter function, a hitherto unrecognized threat to marine populations and ecosystems. Given the ubiquity and conserved function of GABA-A receptors, we predict that rising CO2 levels could cause sensory and behavioural impairment in a wide range of marine species, especially those that tightly control their acid-base balance through regulatory changes in HCO3- and Cl- levels.

  11. Chitosan coated carbon fiber microelectrode for selective in vivo detection of neurotransmitters in live zebrafish embryos

    Energy Technology Data Exchange (ETDEWEB)

    Ozel, Rifat Emrah [Department of Chemistry and Biomolecular Science, 8 Clarkson Ave, Potsdam, NY 136995810 (United States); Wallace, Kenneth N. [Department of Biology, Clarkson University, Potsdam, NY 136995810 (United States); Andreescu, Silvana, E-mail: eandrees@clarkson.edu [Department of Chemistry and Biomolecular Science, 8 Clarkson Ave, Potsdam, NY 136995810 (United States)

    2011-06-10

    Graphical abstract: Chitosan coated fiber electrodes are sensitive to serotonin detection while rejecting physiological levels of ascorbic acid interferences. - Abstract: We report the development of a chitosan modified carbon fiber microelectrode for in vivo detection of serotonin. We find that chitosan has the ability to reject physiological levels of ascorbic acid interferences and facilitate selective and sensitive detection of in vivo levels of serotonin, a common catecholamine neurotransmitter. Presence of chitosan on the microelectrode surface was investigated using scanning electron microscopy (SEM) and cyclic voltammetry (CV). The electrode was characterized using differential pulse voltammetry (DPV). A detection limit of 1.6 nM serotonin with a sensitivity of 5.12 nA/{mu}M, a linear range from 2 to 100 nM and a reproducibility of 6.5% for n = 6 electrodes were obtained. Chitosan modified microelectrodes selectively measure serotonin in presence of physiological levels of ascorbic acid. In vivo measurements were performed to measure concentration of serotonin in the live embryonic zebrafish intestine. The sensor quantifies in vivo intestinal levels of serotonin while successfully rejecting ascorbic acid interferences. We demonstrate that chitosan can be used as an effective coating to reject ascorbic acid interferences at carbon fiber microelectrodes, as an alternative to Nafion, and that chitosan modified microelectrodes are reliable tools for in vivo monitoring of changes in neurotransmitter levels.

  12. Neurotransmitter Transporter-Like: a male germline-specific SLC6 transporter required for Drosophila spermiogenesis.

    Directory of Open Access Journals (Sweden)

    Nabanita Chatterjee

    2011-01-01

    Full Text Available The SLC6 class of membrane transporters, known primarily as neurotransmitter transporters, is increasingly appreciated for its roles in nutritional uptake of amino acids and other developmentally specific functions. A Drosophila SLC6 gene, Neurotransmitter transporter-like (Ntl, is expressed only in the male germline. Mobilization of a transposon inserted near the 3' end of the Ntl coding region yields male-sterile mutants defining a single complementation group. Germline transformation with Ntl cDNAs under control of male germline-specific control elements restores Ntl/Ntl homozygotes to normal fertility, indicating that Ntl is required only in the germ cells. In mutant males, sperm morphogenesis appears normal, with elongated, individualized and coiled spermiogenic cysts accumulating at the base of the testes. However, no sperm are transferred to the seminal vesicle. The level of polyglycylation of Ntl mutant sperm tubulin appears to be significantly lower than that of wild type controls. Glycine transporters are the most closely related SLC6 transporters to Ntl, suggesting that Ntl functions as a glycine transporter in developing sperm, where augmentation of the cytosolic pool of glycine may be required for the polyglycylation of the massive amounts of tubulin in the fly's giant sperm. The male-sterile phenotype of Ntl mutants may provide a powerful genetic system for studying the function of an SLC6 transporter family in a model organism.

  13. Do Proxies for the Neurotransmitter Cortisol Predict Adaptation to Life with Chronic Pain?

    Science.gov (United States)

    Deamond, Wade

    Among the numerous difficulties encountered by chronic pain patients, impulsive and dysfunctional decision-making complicate their already difficult life situations yet remains relatively understudied. This study examined a recently published neurobiological decision making model that identifies eight specific neurotransmitters and hormones (Dopamine, Testosterone, Endogenous Opioids Glutamate, Serotonin, Norepinephrine, Cortisol, and GABA) linked to unsound decision making related to cognitive, motivational and emotional dysregulation (Nussbaum et al., 2011) (see Appendix 2). The Perceived Stress Scale (PSS), a proxy for the cortisol element in the pharmacological decision making model was analyzed for the neurotransmitter's relationship to functionality and quality of life in a group of 37 chronic pain patients. Participants were comprised of males and females ranging from 23 to 52 years of age and were classified with respect to levels of adjustment to living with chronic pain based on the Quality of Life Scale (QLS), the Dartmouth WONCA COOP Charts and the Global Assessment of Functioning (GAF). The Iowa Gambling Task (IGT) and Frontal System Behavioral Scale (FSBS) measured decision making related to immediate gratification and daily living respectively. Results suggest that emotional dysregulation, as measured by the PSS is a significant predictor for adaptation to life with chronic pain and the PSS is superior to predicting adaptation to life with chronic pain than reported levels of pain as measured by the McGill Pain Questionnaire.

  14. Unsupported platinum nanoparticles as effective sensors of neurotransmitters and possible drug curriers

    Science.gov (United States)

    Tąta, Agnieszka; Gralec, Barbara; Proniewicz, Edyta

    2018-03-01

    Herein, surface-enhanced Raman scattering (SERS) activity of positively charged unsupported platinum nanoparticles (PtNPs) with ∼12 nm size and narrow size distribution, in an aqueous solution, towards neurotransmitters was monitored at 785 nm excitation wavelength. The pure PtNPs were synthetized by polyol method. Their morphology and structure were checked by scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) measurements. As a neurotransmitter bombesin (BN), which exhibits autocrine effect on the growth of normal and tumour tissues, and its fragments from the C-terminal end: BN13-14, BN12-14, BN11-14, BN10-14, BN9-14, and BN8-14 (X-14 fragments of the BN amino acid sequence) were chosen. The collected spectra were interpreted and discussed. This is to determine the adsorption mode of bombesin onto the PtNPs surface and changes in this mode as a result of the bombesin backbone shortening from the N-terminal end. This is important from the point of using PtNPs as potential BN carrier into the cancerous tissue and antitumor drug.

  15. Cerebellar level of neurotransmitters in rats exposed to paracetamol during development.

    Science.gov (United States)

    Blecharz-Klin, Kamilla; Joniec-Maciejak, Ilona; Jawna-Zboińska, Katarzyna; Pyrzanowska, Justyna; Piechal, Agnieszka; Wawer, Adriana; Widy-Tyszkiewicz, Ewa

    2016-12-01

    The present study was designed to clarify the effect of prenatal and postnatal paracetamol administration on the neurotransmitter level and balance of amino acids in the cerebellum. Biochemical analysis to determine the concentration of neurotransmitters in this brain structure was performed on two-month-old Wistar male rats previously exposed to paracetamol in doses of 5 (P5, n=10) or 15mg/kg (P15, n=10) throughout the entire prenatal period, lactation and until the completion of the second month of life, when the experiment was terminated. Control animals were given tapped water (Con, n=10). The cerebellar concentration of monoamines, their metabolites and amino acids were assayed using High Performance Liquid Chromatography (HPLC). The present experiment demonstrates that prenatal and postnatal paracetamol exposure results in modulation of cerebellar neurotransmission with changes concerning mainly 5-HIAA and MHPG levels. The effect of paracetamol on monoaminergic neurotransmission in the cerebellum is reflected by changes in the level of catabolic end-products of serotonin (5-HIAA) and noradrenaline (MHPG) degradation. Further work is required to define the mechanism of action and impact of prenatal and postnatal exposure to paracetamol in the cerebellum and other structures of the central nervous system (CNS). Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  16. Metabolic Profiling and Quantification of Neurotransmitters in Mouse Brain by Gas Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Jäger, Christian; Hiller, Karsten; Buttini, Manuel

    2016-09-01

    Metabolites are key mediators of cellular functions, and have emerged as important modulators in a variety of diseases. Recent developments in translational biomedicine have highlighted the importance of not looking at just one disease marker or disease inducing molecule, but at populations thereof to gain a global understanding of cellular function in health and disease. The goal of metabolomics is the systematic identification and quantification of metabolite populations. One of the most pressing issues of our times is the understanding of normal and diseased nervous tissue functions. To ensure high quality data, proper sample processing is crucial. Here, we present a method for the extraction of metabolites from brain tissue, their subsequent preparation for non-targeted gas chromatography-mass spectrometry (GC-MS) measurement, as well as giving some guidelines for processing of raw data. In addition, we present a sensitive screening method for neurotransmitters based on GC-MS in selected ion monitoring mode. The precise multi-analyte detection and quantification of amino acid and monoamine neurotransmitters can be used for further studies such as metabolic modeling. Our protocol can be applied to shed light on nervous tissue function in health, as well as neurodegenerative disease mechanisms and the effect of experimental therapeutics at the metabolic level. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

  17. The influence of aripiprazole and olanzapine on neurotransmitters level in frontal cortex of prenatally stressed rats.

    Science.gov (United States)

    Ratajczak, P; Kus, K; Gołembiowska, K; Noworyta-Sokołowska, K; Woźniak, A; Zaprutko, T; Nowakowska, E

    2016-09-01

    The study aims to verify whether alterations in the level of neurotransmitters have occurred in prenatally stressed rats (animal model of schizophrenia), and whether aripiprazole (ARI) and olanzapine (OLA) modify this level. The effects of ARI (1.5mg/kg) and OLA (0.5mg/kg) were studied by means of microdialysis in freely moving rats (observation time 120min). The level of neurotransmitters (DA, 5-HT, NA) and their metabolites (DOPAC, HVA, 5-HIAA) was analyzed by HPLC with coulochemical detection. Obtained results indicate that after a single administration of ARI and OLA in the prenatally stressed rats the increase of DA, DOPAC, and 5-HT was observed. In turn ARI administration increase the level of HVA and 5-HIAA and also decrease the level of NA. After OLA administration the level of NA and HVA increased and no significant change in 5-HIAA was observed. Alterations observed as a result of ARI and OLA administration may be pivotal in identifying animal models of mental disorders and in the analysis of neuroleptics effectiveness. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Dynamical Organization of Syntaxin-1A at the Presynaptic Active Zone.