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Sample records for 5-ht1a receptor binding

  1. [11C]WAY-100635 PET imaging of 5-HT1A receptor binding in patients with temporal lobe epilepsy

    To understand the role of 5-HT in human temporal lobe epilepsy, here we measured 5-HT1A receptor binding potential by positron emission tomography (PET) with [carbonyl-11C]WAY100635, a selective 5-HT1A receptor antagonist, in patients with temporal lobe epilepsy and normal controls. Twelve patients with temporal lobe epilepsy and seventeen healthy controls participated in the study. For each subject, we conducted PET and magnetic resonance imaging (MRI), by which we measured the 5-HT1A receptor binding potential, the R1-value, a relative indicator of cerebral blood flow in regions of interest, and the volume of gray matter. Patients with temporal lobe epilepsy showed significantly reduced 5-HT1A receptor binding potential in the temporal lobe. The laterality of the reduction was coincided with the epileptogenic foci estimated by a scalp electroencephalography (EEG). In contrast, the R1-value and gray matter volume showed no difference between the patient and control groups. Our study revealed that 5-HT1A receptor binding was reduced significantly at the epileptogenic foci. We suggest that PET imaging with [carbonyl-11C]WAY100635 is potentially a useful non-invasive method for determining the epileptogenic foci. (author)

  2. Higher Pre-treatment 5-HT1A Receptor Binding Potential in Bipolar Disorder Depression is Associated with Treatment Remission: A Naturalistic Treatment Pilot PET Study

    Lan, Martin J.; Hesselgrave, Natalie; Ciarleglio, Adam; Ogden, R. Todd; Sullivan, Gregory M.; Mann, J. John; Parsey, Ramin V.

    2013-01-01

    Bipolar Disorder is a major cause of disability and a high risk for suicide. The pathophysiology of the disorder remains largely unknown. Medication choice for bipolar depression patients involves trial and error. Our group reported previously that brain serotonin 1A (5HT1A) receptor binding measured by positron emission tomography (PET) is higher in bipolar depression. We now investigated whether pretreatment 5HT1A levels correlates with antidepressant medication outcome. 41 medication-free ...

  3. The selective labelling of central 5-HT1A receptor binding sites by [3H]5-methoxy-3-(di-n-propylamino)chroman.

    Cossery, J M; Gozlan, H; Spampinato, U; Perdicakis, C; Guillaumet, G; Pichat, L; Hamon, M

    1987-08-11

    Investigations on the pharmacological properties of a series of chroman derivatives indicated that 5-methoxy-3-(di-n-propylamino)chroman (5-MeO-DPAC) acts in the nM range on 5-HT1A sites but recognizes very poorly other 5-HT sites and D2 sites in rat brain membranes. As expected from these observations, the tritiated derivative [3H]5-MeO-DPAC bound to a single class of specific sites which exhibited the same pharmacological properties as 5-HT1A sites labelled by [3H]8-OH-DPAT in hippocampal and cortical membranes. In contrast to [3H]8-OH-DPAT, [3H]5-MeO-DPAC did not bind to presynaptic striatal sites (possibly associated with 5-HT reuptake in serotoninergic terminals), which indicated that this new chroman derivative was even more selective than the [3H]tetralin ligand for the in vitro labelling of 5-HT1A sites. Comparison of the chemical structures of 5-MeO-DPAC and other 5-HT1A ligands suggests that electronic enrichment due to isosteric O-substitution in the chroman derivative may play an important role in the highly selective recognition of the 5-HT1A receptor by this drug. PMID:2959487

  4. Cannabinoid administration increases 5HT1A receptor binding and mRNA expression in the hippocampus of adult but not adolescent rats.

    Zavitsanou, K; Wang, H; Dalton, V S; Nguyen, V

    2010-08-11

    The endocannabinoid and serotonin systems share a high level of overlap in terms of the physiological processes that they regulate, however, little is known about their functional interactions particularly during adolescence, a vulnerable period for both the development of psychosis and for initiation to substance use. In the present study, the effects of cannabinoid treatment on serotonin 5HT1A receptor density and mRNA expression were investigated in two age groups: Adolescent (postnatal day 35) and adult (postnatal day 70) rats were injected with the synthetic cannabinoid HU210 (25, 50 or 100 microg/kg) or vehicle for 1, 4 or 14 days and sacrificed 24 h after the last injection. 5HT1A receptor density was measured in different brain regions using [(3)H]8-OH-DPAT quantitative autoradiography whereas mRNA expression was measured in adjacent brain sections. Higher levels of both serotonin 5HT1A receptor binding and mRNA expression were observed in limbic regions in adolescent control animals compared to adults. 5HT1A receptor density was increased by 23% in the CA1 region of the hippocampus of adult rats treated with 100 microg/kg HU210 for 4 days compared to vehicle treated controls. The same treatment increased mRNA expression by 27% and by 14% in the CA1 region and dentate gyrus of the hippocampus respectively. 5HT1A receptor density was increased by 22% in the CA1 of adult animals treated with 50 microg HU210, by 26% in the dentate gurus of adult rats treated with 100 microg for 14 days. By contrast, 5HT1A receptor density or mRNA expression was not affected in the brain of adolescent animals in any of the brain regions examined. These results suggest that cannabinoid treatment has differential effects on serotonin-related neurochemistry in adolescent compared to adult rats. The effects in the adult brain may compromise hippocampal function and could account for the cognitive deficits seen in habitual heavy cannabis users. PMID:20438810

  5. Higher pretreatment 5-HT1A receptor binding potential in bipolar disorder depression is associated with treatment remission: a naturalistic treatment pilot PET study.

    Lan, Martin J; Hesselgrave, Natalie; Ciarleglio, Adam; Ogden, R Todd; Sullivan, Gregory M; Mann, J John; Parsey, Ramin V

    2013-11-01

    Bipolar disorder is a major cause of disability and a high risk for suicide. The pathophysiology of the disorder remains largely unknown. Medication choice for bipolar depression patients involves trial and error. Our group reported previously that brain serotonin 1A (5-HT(1A)) receptor binding measured by positron emission tomography (PET) is higher in bipolar depression. We now investigated whether pretreatment 5-HT(1A) levels correlates with antidepressant medication outcome. Forty-one medication-free DSM-IV diagnosed, bipolar patients in a major depressive episode had brain PET scans performed using [(11)C]WAY-100635 and a metabolite corrected arterial input function. The patients then received naturalistic psychopharmacologic treatment as outpatients and a follow up Hamilton Depression Rating Scale (HDRS) after 3 months of treatment. Patients with 24 item HDRS scores less than 10 were considered to have remitted. A linear mixed effects model was used to compare BP(F) (binding potential, proportional to the total number of available receptors) in 13 brain regions of interest between remitters and nonremitters. Thirty-four patients completed 3 months of treatment and ratings; 9 had remitted. Remitters and nonremitters did not differ in age, sex, or recent medication history with serotonergic medications. Remitters had higher [(11)C]WAY-100635 BP(F) across all brain regions compared with nonremitters (P = 0.02). Higher pretreatment brain 5-HT(1A) receptor binding was associated with remission after 3 months of pharmacological treatment in bipolar depression. Prospective treatment studies are warranted to determine whether this test predicts outcome of specific types of treatment. PMID:23720414

  6. Women with multiple chemical sensitivity have increased harm avoidance and reduced 5-HT(1A receptor binding potential in the anterior cingulate and amygdala.

    Lena Hillert

    Full Text Available Multiple chemical sensitivity (MCS is a common condition, characterized by somatic distress upon exposure to odors. As in other idiopathic environmental intolerances, the underlying mechanisms are unknown. Contrary to the expectations it was recently found that persons with MCS activate the odor-processing brain regions less than controls, while their activation of the anterior cingulate cortex (ACC is increased. The present follow-up study was designed to test the hypotheses that MCS subjects have increased harm avoidance and deviations in the serotonin system, which could render them intolerant to environmental odors. Twelve MCS and 11 control subjects, age 22-44, all working or studying females, were included in a PET study where 5-HT(1A receptor binding potential (BP was assessed after bolus injection of [(11C]WAY100635. Psychological profiles were assessed by the Temperament and Character Inventory and the Swedish universities Scales of Personality. All MCS and 12 control subjects were also tested for emotional startle modulation in an acoustic startle test. MCS subjects exhibited significantly increased harm avoidance, and anxiety compared to controls. They also had a reduced 5-HT(1A receptor BP in amygdala (p = 0.029, ACC (p = 0.005 (planned comparisons, significance level 0.05, and insular cortex (p = 0.003; significance level p<0.005 with Bonferroni correction, and showed an inverse correlation between degree of anxiety and the BP in the amygdala (planned comparison. No group by emotional category difference was found in the startle test. Increased harm avoidance and the observed changes in the 5-HT(1A receptor BP in the regions processing harm avoidance provides a plausible pathophysiological ground for the symptoms described in MCS, and yields valuable information for our general understanding of idiopathic environmental intolerances.

  7. Design and biological evaluation of 99mTc ligands derived from WAY 100635 and desmethyl WAY 100635 for serotonin 5-HT1A and α1-adrenergic receptor binding

    Investigations on Tc labelled ligands for the 5-HT1A receptor carried out at Forschungszentrum Rossendorf from 1999 to 2001 in collaboration with the Karolinska Institute, Stockholm, are reported. The novel Tc labelled receptor ligands basically consist of a Tc chelate unit with the metal in the oxidation state +5 or +3 and 1-(2-methoxyphenyl) piperazine as the receptor targeting domain. Both moieties are linked by alkyl spacers of various chain lengths. Rhenium was used as Tc surrogate for complete chemical characterization and in vitro receptor binding studies. All complexes display in competition experiments not only subnanomolar affinities for the 5-HT1A receptor but also high affinities for the α1-adrenergic receptor. Biodistribution studies in rats show brain uptakes between 0.2 and 0.6% of the injected dose five minutes post-injection. In vitro autoradiographic studies in rat brains and post-mortem human brains indicate the accumulation of the 99mTc complexes in areas which are rich in 5-HT1A receptors and additionally in areas rich in α1-adrenergic receptors. This in vitro enrichment can be blocked respectively by the 5-HT1A receptor agonist 8-OH-DPAT or by prazosin hydrochloride, an α1-adrenergic receptor antagonist. (author)

  8. Serotonin 5HT1A receptor availability and pathological crying after stroke

    Møller, Mette; Andersen, G; Gjedde, A

    2007-01-01

    OBJECTIVES: Post-stroke depression and pathological crying (PC) implicate an imbalance of serotonergic neurotransmission. We claim that PC follows serotonin depletion that raises the binding potential (p(B)) of the 5-HT(1A) receptor antagonist [carbonyl-(11)C]WAY-100635, which is reversible by...

  9. No change in [¹¹C]CUMI-101 binding to 5-HT(1A) receptors after intravenous citalopram in human

    Pinborg, Lars H; Feng, Ling; Haahr, Mette E;

    2012-01-01

    The main objective of this study was to determine the sensitivity of [¹¹C]CUMI-101 to citalopram challenge aiming at increasing extracellular 5-HT. CUMI-101 has agonistic properties in human embryonic kidney 293 cells transfected with human recombinant 5-HT(1A) receptors (Hendry et al. [2011] Nucl...... Med Biol 38:273-277; Kumar et al. [2006] J Med Chem 49:125-134) and has previously been demonstrated to be sensitive to bolus citalopram in monkeys (Milak et al. [2011] J Cereb Blood Flow Metab 31:243-249). We studied six healthy individuals. Two PET-scans were performed on the same day in each...... individual before and after constant infusion of citalopram (0.15 mg/kg). The imaging data were analyzed using two tissue compartment kinetic modeling with metabolite corrected arterial input and Simplified Reference Tissue Modeling using cerebellum as a reference region. There was no significant difference...

  10. Enhanced 5-HT1A receptor expression in forebrain regions of aggressive house mice.

    Korte, SM; Meijer, OC; deKloet, ER; Buwalda, B.; Sluyter, F; vanOortmerssen, G; BOHUS, B; Meijer, Onno C.; de Kloet, E. Ronald; Keijser, Jan N.

    1996-01-01

    The brain 5-HT1A receptor system in male wild house mice selected for high and low offensive aggression was investigated by autoradiographic analysis of in situ hybridization and radioligand binding. In high-aggressive mice, characterized by a short attack latency, the rise in plasma corticosterone concentration during thr early dark; phase was reduced, At that time the level of 5-HT1A mRNA in the dorsal hippocampus (dentate gyrus and CA1) was twice the amount measured in low-aggressive mice ...

  11. Effect of fentanyl on 5-HT efflux involves both opioid and 5-HT1A receptors

    Tao, Rui; Karnik, Meghana; Ma, Zhiyuan; Auerbach, Sidney B

    2003-01-01

    Fentanyl is a μ-opioid analgesic that might disinhibit 5-HT neurons and thus increase 5-HT efflux. However, fentanyl also binds to 5-HT1A receptors, and if it activates 5-HT1A somatodendritic autoreceptors, the resultant inhibition might offset opioid-mediated increases in 5-HT efflux. To test this hypothesis, we used microdialysis to study effects of fentanyl on extracellular 5-HT in the dorsal raphe nucleus (DRN) of unanesthetized rats.Systemic administration of fentanyl (0.01–0.2 mg kg−1, ...

  12. Synergistic Effect between Maternal Infection and Adolescent Cannabinoid Exposure on Serotonin 5HT1A Receptor Binding in the Hippocampus: Testing the "Two Hit" Hypothesis for the Development of Schizophrenia,

    DALTON, VICTORIA

    2012-01-01

    Infections during pregnancy and adolescent cannabis use have both been identified as environmental risk factors for schizophrenia. We combined these factors in an animal model and looked at their effects, alone and in combination, on serotonin 5HT1A receptor binding (5HT1AR) binding longitudinally from late adolescence to adulthood. Pregnant rats were exposed to the viral mimic poly I:C on embryonic day 15. Adolescent offspring received daily injections of the cannabinoid HU210 for 14 days st...

  13. Synergistic Effect between Maternal Infection and Adolescent Cannabinoid Exposure on Serotonin 5HT1A Receptor Binding in the Hippocampus: Testing the “Two Hit” Hypothesis for the Development of Schizophrenia

    Katerina Zavitsanou; Deborah M. Hodgson; Adam Walker; Mathieu Verdurand; Dalton, Victoria S.

    2012-01-01

    Infections during pregnancy and adolescent cannabis use have both been identified as environmental risk factors for schizophrenia. We combined these factors in an animal model and looked at their effects, alone and in combination, on serotonin 5HT1A receptor binding (5HT1AR) binding longitudinally from late adolescence to adulthood. Pregnant rats were exposed to the viral mimic poly I:C on embryonic day 15. Adolescent offspring received daily injections of the cannabinoid HU210 for 14 days st...

  14. Differential interactions of dimethyltryptamine (DMT) with 5-HT1A and 5-HT2 receptors.

    Deliganis, A V; Pierce, P A; Peroutka, S J

    1991-06-01

    The interactions of the indolealkylamine N,N-dimethyltryptamine (DMT) with 5-hydroxytryptamine1A (5-HT1A) and 5-HT2 receptors in rat brain were analyzed using radioligand binding techniques and biochemical functional assays. The affinity of DMT for 5-HT1A sites labeled by [3H]-8-hydroxy-2-(di-n-propylamino)tetralin ([3H]-8-OH-DPAT) was decreased in the presence of 10(-4) M GTP, suggesting agonist activity of DMT at this receptor. Adenylate cyclase studies in rat hippocampi showed that DMT inhibited forskolin-stimulated cyclase activity, a 5-HT1A agonist effect. DMT displayed full agonist activity with an EC50 of 4 x 10(-6) M in the cyclase assay. In contrast to the agonist actions of DMT at 5-HT1A receptors, DMT appeared to have antagonistic properties at 5-HT2 receptors. The ability of DMT to compete for [3H]-ketanserin-labeled 5-HT2 receptors was not affected by the presence of 10(-4) M GTP, suggesting antagonist activity of DMT at 5-HT2 receptors. In addition, DMT antagonized 5-HT2-receptor-mediated phosphatidylinositol (PI) turnover in rat cortex at concentrations above 10(-7) M, with 70% of the 5-HT-induced PI response inhibited at 10(-4) M DMT. Micromolar concentrations of DMT produced a slight PI stimulation that was not blocked by the 5-HT2 antagonist ketanserin. These studies suggest that DMT has opposing actions on 5-HT receptor subtypes, displaying agonist activity at 5-HT1A receptors and antagonist activity at 5-HT2 receptors. PMID:1828347

  15. Buspirone improves haloperidol-induced Parkinson disease in mice through 5-HT1A receptors

    A. Mohajjel Nayebi; H Sheidaei

    2010-01-01

    "nBackground and the purpose of the study: The available literatures show that 5-HT1A receptors are widely distributed throughout the basal ganglia, and their activation facilitate dopamine release. Neuroleptic drugs such as haloperidol induce Parkinson-like syndrome through blocking brain D2 receptors. This study aimed to investigate effect of buspirone, a partial agonist of 5HT1A receptor, on motor dysfunctions induced by haloperidol and involvement of 5HT1A receptors in this regard. &...

  16. Novel benzodioxopiperazines acting as antagonists at postsynaptic 5-HT1A receptors and as agonists at 5-HT1A autoreceptors: a comparative pharmacological characterization with proposed 5-HT1A antagonists.

    Millan, M J; Canton, H; Gobert, A; Lejeune, F; Rivet, J M; Bervoets, K; Brocco, M; Widdowson, P; Mennini, T; Audinot, V

    1994-01-01

    The novel benzodioxopiperazines [4-(benzodioxan-5-yl)1-[2- (benzocyclobutane-1-yl)ethyl]piperazine] (S 14489), [4-(benzodioxan-5-yl)1-(indan-2-yl)piperazine)] (S 15535) and [4-(benzodioxan-5-yl)1-[2(indan-1-yl)ethyl]piperazine (S15931) competitively displaced the binding of [3H]-8-OH-DPAT at serotonin (5-HT)1A receptors with affinities (pKis) of 9.2, 8.8 and 8.9, respectively. These values compared favorably with those of the structurally related eltoprazine (8.0) and the proposed 5-HT1A antagonists NAN-190 (9.2), MDL 73005 EF (8.9), SDZ 216-525 (8.8), BMY 7378 (8.7), (-)-tertatolol (8.1), (-)-alprenolol (7.7), WAY 100,135 (7.5) and spiperone (6.9). The affinities of S 14489, S 15535 and S 15931 for other 5-HT receptor types (5-HT1B, 5-HT1C, 5-HT1D, 5-HT2 and 5-HT3) were about 50 to 1000-fold lower. The spontaneous tail-flicks, flat-body posture and hypothermia mediated by an action of the 5-HT1A agonist 8-OH-DPAT at postsynaptic 5-HT1A receptors were dose-dependently and completely antagonized by S 14489, S 15535 and S15931 at doses of 0.63 to 10.0 and 2.5 to 40.0 mg/kg for s.c. and oral administration, respectively. They did not induce these responses alone, and in their presence, dose-response curves for 8-OH-DPAT were shifted in parallel to the right without loss of maximal effect. By contrast, eltoprazine, MDL 73005 EF, BMY 7378 and NAN-190 behaved as "partial" agonists and only incompletely antagonized the actions of 8-OH-DPAT in these tests. At 5-HT1A autoreceptors, S 14489, S 15535 and S 15931 acted as agonists in inhibiting striatal 5-hydroxytryptophan accumulation (0.16-2.5 mg/kg, s.c.) and in abolishing the electrical activity of the dorsal raphe nucleus (0.005-0.100 mg/kg, i.v.). Eltoprazine, BMY 7378, NAN-190 and MDL 73005 EF also behaved as agonists at these 5-HT1A autoreceptors, whereas WAY 100,135, spiperone, (-)-tertatolol, (-)-alprenolol and SDZ 216-525 inhibited neither accumulation nor firing. WAY 100,135 and spiperone antagonized the inhibition

  17. Visualisation of serotonin-1A (5-HT1A) receptors in the central nervous system

    Passchier, Jan; van Waarde, A

    2001-01-01

    The 5-HT1A subtype of receptors for the neurotransmitter serotonin is predominantly located in the limbic forebrain and is involved in the modulation of emotion and the function of the hypothalamus. Since 5-HT1A receptors are implicated in the pathogenesis of anxiety, depression, hallucinogenic beha

  18. Modifying 5-HT1A receptor gene expression as a new target for antidepressant therapy

    Paul R Albert

    2010-06-01

    Full Text Available Major depression is the most common form of mental illness, and is treated with antidepressant compounds that increase serotonin (5-HT neurotransmission. Increased 5-HT1A autoreceptor levels in the raphe nuclei act as a “brake” to inhibit the 5-HT system, leading to depression and resistance to antidepressants. Several 5-HT1A receptor agonists (buspirone, flesinoxan, ipsapirone that preferentially desensitize 5-HT1A autoreceptors have been tested for augmentation of antidepressant drugs with mixed results. One explanation could be the presence of the C(-1019G 5-HT1A promoter polymorphism that prevents gene repression of the 5-HT1A autoreceptor. Furthermore, down-regulation of 5-HT1A autoreceptor expression, not simply desensitization of receptor signaling, appears to be required to enhance and accelerate antidepressant action. The current review focuses on the transcriptional regulators of 5-HT1A autoreceptor expression, their roles in permitting response to 5-HT1A-targeted treatments and their potential as targets for new antidepressant compounds for treatment-resistant depression.

  19. Development of novel mixed ligand technetium complexes for imaging 5-HT1A neural system receptors

    The development of 99mTc complexes for imaging 5-HT1A neural system receptors using the 3 + 1 mixed ligand approach is described. Six novel complexes (I-VI) were designed using two different strategies. In complexes I-IV the pharmacophore 1-(2-methoxyphenyl)piperazine was attached to a monodentate thiol used as co-ligand and combined with tridentate dianionic aminothiols (SNS and NNS). On the other hand, complexes V and VI were obtained using thiophenol and 4-methoxy-thiophenol as co-ligand and a tridentate ligand (SNS) with the pharmacophore bound to the nitrogen through an alkyl chain. All complexes were prepared at tracer level using 99mTc-glucoheptonate as precursor. Ligand and co-ligand concentration, reaction time and temperature were optimized to achieve high substitution yield and radiochemical purity. Structure was studied at carrier level through the corresponding rhenium complexes. Complexes I and II presented the expected ReOLK structure and a distorted trigonal bipyramidal geometry. The structure of the other four complexes has not been completely elucidated yet. Biodistribution studies of all the complexes demonstrated selective brain uptake and retention. Uptake of complex I in receptor-rich hippocampus was significantly higher than that of the cerebellum (P = 0.05) 1 h post-injection. Oxorhenium complexes I and II showed affinity for the 5-HT1A receptor binding sites, with IC50 values in the nanomolar range. The results demonstrate the potential of the mixed ligand approach for the design of 99mTc complexes with the ability to bind neuroreceptors. However, the goal of imaging 5-HT1A receptors with technetium requires further development of complexes with improved biological profiles. (author)

  20. Visualisation of serotonin-1A (5-HT1A) receptors in the central nervous system

    The 5-HT1A subtype of receptors for the neurotransmitter serotonin is predominantly located in the limbic forebrain and is involved in the modulation of emotion and the function of the hypothalamus. Since 5-HT1A receptors are implicated in the pathogenesis of anxiety, depression, hallucinogenic behaviour, motion sickness and eating disorders, they are an important target for drug therapy. Here, we review the radioligands which are available for visualisation and quantification of this important neuroreceptor in the human brain, using positron emission tomography (PET) or single-photon emission tomography (SPET). More than 20 compounds have been labelled with carbon-11 (half-life 20 min), fluorine-18 (half-life 109.8 min) or iodine-123 (half-life 13.2 h): structural analogues of the agonist, 8-OH-DPAT, structural analogues of the antagonist, WAY 100635, and apomorphines. The most successful radioligands thus far are [carbonyl-11C] WAY-100635 (WAY), [carbonyl-11C]desmethyl-WAY-100635 (DWAY), p-[18F]MPPF and [11C]robalzotan (NAD-299). The high-affinity ligands WAY and DWAY produce excellent images of 5-HT1A receptor distribution in the brain (even the raphe nuclei are visualised), but they cannot be distributed to remote facilities and they probably cannot be used to measure changes in endogenous serotonin. Binding of the moderate-affinity ligands MPPF and NAD-299 may be more sensitive to serotonin competition and MPPF can be distributed to PET centres within a flying distance of a few hours. Future research should be directed towards: (a) improvement of the metabolic stability in primates; (b) development of a fluorinated radioligand which can be produced in large quantities and (c) production of a radioiodinated or technetium-labelled ligand for SPET. (orig.)

  1. Positron emission tomography study of pindolol occupancy of 5-HT1A receptors in humans: preliminary analyses

    Preclinical studies in rodents suggest that augmentation of serotonin reuptake inhibitors (SSRIs) therapy by the 5-hydroxytryptamine1A (5-HT1A) receptor agent pindolol might reduce the delay between initiation of treatment and antidepressant response. This hypothesis is based on the ability of pindolol to potentiate the increase in serotonin (5-HT) transmission induced by SSRIs, an effect achieved by blockade of the 5-HT1A autoreceptors in the dorsal raphe nuclei (DRN). However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT1A receptors following treatment with controlled release pindolol in nine healthy volunteers with positron-emission tomography (PET). Each subject was studied four times: at baseline (scan 1), following 1 week of oral administration of pindolol CR (7.5 mg/day) at peak level, 4 h after the dose (scan 2), and at 10 h following the dose (scan 3), and following one dose of pindolol CR (30 mg) (at peak level, 4 h) (scan 4). Pindolol occupancy of 5-HT1A receptors was evaluated in the DRN and cortical regions as the decrease in binding potential (BP) of the radiolabelled selective 5-HT1A antagonist [carbonyl-11C]WAY-100635 or [carbonyl-11C] N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide abbreviated as [11C]WAY-100635. Pindolol dose-dependently decreased [11C]WAY-100635 BP. Combining all the regions, occupancy was 20 ± 8% at scan 2, 14 ± 8% at scan 3, and 44 ± 8% at scan 4. The results of this study suggest that at doses used in clinical studies of augmentation of the SSRI effect by pindolol (2.5 mg t.i.d.), the occupancy of 5-HT1A receptors is moderate and highly variable between subjects. This factor might explain the variable results obtained in clinical studies. On the other hand, at each dose tested, pindolol occupancy of 5-HT1A receptors was higher in the DRN compared to cortical regions

  2. Verbal memory and 5-HT1A receptors in healthy volunteers - A PET study with [carbonyl-(11)C]WAY-100635.

    Penttilä, Jani; Hirvonen, Jussi; Tuominen, Lauri; Lumme, Ville; Ilonen, Tuula; Någren, Kjell; Hietala, Jarmo

    2016-03-01

    The serotonin 5-HT1A receptor is a putative drug development target in disorders with cognitive and in particular memory deficits. However, previous human positron emission tomography (PET) studies on 5-HT1A receptor binding and memory functions have yielded discrepant results. We explored the association between verbal memory and 5-HT1A receptor binding in 24 healthy subjects (14 male, 10 female, aged 18-41 years). The cognitive tests included the Wechsler Memory Scale-Revised (WMS-R), Wechsler Adult Intelligence Scale-Revised (WAIS-R) and Wisconsin Card Sorting Test (WCST). 5-HT1A receptor binding was measured with PET and the radioligand [carbonyl-(11)C]WAY-100635, which was quantified with the gold standard method based on kinetic modeling using arterial blood samples. We found that global 5-HT1A receptor binding was positively correlated with measures of verbal memory, such that subjects who had higher receptor binding tended to have better verbal memory than subjects who had lower receptor binding. Regional analyses suggested significant correlations in multiple neocortical brain regions and the raphe nuclei. We did not find significant correlations between 5-HT1A receptor binding and executive functions as measured with WCST. We conclude that neocortical as well as raphe 5-HT1A receptors are involved in verbal memory function in man. PMID:26775837

  3. Role of 5-HT(1A) receptors in fluoxetine-induced lordosis inhibition.

    Guptarak, Jutatip; Sarkar, Jhimly; Hiegel, Cindy; Uphouse, Lynda

    2010-07-01

    The selective serotonin reuptake inhibitor (SSRI), fluoxetine (Prozac(R)), is an effective antidepressant that is also prescribed for other disorders (e.g. anorexia, bulimia, and premenstrual dysphoria) that are prevalent in females. However, fluoxetine also produces sexual side effects that may lead patients to discontinue treatment. The current studies were designed to evaluate several predictions arising from the hypothesis that serotonin 1A (5-HT(1A)) receptors contribute to fluoxetine-induced sexual dysfunction. In rodent models, 5-HT(1A) receptors are potent negative modulators of female rat sexual behavior. Three distinct experiments were designed to evaluate the contribution of 5-HT(1A) receptors to the effects of fluoxetine. In the first experiment, the ability of the 5-HT(1A) receptor antagonist, N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY100635), to prevent fluoxetine-induced lordosis inhibition was examined. In the second experiment, the effects of prior treatment with fluoxetine on the lordosis inhibitory effect of the 5-HT(1A) receptor agonist, (+/-)-8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT), were studied. In the third experiment, the ability of progesterone to reduce the acute response to fluoxetine was evaluated. WAY100635 attenuated the effect of fluoxetine; prior treatment with fluoxetine decreased 8-OH-DPAT's potency in reducing lordosis behavior; and progesterone shifted fluoxetine's dose-response curve to the right. These findings are consistent with the hypothesis that 5-HT(1A) receptors contribute to fluoxetine-induced sexual side effects. PMID:20223238

  4. Anxiolytic effects of prelimbic 5-HT(1A) receptor activation in the hemiparkinsonian rat.

    Hui, Yan Ping; Wang, Tao; Han, Ling Na; Li, Li Bo; Sun, Yi Na; Liu, Jian; Qiao, Hong Fei; Zhang, Qiao Jun

    2015-01-15

    This study sought to assess whether unilateral lesions of the medial forebrain bundle (MFB) using 6-hydroxydopamine in rats are able to induce anxiety-like behaviors, the role of serotonin-1A (5-HT1A) receptors of the prelimbic (PrL) sub-region of ventral medial prefrontal cortex in the regulation of these behaviors, the density of 5-HT neurons in the dorsal raphe nucleus (DRN) and co-localization of 5-HT1A receptor and neuronal glutamate transporter EAAC1-immunoreactive (EAAC1-ir) cells in the PrL. Unilaterally lesioning the MFB induced anxiety-like behaviors as measured by the open-field and elevated plus maze tests when compared to sham-operated rats. Intra-PrL injection of 5-HT1A receptor agonist 8-OH-DPAT (50, 100, and 500 ng/rat) decreased the percentage of time spent in the center of the open-field and percentages of open arm entries and open arm time in sham-operated rats, indicating the induction of anxiogenic responses, and administration of 5-HT1A receptor antagonist WAY-100635 (60, 120, and 240 ng/rat) showed anxiolytic effects. However, 8-OH-DPAT, at the same doses, increased the percentage of time spent in the center of the open-field and percentages of open arm entries and open arm time in the lesioned rats, indicating the induction of anxiolytic effects, and WAY-100635 produced anxiogenic responses. Unilateral MFB lesion decreased the density of 5-HT neurons in the DRN, and percentage of EAAC1-ir cells expressing 5-HT1A receptors in the PrL. These results suggest that unilateral lesions of the MFB in rats may induce anxiety-like behaviors, and activation of 5-HT1A receptors in the PrL has anxiolytic effects in the rat model of Parkinson's disease. PMID:24906197

  5. Chronic Administration of 5-HT1A Receptor Agonist Relieves Depression and Depression-Induced Hypoalgesia

    Zhao-Cai Jiang; Wei-Jing Qi; Jin-Yan Wang; Fei Luo

    2014-01-01

    Previous studies have shown that depressed patients as well as animal models of depression exhibit decreased sensitivity to evoked pain stimuli, and serotonin is indicated to be involved in depression-induced hypoalgesia. The purpose of this study was to investigate the potential role of 5-HT1A receptor in the depression-induced hypoalgesia. Acute or chronic administration of 5-HT1A receptor agonist, 8-OH-DPAT, was performed in olfactory bulbectomy (OB) and sham-operated rats. The depression-...

  6. 5-HT1A gene promoter polymorphism and [18F]MPPF binding potential in healthy subjects: a PET study

    Gorwood Philip

    2010-07-01

    Full Text Available Abstract Background Previous Positron Emission Tomography (PET studies of 5-HT1A receptors have shown an influence of several genetic factors, including the triallelic serotonin transporter gene-linked polymorphic region on the binding potential (BPND of these receptors. The aim of our study was to investigate the relationship between a 5-HT1A promoter polymorphism and the binding potential of another selective 5-HT1A receptor antagonist, [18F]MPPF, in healthy subjects. Methods Thirty-five volunteers, including 23 women, underwent an [18F]MPPF scan and were genotyped for both the C(-1019G 5-HT1A promoter polymorphism and the triallelic serotonin transporter gene-linked polymorphic region. We used a simplified reference tissue model to generate parametric images of BPND. Whole brain Statistical Parametric Mapping and raphe nuclei region of interest analyses were performed to look for an association of [18F]MPPF BPND with the C(-1019G 5-HT1A promoter polymorphism. Results Among the 35 subjects, 5-HT1A promoter genotypes occurred with the following frequencies: three G/G, twenty-one G/C, and eleven C/C. No difference of [18F]MPPF BPND between groups was observed, except for two women who were homozygote carriers for the G allele and showed greater binding potential compared to other age-matched women over the frontal and temporal neocortex. However, the biological relevance of this result remains uncertain due to the very small number of subjects with a G/G genotype. These findings were not modified by excluding individuals carrying the S/S genotype of the serotonin transporter gene-linked polymorphic region. Conclusions We failed to observe an association between the C(-1019G 5-HT1A promoter polymorphism and [18F]MPPF binding in healthy subjects. However our data suggest that the small number of women homozygote for the G allele might have greater [18F]MPPF BPND relative to other individuals. This finding should be confirmed in a larger sample.

  7. Autonomic changes associated with enhanced anxiety in 5-HT(1A) receptor knockout mice.

    Pattij, T.; Groenink, L.; Hijzen, T.H.; Oosting, R.S.; Maes, R.A.A.; Gugten, J. van der; Olivier, B.

    2002-01-01

    5-HT(1A) receptor knockout (KO) mice have been described as more anxious in various anxiety paradigms. Because anxiety is often associated with autonomic changes like elevated body temperature and tachycardia, radiotelemetry was used to study these parameters in wild type (WT) and KO mice in stress-

  8. Synergistic Effect between Maternal Infection and Adolescent Cannabinoid Exposure on Serotonin 5HT1A Receptor Binding in the Hippocampus: Testing the "Two Hit" Hypothesis for the Development of Schizophrenia.

    Dalton, Victoria S; Verdurand, Mathieu; Walker, Adam; Hodgson, Deborah M; Zavitsanou, Katerina

    2012-01-01

    Infections during pregnancy and adolescent cannabis use have both been identified as environmental risk factors for schizophrenia. We combined these factors in an animal model and looked at their effects, alone and in combination, on serotonin 5HT1A receptor binding (5HT1AR) binding longitudinally from late adolescence to adulthood. Pregnant rats were exposed to the viral mimic poly I:C on embryonic day 15. Adolescent offspring received daily injections of the cannabinoid HU210 for 14 days starting on postnatal day (PND) 35. Hippocampal and cortical 5HT1AR binding was quantified autoradiographically using [(3)H]8-OH-DPAT, in late adolescent (PND 55), young adult (PND 65) and adult (PND 90) rats. Descendants of poly I:C treated rats showed significant increases of 15-18% in 5HT1AR in the hippocampus (CA1) compared to controls at all developmental ages. Offspring of poly I:C treated rats exposed to HU210 during adolescence exhibited even greater elevations in 5HT1AR (with increases of 44, 29, and 39% at PNDs 55, 65, and 90). No effect of HU210 alone was observed. Our results suggest a synergistic effect of prenatal infection and adolescent cannabinoid exposure on the integrity of the serotoninergic system in the hippocampus that may provide the neurochemical substrate for abnormal hippocampal-related functions relevant to schizophrenia. PMID:23738203

  9. CHAPS solubilization of a G-protein sensitive 5-HT1A receptor from bovine hippocampus

    The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high affinity and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the ternary complex rather than to promote its formation. 8-OH-DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC50 values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form

  10. Systematic Screening of the Serotonin Receptor 1A (5-HT1A) Gene in Chronic Tinnitus

    Kleinjung T; Langguth B; Fischer B; Hajak G; Eichhammer P; Sand PG

    2006-01-01

    Objective Chronic tinnitus is a highly prevalent condition and has been hypothesized to result from an innate disturbance in central nervous serotonergic transmission. Given the frequent comorbidity with major depression and anxiety, we argue that candidate genes for these disorders are likely to overlap. The present study addresses the gene encoding for the 5-HT1A receptor as a putative risk factor for tinnitus. Methods In 88 subjects with a diagnosis of chronic subjective tinnitus who underwent a detailed neurootological examination, the entire 5-HT1A gene was amplified using overlapping PCR products. Amplicons were custom sequenced bidirectionally and were screened for variants in multiple alignments against the human genome reference. Results We identified a synonymous C > T exchange at residue 184 (Pro) in 7/88 subjects, but detected no missense variants in the population under study. Specifically, the following residues were fully conserved: 16 (Pro), 22 (Gly), 28 (Ile), 98 (Val), 220(Arg), 267 (Val), 273 (Gly), and 418 (Asn). Discussion The present data count against the causation of chronic tinnitus by a change in the 5-HT1A receptor's amino acid sequence. However, the allele frequency for the 184Pro minor allele (0.04) reached twice the frequency reported in control cohorts from the same ethnicity.Additional investigations are invited to clarify the role of the 5-HT1A polymorphism in larger samples, and to control for comorbid affective disorders.

  11. Modulation of reflexly evoked vagal bradycardias by central 5-HT1A receptors in anaesthetized rabbits

    Skinner, Matthew R; Ramage, Andrew G; Jordan, David

    2002-01-01

    The role of central 5-HT1A receptors in the control of the bradycardia and changes in central respiratory drive, renal nerve activity and blood pressure evoked by stimulating cardiopulmonary afferents with phenylbiguanide, baroreceptors by electrical stimulation of the aortic nerve and chemoreceptors by injections of sodium cyanide (NaCN) in atenolol-pretreated anaesthetized rabbits were studied.Buspirone (100 μg kg−1; i.c.) potentiated the bradycardia (increase in R-R interval) and the chang...

  12. ROLE OF 5-HT1A RECEPTORS IN FLUOXETINE-INDUCED LORDOSIS INHIBITION

    Guptarak, Jutatip; Sarkar, Jhimly; Hiegel, Cindy; Uphouse, Lynda

    2010-01-01

    The selective serotonin reuptake inhibitor (SSRI), fluoxetine (Prozac®), is an effective antidepressant that is also prescribed for other disorders (e.g. anorexia, bulimia, and premenstrual dysphoria) that are prevalent in females. However, fluoxetine also produces sexual side effects that may lead patients to discontinue treatment. The current studies were designed to evaluate several predictions arising from the hypothesis that serotonin 1A (5-HT1A) receptors contribute to fluoxetine-induce...

  13. Synthesis, radiolabeling and bioevaluation of a novel arylpiperazine derivative containing triazole as a 5-HT1A receptor imaging agents

    Introduction: It has been recognized that serotonin plays a main role in various pathological conditions such as anxiety, depression, aggressiveness, schizophrenia, suicidal behavior, panic and autism. 1-(2-Methoxyphenyl) piperazine pharmacophore, a fragment of the true 5-HT1A antagonist WAY100635, is found in numerous selective 5-HT1A imaging agents. In this paper, we have reported the synthesis of a novel derivative of 1-(2-methoxyphenyl) piperazine that is labeled with 99mTc (CO)3 via click chemistry. Methods: The bidentate alkyne, propargylglycine was reacted with phenyl piperazine triazole derivative in the presence of a catalytic amount of Cu (I) to form tridentate ligand. The ligand was radiolabeled with the precursor [99mTc] [(H2O)3 (CO)3]+ and characterized by HPLC. The bioevaluation of radio labeled ligand was carried out in rats. Results: Triazole complex was labeled by 99mTc-tricarbonyl and its radiochemical yield was more than > 95% which was determined by HPLC. In vivo stability studies in human serum albumin show a 93% ratio of complex after a 24 h period. The calculated partition coefficient (logP) was 0.34 ± 0.02. Receptor binding assays indicated about 70% specific binding of radioligand to 5-HT1A receptors. Biodistribution studies have shown brain hippocampus uptake of 0.40 ± 0.08 %ID/g at 30 min post injection. Conclusions: Results indicate that this 99mTc-tricabonyl-arylpiperazine derivative has specific binding to 5-HT1A receptors and presented suitable characters for its use as a CNS imaging agent

  14. Synthesis and Evaluation of Mefway Analogs as Ligands for Serotonin 5HT1A Receptors

    Thio, Joanne P.; Liang, Christopher; Bajwa, Alisha K; Wooten, Dustin W; Christian, Bradley T; Mukherjee, Jogeshwar

    2014-01-01

    18F-Mefway (N-{2-[4-(2′-methoxyphenyl)piperazinyl]ethyl}-N-(2-pyridyl)-N-(4′-18F-fluoro-methylcyclohexane)carboxamide) was developed and evaluated for use as a PET ligand for imaging 5-HT1A receptors. Ongoing studies of 18F-Mefway have shown it to be an effective PET radiotracer. We have synthesized isomers of Mefway by changing the position of the methyl-group in attempts to evaluate stability for imaging purposes. 2-Methyl-, 3-methyl-, and 4-methyl-cyclohexane-1-carboxylic acids and 3-carbo...

  15. A selective 5-HT1a receptor agonist improves respiration in a mouse model of Rett syndrome.

    Levitt, Erica S; Hunnicutt, Barbara J; Knopp, Sharon J; Williams, John T; Bissonnette, John M

    2013-12-01

    Rett syndrome is a neurological disorder caused by loss of function mutations in the gene that encodes the DNA binding protein methyl-CpG-binding protein 2 (Mecp2). A prominent feature of the syndrome is disturbances in respiration characterized by frequent apnea and an irregular interbreath cycle. 8-Hydroxy-2-dipropylaminotetralin has been shown to positively modulate these disturbances (Abdala AP, Dutschmann M, Bissonnette JM, Paton JF, Proc Natl Acad Sci U S A 107: 18208-18213, 2010), but the mode of action is not understood. Here we show that the selective 5-HT1a biased agonist 3-chloro-4-fluorophenyl-(4-fluoro-4-{[(5-methylpyrimidin-2-ylmethyl)-amino]-methyl}-piperidin-1-yl)-methanone (F15599) decreases apnea and corrects irregularity in both heterozygous Mecp2-deficient female and in Mecp2 null male mice. In whole cell voltage-clamp recordings from dorsal raphe neurons, F15599 potently induced an outward current, which was blocked by barium, reversed at the potassium equilibrium potential, and was antagonized by the 5-HT1a antagonist WAY100135. This is consistent with somatodendritic 5-HT1a receptor-mediated activation of G protein-coupled inwardly rectifying potassium channels (GIRK). In contrast, F15599 did not activate 5-HT1b/d receptors that mediate inhibition of glutamate release from terminals in the nucleus accumbens by a presynaptic mechanism. Thus F15599 activated somatodendritic 5-HT1a autoreceptors, but not axonal 5-HT1b/d receptors. In unanesthetized Mecp2-deficient heterozygous female mice, F15599 reduced apnea in a dose-dependent manner with maximal effect of 74.5 ± 6.9% at 0.1 mg/kg and improved breath irrregularity. Similarly, in Mecp2 null male mice, apnea was reduced by 62 ± 6.6% at 0.25 mg/kg, and breathing became regular. The results indicate respiration is improved with a 5-HT1a agonist that activates GIRK channels without affecting neurotransmitter release. PMID:24092697

  16. Increase in serotonin 5-HT1A receptors in prefrontal and temporal cortices of brains from patients with chronic schizophrenia

    Binding studies with [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT), a specific serotonin1A (5-HT1A) receptor agonist, were done on the autopsied brains from control subjects and from patients with chronic schizophrenia. In the controls, representative Scatchard plots for the specific [3H]8-OH-DPAT bindings in the prefrontal cortex and hippocampus revealed a single component of high affinity binding site. The [3H]8-OH-DPAT bindings to the prefrontal cortex and hippocampus were potently inhibited by serotonin and 5-HT1A agonists, while other neurotransmitters, 5-HT2 and 5-HT3 related compounds did not inhibit the binding. The bindings were decreased in the presence of 0.1mM GTP and 0.1mM GppNHp but not in the presence of 0.1mM GMP. In the prefrontal and temporal cortices of schizophrenics, there was a significant increase in the specific [3H]8-OH-DPAT binding, by 40% and 60%, respectively, with no change in the hippocampus, amygdala, cingulum, motor cortex, parietal or occipital cortex, as compared to findings in the controls

  17. Similar anxiolytic effects of agonists targeting serotonin 5-HT1A or cannabinoid CB receptors on zebrafish behavior in novel environments.

    Connors, Kristin A; Valenti, Theodore W; Lawless, Kelly; Sackerman, James; Onaivi, Emmanuel S; Brooks, Bryan W; Gould, Georgianna G

    2014-06-01

    The discovery that selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are present and bioaccumulate in aquatic ecosystems have spurred studies of fish serotonin transporters (SERTs) and changes in SSRI-sensitive behaviors as adverse outcomes relevant for risk assessment. Many SSRIs also act at serotonin 5-HT1A receptors. Since capitalizing on this action may improve treatments of clinical depression and other psychiatric disorders, novel multimodal drugs that agonize 5-HT1A and block SERT were introduced. In mammals both 5-HT1A and CB agonists, such as buspirone and WIN55,212-2, reduce anxious behaviors. Immunological and behavioral evidence suggests that 5-HT1A-like receptors may function similarly in zebrafish (Danio rerio), yet their pharmacological properties are not well characterized. Herein we compared the density of [(3)H] 8-hydroxy-2-di-n-propylamino tetralin (8-OH-DPAT) binding to 5-HT1A-like sites in the zebrafish brain, to that of similarly Gαi/o-coupled cannabinoid receptors. [(3)H] 8-OH-DPAT specific binding was 176±8, 275±32, and 230±36fmol/mg protein in the hypothalamus, optic tectum, and telencephalon. [(3)H] WIN55,212-2 binding density was higher in those same brain regions at 6±0.3, 5.5±0.4 and 7.3±0.3pm/mg protein. The aquatic light-dark plus maze was used to examine behavioral effects of 5-HT1A and CB receptor agonists on zebrafish novelty-based anxiety. With acute exposure to the 5-HT1A partial-agonist buspirone (50mg/L), or dietary exposure to WIN55,212-2 (7μg/week) zebrafish spent more time in and/or entered white arms more often than controls (pecological risks of azapirones and multimodal antidepressants in the future. PMID:24411165

  18. Cyclopentadienyl tricarbonyl complexes of 99mTc for the in vivo imaging of the serotonin 5-HT 1a receptor in the brain

    The present interest in the 5-HT 1a receptor is due to its implicated role in several major neuropsychiatric disorders such as depression, eating disorders and anxiety. For the diagnosis of these pathophysiological processes it is important to have radioligands in hand able to specifically bind on the 5-HT 1a receptor in order to allow brain imaging. due to the optimal radiation properties of 99mTc there is a considerable interest in the development of 99mTc radiopharmaceuticals for imaging serotonergic CNS receptors using single-photon emission tomography (SPET). Here we introduce two cyclopentadienyl technitium tricarbonyl conjugates of piperidine derivatives which show high accumulation of radioactivity in brain areas rich in 5-HT 1a receptors

  19. Characterization of the 5-HT1A receptor of the honeybee (Apis mellifera) and involvement of serotonin in phototactic behavior.

    Thamm, Markus; Balfanz, Sabine; Scheiner, Ricarda; Baumann, Arnd; Blenau, Wolfgang

    2010-07-01

    Serotonin plays a key role in modulating various physiological and behavioral processes in both protostomes and deuterostomes. The vast majority of serotonin receptors belong to the superfamily of G-protein-coupled receptors. We report the cloning of a cDNA from the honeybee (Am5-ht1A) sharing high similarity with members of the 5-HT(1) receptor class. Activation of Am5-HT(1A) by serotonin inhibited the production of cAMP in a dose-dependent manner (EC(50) = 16.9 nM). Am5-HT(1A) was highly expressed in brain regions known to be involved in visual information processing. Using in vivo pharmacology, we could demonstrate that Am5-HT(1A) receptor ligands had a strong impact on the phototactic behavior of individual bees. The data presented here mark the first comprehensive study-from gene to behavior-of a 5-HT(1A) receptor in the honeybee, paving the way for the eventual elucidation of additional roles of this receptor subtype in the physiology and behavior of this social insect. PMID:20349263

  20. Behavioural evidence for a functional interaction between central 5-HT2 and 5-HT1A receptors.

    Backus, L. I.; Sharp, T; Grahame-Smith, D.G.

    1990-01-01

    1. The possibility of 5-HT2 receptor modulation of central 5-HT1A receptor function has been examined using the 5-hydroxytryptamine (5-HT) behavioural syndrome induced by 5-HT1A receptor active drugs in rats. 2. The 5-HT2/5-HTIC antagonist ritanserin (0.1-2 mg kg-1) increased the 5-HT behavioural syndrome induced by submaximally effective doses of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) and gepirone. 3. Pretreatment with the 5-HT2/5-HT1C...

  1. Auraptenol attenuates vincristine-induced mechanical hyperalgesia through serotonin 5-HT1A receptors.

    Wang, Yunfei; Cao, Shu-e; Tian, Jianmin; Liu, Guozhe; Zhang, Xiaoran; Li, Pingfa

    2013-01-01

    Common chemotherapeutic agents such as vincristine often cause neuropathic pain during cancer treatment in patients. Such neuropathic pain is refractory to common analgesics and represents a challenging clinical issue. Angelicae dahuricae radix is an old traditional Chinese medicine with demonstrated analgesic efficacy in humans. However, the active component(s) that attribute to the analgesic action have not been identified. This work described the anti-hyperalgesic effect of one coumarin component, auraptenol, in a mouse model of chemotherapeutic agent vincristine-induced neuropathic pain. We reported that auraptenol dose-dependently reverted the mechanical hyperalgesia in mice within the dose range of 0.05-0.8 mg/kg. In addition, the anti-hyperalgesic effect of auraptenol was significantly blocked by a selective serotonin 5-HT1A receptor antagonist WAY100635 (1 mg/kg). Within the dose range studied, auraptenol did not significantly alter the general locomotor activity in mice. Taken together, this study for the first time identified an active component from the herbal medicine angelicae dahuricae radix that possesses robust analgesic efficacy in mice. These data support further studies to assess the potential of auraptenol as a novel analgesic for the management of neuropathic pain. PMID:24287473

  2. Independent of 5-HT1A receptors, neurons in the paraventricular hypothalamus mediate ACTH responses from MDMA

    Zaretsky, Dmitry V.; Zaretskaia, Maria V.; DiMicco, Joseph A.; Durant, Pamela J.; Ross, Christian T.; Rusyniak, Daniel E

    2013-01-01

    Acute and chronic complications from the substituted amphetamine 3,4-methylenedioxymethamphetamine (MDMA) are linked to activation of the hypothalamic-pituitary-adrenal (HPA) axis. How MDMA activates the HPA axis is not known. HPA responses to stress are known to be mediated through the paraventricular (PVH) hypothalamus and to involve serotonin-1a (5-HT1A) receptors. We sought to determine if the PVH and 5-HT1A receptors were also involved in mediating HPA responses to MDMA. Rats were pretre...

  3. Selective serotonin 5-HT1A receptor biased agonists elicitdistinct brain activation patterns: a pharmacoMRI study.

    Becker, G; Bolbos, R; Costes, N; Redouté, J; Newman-Tancredi, A; Zimmer, L

    2016-01-01

    Serotonin 1A (5-HT1A) receptors are involved in several physiological and pathological processes and constitute therefore an important therapeutic target. The recent pharmacological concept of biased agonism asserts that highly selective agonists can preferentially direct receptor signaling to specific intracellular responses, opening the possibility of drugs targeting a receptor subtype in specific brain regions. The present study brings additional support to this concept thanks to functional magnetic resonance imaging (7 Tesla-fMRI) in anaesthetized rats. Three 5-HT1A receptor agonists (8-OH-DPAT, F13714 and F15599) and one 5-HT1A receptor antagonist (MPPF) were compared in terms of influence on the brain blood oxygen level-dependent (BOLD) signal. Our study revealed for the first time contrasting BOLD signal patterns of biased agonists in comparison to a classical agonist and a silent antagonist. By providing functional information on the influence of pharmacological activation of 5-HT1A receptors in specific brain regions, this neuroimaging approach, translatable to the clinic, promises to be useful in exploring the new concept of biased agonism in neuropsychopharmacology. PMID:27211078

  4. Establishment of Radiolabelling Method for the Development of Neurodegenerative Disease Imaging Agent Using 5-HT1A Subtype of Receptor Anatagonist

    The 5-HT1A subtype of receptors for the neurotransmitter serotonin is predominantly located in the limbic forebrain. And it is involved in the modulation of emotion and the function of the hypothalamus. Since 5-HT1A receptors are implicated in the pathogenesis of anxiety, depression, hallucinogenic behaviour, motion sickness and eating disorders, they are an important target for drug therapy and diagnosis of diseases. Serotonin is synthesized from the amino acid L-tryptophan by sequential hydroxylation and decarboxylation. It is stored in presynaptic vesicles and released from nerve terminals during neuronal firing. One of the best-characterised binding sites for serotonin is the 5-HT1A receptor. This is mainly due to the relatively early discovery of a selective ligand, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) for this subpopulation. Thus, many researchers have tried to develop a radioligand capable of assessing in vivo changes in 5-HT1A receptors in depressed subjects, people with anxiety disorders, patients with Alzheimer's disease and schizophrenics. In present study, we studied the radioligands which would play a role in visualization and quantification of this important neuroreceptor for single-photon emission tomography (SPET)

  5. New 99mTc(CO)3(NNO) complexes in the development of 5-HT1A receptor imaging agents

    In this work we report the synthesis, characterization and biological evaluation of two new neutral tricarbonyl fac-M(CO)3(NNO) (M=Re, 99mTc) derivatives of WAY-100635 as potential 99mTc agents for the in vivo imaging of 5-HT1A receptors. The new pharmacophore NNO ligands are based on the picolylamine N,N-diacetic acid (PADA) ligand and their synthesis was achieved through the PADA anhydride, showing thus the applicability of this synthetic approach, developed in our laboratory, for the incorporation of bioactive amines in the PADA molecule and the development of target specific radiopharmaceuticals. The rhenium complexes were synthesized using [NEt4]2[Re(CO)3Br3] as a precursor and fully characterized by elemental analysis and spectroscopic methods. The analogous technetium-99m complexes were also prepared quantitatively using the [99mTc(CO)3(H2O)3]+ precursor and their structure corroborated by means of the rhenium complexes. The lipophilicity of the Tc complexes is in the range normally accepted for substances to be able to cross the BBB. Competition binding tests showed moderate affinity for the 5-HT1A receptors, with IC50 values at the nanomolar range (30 and 116 nM). Biodistribution in healthy animals was characterized by high initial blood and liver uptake and fast blood and tissue depuration with excretion taking place mainly through the hepatobiliary system. None of the new complexes showed any significant brain uptake, suggesting that the ability of a compound to cross the BBB is determined by more factors than charge, lipophilicity and size. (orig.)

  6. Potential anxiolytic properties of R-(+)-8-OSO2CF3-PAT, a 5-HT1A receptor agonist

    Barf, T; Korte, SM; KorteBouws, G; Sonesson, C; Damsma, G; Bohus, B; Wikstrom, H

    1996-01-01

    The anxiolytic property of R-(+)-8-OSO3CF3-PAT (R-(+)-8-[[(trifluoromethyl)sulfonyl]oxy]-2-(n-propyl-amino)tetralin), a 5-HT1A receptor agonist, was evaluated in Wistar rats by means of animal models of anxiety, the conditioned defensive burying model and the conditioned stress-induced freezing resp

  7. Prenatal stress alters diazepam withdrawal syndrome and 5HT1A receptor expression in the raphe nuclei of adult rats.

    Lakehayli, S; Said, N; El Khachibi, M; El Ouahli, M; Nadifi, S; Hakkou, F; Tazi, A

    2016-08-25

    Early-life events have long-term effects on brain structures and cause behavioral alterations that persist into adulthood. The present experiments were designed to investigate the effects of prenatal stress on diazepam-induced withdrawal syndrome and serotonin-1A (5HT1A) receptor expression in the raphe nuclei of adult offspring. The results of the present study reveal that maternal exposure to chronic footshock stress increased the anxiety-like behavior in the prenatally stressed (PS) animals withdrawn from chronic diazepam (2.5mg/kg/day i.p for 1week). Moreover, prenatal stress induced a down-regulation of 5HT1A mRNA in the raphe nuclei of adult offspring. To our knowledge, this study is the first to demonstrate that maternal exposure to chronic footshock stress enhances diazepam withdrawal symptoms and alters 5HT1A receptor gene expression in the raphe nuclei of adult offspring. Thus, more studies are needed to clarify the mechanisms underlying the decrease of 5HT1A receptors expression in the raphe nuclei of PS rats. PMID:27235743

  8. 5-HT1A/7 receptor agonist excites cardiac vagal neurons via inhibition of both GABAergic and glycinergic inputs

    Yong-hua CHEN; Li-li HOU; Ji-jiang WANG

    2008-01-01

    Aim: To study the synaptic mechanisms involved in the 5-hydroxytryptaminel AF/7 (5-HT1A/7) receptor-mediated reflex control of cardiac vagal preganglionic neurons (CVPN). Methods: CVPN were retrogradely labeled and identified in brain stem slices of newborn rats, and their synaptic activity was examined using whole-cell patch-clamp. Results: 8-Hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), an agonist of 5-HT1A/7 receptors, had no effect on the glutamatergic inputs of CVPN. In contrast, it significantly decreased the frequency and the amplitude of both the GABAergic and the glycinergic spontaneous inhibitory postsynaptic currents (slPSC). 8-OH-DPAT also caused significant amplitude decrease of the GABAergic currents evoked by stimulation of the nucleus tractus solitarius. Both the fre-quency inhibition and the amplitude inhibition of the GABAergic and the glycinergic sIPSC by 8-OH-DPAT had dose-dependent tendencies and could be reversed by WAY-100635, an antagonist of 5-HT1A/7 receptors. In the pre-exist-ence of tetrodotoxin, 8-OH-DPAT had no effect on the GABAergic or the glycinergic miniature inhibitory postsynaptic currents, and had no effect on the GABAergic or the glycinergic currents evoked by exogenous GABA or glycine. Conclusion:The 5-HT1A/7 receptor agonist excites CVPN indirectly via the inhibition of both the GABAergic and glycinergic inputs. These findings have at least in part re-vealed the synaptic mechanisms involved in the 5-HT1A/7 receptor-mediated reflex control of cardiac vagal nerves in intact animals.

  9. Changes in 5-HT2A-mediated behavior and 5-HT2A- and 5-HT1A receptor binding and expression in conditional brain-derived neurotrophic factor knock-out mice

    Klein, A B; Santini, M A; Aznar, S;

    2010-01-01

    )R binding was reflected in reduced functional output in two 5-HT(2A)-receptor mediated behavioral tests, the head-twitch response (HTR) and the ear-scratch response (ESR). BDNF(2L/2LCk-cre) mutants treated with the 5-HT(2A) receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) showed a clearly...

  10. HBK-7 - A new xanthone derivative and a 5-HT1A receptor antagonist with antidepressant-like properties.

    Pytka, Karolina; Kazek, Grzegorz; Siwek, Agata; Mordyl, Barbara; Głuch-Lutwin, Monika; Rapacz, Anna; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara; Zygmunt, Małgorzata

    2016-01-01

    Xanthone derivatives possess many biological properties, including neuroprotective, antioxidant or antidepressant-like. In this study we aimed to investigate antidepressant- and anxiolytic-like properties of a new xanthone derivative - 6-methoxy-4-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-7), as well as its possible mechanism of action, and the influence on cognitive and motor function. HBK-7 in our earlier studies showed high affinity for serotonergic 5-HT1A receptor. We determined the affinity of HBK-7 for CNS receptors and transporters using radioligand assays and examined its intrinsic activity towards 5-HT1A receptor. We evaluated antidepressant- and anxiolytic-like activity of HBK-7 in the mouse forced swim test, and four-plate test, respectively. We examined the influence on locomotor activity in mice to determine if the effect observed in the forced swim test was specific. We used step-through passive avoidance and rotarod tests to evaluate the influence of HBK-7 on cognitive and motor function, respectively. HBK-7 showed moderate affinity for dopaminergic D2 receptor and very low for serotonergic 5-HT2A, adrenergic α2 receptors, as well as serotonin transporter. Functional studies revealed that HBK-7 was a 5-HT1A receptor antagonist. HBK-7 (10mg/kg) decreased immobility time in the forced swim test. Combined treatment with sub-effective doses of HBK-7 and fluoxetine reduced immobility of mice in the forced swim test. Pretreatment with p-chlorophenylalanine and WAY-100,635 antagonized the antidepressant-like effect of HBK-7. Neither of the treatments influenced locomotor activity of mice. HBK-7 at antidepressant-like dose did not impair memory or motor coordination in mice. We demonstrated that HBK-7 was a 5-HT1A receptor antagonist with potent, comparable to mianserin, antidepressant-like activity. HBK-7 mediated its effect through serotonergic system and its antidepressant-like action required the activation of 5-HT1A receptors. At active

  11. Uncoupling of 5-HT1A receptors in the brain by estrogens: regional variations in antagonism by ICI 182,780.

    Mize, A L; Young, L J; Alper, R H

    2003-04-01

    Previously we have shown that 17beta-estradiol (in vivo and in vitro) rapidly decreases the function of serotonin(1A) (5-HT(1A)) receptors, allowing us to hypothesize that 17beta-estradiol accomplished this via activation of a membrane estrogen receptor. Hippocampus and frontal cortex obtained from ovariectomized rats were incubated with 17beta-estradiol or bovine serum albumin (BSA)-estradiol in the presence or absence of the estrogen receptor (ER) antagonist ICI 182,780. Membranes were prepared to measure R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding (a measure of 5-HT(1A) receptor coupling and function). In both hippocampus and frontal cortex, 17beta-estradiol and BSA-estradiol (50 nM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 blocked the effect of both the estrogens in hippocampus, but only the effect of 17beta-estradiol in frontal cortex. Due to the inability of ICI 182,780 to block the effects of BSA-estradiol in frontal cortex, similar experiments were performed using the selective estrogen receptor modulator tamoxifen as the agonist. Tamoxifen (100 nM and 1 microM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 (1 microM) blocked the ability of tamoxifen to decrease 5-HT(1A) receptor coupling in the hippocampus, but not in the frontal cortex. Taken together, these data support the existence of a pharmacologically distinct ER in hippocampus vs. frontal cortex that might be responsible for rapid uncoupling of 5-HT(1A) receptors. PMID:12668044

  12. Rivastigmine improves hippocampal neurogenesis and depression-like behaviors via 5-HT1A receptor stimulation in olfactory bulbectomized mice.

    Islam, M R; Moriguchi, S; Tagashira, H; Fukunaga, K

    2014-07-11

    Rivastigmine is a non-competitive inhibitor of both acetylcholinesterase (AChE) and butylcholinesterase (BuChE) used to treat mild to moderate dementia in Alzheimer's disease (AD) patients. Although rivastigmine reportedly ameliorates cognitive dysfunction in these patients, its ability to improve Behavioral and Psychological Symptoms of Dementia (BPSD) remains unclear. To determine whether rivastigmine treatment antagonizes depression-like behaviors, we chronically administered rivastigmine (0.1-1.0mg/kg) to olfactory bulbectomized (OBX) mice once a day for 2weeks, starting 2weeks after bulbectomy. Chronic treatment at 0.3 or 1.0mg/kg dose dependently and significantly improved depression-like behaviors, as assessed by tail suspension (TST), forced swim (FST), locomotion and novelty-suppressed feeding (NSFT) tests. Importantly, co-administration with WAY-100635 (1.0mg/kg), a 5-HT1A receptor antagonist, but not ketanserin (1.0mg/kg,), a 5-HT2A receptor antagonist, completely blocked rivastigmine-induced anti-depressive effects, suggesting that 5-HT1A receptor stimulation mediates this activity. Consistent with this observation, rivastigmine treatment significantly rescued impaired neurogenesis observed in OBX mice in a 5-HT1A receptor-dependent manner. Furthermore, enhanced protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) phosphorylation seen following rivastigmine treatment was closely associated with improved neurogenesis. These effects were blocked by WAY-100635 but not ketanserin treatment. Finally, we confirmed that 5-HT1A but not 5-HT2A receptor stimulation by specific agonists mimicked rivastigmine-induced anti-depression activity and promoted hippocampal neurogenesis. We conclude that, in addition to enhancing the cholinergic system, rivastigmine treatment restores normal function of the hippocampal serotonergic system, an activity that likely ameliorates depressive behaviors in AD patients. PMID:24797332

  13. Layer II/III of the prefrontal cortex: inhibition by the serotonin 5-HT1A receptor in development and stress

    Goodfellow, Nathalie M.; Benekareddy, Madhurima; Vaidya, Vidita A.; Lambe, Evelyn K.

    2009-01-01

    The modulation of the prefrontal cortex by the neurotransmitter serotonin (5-HT) is thought to play a key role in determining adult anxiety levels. Layer II/III of the prefrontal cortex, which mediates communication across cortical regions, displays a of high level 5-HT1A receptor binding in normal individuals and a significantly lower level in patients with mood and anxiety disorders. Here, we examine how serotonin modulates pyramidal neurons in layer II/III of the rat prefrontal cortex thro...

  14. Effects of dominance status on conditioned defeat and expression of 5-HT1A and 5-HT2A receptors

    Morrison, Kathleen E.; Swallows, Cody L.; Cooper, Matthew A.

    2011-01-01

    Past experience can alter how individuals respond to stressful events. The brain serotonin system is a key factor modulating stress-related behavior and may contribute to individual variation in coping styles. In this study we investigated whether dominant and subordinate hamsters respond differently to social defeat and whether their behavioral responses are associated with changes in 5-HT1A and 5-HT2A receptor immunoreactivity in several limbic brain regions. We paired weight-matched hamste...

  15. Serotonin Transporter Genotype Affects Serotonin 5-HT1A Binding in Primates

    Christian, Bradley T; Wooten, Dustin W.; Hillmer, Ansel T; Tudorascu, Dana L.; Converse, Alexander K.; Moore, Colleen F.; Ahlers, Elizabeth O.; Barnhart, Todd E; Kalin, Ned H.; Barr, Christina S.; Schneider, Mary L.

    2013-01-01

    Disruption of the serotonin system has been implicated in anxiety and depression and a related genetic variation has been identified that may predispose individuals for these illnesses. The relationship of a functional variation of the serotonin transporter promoter gene (5-HTTLPR) on serotonin transporter binding using in vivo imaging techniques have yielded inconsistent findings when comparing variants for short (s) and long (l) alleles. However, a significant 5-HTTLPR effect on receptor bi...

  16. Is the anxiolytic-like effect of acute 8-0H-DPAT mediated by 5-HT1A receptors? O efeito ansiolítico do 8-OH-DPAT é mediado por receptores 5-HT1A?

    Marcos Alberto Trombelli

    1998-07-01

    Full Text Available Para estudar o papel dos receptores 5-HT1A na ansiedade, realizamos uma curva dose-efeito com o agonista pleno de receptores 5HT1A administrado em ratos expostos ao labirinto em cruz elevado. A dose de 0,5mg/kg (IP de 8-OH-DPAT aumentou significativamente a porcentagem de entradas e de tempo dispendido nos braços abertos. Esses resultados são indicativos de efeito ansiolítico. O número total de entradas nos braços fechados, que é um índice de atividade locomotora, também foi significativamente aumentado. Nenhuma alteração significativa foi verificada com a administração (IP da dose mais baixa (0,25mg/kg ou da dose mais alta (1,0mg/kg do 8-OH-DPAT. Contrastantemente, a administração de 2,0mg/kg (IP de diazepam produziu um efeito ansiolítico similar, mas não afetou a locomoção. O pré-tratamento com 1,0mg/kg do WAY 100135 não antagonizou os efeitos obtidos com a administração de 0,5mg/kg do 8-OH-DPAT sobre os índices de ansiedade e locomoção. Esses resultados demonstram que o 8-OH-DPAT produziu um efeito ansiolítico e estimulante de atividade locomotora no labirinto em cruz elevado. Entretanto, estes efeitos não parecem ser mediados por receptores 5-HT1A.In the study of the role of 5-HT1A receptors in anxiety, dose-effect curve for the full 5-HT1A receptor agonist 8-OH-DPAT was determined in rats exploring the elevated plus-maze. Dose of 0.5mg/kg, IP, of 8-OH-DPAT significantly increased the percentage of open arm entries and of time spent on the open arms, displaying an anxiolytic effect. Total number of entries into the enclosed arms, an index of locomotion, was also significantly increased. A lower (0.25mg/kg and a higher dose (1.0mg/kg of 8-OH-DPAT were ineffective. Contrastly, 2.0mg/kg, IP, of diazepam had a similar anxiolytic effect, but did not affect locomotion. The pretreatment with 1.0mg/kg of WAY 100135 did not antagonize the effects of 0.5mg/kg of 8-OH-DPAT on the indexes of anxiety and locomotion. These

  17. Synthesis and initial biological evaluation of a novel Tc-99m radioligand as a potential agent for 5-HT1A receptor imaging

    Abdelounis, Najoua Mejri; Saied, Nadia Malek; Essouissi, Imen; Guizani, Sihem; Saidi, Mouldi [CNSTN, Sidi Thabet (Tunisia). Research Unit of Medical, Agricultural and Environmental Use of Nuclear Applications

    2014-09-01

    The synthesis, characterization and biological evaluation of N-Tolueneferrocenecarboxamide labeled with technetium-99m ({sup 99m}Tc-TTCC) is reported. Biological studies in Wistar rats showed the ability of {sup 99m}Tc-TPCC to cross the intact blood-brain barrier. In vivo biodistribution indicated that this complex had good brain uptake (1.32%ID/g at 5 min and 0.64%ID/g at 60 min) and good retention (about 50% of the activity was retained in the brain at 60 min post-injection). Regional brain distribution study showed that hippocampus, where the 5-HT1A receptor density is high, had the highest uptake (0.73%ID/g at 5 min p.i.) and the cerebellum, where the 5-HT1A receptor density is low, had the lowest uptake (0.12%ID/gID/g at 5 min p.i.). After blocking with 8-hydroxy-2-(dipropylamino) tetralin, the uptake of hippocampus was decreased significantly from 0.73%ID/g to 0.20%ID/g at 5 min p.i., while the cerebellum had no significant decrease. This result indicates that 99mTc complex has specific binding to 5-HT1A receptor. (orig.)

  18. Synthesis and initial biological evaluation of a novel Tc-99m radioligand as a potential agent for 5-HT1A receptor imaging

    The synthesis, characterization and biological evaluation of N-Tolueneferrocenecarboxamide labeled with technetium-99m (99mTc-TTCC) is reported. Biological studies in Wistar rats showed the ability of 99mTc-TPCC to cross the intact blood-brain barrier. In vivo biodistribution indicated that this complex had good brain uptake (1.32%ID/g at 5 min and 0.64%ID/g at 60 min) and good retention (about 50% of the activity was retained in the brain at 60 min post-injection). Regional brain distribution study showed that hippocampus, where the 5-HT1A receptor density is high, had the highest uptake (0.73%ID/g at 5 min p.i.) and the cerebellum, where the 5-HT1A receptor density is low, had the lowest uptake (0.12%ID/gID/g at 5 min p.i.). After blocking with 8-hydroxy-2-(dipropylamino) tetralin, the uptake of hippocampus was decreased significantly from 0.73%ID/g to 0.20%ID/g at 5 min p.i., while the cerebellum had no significant decrease. This result indicates that 99mTc complex has specific binding to 5-HT1A receptor. (orig.)

  19. [3H]WB4101 labels the 5-HT1A serotonin receptor subtype in rat brain. Guanine nucleotide and divalent cation sensitivity

    In the presence of a 30 nM prazosin mask, [3H]-2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1,4-benzodioxane ([3H]WB4101) can selectively label 5-HT1 serotonin receptors. Serotonin exhibits high affinity (Ki = 2.5 nM) and monophasic competition for [3H] WB4101 binding in cerebral cortex. We have found a significant correlation (r = 0.96) between the affinities of a number of serotonergic and nonserotonergic compounds at [3H]WB4101-binding sites in the presence of 30 nM prazosin and [3H] lysergic acid diethylamide ([3H]LSD)-labeled 5-HT1 serotonin receptors in homogenates of rat cerebral cortex. Despite similar pharmacological profiles, distribution studies indicate that, in the presence of 5 mM MgSO4, the Bmax of [3H]WB4101 is significantly lower than the Bmax of [3H]LSD in various brain regions. WB4101 competition for [3H] LSD-labeled 5-HT1 receptors fits best to a computer-derived model assuming two binding sites, with the KH for WB4101 being similar to the KD of [3H]WB4101 binding derived from saturation experiments. This suggests that [3H]WB4101 labels only one of the subtypes of the 5-HT1 serotonin receptors labeled by [3H]LSD. The selective 5-HT1A serotonin receptor antagonist, spiperone, and the selective 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino) tetraline, exhibit high affinity and monophasic competition for [3H]WB4101 but compete for multiple [3H]LSD 5-HT1 binding sites. These data indicate that [3H]WB4101 selectively labels the 5-HT1A serotonin receptor, whereas [3H] LSD appears to label both the 5-HT1A and the 5-HT1B serotonin receptor subtypes. The divalent cations, Mn2+, Mg2+, and Ca2+ were found to markedly increase the affinity and Bmax of [3H]WB4101 binding in cerebral cortex. Conversely, the guanine nucleotides guanylylimidodiphosphate and GTP, but not the adenosine nucleotide ATP, markedly reduce the Bmax of [3H]WB4101 binding

  20. 5-HT1A receptors mediate the effect of the bulbospinal serotonin system on spinal dorsal horn nociceptive neurons.

    Zemlan, F P; Murphy, A Z; Behbehani, M M

    1994-01-01

    The present study examined whether the effect of stimulation of the nucleus raphe magnus (NRM) is mediated by spinal cord dorsal horn serotonin1A (5-HT1A) receptors in the rat. This hypothesis predicts that nociceptive dorsal horn units inhibited by NRM stimulation or iontophoretic 5-HT application would also be inhibited by iontophoresis of the selective 5-HT1A agonists 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and buspirone. A total of 78 dorsal horn wide-dynamic-range neurons were recorded. Overall, 62% of the cells tested (48/78) were responsive to electrical stimulation of the NRM with the predominant response being inhibitory (38/48; 79%). Fifty-eight cells were tested for their response to both NRM stimulation and 8-OH-DPAT iontophoresis: 20/58 cells were inhibited by NRM stimulation and 50% of the cells inhibited by NRM stimulation were also inhibited by 8-OH-DPAT. Fifty-two cells were tested for their response to both NRM stimulation and buspirone iontophoresis: 14/52 cells were inhibited by NRM stimulation with 9/14 similarly inhibited by buspirone. To examine whether exogenously applied serotonin produced an effect through 5-HT1A receptors, the effect of both 5-HT and 8-OH-DPAT iontophoresis was tested on 57 dorsal horn neurons. The majority of cells (25/57) were inhibited by 5-HT application; 15/25 were similarly inhibited by 8-OH-DPAT. The response of 48 dorsal horn cells to 5-HT and buspirone iontophoresis was compared. Forty-four percent (21/48) of the cells were inhibited by 5-HT; 16/21 were also inhibited by buspirone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8309982

  1. Alternative methods of making [11C]amides: Application to the preparation of 5-HT1A receptor radioligands

    Many ligands for brain 5-HT1A receptors contain an amide group that is subject to hydrolysis in vivo. In the development of radioligands for use with positron emission tomography (PET), labelling in the carbonyl function of an amide group may be advantageous for avoiding radioactive metabolites that would readily enter the brain to confound PET receptor measurements. Several methods of labelling secondary and tertiary amides in their carbonyl functions with 11C (T1/2 = 20.4 min) have been developed over the past two decades or so. These methods include reaction of a [carbonyl-11C]acid chloride, [carboxyl-11C]magnesium halide carboxylate or [carboxyl-11C]acid with an amine or reaction of [11C]carbon monoxide with an amine plus an aryl halide, alkyl halide or aryl triflate. Some of these processes are successfully promoted with microwaves, palladium complexes, light or thermally initiated radicals. These methods are surveyed here and especially exemplified from research on the development of 5-HT1A receptor radioligands for brain imaging applications with PET. (author)

  2. Rational planning of antagonist analogues for imaging serotonin 5-HT1A receptor subtypes based on 99mTc

    Rational planning follows some logical steps in order to reduce the probability of synthesizing chemical compounds that possess low performance. The first step of this kind of procedure is to collect the maximum amount of information available in databases and the literature. Data are normally collected about quantitative structure activity and quantitative structure property studies. The goal is achieved when the main molecular descriptor is discovered in terms of biological activity. This descriptor is then quantified, allowing the choice of the most promising molecular candidates. In this paper, the aim is to convert molecules with high 5-HT1A affinity to 99mTc derivatives. Once such derivatives have to retain receptor affinity, it is very important to find drug-receptor interactions due to: chemical groups with common drug structures, the existence of intra-atomic distances between chemical ligands and physico-chemical properties that drive drug-receptor complexation. (author)

  3. A role for 5-HT1A receptors in the basolateral amygdala in the development of conditioned defeat in Syrian hamsters

    Morrison, Kathleen E.; Cooper, Matthew A.

    2011-01-01

    The basolateral nucleus of the amygdala (BLA) is a key brain region regulating behavioral changes following stressful events, including social defeat. Previous research has shown that activation of serotonin (5-HT) 1A receptors in the BLA reduces conditioned fear and anxiety-like behavior. The objective of this study was to test whether 5-HT1A receptors in the BLA contribute to conditioned defeat in male Syrian hamsters (Mesocricetus auratus). We tested whether injection of the selective 5-HT...

  4. Effects of repeated treatment with fluoxetine and citalopram, 5-HT uptake inhibitors, on 5-HT1A and 5-HT2 receptors in the rat brain.

    Klimek, V; Zak-Knapik, J; Mackowiak, M.

    1994-01-01

    Repeated treatment with fluoxetine and citalopram, which are potent 5-HT reuptake inhibitors, resulted in different regulation of 5-HT1A and 5-HT2 receptors in the rat brain. Their effects were compared with those of other antidepressants: imipramine, mianserin and levoprotiline. The density of 5-HT1A receptors, labelled with [3H]8-OH-DPAT, in the rat hippocampus was enhanced after citalopram, imipramine, mianserin and levoprotiline, but not altered after fluoxetine administration. [3H]Ketans...

  5. Chemoproteomic Approach to Explore the Target Profile of GPCR ligands: Application to 5-HT1A and 5-HT6 Receptors.

    Gamo, Ana M; González-Vera, Juan A; Rueda-Zubiaurre, Ainoa; Alonso, Dulce; Vázquez-Villa, Henar; Martín-Couce, Lidia; Palomares, Óscar; López, Juan A; Martín-Fontecha, Mar; Benhamú, Bellinda; López-Rodríguez, María L; Ortega-Gutiérrez, Silvia

    2016-01-22

    Determination of the targets of a compound remains an essential aspect in drug discovery. A complete understanding of all binding interactions is critical to recognize in advance both therapeutic effects and undesired consequences. However, the complete polypharmacology of many drugs currently in clinical development is still unknown, especially in the case of G protein-coupled receptor (GPCR) ligands. In this work we have developed a chemoproteomic platform based on the use of chemical probes to explore the target profile of a compound in biological systems. As proof of concept, this methodology has been applied to selected ligands of the therapeutically relevant serotonin 5-HT1A and 5-HT6 receptors, and we have identified and validated some of their off-targets. This approach could be extended to other drugs of interest to study the targeted proteome in disease-relevant systems. PMID:26560738

  6. Parametric mapping of 5HT1A receptor sites in the human brain with the Hypotime method: theory and normal values

    Møller, Mette; Rodell, Anders; Gjedde, Albert

    2009-01-01

    The radioligand [carbonyl-(11)C]WAY-100635 ((11)C-WAY) is a PET tracer of the serotonin 5HT(1A) receptors in the human brain. It is metabolized so rapidly in the circulation that it behaves more as a chemical microsphere than as a tracer subject to continuous exchange between the circulation and...... brain tissue. Although reference tissue methods are useful as analyses of uptake of some radioligands with indeterminate arterial input functions, their use to analyze (11)C-WAY uptake and binding is challenged by the rapid plasma metabolism, which violates the assumption that regions of interest and...... analysis. METHODS: A total of 19 healthy volunteers (age range, 23-73 y) underwent PET to test the Hypotime application of the chemical microsphere properties of (11)C-WAY to identify regions of binding and nonbinding on the exclusive basis of the rate of washout of (11)C-WAY. RESULTS: The results of the...

  7. 125I-BH-8-MeO-N-PAT, a new ligand for studying 5-HT1A receptors in the central nervous system

    Specific radioactive ligands are needed for studying the pharmacological properties and the regional distribution of the different classes of 5-HT1 receptors within the central nervous system. We describe here the synthesis and some characteristics of the first iodinated specific ligand of 5-HT1A receptors. Like its parent compound, the agonist 8-hydroxy-2-(di-n-propylamino)tetralin or 8-OH-DPAT, [125I]-BH-8-MeO-N-PAT, exhibits a high affinity and excellent selectivity for 5-HT1A sites. Its high specific radioactivity makes this ligand a useful tool for studying 5-HT1A receptors in membranes and sections of the rat brain

  8. Characterization of potent and selective antagonists at postsynaptic 5-HT1A receptors in a series of N4-substituted arylpiperazines.

    Peglion, J L; Canton, H; Bervoets, K; Audinot, V; Brocco, M; Gobert, A; Le Marouille-Girardon, S; Millan, M J

    1995-09-29

    Benzocycloalkyl and benzocycloalkenyl moities linked, directly or via an alkyl chain, to oxygen-bearing heteroarylpiperazines were synthesized, in an attempt to obtain potent and selective antagonists at postsynaptic 5-HT1A receptors. From the numerous arylpiperazines described in the literature, 1-(2,3-dihydro-1,4-benzodioxin-5-yl)piperazine (3a) was chosen as a model of an arylpiperazine in view of its selectivity for 5-HT1A receptors versus alpha 1-, alpha 2-, and beta-adrenergic receptors, as well as dopamine D1 and D2 receptors. Two other closely-related arylpiperazines, 1-(1,5-benzodioxepin-6-yl)piperazine (3b) and 1-(benzofuran-7-yl)piperazine (3c), were also examined in this study. All compounds showed high affinity at 5-HT1A sites (8.10 pKis 10-fold selectivity in vitro for 5-HT1A versus alpha 1-adrenergic receptors. Compound 14 displayed an optimal compromise between potency (pKi = 8.75), marked antagonist activity, and selectivity toward alpha 1-adrenergic (81-fold) and dopamine D2 (195-fold) receptors. These characteristics clearly distinguish 14 from previously-reported ligands such as the postsynaptic 5-HT1A antagonist BMY 7378 and the weak partial agonist NAN 190 which, in contrast to the compounds of this series, belong to the well-exemplified class of imido derivatives of (o-methoxyphenyl)piperazines. The availability of 14 (S 15535) should facilitate the further elucidation of the functional role and potential therapeutic significance of 5-HT1A receptors. PMID:7562940

  9. TREK1 channel blockade induces an antidepressant-like response synergizing with 5-HT1A receptor signaling.

    Ye, Dongqing; Li, Yang; Zhang, Xiangrong; Guo, Fei; Geng, Leiyu; Zhang, Qi; Zhang, Zhijun

    2015-12-01

    Current antidepressants often remain the inadequate efficacy for many depressive patients, which warrant the necessary endeavor to develop the new molecules and targets for treating depression. Recently, the two-pore domain potassium channel TREK1 has been implicated in mood regulation and TREK-1 antagonists could be the promising antidepressant. This study has screened a TREK1 blocker (SID1900) with a satisfactory blood-brain barrier permeation and bioavailability. Electrophysiological research has shown that SID1900 and the previously reported TREK1 blocker (spadin) efficiently blocked TREK-1 current in HEK293 cells and specifically blocked two-pore domain potassium channels in primary-cultured rat hippocampal neurons. SID1900 and spadin induced a significant antidepressant-like response in the rat model of chronic unpredictable mild stress (CUMS). Both two TREK1 blockers substantially increased the firing rate of 5-HT-ergic neurons in the dorsal raphe nuclei (DRN) and PFC of CUMS rats. SID1900 and spadin significantly up-regulated the expression of PKA-pCREB-BDNF signaling in DRN, hippocampus and PFC of CUMS rats, which were enhanced and reversed by a 5-HTR1A agonist (8-OH-DPAT) and antagonist (WAY100635) respectively. The present findings suggested that TREK1 channel blockers posses the substantial antidepressant-like effect and have the potential synergistic effect with 5-HT1A receptor activation through the common CREB-BDNF signal transduction. PMID:26441141

  10. Chronic mild stress and antidepressant treatment alter 5-HT1A receptor expression by modifying DNA methylation of a conserved Sp4 site.

    Le François, Brice; Soo, Jeremy; Millar, Anne M; Daigle, Mireille; Le Guisquet, Anne-Marie; Leman, Samuel; Minier, Frédéric; Belzung, Catherine; Albert, Paul R

    2015-10-01

    The serotonin 1A receptor (5-HT1A), a critical regulator of the brain serotonergic tone, is implicated in major depressive disorder (MDD) where it is often found to be dys-regulated. However, the extent to which stress and antidepressant treatment impact 5-HT1A expression in adults remains unclear. To address this issue, we subjected adult male BALB/c mice to unpredictable chronic mild stress (UCMS) to induce a depression-like phenotype that was reversed by chronic treatment with the antidepressant imipramine. In prefrontal cortex (PFC) and midbrain tissue, UCMS increased 5-HT1A RNA and protein levels, changes that are expected to decrease the brain serotonergic activity. The stress-induced increase in 5-HT1A expression was paralleled by a specific increase in DNA methylation of the conserved -681 CpG promoter site, located within a Sp1-like element. We show that the -681 CpG site is recognized and repressed by Sp4, the predominant neuronal Sp1-like factor and that Sp4-induced repression is attenuated by DNA methylation, despite a stress-induced increase in PFC Sp4 levels. These results indicate that adult life stress induces DNA methylation of a conserved promoter site, antagonizing Sp4 repression to increase 5-HT1A expression. Chronic imipramine treatment fully reversed the UCMS-induced increase in methylation of the -681 CpG site in the PFC but not midbrain of stressed animals and also increased 5-HT1A expression in the PFC of control animals. Incomplete reversal by imipramine of stress-induced changes in 5-HT1A methylation and expression indicates a persistence of stress vulnerability, and that sustained reversal of behavioral impairments may require additional pathways. PMID:26188176

  11. The Antidepressant-Like Effect of Fish Oil: Possible Role of Ventral Hippocampal 5-HT1A Post-synaptic Receptor.

    Carabelli, Bruno; Delattre, Ana Marcia; Pudell, Claudia; Mori, Marco Aurélio; Suchecki, Deborah; Machado, Ricardo B; Venancio, Daniel Paulino; Piazzetta, Sílvia Regina; Hammerschmidt, Ivilim; Zanata, Sílvio M; Lima, Marcelo M S; Zanoveli, Janaína Menezes; Ferraz, Anete Curte

    2015-08-01

    The pathophysiology of depression is not completely understood; nonetheless, numerous studies point to serotonergic dysfunction as a possible cause. Supplementation with fish oil rich docosahexaenoic (DHA) and eicosapentaenoic acids (EPA) during critical periods of development produces antidepressant effects by increasing serotonergic neurotransmission, particularly in the hippocampus. In a previous study, the involvement of 5-HT1A receptors was demonstrated and we hypothesized that fish oil supplementation (from conception to weaning) alters the function of post-synaptic hippocampal 5-HT1A receptors. To test this hypothesis, female rats were supplemented with fish oil during habituation, mating, gestation, and lactation. The adult male offspring was maintained without supplementation until 3 months of age, when they were subjected to the modified forced swimming test (MFST) after infusion of vehicle or the selective 5-HT1A antagonist, WAY100635, and frequency of swimming, immobility, and climbing was recorded for 5 min. After the behavioral test, the hippocampi were obtained for quantification of serotonin (5-HT) and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA) and for 5-HT1A receptor expression by Western blotting analysis. Fish oil-supplemented offspring displayed less depressive-like behaviors in the MFST reflected by decreased immobility and increased swimming and higher 5-HT hippocampal levels. Although there was no difference in the expression of hippocampal 5-HT1A receptors, intra-hippocampal infusion of a sub-effective dose of 8-OH-DPAT enhanced the antidepressant effect of fish oil in supplemented animals. In summary, the present findings suggest that the antidepressant-like effects of fish oil supplementation are likely related to increased hippocampal serotonergic neurotransmission and sensitization of hippocampal 5-HT1A receptors. PMID:25139282

  12. Enhanced down regulation of cortical ±-propranolol sensitive [3H]-DHA binding sites by co-administration of DMI and 5-HT1A partial agonist gepirone

    The putative interrelationship between the noradrenergic and serotonergic systems has been supported by numerous studies. Recently, Dudley et al. (1989) demonstrated significant down regulation of cortical β-adrenergic receptors by co-administration of desipramine (DMI), a norepinephrine uptake inhibitor, and the full 5-HT1A agonist 8-OH-DPAT. To this end, the effects of acute and chronic (4 and 14 day) administration of DMI, gepirone, a selective 5-HT1A post-synaptic partial agonist, as well as a combination of the two, on cortical (±)-propranolol sensitive [3H]-DHA binding sites were examined in rats. Down regulation was apparent after 4 and 14 day treatment with DMI. However, this was not the case with gepirone. Of particular importance is the demonstration of a greater magnitude of down regulation with co-administration of a greater magnitude of down regulation with co-administration of DMI and gepirone. These results suggests that alteration in rat cortical (±)-propranolol sensitive [3H]-DHA binding sites by noradrenergic uptake inhibitors can be further modulated by selective partial agonist activity at central 5-HT1A postsynaptic receptors. Further data on the co-administration of DMI and BMY 7378 (7,9-dioxo-8-[2-(4-o-methoxyphenylpiperazinyl)ethyl]-8-azaspiro[4,5]decane dihydrochloride), a weak partial agonist at postsynaptic 5-HT1A receptors, are also presented

  13. Design of a new serotonin receptor 5-HT1A imaging agent based on 99mTc

    Serotonin is one of the neurotransmitters found in the brain and mediates brain functions. It is very well known that serotonin related brain abnormalities are exerted mainly via serotonin receptors in a similar manner to other neurotransmitters found in the brain. Recently, it has also been found that serotonin is involved in Alzheimer's disease either directly or indirectly by its actions on serotonergic neurons. To understand and treat the diseases caused by abnormalities in the serotonergic system in the brain, it is certain that its mechanism of function has to be well investigated. So far several 5-HT receptors and receptor subtypes have been well characterized. Moreover, serotonin agonists and antagonists acting on specific receptors are chemically synthesized and are now available for the prevention or treatment of serotonergic related diseases. In recent years, a great demand for developing neuroimaging agents has emerged for the diagnosis of abnormal brain functions in the area of nuclear medicine. Since arylpiperazine, WAY 100635, in the present investigation, has been recognized as a highly selective ligand for the 5-HT1A receptor, it has been used for the development of brain imaging agents based on serotonin receptors. First, S,S'-bis(trityl) monoamide monoamine (MAMA-Tr2) was synthesized, followed by synthesis of an arylpiperazine ligand. The synthesis of the analogue of WAY 100635 was completed and it lead to successful labelling with 99mTc without a by-product. Deprotection of the S,S-Tr2 group of MAMA-Tr2 was efficiently conducted by incubation at 100 deg. C for 1 h under acidic conditions (pH2-3), followed by labelling with 99mTc. Its radiochemical purity was checked by high performance liquid chromatography, and a labelled compound of >99% radiochemical purity was used for an in vivo bioavailability study using a gamma ray camera. An animal biodistribution study was also conducted to ascertain the serotonergic neuronal imaging effect of 99m

  14. Chronic exercise improves repeated restraint stress-induced anxiety and depression through 5HT1A receptor and cAMP signaling in hippocampus

    Kim, Mun Hee; Leem, Yea Hyun

    2014-01-01

    [Purpose] Mood disorders such as anxiety and depression are prevalent psychiatric illness, but the role of 5HT1A in the anti-depressive effects of exercise has been rarely known yet. We investigated whether long-term exercise affected a depressive-like behavior and a hippocampal 5HT1A receptor-mediated cAMP/PKA/CREB signaling in depression mice model. [Methods] To induce depressive behaviors, mice were subjected to 14 consecutive days of restraint stress (2 hours/day). Depression-like behavio...

  15. Antagonist properties of (−)-pindolol and WAY 100635 at somatodendritic and postsynaptic 5-HT1A receptors in the rat brain

    Corradetti, Renato; Laaris, Nora; Hanoun, Naima; Laporte, Anne-Marie; Le Poul, Emmanuel; Hamon, Michel; Lanfumey, Laurence

    1998-01-01

    The aim of the present work was to characterize the 5-hydroxytryptamine1A (5-HT1A) antagonistic actions of (−)-pindolol and WAY 100635 (N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl) cyclohexane carboxamide). Studies were performed on 5-HT1A receptors located on 5-hydroxytryptaminergic neurones in the dorsal raphe nucleus (DRN) and on pyramidal cells in the CA1 and CA3 regions of the hippocampus in rat brain slices.Intracellular electrophysiological recording of CA1 pyramidal ...

  16. Targeting Dopamine D3 and Serotonin 5-HT1A and 5-HT2A Receptors for Developing Effective Antipsychotics

    Brindisi, Margherita; Butini, Stefania; Franceschini, Silvia; Brogi, Simone; Trotta, Francesco; Ros, Sindu; Cagnotto, Alfredo; Salmona, Mario; Casagni, Alice; Andreassi, Marco; Saponara, Simona; Gorelli, Beatrice; Weikop, Pia; Mikkelsen, Jens D.; Scheel-Kruger, Jorgen; Sandager-Nielsen, Karin; Novellino, Ettore; Campiani, Giuseppe; Gemma, Sandra

    2014-01-01

    Combination of dopamine D3 antagonism, serotonin 5-HT1A partial agonism, and antagonism at 5-HT2A leads to a novel approach to potent atypical antipsychotics. Exploitation of the original structure-activity relationships resulted in the identification of safe and effective antipsychotics devoid of...

  17. Preparation and biodistribution of 99mTc-tricarbonyl complex with 4-[(2-methoxyphenyl)piperazin-1-yl]-dithioformate as a potential 5-HT1A receptor imaging agent

    The goal of this study is to develop a novel 5-HT1A receptor imaging agent. 4-[(2-methoxyphenyl)piperazin-1-yl]-dithioformate (MPPDTF) was labeled with 99mTc-tricarbonyl core via dithioformate moiety in high yield (>96% by HPLC). 99mTc(CO)3-MPPDTF is a neutral and lipophilic complex, which was confirmed by paper electrophoresis and octanol/water partition coefficient (P=27.0±1.4, n=3), respectively. In vivo biodistribution indicated that this complex had moderate brain uptake (0.53±0.10% ID/g at 5 min and 0.42±0.02% ID/g at 120 min) and good retention (about 80% of the activity was retained in the brain at 120 min post-injection). Regional brain distribution study showed that hippocampus, where the 5-HT1A receptor density is high, had the highest uptake (0.60±0.02% ID/g at 5 min p.i.) and the cerebellum, where the 5-HT1A receptor density is low, had the lowest uptake (0.10±0.02% ID/g at 5 min p.i.). After blocking with 8-OH-DPAT, the hippocampus uptake was decreased obviously while the cerebellum uptake was increased slightly. This result indicates that 99mTc(CO)3-MPPDTF complex has specific binding to 5-HT1A receptor

  18. Differences in the effects of 5-HT1A receptor agonists on forced swimming behavior and brain 5-HT metabolism between low and high aggressive mice

    Veenema, AH; Cremers, TIFH; Jongsma, ME; Steenbergen, PJ; de Boer, SF; Koolhaas, JM; Jongsma, Minke E.; Koolhaas, Jaap M.

    2005-01-01

    Rationale: Male wild house- mice genetically selected for long attack latency ( LAL) and short attack latency ( SAL) differ in structural and functional properties of postsynaptic serotonergic- 1A ( 5- HT1A) receptors. These mouse lines also show divergent behavioral responses in the forced swimming

  19. Effect of Sarizotan, a 5-HT1a and D2-like receptor agonist, on respiration in three mouse models of Rett syndrome.

    Abdala, Ana P; Lioy, Daniel T; Garg, Saurabh K; Knopp, Sharon J; Paton, Julian F R; Bissonnette, John M

    2014-06-01

    Disturbances in respiration are common and debilitating features of Rett syndrome (RTT). A previous study showed that the 5-HT1a receptor agonist (R)-(+)-8-hydroxy-dipropyl-2-aminotetralin hydrobromide (8-OH-DPAT) significantly reduced the incidence of apnea and the irregular breathing pattern in a mouse model of the disorder. 8-OH-DPAT, however, is not available for clinical practice. Sarizotan, a full 5-HT1a agonist and a dopamine D2-like agonist/partial agonist, has been used in clinical trials for the treatment of l-dopa-induced dyskinesia. The purpose of this study was to evaluate the effects of sarizotan on respiration and locomotion in mouse models of RTT. Studies were performed in Bird and Jaenisch strains of methyl-CpG-binding protein 2--deficient heterozygous female and Jaenisch strain Mecp2 null male mice and in knock-in heterozygous female mice of a common nonsense mutation (R168X). Respiratory pattern was determined with body plethysmography, and locomotion was determined with open-field recording. Sarizotan or vehicle was administered 20 minutes before a 30-minute recording of respiratory pattern or motor behavior. In separate studies, a crossover design was used to administer the drug for 7 and for 14 days. Sarizotan reduced the incidence of apnea in all three RTT mouse models to approximately 15% of their pretreatment levels. The irregular breathing pattern was corrected to that of wild-type littermates. When administered for 7 or 14 days, apnea decreased to 25 to 33% of the incidence seen with vehicle. This study indicates that the clinically approved drug sarizotan is an effective treatment for respiratory disorders in mouse models of RTT. PMID:24351104

  20. 5-HT1A Receptor Activation Reduces Fear-related Behavior Following Social Defeat in Syrian Hamsters

    Bader, Lauren R.; Carboni, Joseph D.; Burleson, Cody A.; Cooper, Matthew A.

    2014-01-01

    Social defeat leads to selective avoidance of familiar opponents as well as general avoidance of novel, non-threatening intruders. Avoidance of familiar opponents represents a fear-related memory whereas generalized social avoidance indicates anxiety-like behavior. We have previously shown that serotonin signaling alters responses to social defeat in Syrian hamsters, although it is unclear whether serotonin modulates defeat-induced fear, anxiety, or both. In this study we focus on 5-HT1A rece...

  1. [18F]p-MPPF: A Radiolabeled Antagonist for the Study of 5-HT1A Receptors with PET

    This paper summarizes the present status of the researches conducted with [18F]4-(2'-methoxyphenyl)-1-[2'-[N-(2''-pyridinyl)-p-fluoro benzamido]ethyl] -piperazine known as [18F]p-MPPF, a new 5-HT1A antagonist for the study of the serotonergic neurotransmission with positron emission tomography (PET). This includes chemistry, radiochemistry, animal data (rats, cats, and monkeys) with autoradiography and PET, human data with PET, toxicity, and metabolism

  2. Enhanced effects of amphetamine but reduced effects of the hallucinogen, 5-MeO-DMT, on locomotor activity in 5-HT1A receptor knockout mice: Implications for schizophrenia

    van den Buuse, Maarten; Ruimschotel, Emma; Martin, Sally; Risbrough, Victoria B.; Halberstadt, Adam L.

    2011-01-01

    Serotonin-1A (5-HT1A) receptors may play a role in schizophrenia and the effects of certain antipsychotic drugs. However, the mechanism of interaction of 5-HT1A receptors with brain systems involved in schizophrenia, remains unclear. Here we show that 5-HT1A receptor knockout mice display enhanced locomotor hyperactivity to acute treatment with amphetamine, a widely used animal model of hyperdopaminergic mechanisms in psychosis. In contrast, the effect of MK-801 on locomotor activity, modelin...

  3. Relación del efecto analgésico de fentanilo agudo con la regulación a la alta de los receptores 5-HT1A cerebrales en la rata Relationship between the analgesic effect of acute fentanyl and upregulation of brain 5-HT1A receptors in the rat

    I. Bellido

    2004-07-01

    Full Text Available Los agonistas 5-HT1A presentan efecto analgésico. El efecto analgésico de los agonistas µ puede ser bloqueado por antagonistas selectivos 5-HT1A. Para determinar el mecanismo de producción del sinergismo observado entre los receptores µ y serotoninérgico 5-HT1A en relación con su efecto antinociceptivo, determinamos el efecto analgésico de fentanilo tras estímulo nociceptivo de tipo térmico y mecánico en la rata relacionándolo con la afinidad y la densidad máxima de los receptores 5-HT1A de trece áreas cerebrales mediante técnicas de autorradiografía. Fentanilo presentó un efecto analgésico dosis y tiempo dependiente ante los dos estímulos nociceptivos. Paralelamente a la aparición del efecto analgésico, fentanilo originó una regulación a la alta de los receptores 5-HT1A al incrementar de forma dosis-dependiente su densidad sin modificar su afinidad. La dosis mayor de fentanilo (12,8 µg.kg-1 originó un incremento de la densidad de los receptores 5-HT1A estadísticamente significativo y que se correlacionó de forma positiva con su efecto analgésico en las áreas terminales corticales fronto-parietal externa (+64%, interna (+69% y piriforme (+113%, las regiones del hipocampo CA1 (+111% y DGm (+60%, los núcleos amigdalinos PMCo (+101% y AHiAL (+91% y el hipotálamo (+127%. El efecto analgésico de fentanilo en tratamiento agudo se explicaría, al menos, por dos mecanismos. Su capacidad de estimular la neurotransmisión opiácea actuando directamente sobre los receptores opiáceos µ. Y porque, al incrementar los niveles de 5-HT a nivel central y al regular a la alta los receptores 5-HT1A de zonas cerebrales terminales, se facilitaría la estimulación de estos receptores. Dado que los receptores 5-HT1A postsinápticos actúan como heteroreceptores de efecto inhibidor sobre neuronas no serotoninérgicas originando una hiperpolarización neuronal, fentanilo, al facilitar el estímulo de estos receptores originaría una

  4. Synthesis and biological evaluation of technetium(III) mixed-ligand complexes with high affinity for the cerebral 5-HT1A receptor and the alpha1-adrenergic receptor

    Tc(III) and Re(III) complexes [M(NS3)(CNR)] (M=Re, 99mTc, NS3=2,2',2''-nitrilotris(ethanethiol), CNR = functionalized isocyanide bearing a derivative of WAY 100635) have been synthesized and characterized. Re was used as Tc surrogate for chemical characterization and in vitro receptor-binding studies. For two representatives subnanomolar affinities for the 5-HT1A as well as for the alpha1-adrenergic receptor were reached. Biodistribution studies in rats of the 99mTc complexes showed brain uptakes between 0.3 and 0.5% ID/organ (5 min p.i.). In vitro autoradiography of one 99mTc representative in sections of post mortem human brain indicate its accumulation in 5-HT1A receptor-rich brain regions. However, addition of the specific 5-HT1A receptor agonist 8-OH-DPAT as well as the alpha1-adrenoceptor antagonist prazosin could not substantially block this tracer accumulation. A preliminary SPET study in a monkey showed negligible brain uptake

  5. Food restriction and streptozotocin treatment decrease 5-HT1A and 5-HT2A receptor mediated behavioral effects in rats

    Li, Jun-Xu; France, Charles P.

    2008-01-01

    Food restriction and hypoinsulinemia can affect the synthesis, turnover and receptor function of serotonin (5-HT) in brain. This study explored the effects of food restriction and streptozotocin treatment on behavioral effects related to 5-HT1A (8-OH-DPAT) and 5-HT2A (DOI) receptor activation. Lower lip retraction and flat body posture (8-OH-DPAT) and head twitching (DOI) were measured in rats during free feeding, food restriction, after treatment with streptozotocin, and finally after insuli...

  6. Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

    Sonego, Andreza B; Gomes, Felipe V; Del Bel, Elaine A; Guimaraes, Francisco S

    2016-08-01

    Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant. Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic. In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol. To further investigate this latter effect, we tested whether CBD (15-60mg/kg) would attenuate the catalepsy and c-Fos protein expression in the dorsal striatum induced by haloperidol (0.6mg/kg). We also evaluated if these effects occur through the facilitation of 5-HT1A receptor-mediated neurotransmission. For this, male Swiss mice were treated with CBD and haloperidol systemically and then subjected to the catalepsy test. Independent groups of animals were also treated with the 5-HT1A receptor antagonist WAY100635 (0.1mg/kg). As expected, haloperidol induced catalepsy throughout the experiments, an effect that was prevented by systemic CBD treatment 30min before haloperidol administration. Also, CBD, administered 2.5h after haloperidol, reversed haloperidol-induced catalepsy. Haloperidol also increased c-Fos protein expression in the dorsolateral striatum, an effect attenuated by previous CBD administration. CBD effects on catalepsy and c-Fos protein expression induced by haloperidol were blocked by the 5-HT1A receptor antagonist. We also evaluated the effects of CBD (60nmol) injection into the dorsal striatum on haloperidol-induced catalepsy. Similar to systemic administration, this treatment reduced catalepsy induced by haloperidol. Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT1A receptors. PMID:27131780

  7. Interaction between a selective 5-HT1A receptor antagonist and an SSRI in vivo: effects on 5-HT cell firing and extracellular 5-HT.

    Gartside, S E; Umbers, V; Hajós, M.; Sharp, T.

    1995-01-01

    1. The acute inhibitory effect of selective 5-hydroxytryptamine (serotonin) reuptake inhibitors (SSRIs) on 5-HT neuronal activity may offset their ability to increase synaptic 5-HT in the forebrain. 2. Here, we determined the effects of the SSRI, paroxetine, and a novel selective 5-HT1A receptor antagonist, WAY 100635, on 5-HT cell firing in the dorsal raphé nucleus (DRN), and on extracellular 5-HT in both the DRN and the frontal cortex (FCx). Extracellular electrophysiological recording and ...

  8. Escitalopram attenuates β-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway.

    Wang, Yan-Juan; Ren, Qing-Guo; Gong, Wei-Gang; Wu, Di; Tang, Xiang; Li, Xiao-Li; Wu, Fang-Fang; Bai, Feng; Xu, Lin; Zhang, Zhi-Jun

    2016-03-22

    Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-β (Aβ)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aβ1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aβ1-42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3β pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3β pathway and decreased Aβ1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3β pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aβ1-42 induced impairment of neurite outgrowth and spine density, and reversed Aβ1-42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aβ1-42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway. PMID:26950279

  9. Radioligands for the study of brain 5-HT1A receptors in vivo-development of some new analogues of way

    [Carbonyl-11C]WAY-100635 (WAY) has proved to be a very useful radioligand for the imaging of brain 5-HT1A receptors in human brain in vivo with positron emission tomography (PET). WAY is now being applied widely for clinical research and drug development. However, WAY is rapidly cleared from plasma and is also rapidly metabolised. A comparable radioligand, with a higher and more sustained delivery to brain, is desirable since these properties might lead to better biomathematical modelling of acquired PET data. There are also needs for other types of 5-HT1A receptor radioligands, for example, ligands sensitive to elevated serotonin levels, ligands labelled with longer-lived fluorine-18 for distribution to 'satellite' PET centres, and ligands labelled with iodine-123 for single photon emission computerised tomography (SPECT) imaging. Here we describe our progress toward these aims through the exploration of WAY analogues, including the development of [carbonyl-11C]desmethyl-WAY (DWAY) as a promising, more brain-penetrant radioligand for PET imaging of human 5-HT1A receptors, and (pyridinyl-6-halo)-analogues as promising leads for the development of radiohalogenated ligands

  10. Vilazodone does not inhibit sexual behavior in male rats in contrast to paroxetine: A role for 5-HT1A receptors?

    Oosting, Ronald S; Chan, Johnny S W; Olivier, Berend; Banerjee, Pradeep

    2016-08-01

    Vilazodone (VLZ) is a selective serotonin reuptake inhibitor (SSRI) and 5-HT1A receptor partial agonist approved for the treatment of major depressive disorder in adults. In preclinical studies, VLZ had significantly lower sexual side effects than SSRIs and reduced serotonin transporter (SERT) levels in forebrain regions. In the current study, once-daily paroxetine (PAR, 10 mg/kg), VLZ (10 mg/kg), PAR + buspirone (BUS, 3 mg/kg; a 5-HT1A partial agonist), or vehicle (VEH) was administered to male rats for 2 weeks then switched for 7 days (eg, PAR switched to VLZ, PAR + BUS, or VEH). Sexual behavior (eg, ejaculation frequency and latency) was evaluated 1-hr postdose on days 1, 7, 14, and 21. After 2 weeks, treatment with PAR but not VLZ resulted in a significant decrease in sexual behavior. In a 30-min test, the range of ejaculation frequency was 3.08-3.5 with VLZ and 1.00-1.92 with PAR (P < 0.05 vs VEH). After switching from PAR to VEH, PAR + BUS, or VEH, sexual behaviors were normalized to control levels. In contrast, the switch from VLZ to PAR resulted in reduced sexual behaviors. This preclinical study showed that unlike PAR, an SSRI with no 5-HT1A receptor activity, initial treatment with VLZ did not result in sexual side effects at therapeutically relevant doses. Results in male rats switched from PAR to VLZ or PAR + BUS strongly suggest that activation of 5-HT1A receptors may mitigate the sexual side effects associated with conventional SSRIs. PMID:27040795

  11. Citalopram-induced hypophagia is enhanced by blockade of 5-HT1A receptors: role of 5-HT2C receptors

    Grignaschi, G.; Invernizzi, R W; Fanelli, E.; Fracasso, C; Caccia, S.; Samanin, R.

    1998-01-01

    The selective 5-hydroxytryptamine reuptake inhibitor citalopram (10 and 20 mg kg−1, i.p.) significantly reduced food intake in male rats (CD-COBS) habituated to eat their daily food during a 4-h period.The 5-HT1A receptor antagonist WAY100635 (0.3 mg kg−1) administered systemically did not modify feeding but significantly potentiated the reduction in food intake caused by 10 mg kg−1 i.p. citalopram. The dose of 5 mg kg−1 i.p. citalopram was not active in animals pretreated with vehicle but si...

  12. Discovery of a new class of potential multifunctional atypical antipsychotic agents targeting dopamine D3 and serotonin 5-HT1A and 5-HT2A receptors: design, synthesis, and effects on behavior

    Butini, Stefania; Gemma, Sandra; Campiani, Giuseppe;

    2009-01-01

    Dopamine D(3) antagonism combined with serotonin 5-HT(1A) and 5-HT(2A) receptor occupancy may represent a novel paradigm for developing innovative antipsychotics. The unique pharmacological features of 5i are a high affinity for dopamine D(3), serotonin 5-HT(1A) and 5-HT(2A) receptors, together w...

  13. Lithium differs from anticonvulsant mood stabilizers in prefrontal cortical and accumbal dopamine release: role of 5-HT(1A) receptor agonism.

    Ichikawa, Junji; Dai, Jin; Meltzer, Herbert Y

    2005-07-12

    Anticonvulsant mood stabilizers, e.g., valproic acid and carbamazepine, and atypical antipsychotic drugs (APDs), e.g., clozapine, quetiapine, olanzapine, risperidone, and ziprasidone, have been reported to preferentially increase dopamine (DA) release in rat medial prefrontal cortex (mPFC), an effect partially or fully inhibited by WAY100635, a selective 5-HT(1A) antagonist. These atypical APDs have themselves been reported to be effective mood stabilizers, although the importance of increased cortical DA release to mood stabilization has not been established. The purpose of the present study was to determine whether zonisamide, another anticonvulsant mood stabilizer, as well as lithium, a mood stabilizer without anticonvulsant properties, also increases prefrontal cortical DA release and, if so, whether this release is also inhibited by 5-HT(1A) antagonism. As with valproic acid and carbamazepine, zonisamide (12.5 and 25 mg/kg) increased DA release in the mPFC, but not the NAC, an increase abolished by WAY100635 (0.2 mg/kg). However, lithium (100 and 250 mg/kg) decreased DA release in the NAC, an effect also attenuated by WAY100635 (0.2 mg/kg). Lithium itself had no effect in the mPFC but the combination of WAY100635 (0.2 mg/kg) and lithium (100 and 250 mg/kg) markedly increased DA release in the mPFC. Furthermore, M100907 (0.1 mg/kg), a selective 5-HT(2A) antagonist, abolished this increase in DA release in the mPFC. These results indicate that not all mood-stabilizing agents but only those, which have anticonvulsant mood-stabilizing properties, increase DA release in the cortex, and that the effect is dependent upon 5-HT(1A) receptor stimulation. However, the combination of lithium and 5-HT(1A) blockade may result in excessive 5-HT(2A) receptor stimulation, relative to 5-HT(1A) receptor stimulation, both of which can increase prefrontal cortical DA release. PMID:15936730

  14. 5-HT1A receptors of the rat dorsal raphe lateral wings and dorsomedial subnuclei differentially control anxiety- and panic-related defensive responses.

    Spiacci, Ailton; Pobbe, Roger Luis Henschel; Matthiesen, Melina; Zangrossi, Helio

    2016-08-01

    The dorsal raphe nucleus (DR), the main source of 5-HT projections to brain areas involved in anxiety regulation, is composed by 5 subnuclei that differ morphologically, functionally and neurochemically. Based on immunohistochemical evidence, it has been proposed that whereas 5-HT cells of the dorsomedial (dmDR) and caudal subnuclei are implicated in the pathophysiology of generalized anxiety disorder (GAD), neurons of the lateral wings (lwDR) are associated with panic disorder (PD). We here tested this hypothesis from a behavioral perspective by investigating the consequences of the non-selective stimulation of neurons within the dmDR and lwDR, or the pharmacological manipulation of 5-HT1A receptors located in these nuclei, of male Wistar rats exposed to the elevated T-maze. This test allows the measurement of both a GAD- (i.e. inhibitory avoidance) and a PD- (i.e. escape) related response in the same animal. Intra-dmDR injection of either the excitatory amino acid kainic acid or the 5-HT1A receptor antagonist WAY-100635 facilitated inhibitory avoidance acquisition, suggesting an anxiogenic effect, and inhibited escape expression, a panicolytic-like effect. Microinjection of the 5-HT1A receptor agonist 8-OH-DPAT caused the opposite effect. Administration of the same drugs into the lwDR only altered escape performance. Whereas kainic acid and 8-OH-DPAT facilitated its expression, WAY-100635 inhibited it. At higher doses, kainic acid administration evoked vigorous escape reactions as measured in an open-field. These findings implicate 5-HT neurons of the dmDR in the regulation of both GAD- and PD-related defensive behaviors. They also support a primary role of the lwDR in the mediation of PD-associated responses. PMID:26145183

  15. Depressed GABA and glutamate synaptic signaling by 5-HT1A receptors in the nucleus tractus solitarii and their role in cardiorespiratory function

    Ostrowski, Tim D.; Ostrowski, Daniela; Hasser, Eileen M.; Kline, David D.

    2014-01-01

    Serotonin (5-HT), and its 5-HT1A receptor (5-HT1AR) subtype, is a powerful modulator of the cardiorespiratory system and its sensory reflexes. The nucleus tractus solitarii (nTS) serves as the first central station for visceral afferent integration and is critical for cardiorespiratory reflex responses. However, the physiological and synaptic role of 5-HT1ARs in the nTS is relatively unknown. In the present study, we examined the distribution and modulation of 5-HT1ARs on cardiorespiratory an...

  16. 5-HT1A receptor gene silencers Freud-1 and Freud-2 are differently expressed in the brain of rats with genetically determined high level of fear-induced aggression or its absence.

    Kondaurova, Elena M; Ilchibaeva, Tatiana V; Tsybko, Anton S; Kozhemyakina, Rimma V; Popova, Nina K; Naumenko, Vladimir S

    2016-09-01

    Serotonin 5-HT1A receptor is known to play a crucial role in the mechanisms of genetically defined aggression. In its turn, 5-HT1A receptor functional state is under control of multiple factors. Among others, transcriptional factors Freud-1 and Freud-2 are known to be involved in the repression of 5-HT1A receptor gene expression. However, implication of these factors in the regulation of behavior is unclear. Here, we investigated the expression of 5-HT1A receptor and silencers Freud-1 and Freud-2 in the brain of rats selectively bred for 85 generations for either high level of fear-induced aggression or its absence. It was shown that Freud-1 and Freud-2 levels were different in aggressive and nonaggressive animals. Freud-1 protein level was decreased in the hippocampus, whereas Freud-2 protein level was increased in the frontal cortex of highly aggressive rats. There no differences in 5-HT1A receptor gene expression were found in the brains of highly aggressive and nonaggressive rats. However, 5-HT1A receptor protein level was decreased in the midbrain and increased in the hippocampus of highly aggressive rats. These data showed the involvement of Freud-1 and Freud-2 in the regulation of genetically defined fear-induced aggression. However, these silencers do not affect transcription of the 5-HT1A receptor gene in the investigated rats. Our data indicate the implication of posttranscriptional rather than transcriptional regulation of 5-HT1A receptor functional state in the mechanisms of genetically determined aggressive behavior. On the other hand, the implication of other transcriptional regulators for 5-HT1A receptor gene in the mechanisms of genetically defined aggression could be suggested. PMID:27150226

  17. Distinct effect of 5-HT1A and 5-HT2A receptors in the medial nucleus of the amygdala on tonic immobility behavior.

    de Paula, Bruna Balbino; Leite-Panissi, Christie Ramos Andrade

    2016-07-15

    The tonic immobility (TI) response is an innate fear behavior associated with intensely dangerous situations, exhibited by many species of invertebrate and vertebrate animals. In humans, it is possible that TI predicts the severity of posttraumatic stress disorder symptoms. This behavioral response is initiated and sustained by the stimulation of various groups of neurons distributed in the telencephalon, diencephalon and brainstem. Previous research has found the highest Fos-IR in the posteroventral part of the medial nucleus of the amygdala (MEA) during TI behavior; however, the neurotransmission of this amygdaloid region involved in the modulation of this innate fear behavior still needs to be clarified. Considering that a major drug class used for the treatment of psychopathology is based on serotonin (5-HT) neurotransmission, we investigated the effects of serotonergic receptor activation in the MEA on the duration of TI. The results indicate that the activation of the 5HT1A receptors or the blocking of the 5HT2 receptors of the MEA can promote a reduction in fear and/or anxiety, consequently decreasing TI duration in guinea pigs. In contrast, blocking the 5HT1A receptors or activating the 5HT2 receptors in this amygdalar region increased the TI duration, suggesting an increase in fear and/or anxiety. These alterations do not appear to be due to a modification of spontaneous motor activity, which might non-specifically affect TI duration. Thus, these results suggest a distinct role of the 5HT receptors in the MEA in innate fear modulation. PMID:27150816

  18. The paradox of 5-methoxy-N,N-dimethyltryptamine: an indoleamine hallucinogen that induces stimulus control via 5-HT1A receptors.

    Winter, J C; Filipink, R A; Timineri, D; Helsley, S E; Rabin, R A

    2000-01-01

    Stimulus control was established in rats trained to discriminate either 5-methoxy-N,N-dimethyltryptamine (3 mg/kg) or (-)-2,5-dimethoxy-4-methylamphetamine (0.56 mg/kg) from saline. Tests of antagonism of stimulus control were conducted using the 5-HT1A antagonists (+/-)-pindolol and WAY-100635, and the 5-HT2 receptor antagonist pirenperone. In rats trained with 5-MeO-DMT, pindolol and WAY-100635 both produced a significant degree of antagonism of stimulus control, but pirenperone was much less effective. Likewise, the full generalization of 5-MeO-DMT to the selective 5-HT1A agonist [+/-]-8-hydroxy-dipropylaminotetralin was blocked by WAY-100635, but unaffected by pirenperone. In contrast, the partial generalization of 5-MeO-DMT to the 5-HT2 agonist DOM was completely antagonized by pirenperone, but was unaffected by WAY-100635. Similarly, in rats trained with (-)-DOM, pirenperone completely blocked stimulus control, but WAY-100635 was inactive. The results obtained in rats trained with (-)-DOM and tested with 5-MeO-DMT were more complex. Although the intraperitoneal route had been used for both training drugs, a significant degree of generalization of (-)-DOM to 5-MeO-DMT was seen only when the latter drug was administered subcutaneously. Furthermore, when the previously effective dose of pirenperone was given in combination with 5-MeO-DMT (s.c.), complete suppression of responding resulted. However, the combination of pirenperone and WAY-100635 given prior to 5-MeO-DMT restored responding in (-)-DOM-trained rats, and provided evidence of antagonism of the partial substitution of 5-MeO-DMT for (-)-DOM. The present data indicate that 5-MeO-DMT-induced stimulus control is mediated primarily by interactions with 5-HT1A receptors. In addition, however, the present findings suggest that 5-MeO-DMT induces a compound stimulus that includes an element mediated by interactions with a 5-HT2 receptors. The latter component is not essential for 5-MeO-DMT-induced stimulus

  19. Third Trimester Equivalent Alcohol Exposure Reduces Modulation of Glutamatergic Synaptic Transmission by 5-HT1A Receptors in the Rat Hippocampal CA3 Region

    Morton, Russell A.; Valenzuela, C. Fernando

    2016-01-01

    Fetal alcohol exposure has been associated with many neuropsychiatric disorders that have been linked to altered serotonin (5-hydroxytryptamine; 5-HT) signaling, including depression and anxiety. During the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) 5-HT neurons undergo significant functional maturation and their axons reach target regions in the forebrain (e.g., cortex and hippocampus). The objective of this study was to identify the effects of third trimester ethanol (EtOH) exposure on hippocampal 5-HT signaling. Using EtOH vapor inhalation chambers, we exposed rat pups to EtOH for 4 h/day from postnatal day (P) 2 to P12. The average serum EtOH concentration in the pups was 0.13 ± 0.04 g/dl (legal intoxication limit in humans = 0.08 g/dl). We used brain slices to assess the modulatory actions of 5-HT on field excitatory postsynaptic potentials in the hippocampal CA3 region at P13-P15. Application of the GABAA/glycine receptor antagonist, picrotoxin, caused broadening of field excitatory postsynaptic potentials (fEPSPs), an effect that was reversed by application of 5-HT in slices from air exposed rats. However, this effect of 5-HT was absent in EtOH exposed animals. In slices from naïve animals, application of a 5-HT1A receptor antagonist blocked the effect of 5-HT on the fEPSPs recorded in presence of picrotoxin, suggesting that third trimester ethanol exposure acts by inhibiting the function of these receptors. Studies indicate that 5-HT1A receptors play a critical role in the development of hippocampal circuits. Therefore, inhibition of these receptors by third trimester ethanol exposure could contribute to the pathophysiology of fetal alcohol spectrum disorders. PMID:27375424

  20. Involvement of 5-HT1A Receptors in the Anxiolytic-Like Effects of Quercitrin and Evidence of the Involvement of the Monoaminergic System

    Li, Jian; Liu, Qian-tong; Chen, Yi; Liu, Jie; Shi, Jin-li; Liu, Yong; Guo, Jian-you

    2016-01-01

    Quercitrin is a well-known flavonoid that is contained in Flos Albiziae, which has been used for the treatment of anxiety. The present study investigated the anxiolytic-like effects of quercitrin in experimental models of anxiety. Compared with the control group, repeated treatment with quercitrin (5.0 and 10.0 mg/kg/day, p.o.) for seven days significantly increased the percentage of entries into and time spent on the open arms of the elevated plus maze. In the light/dark box test, quercitrin exerted an anxiolytic-like effect at 5 and 10 mg/kg. In the marble-burying test, quercitrin (5.0 and 10.0 mg/kg) also exerted an anxiolytic-like effect. Furthermore, quercitrin did not affect spontaneous locomotor activity. The anxiolytic-like effects of quercitrin in the elevated plus maze and light/dark box test were blocked by the serotonin-1A (5-hydroxytryptamine-1A (5-HT1A)) receptor antagonist WAY-100635 (3.0 mg/kg, i.p.) but not by the γ-aminobutyric acid-A (GABAA) receptor antagonist flumazenil (0.5 mg/kg, i.p.). The levels of brain monoamines (5-HT and dopamine) and their metabolites (5-hydroxy-3-indoleacetic acid, 3,4-dihydroxyphenylacetic acid, and homovanillic acid) were decreased after quercitrin treatment. These data suggest that the anxiolytic-like effects of quercitrin might be mediated by 5-HT1A receptors but not by benzodiazepine site of GABAA receptors. The results of the neurochemical studies suggest that these effects are mediated by modulation of the levels of monoamine neurotransmitters. PMID:27298626

  1. An Orally Active Phenylaminotetralin-Chemotype Serotonin 5-HT7 and 5-HT1A Receptor Partial Agonist that Corrects Motor Stereotypy in Mouse Models.

    Canal, Clinton E; Felsing, Daniel E; Liu, Yue; Zhu, Wanying; Wood, JodiAnne T; Perry, Charles K; Vemula, Rajender; Booth, Raymond G

    2015-07-15

    Stereotypy (e.g., repetitive hand waving) is a key phenotype of autism spectrum disorder, Fragile X and Rett syndromes, and other neuropsychiatric disorders, and its severity correlates with cognitive and attention deficits. There are no effective treatments, however, for stereotypy. Perturbation of serotonin (5-HT) neurotransmission contributes to stereotypy, suggesting that distinct 5-HT receptors may be pharmacotherapeutic targets to treat stereotypy and related neuropsychiatric symptoms. For example, preclinical studies indicate that 5-HT7 receptor activation corrects deficits in mouse models of Fragile X and Rett syndromes, and clinical trials for autism are underway with buspirone, a 5-HT1A partial agonist with relevant affinity at 5-HT7 receptors. Herein, we report the synthesis, in vitro molecular pharmacology, behavioral pharmacology, and pharmacokinetic parameters in mice after subcutaneous and oral administration of (+)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine ((+)-5-FPT), a new, dual partial agonist targeting both 5-HT7 (Ki = 5.8 nM, EC50 = 34 nM) and 5-HT1A (Ki = 22 nM, EC50 = 40 nM) receptors. Three unique, heterogeneous mouse models were used to assess the efficacy of (+)-5-FPT to reduce stereotypy: idiopathic jumping in C58/J mice, repetitive body rotations in C57BL/6J mice treated with the NMDA antagonist, MK-801, and repetitive head twitching in C57BL/6J mice treated with the 5-HT2 agonist, DOI. Systemic (+)-5-FPT potently and efficaciously reduced or eliminated stereotypy in each of the mouse models without altering locomotor behavior on its own, and additional tests showed that (+)-5-FPT, at the highest behaviorally active dose tested, enhanced social interaction and did not cause behaviors indicative of serotonin syndrome. These data suggest that (+)-5-FPT is a promising medication for treating stereotypy in psychiatric disorders. PMID:26011730

  2. Antidepressant-like activity of Tagetes lucida Cav. is mediated by 5-HT(1A) and 5-HT(2A) receptors.

    Bonilla-Jaime, H; Guadarrama-Cruz, G; Alarcon-Aguilar, F J; Limón-Morales, O; Vazquez-Palacios, G

    2015-10-01

    It has been demonstrated that the aqueous extract of Tagetes lucida Cav. shows an antidepressant-like effect on the forced swimming test (FST) in rats. The aim of this study was to analyze the participation of the serotoninergic system in the antidepressant-like effect of the aqueous extract of T. lucida. Different doses of the extract of T. lucida were administered at 72, 48, 24, 18 and 1 h before FST. The animals were pretreated with a 5-HT1A receptor antagonist (WAY-100635, 0.5 mg/kg), a 5-HT2A receptor antagonist (ketanserin, 5 mg/kg), a β-noradrenergic receptor antagonist (propranolol, 200 mg/kg), and with a α2-noradrenergic receptor antagonist (yohimbine, 1 mg/kg) alone or combined with the extract and pretreated with a serotonin synthesis inhibitor (PCPA) before treatment with 8-OH-DPAT + the extract of T. lucida. In addition, suboptimal doses of the 5-HT1A agonist (8-OH-DPAT) + non-effective dose of extract was analyzed in the FST. To determine the presence of flavonoids, the aqueous extract of T. lucida (20 µl, 4 mg/ml) was injected in HPLC; however, a quercetin concentration of 7.72 mg/g of extract weight was detected. A suboptimal dose of 8-OH-DPAT + extract of T. lucida decreased immobility and increased swimming and climbing. An antidepressant-like effect with the aqueous extract of T. lucida at doses of 100 and 200 mg/kg was observed on the FST with decreased immobility behavior and increased swimming; however, this effect was blocked by WAY-100635, ketanserin and PCPA but not by yohimbine and propranolol, suggesting that the extract of T. lucida could be modulating the release/reuptake of serotonin. PMID:26062718

  3. 柴胡疏肝散对抑郁症大鼠海马5-HT 及5-HT1A 表达的影响%Influences of Bupleurum Liver-Coursing Powder on 5-HT Level and Expression of 5-HT1A Receptor in Hippocampus of Depressive Rats

    刘英; 徐爱军; 田艳霞; 刘昊; 王凤玲

    2013-01-01

    目的:研究柴胡疏肝散对抑郁大鼠海马5-HT 及5-HT1A 的作用,探讨柴胡疏肝散抗抑郁作用机制。方法选用成年 Wistar 大鼠45只,分为对照组、模型组和治疗组。给予慢性不可预性温和应激(CUMS)建立抑郁模型,治疗组给予柴胡疏肝散饮片灌胃。采用糖水偏好实验和悬尾实验进行行为学检测,采用高效液相色谱法测定海马5-HT 浓度,Western blot 检测5-HT1A 表达。结果模型组大鼠糖水偏好百分比明显降低(P <0.05),悬尾不动时间明显延长(P <0.05);治疗组能逆转此改变;模型组大鼠海马5-HT 含量和5-HT1A 受体表达水平明显低于对照组(P <0.05),治疗组5-HT 含量和5-HT1A 受体表达水平明显升高,但仍低于对照组(P <0.05)。结论柴胡疏肝散抗抑郁作用可能与影响海马5-HT 水平及5-HT1A 受体表达有关。%Objective To observe the effcet of bupleurum liver-coursing powder on 5-HT level and ex-pression of 5-HT1A receptor in hippocampus of depressive rats.Methods Forty-five male Wistar rats were randomly divided into control,model and treatment groups.The depression animal model was pro-duced by giving rats chronic unpredicted mild stress while the depressional behavior was examined using sucrose preference test and tail-suspension test.The level of 5-HT and expression of 5-HT1A receptor protein were detected using high performance liquid chromatography (HPLC)and Western blot respective-ly.Results Change in preference of sucrose of model and treatment groups’rats were significantly lower, while tail-suspension immobility was higher than those of control group rats (P < 0.05).These index were reversed in treatment group.The content of 5-HT and expression of 5-HT1A receptor protein of model and treatment groups were higher than that of control group,while the index was lower after treatment with bupleurum liver-coursing powder (P < 0.05).Conclusion Effect of bupleurum

  4. 99mTc-labeling of a dithiocarbamate-DWAY fragment using [99mTcN]2+ core for the preparation of potential 5HT1A receptor imaging agents

    1-(2-methoxy phenyl) piperazine fragment of WAY100635 or its phenolic analogue, derived from DWAY is used to design the desired structure of 5HT1A receptor imaging agents. In this study a DWAY analogue was labeled with 99mTc-nitrido ([99mTcN]2+) core via dithiocarbamate. 2-(piperazin-1-yl) phenol dithiocarbamate was synthesized by the reaction of 2-(piperazin-1-yl) phenol with an equivalent amount of carbon disulfide in KOH solution then radiolabeled with 99mTc-nitrido core. The final complex was characterized by HPLC and its radiochemical purity was more than 90 %. In vitro stability studies have shown the complex was stable at least 4 h after labeling at room temperature. The n-octanol/water partition coefficient experiment demonstrated log p = 1.34 for 99mTcN-OHPP-DTC. Biodistribution results showed that radio tracer had moderate brain uptake (0.39 ± 0.03 %ID/g at 15 min and 0.29 ± 0.02 %ID/g at 120 min) and good retention, suggesting that this complex may lead to a further development of a radiotracer with specific binding to 5-HT1A receptor. (author)

  5. 5-HT1A/1B receptors as targets for optimizing pigmentary responses in C57BL/6 mouse skin to stress.

    Hua-Li Wu

    Full Text Available Stress has been reported to induce alterations of skin pigmentary response. Acute stress is associated with increased turnover of serotonin (5-hydroxytryptamine; 5-HT whereas chronic stress causes a decrease. 5-HT receptors have been detected in pigment cells, indicating their role in skin pigmentation. To ascertain the precise role of 5-HT in stress-induced pigmentary responses, C57BL/6 mice were subjected to chronic restraint stress and chronic unpredictable mild stress (CRS and CUMS, two models of chronic stress for 21 days, finally resulting in abnormal pigmentary responses. Subsequently, stressed mice were characterized by the absence of a black pigment in dorsal coat. The down-regulation of tyrosinase (TYR and tyrosinase-related proteins (TRP1 and TRP2 expression in stressed skin was accompanied by reduced levels of 5-HT and decreased expression of 5-HT receptor (5-HTR system. In both murine B16F10 melanoma cells and normal human melanocytes (NHMCs, 5-HT had a stimulatory effect on melanin production, dendricity and migration. When treated with 5-HT in cultured hair follicles (HFs, the increased expression of melanogenesis-related genes and the activation of 5-HT1A, 1B and 7 receptors also occurred. The serum obtained from stressed mice showed significantly decreased tyrosinase activity in NHMCs compared to that from nonstressed mice. The decrease in tyrosinase activity was further augmented in the presence of 5-HTR1A, 1B and 7 antagonists, WAY100635, SB216641 and SB269970. In vivo, stressed mice received 5-HT precursor 5-hydroxy-l-tryptophan (5-HTP, a member of the class of selective serotonin reuptake inhibitors (fluoxetine; FX and 5-HTR1A/1B agonists (8-OH-DPAT/CP94253, finally contributing to the normalization of pigmentary responses. Taken together, these data strongly suggest that the serotoninergic system plays an important role in the regulation of stress-induced depigmentation, which can be mediated by 5-HT1A/1B receptors. 5-HT

  6. Potentiation of 5-methoxy-N,N-dimethyltryptamine-induced hyperthermia by harmaline and the involvement of activation of 5-HT1A and 5-HT2A receptors.

    Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2015-02-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are serotonin (5-HT) analogs often abused together, which alters thermoregulation that may indicate the severity of serotonin toxicity. Our recent studies have revealed that co-administration of monoamine oxidase inhibitor harmaline leads to greater and prolonged exposure to 5-HT agonist 5-MeO-DMT that might be influenced by cytochrome P450 2D6 (CYP2D6) status. This study was to define the effects of harmaline and 5-MeO-DMT on thermoregulation in wild-type and CYP2D6-humanized (Tg-CYP2D6) mice, as well as the involvement of 5-HT receptors. Animal core body temperatures were monitored noninvasively in the home cages after implantation of telemetry transmitters and administration of drugs. Harmaline (5 and 15 mg/kg, i.p.) alone was shown to induce hypothermia that was significantly affected by CYP2D6 status. In contrast, higher doses of 5-MeO-DMT (10 and 20 mg/kg) alone caused hyperthermia. Co-administration of harmaline (2, 5 or 15 mg/kg) remarkably potentiated the hyperthermia elicited by 5-MeO-DMT (2 or 10 mg/kg), which might be influenced by CYP2D6 status at certain dose combination. Interestingly, harmaline-induced hypothermia was only attenuated by 5-HT1A receptor antagonist WAY-100635, whereas 5-MeO-DMT- and harmaline-5-MeO-DMT-induced hyperthermia could be suppressed by either WAY-100635 or 5-HT2A receptor antagonists (MDL-100907 and ketanserin). Moreover, stress-induced hyperthermia under home cage conditions was not affected by WAY-100635 but surprisingly attenuated by MDL-100907 and ketanserin. Our results indicate that co-administration of monoamine oxidase inhibitor largely potentiates 5-MeO-DMT-induced hyperthermia that involves the activation of both 5-HT1A and 5-HT2A receptors. These findings shall provide insights into development of anxiolytic drugs and new strategies to relieve the lethal hyperthermia in serotonin toxicity. PMID:25446678

  7. No evidence that MDMA-induced enhancement of emotional empathy is related to peripheral oxytocin levels or 5-HT1a receptor activation.

    Kim P C Kuypers

    Full Text Available The present study aimed at investigating the effect of MDMA on measures of empathy and social interaction, and the roles of oxytocin and the 5-HT1A receptor in these effects. The design was placebo-controlled within-subject with 4 treatment conditions: MDMA (75 mg, with or without pindolol (20 mg, oxytocin nasal spray (40 IU+16 IU or placebo. Participants were 20 healthy poly-drug MDMA users, aged between 18-26 years. Cognitive and emotional empathy were assessed by means of the Reading the Mind in the Eyes Test and the Multifaceted Empathy Test. Social interaction, defined as trust and reciprocity, was assessed by means of a Trust Game and a Social Ball Tossing Game. Results showed that MDMA selectively affected emotional empathy and left cognitive empathy, trust and reciprocity unaffected. When combined with pindolol, these effects remained unchanged. Oxytocin did not affect measures of empathy and social interaction. Changes in emotional empathy were not related to oxytocin plasma levels. It was concluded that MDMA (75 mg selectively enhances emotional empathy in humans. While the underlying neurobiological mechanism is still unknown, it is suggested that peripheral oxytocin does not seem to be the main actor in this; potential candidates are the serotonin 2A and the vasopressin 1A receptors. Trial registration: MDMA & PSB NTR 2636.

  8. New halogenated [11C]WAY analogues, [11C]6FPWAY and [11C]6BPWAY--Radiosynthesis and assessment as radioligands for the study of brain 5-HT1A receptors in living monkey

    [Carbonyl-11C]WAY-100635 ([11C]WAY) is an established radioligand for the study of brain serotonin1A (5-HT1A) receptors in living animals and humans with positron emission tomography (PET). There is a recognised need to develop halogenated ligands for 5-HT1A receptors, either for labelling with longer-lived fluorine-18 for more widespread application with PET or with iodine-123 for application with single photon emission tomography (SPET). Here we used autoradiography and PET to assess two new halogenated anlogues of WAY, namely 6BPWAY and 6FPWAY [N-(2-(1-(4-(2-methoxyphenyl)-piperazinyl)ethyl))-N-(2- (6-bromo-/fluoro-pyridinyl))cyclohexanecarboxamide] as prospective radioligands, initially using carbon-11 as the radiolabel. Labelling of 6BPWAY and 6FPWAY with carbon-11 was accomplished by acylation of the corresponding secondary amine precursors with [carbonyl-11C]cyclohexanecarbonyl chloride. After incubation of human brain crysections with [11C]6BPWAY or [11C]6FPWAY, the highest accumulation of radioactivity was observed in cortical areas and the hippocampal formation. Both radioligands had high nonspecific binding. There was a rapid accumulation of radioactivity in the monkey brain after intravenous injection of [11C]6BPWAY and [11C]6FPWAY. High accumulation of radioactivity was observed in the frontal and temporal cortex and the raphe nuclei, areas known to contain a high density of 5-HT1A receptors. The ratios of radioactivity in receptor-rich temporal cortex to that in receptor-poor cerebellum at peak equilibrium were 1.9 (at 10 min) and 3.0 at (at 20 min) for [11C]6BPWAY and [11C]6FPWAY, respectively. In pretreatment experiments with high doses of unlabelled WAY, the level of radioactivity in the frontal and temporal cortex and the raphe nuclei was reduced to the same level as in the cerebellum. Radioactive metabolites of [11C]6FPWAY appeared at a rate similar to those for [11C]WAY, with 17% of the radioactivity in plasma represented by unchanged

  9. The guinea-pig ileum preparation as a model for 5-HT1A receptors: anomalous effects with RS-30199-193.

    Small, C.; Brown, C. M.; Redfern, W. S.; Spedding, M.

    1991-01-01

    1. Agents that have high and selective affinity for the 5-HT1A site such as 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and N,N-dipropyl-5-carboxamidotryptamine (DP5CT) inhibited the responses to field stimulation in guinea-pig ileum preparations; the inhibitory effects were antagonized by methiothepin and spiperone, consistent with effects at the 5-HT1A site. 2. The inhibitory effects of DP5CT were pronounced in Tyrode solution containing low Ca2+ (0.9 mM), but were much less apparent...

  10. Distribution of the 5-HT1A receptor antagonist [18F]FPWAY in blood and brain of the rat with and without isoflurane anesthesia

    To determine whether brain and plasma equilibrium of a proposed PET tracer for 5-HT1A, [18F]FPWAY, can be achieved in a sufficiently short time for practical use of the brain to plasma equilibrium distribution ratio (DR) to monitor receptor availability with and without isoflurane anesthesia. Awake (n=4) and isoflurane-anesthetized (n=4) rats were administered a continuous 60 min intravenous infusion of [18F]FPWAY with timed arterial blood sampling. Brains of the isoflurane-anesthetized rats were scanned with the ATLAS small animal PET scanner; awake rats were not. All rats were killed at 60 min and scanned postmortem for 15 min, followed by brain slicing for autoradiography. Several regions of interest (ROIs) were defined in the PET images as well as in the autoradiographic images. Regional DRs were calculated as total activity in the brain ROI divided by plasma [18F]FPWAY activity. DRs in the anesthetized animals were constant between 30 and 60 min, indicating that near equilibrium between brain and plasma had been achieved by ∝30 min. DRs determined from postmortem PET data were higher in the isoflurane-anesthetized rats by 24% (not significant) and 33% (p=0.065) in whole brain and hippocampus, respectively. DRs determined from autoradiographic data were greater in isoflurane-anesthetized rats in medial hippocampus, lateral hippocampus, and cerebellum by 33% (p=0.054), 63% (p18F]FPWAY could be an appropriate ligand for monitoring changes in receptor availability in the serotonergic system using a bolus/infusion paradigm. One possible explanation for higher DRs in anesthetized rats may be a reduction in endogenous 5-HT secretion under isoflurane anesthesia. (orig.)

  11. 5-HT1A-receptor agonist modified amygdala activity and amygdala-associated social behavior in a valproate-induced rat autism model.

    Wang, Chao-Chuan; Lin, Hui-Ching; Chan, Yun-Han; Gean, Po-Wu; Yang, Yen Kung; Chen, Po See

    2013-10-01

    Accumulating evidence suggests that dysfunction of the amygdala is related to abnormal fear processing, anxiety, and social behaviors noted in autistic spectrum disorders (ASDs). In addition, studies have shown that disrupted brain serotonin homeostasis is linked to ASD. With a valproate (VPA)-induced rat ASD model, we investigated the possible role of amygdala serotonin homeostasis in autistic phenotypes and further explored the underlying mechanism. We first discovered that the distribution of tryptophan hydroxylase immunoreactivity in the caudal raphe system was modulated on postnatal day (PD) 28 of the VPA-exposed offspring. Then, we found a significantly higher serotonin transporter availability in the amygdala of the VPA-exposed offspring on PD 56 by using single photon emission computed tomography and computed tomography co-registration following injection of (123)I-labeled 2-((2-(dimethylamino)methyl)phenyl)thio)-5-iodophenylamine((123)I[ADAM]). Furthermore, treatment with 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A receptor agonist, increased social interaction and improved fear memory extinction in the VPA-exposed offspring. 8-OH-DPAT treatment also reversed the characteristics of miniature excitatory post-synaptic currents as well as paired pulse facilitation observed in lateral amygdala slices. These results provided further evidence to support the role of the amygdala in characteristic behavioral changes in the rat ASD model. The serotonergic projections that modulate the amygdala function might play a certain role in the development and treatment of behavioral symptoms exhibited in individuals with ASD. PMID:23823694

  12. 5-HT 1A polymorphism and self-transcendence in mood disorders.

    Lorenzi, Cristina; Serretti, Alessandro; Mandelli, Laura; Tubazio, Viviana; Ploia, Cristina; Smeraldi, Enrico

    2005-08-01

    Recently, an association between serotonin 1A receptor binding potential and self-transcendence scores at the temperament and character inventory (TCI) has been reported. We tested involvement of 5-HT(1A) gene in this trait, in a sample of 40 remitted mood disorder patients. Subjects with the 5-HT(1A)*C/C genotype showed significantly lower scores at the total self-transcendence and at the sub-scales of transpersonal identification and spiritual acceptance. Our preliminary results further support the involvement of the serotoninergic pattern in the self-transcendence character trait. PMID:15952185

  13. Actions of the prototypical 5-HT1A receptor agonist 8-OH-DPAT at human alpha2-adrenoceptors: (+)8-OH-DPAT, but not (-)8-OH-DPAT is an alpha2B subtype preferential agonist.

    Heusler, Peter; Rauly-Lestienne, Isabelle; Tourette, Amélie; Tardif, Stéphanie; Ailhaud, Marie-Christine; Croville, Guillaume; Cussac, Didier

    2010-08-25

    8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] is the prototypical agonist at serotonin 5-HT1A receptors; however, activity at other targets contributes to the functional effects of the compound as well. We examined the properties of 8-OH-DPAT and its enantiomers at recombinant human (h)alpha2-adrenoceptor subtypes, using a panel of radioligand binding and functional tests. In competition binding experiments using [3H]-RX821002, about 10-fold selectivity of (+)8-OH-DPAT for the halpha2B subtype (pKi about 7) over halpha2A- and halpha2C-adrenoceptors was observed. In contrast, the S(-) enantiomer of 8-OH-DPAT showed similar weak affinities for the three receptor subtypes (pKis<6). The binding affinity of (+)8-OH-DPAT at the halpha2B- and the halpha2A-adrenoceptor was found sensitive to GTPgammaS, a receptor/G protein-uncoupling agent, indicating agonist properties of the drug. Furthermore, using [35S]GTPgammaS binding determination at CHO-halpha2B or CHO-halpha2A cell membranes and G protein coupled inwardly rectifying potassium (GIRK) current recordings in Xenopus oocytes expressing halpha2B, partial agonist activity of (+)8-OH-DPAT at the respective receptors was confirmed in these two different functional assays. Potency of (+)8-OH-DPAT for stimulation of [35S]GTPgammaS incorporation was lower at the halpha2A- than at the halpha2B-adrenoceptor, consistent with binding affinities. Thus, (+)8-OH-DPAT and, as a consequence, racemic (+/-)8-OH-DPAT are partial agonists at halpha2-adrenoceptors with selectivity for the halpha2B subtype, a property that might contribute to the effects of the compound described in native systems. PMID:20450907

  14. Linoleic acid derivative DCP-LA ameliorates stress-induced depression-related behavior by promoting cell surface 5-HT1A receptor translocation, stimulating serotonin release, and inactivating GSK-3β.

    Kanno, Takeshi; Tanaka, Akito; Nishizaki, Tomoyuki

    2015-04-01

    Impairment of serotonergic neurotransmission is the major factor responsible for depression and glycogen synthase kinase 3β (GSK-3β) participates in serotonergic transmission-mediated signaling networks relevant to mental illnesses. In the forced-swim test to assess depression-like behavior, the immobility time for mice with restraint stress was significantly longer than that for nonstressed control mice. Postsynaptic cell surface localization of 5-HT1A receptor, but not 5-HT2A receptor, in the hypothalamus for mice with restraint stress was significantly reduced as compared with that for control mice, which highly correlated to prolonged immobility time, i.e., depression-like behavior. The linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) restored restraint stress-induced reduction of cell surface 5-HT1A receptor and improved depression-like behavior in mice with restraint stress. Moreover, DCP-LA stimulated serotonin release from hypothalamic slices and cancelled restraint stress-induced reduction of GSK-3β phosphorylation at Ser9. Taken together, the results of the present study indicate that DCP-LA could ameliorate depression-like behavior by promoting translocation of 5-HT1A receptor to the plasma membrane on postsynaptic cells, stimulating serotonin release, and inactivating GSK-3β. PMID:24788685

  15. Tandospirone, a 5-HT1A partial agonist, ameliorates aberrant lactate production in the prefrontal cortex of rats exposed to blockade of N-methy-D-aspartate receptors; Towards the therapeutics of cognitive impairment of schizophrenia

    Takashi eUehara

    2014-09-01

    Full Text Available Rationale Augmentation therapy with serotonin-1A (5-HT1A receptor partial agonists has been suggested to improve cognitive deficits in patients with schizophrenia. Decreased activity of prefrontal cortex may provide a basis for cognitive deficits of the disease. Lactate plays a significant role in the supply of energy to the brain, and glutamatergic neurotransmission contributes to lactate production.Objectives and methods The purposes of this study were to examine the effect of repeated administration (once a daily for 4 days of tandospirone (0.05 and 5 mg/kg on brain energy metabolism, as represented by extracellular lactate concentration (eLAC in the medial prefrontal cortex (mPFC of young adult rats..Results Four-day treatment with MK-801, an NMDA-R antagonist, prolonged eLAC elevation induced by foot shock stress (FS. Co-administration with the high-dose tandospirone suppressed prolonged FS-induced eLAC elevation in rats receiving MK-801, whereas tandospirone by itself did not affected eLAC increment.Conclusions These results suggest that stimulation of 5-HT1A receptors ameliorates abnormalities of energy metabolism in the mPFC due to blockade of NMDA receptors. These findings provide a possible mechanism based on brain energy metabolism by which 5-HT1A agonism improve cognitive impairment in schizophrenia and related disorders.

  16. Buspirone improves haloperidol-induced Parkinson disease in mice through 5-HT1A recaptors

    Mohajjel Nayebi A, A; H Sheidaei

    2010-01-01

    Background and the purpose of the study The available literatures show that 5-HT1A receptors are widely distributed throughout the basal ganglia, and their activation facilitate dopamine release. Neuroleptic drugs such as haloperidol induce Parkinson-like syndrome through blocking brain D2 receptors. This study aimed to investigate effect of buspirone, a partial agonist of 5HT1A receptor, on motor dysfunctions induced by haloperidol and involvement of 5HT1A receptors in this regard. Methods S...

  17. 125I-Bolton-Hunter-8-methoxy-2-[N-propyl-N-propylamino]tetralin as a new selective radioligand of 5-HT1A sites in the rat brain. In vitro binding and autoradiographic studies

    In vitro binding assays with 125I-[8-methoxy-2-[N-propyl-N-(3'-iodo-4'-hydroxyphenyl)-propionamido -N'- propylamino] tetralin] (125I-BH-8-MeO-N-PAT), a 125I-labeled derivative of the potent serotonin (5-HT) agonist 8-hydroxy-2-[di-n-propylamino]tetralin [(3H]-8-OH-DPAT), showed that this compound recognized specific sites with nanomolar affinity for 5-HT and 5-HT1A ligands such as spiroxatrine, ipsapirone, buspirone and gepirone in rat hippocampal membranes. Comparison of the binding characteristics of 125I-BH-8-MeO-N-PAT with those of [3H]-8-OH-DPAT revealed striking similarities: at the hippocampal level, both binding sites exhibited nanomolar affinity for their respective ligands and the same Bmax; their pharmacological profiles defined by the inhibition of each bound ligand by a series of 26 serotonin, dopamine- or norepinephrine-related agonists and antagonists were identical; and their regional distributions examined by membrane binding assays and autoradiography of labeled brain sections were highly correlated. These observations indicate that 125I-BH-8-MeO-N-PAT is the first 125I-reversible ligand for the selective labeling of 5-HT1A sites in the rat central nervous system

  18. The role of 5-HT1A receptors in the anti-aversive effects of cannabidiol on panic attack-like behaviors evoked in the presence of the wild snake Epicrates cenchria crassus (Reptilia, Boidae).

    Twardowschy, André; Castiblanco-Urbina, Maria Angélica; Uribe-Mariño, Andres; Biagioni, Audrey Francisco; Salgado-Rohner, Carlos José; Crippa, José Alexandre de Souza; Coimbra, Norberto Cysne

    2013-12-01

    The potential anxiolytic and antipanic properties of cannabidiol have been shown; however, its mechanism of action seems to recruit other receptors than those involved in the endocannabinoid-mediated system. It was recently shown that the model of panic-like behaviors elicited by the encounters between mice and snakes is a good tool to investigate innate fear-related responses, and cannabidiol causes a panicolytic-like effect in this model. The aim of the present study was to investigate the 5-hydroxytryptamine (5-HT) co-participation in the panicolytic-like effects of cannabidiol on the innate fear-related behaviors evoked by a prey versus predator interaction-based paradigm. Male Swiss mice were treated with intraperitoneal (i.p.) administrations of cannabidiol (3 mg/kg, i.p.) and its vehicle and the effects of the peripheral pre-treatment with increasing doses of the 5-HT1A receptor antagonist WAY-100635 (0.1, 0.3 and 0.9 mg/kg, i.p.) on instinctive fear-induced responses evoked by the presence of a wild snake were evaluated. The present results showed that the panicolytic-like effects of cannabidiol were blocked by the pre-treatment with WAY-100635 at different doses. These findings demonstrate that cannabidiol modulates the defensive behaviors evoked by the presence of threatening stimuli, and the effects of cannabidiol are at least partially dependent on the recruitment of 5-HT1A receptors. PMID:23926240

  19. Design and synthesis of substituted 2-naphthyloxyethylamines as potential 5-HT 1A antagonists

    Joshi Urmila

    2007-01-01

    Full Text Available Although 5-HT 1A antagonists are known to be useful in the treatment of depression, no specific 5-HT 1A antagonist is available clinically. Propranolol is one of the important ligands acting at the presynaptic 5-HT 1A receptor. This article deals with the design of 5-HT 1A antagonists based on propranolol using the pharmacophoric requirements of the receptor and the other SAR data, synthesis of these compounds and their preliminary evaluation for the 5-HT 1A antagonistic activity against a specific partial agonist. This was done by measuring the reversal of agonist-induced hypothermia in mice. The synthesized compounds showed a promising 5-HT 1A antagonistic activity.

  20. Pharmacological evidence that 5-HT1A/1B/1D, α2-adrenoceptors and D2-like receptors mediate ergotamine-induced inhibition of the vasopressor sympathetic outflow in pithed rats.

    Villamil-Hernández, Ma Trinidad; Alcántara-Vázquez, Oscar; Sánchez-López, Araceli; Gutiérrez-Lara, Erika J; Centurión, David

    2014-10-01

    The sympathetic nervous system that innervates the peripheral circulation is regulated by several mechanisms/receptors. It has been reported that prejunctional 5-HT1A, 5-HT1B, 5-HT1D, D2-like receptors and α2-adrenoceptors mediate the inhibition of the vasopressor sympathetic outflow in pithed rats. In addition, ergotamine, an antimigraine drug, displays affinity at the above receptors and may explain some of its adverse/therapeutic effects. Thus, the aims of this study were to investigate in pithed rats: (i) whether ergotamine produces inhibition of the vasopressor sympathetic outflow; and (ii) the major receptors involved in this effect. For this purpose, male Wistar pithed rats were pre-treated with gallamine (25 mg/kg; i.v.) and desipramine (50 µg/kg) and prepared to stimulate the vasopressor sympathetic outflow (T7-T9; 0.03-3 Hz) or to receive i.v. bolus of exogenous noradrenaline (0.03-3 µg/kg). I.v. continuous infusions of ergotamine (1 and 1.8 μg/kgmin) dose-dependently inhibited the vasopressor responses to sympathetic stimulation but not those to exogenous noradrenaline. The sympatho-inhibition elicited by 1.8 μg/kg min ergotamine was (i) unaffected by saline (1 ml/kg); (ii) partially antagonised by WAY 100635 (5-HT1A; 30 μg/kg) and rauwolscine (α2-adrenoceptor; 300 μg/kg), and (iii) dose-dependently blocked by GR 127935 (5-HT1B/1D; 100 and 300 μg/kg) or raclopride (D2-like; 300 and 1000 μg/kg), The above doses of antagonists did not modify per se the sympathetically-induced vasopressor responses. The above results suggest that ergotamine induces inhibition of the vasopressor sympathetic outflow by activation of prejunctional 5-HT1A, 5-HT1B/1D, α2-adrenoceptors and D2-like receptors in pithed rats. PMID:24975101

  1. The role of the serotonin receptor subtypes 5-HT1A and 5-HT7 and its interaction in emotional learning and memory

    Oliver eStiedl

    2015-08-01

    Full Text Available Serotonin (5-hydroxytryptamine, 5-HT is a multifunctional neurotransmitter innervating cortical and limbic areas involved in cognition and emotional regulation. Dysregulation of serotonergic transmission is associated with emotional and cognitive deficits in psychiatric patients and animal models. Drugs targeting the 5-HT system are widely used to treat mood disorders and anxiety-like behaviors. Among the fourteen 5-HT receptor (5-HTR subtypes, the 5-HT1AR and 5-HT7R are associated with the development of anxiety, depression and cognitive function linked to mechanisms of emotional learning and memory. In rodents fear conditioning and passive avoidance (PA are associative learning paradigms to study emotional memory. This review assesses the role of 5-HT1AR and 5-HT7R as well as their interplay at the molecular, neurochemical and behavioral level. Activation of postsynaptic 5-HT1ARs impairs emotional memory through attenuation of neuronal activity, whereas presynaptic 5-HT1AR activation reduces 5-HT release and exerts pro-cognitive effects on PA retention. Antagonism of the 5-HT1AR facilitates memory retention possibly via 5-HT7R activation and evidence is provided that 5HT7R can facilitate emotional memory upon reduced 5-HT1AR transmission. These findings highlight the differential role of these 5-HTRs in cognitive/emotional domains of behavior. Moreover, the results indicate that tonic and phasic 5-HT release can exert different and potentially opposing effects on emotional memory, depending on the states of 5-HT1ARs and 5-HT7Rs and their interaction. Consequently, individual differences due to genetic and/or epigenetic mechanisms play an essential role for the responsiveness to drug treatment, e.g., by SSRIs which increase intrasynaptic 5-HT levels thereby activating multiple pre- and postsynaptic 5-HTR subtypes.

  2. Pre-gestational stress reduces the ratio of 5-HIAA to 5-HT and the expression of 5-HT1A receptor and serotonin transporter in the brain of foetal rat

    Huang Yuejun

    2012-02-01

    Full Text Available Abstract Background Many studies have found that stress before or during pregnancy is linked to an increased incidence of behavioural disorders in offspring. However, few studies have investigated hypothalamic-pituitary-adrenal (HPA axis activity and the serotonergic system as a consequence of pregestational stress. In the present study, we investigated the effect of pre-gestational stress on HPA axis activity in maternal rats and their foetuses and examined whether changes in HPA axis activity of maternal rats produced functional changes in the serotonergic system in the brain of foetuses. Results We used the behavioural tests to assess the model of chronic unpredictable stress (CUS in maternal rats. We found the activity in the open field and sucrose consumption was lower for rats with CUS than for the controls. Body weight but not brain weight was higher for control foetuses than those from the CUS group. Serum corticosterone and corticotrophin-releasing hormone levels were significantly higher for mothers with CUS before pregnancy and their foetuses than for the controls. Levels of 5-hydroxytryptamine (5-HT were higher in the hippocampus and hypothalamus of foetuses in the CUS group than in the controls, and 5-hydroxyindoleacetic acid (5-HIAA levels were lower in the hippocampus in foetuses in the CUS group than in the control group. Levels of 5-HIAA in the hypothalamus did not differ between foetuses in the CUS group and in the control group. The ratio of 5-HIAA to 5-HT was significantly lower for foetuses in the CUS group than in the control group. Levels of 5-HT1A receptor were significantly lower in the foetal hippocampus in the CUS group than in the control group, with no significant difference in the hypothalamus. The levels of serotonin transporter (SERT were lower in both the foetal hippocampus and foetal hypothalamus in the CUS group than in the control group. Conclusions Our data demonstrate that pre-gestational stress alters HPA

  3. Spinal 5-HT1A, not the 5-HT1B or 5-HT3 receptors, mediates descending serotonergic inhibition for late-phase mechanical allodynia of carrageenan-induced peripheral inflammation.

    Kim, Joung Min; Jeong, Seong Wook; Yang, Jihoon; Lee, Seong Heon; Kim, Woon Mo; Jeong, Seongtae; Bae, Hong Beom; Yoon, Myung Ha; Choi, Jeong Il

    2015-07-23

    Previous electrophysiological studies demonstrated a limited role of 5-hydroxytryptamine 3 receptor (5-HT3R), but facilitatory role of 5-HT1AR and 5-HT1BR in spinal nociceptive processing of carrageenan-induced inflammatory pain. The release of spinal 5-HT was shown to peak in early-phase and return to baseline in late-phase of carrageenan inflammation. We examined the role of the descending serotonergic projections involving 5-HT1AR, 5-HT1BR, and 5-HT3R in mechanical allodynia of early- (first 4h) and late-phase (24h after) carrageenan-induced inflammation. Intrathecal administration of 5-HT produced a significant anti-allodynic effect in late-phase, but not in early-phase. Similarly, intrathecal 5-HT1AR agonist (8-OH-DPAT) attenuated the intensity of late-phase allodynia in a dose dependent fashion which was antagonized by 5-HT1AR antagonist (WAY-100635), but produced no effect on the early-phase allodynia. However, other agonists or antagonists of 5-HT1BR (CP-93129, SB-224289) and 5-HT3R (m-CPBG, ondansetron) did not produce any anti- or pro-allodynic effect in both early- and late- phase allodynia. These results suggest that spinal 5-HT1A, but not 5-HT1B or 5-HT3 receptors mediate descending serotonergic inhibition on nociceptive processing of late-phase mechanical allodynia in carrageenan-induced inflammation. PMID:26037417

  4. The serotonergic hallucinogen 5-methoxy-N,N-dimethyltryptamine disrupts cortical activity in a regionally-selective manner via 5-HT(1A) and 5-HT(2A) receptors.

    Riga, Maurizio S; Bortolozzi, Analia; Campa, Letizia; Artigas, Francesc; Celada, Pau

    2016-02-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen, acting as a non-selective serotonin 5-HT(1A)/5-HT(2A)-R agonist. Psychotomimetic agents such as the non-competitive NMDA-R antagonist phencyclidine and serotonergic hallucinogens (DOI and 5-MeO-DMT) disrupt cortical synchrony in the low frequency range (DMT on low frequency cortical oscillations (LFCO, DMT reduced LFCO in the PFC of WT and KO2A mice. The effect in KO2A mice was fully prevented by the 5-HT(1A)-R antagonist WAY-100635. Systemic and local 5-MeO-DMT reduced 5-HT release in PFC mainly via 5-HT(1A)-R. Moreover, 5-MeO-DMT reduced LFCO in S1, Au1 and V1 of WT mice and only in V1 of KO2A mice, suggesting the involvement of 5-HT(1A)-R activation in the 5-MeO-DMT-induced disruption of V1 activity. In addition, antipsychotic drugs reversed 5-MeO-DMT effects in WT mice. The present results suggest that the hallucinogen action of 5-MeO-DMT is mediated by simultaneous alterations of the activity of sensory (S1, Au1, V1) and associative (PFC) cortical areas, also supporting a role of 5-HT(1A)-R stimulation in V1 and PFC, in addition to the well-known action on 5-HT(2A)-R. Moreover, the reversal by antipsychotic drugs of 5-MeO-DMT effects adds to previous literature supporting the usefulness of the present model in antipsychotic drug development. PMID:26477571

  5. Transcriptional dysregulation of 5-HT1A autoreceptors in mental illness

    Albert Paul R

    2011-05-01

    Full Text Available Abstract The serotonin-1A (5-HT1A receptor is among the most abundant and widely distributed 5-HT receptors in the brain, but is also expressed on serotonin neurons as an autoreceptor where it plays a critical role in regulating the activity of the entire serotonin system. Over-expression of the 5-HT1A autoreceptor has been implicated in reducing serotonergic neurotransmission, and is associated with major depression and suicide. Extensive characterization of the transcriptional regulation of the 5-HT1A gene (HTR1A using cell culture systems has revealed a GC-rich "housekeeping" promoter that non-selectively drives its expression; this is flanked by a series of upstream repressor elements for REST, Freud-1/CC2D1A and Freud-2/CC2D1B factors that not only restrict its expression to neurons, but may also regulate the level of expression of 5-HT1A receptors in various subsets of neurons, including serotonergic neurons. A separate set of allele-specific factors, including Deaf1, Hes1 and Hes5 repress at the HTR1A C(-1019G (rs6295 polymorphism in serotonergic neurons in culture, as well as in vivo. Pet1, an obligatory enhancer for serotonergic differentiation, has been identified as a potent activator of 5-HT1A autoreceptor expression. Taken together, these results highlight an integrated regulation of 5-HT1A autoreceptors that differs in several aspects from regulation of post-synaptic 5-HT1A receptors, and could be selectively targeted to enhance serotonergic neurotransmission.

  6. 5-HT1A Autoreceptors in the Dorsal Raphe Nucleus Convey Vulnerability to Compulsive Cocaine Seeking.

    You, In-Jee; Wright, Sherie R; Garcia-Garcia, Alvaro L; Tapper, Andrew R; Gardner, Paul D; Koob, George F; David Leonardo, E; Bohn, Laura M; Wee, Sunmee

    2016-04-01

    Cocaine addiction and depression are comorbid disorders. Although it is well recognized that 5-hydroxytryptamine (5-HT; serotonin) plays a central role in depression, our understanding of its role in addiction is notably lacking. The 5-HT system in the brain is carefully controlled by a combined process of regulating 5-HT neuron firing through 5-HT autoreceptors, neurotransmitter release, enzymatic degradation, and reuptake by transporters. This study tests the hypothesis that activation of 5-HT1A autoreceptors, which would lessen 5-HT neuron firing, contributes to cocaine-seeking behaviors. Using 5-HT neuron-specific reduction of 5-HT1A autoreceptor gene expression in mice, we demonstrate that 5-HT1A autoreceptors are necessary for cocaine conditioned place preference. In addition, using designer receptors exclusively activated by designer drugs (DREADDs) technology, we found that stimulation of the serotonergic dorsal raphe nucleus (DRN) afferents to the nucleus accumbens (NAc) abolishes cocaine reward and promotes antidepressive-like behaviors. Finally, using a rat model of compulsive-like cocaine self-administration, we found that inhibition of dorsal raphe 5-HT1A autoreceptors attenuates cocaine self-administration in rats with 6 h extended access, but not 1 h access to the drug. Therefore, our findings suggest an important role for 5-HT1A autoreceptors, and thus DRNNAc 5-HT neuronal activity, in the etiology and vulnerability to cocaine reward and addiction. Moreover, our findings support a strategy for antagonizing 5-HT1A autoreceptors for treating cocaine addiction. PMID:26324408

  7. Modulatory effect of the 5-HT1A agonist buspirone and the mixed non-hallucinogenic 5-HT1A/2A agonist ergotamine on psilocybin-induced psychedelic experience.

    Pokorny, Thomas; Preller, Katrin H; Kraehenmann, Rainer; Vollenweider, Franz X

    2016-04-01

    The mixed serotonin (5-HT) 1A/2A/2B/2C/6/7 receptor agonist psilocybin dose-dependently induces an altered state of consciousness (ASC) that is characterized by changes in sensory perception, mood, thought, and the sense of self. The psychological effects of psilocybin are primarily mediated by 5-HT2A receptor activation. However, accumulating evidence suggests that 5-HT1A or an interaction between 5-HT1A and 5-HT2A receptors may contribute to the overall effects of psilocybin. Therefore, we used a double-blind, counterbalanced, within-subject design to investigate the modulatory effects of the partial 5-HT1A agonist buspirone (20mg p.o.) and the non-hallucinogenic 5-HT2A/1A agonist ergotamine (3mg p.o.) on psilocybin-induced (170 µg/kg p.o.) psychological effects in two groups (n=19, n=17) of healthy human subjects. Psychological effects were assessed using the Altered State of Consciousness (5D-ASC) rating scale. Buspirone significantly reduced the 5D-ASC main scale score for Visionary Restructuralization (VR) (pergotamine did not show any effects on the psilocybin-induced 5D-ASC main scale scores. The present finding demonstrates that buspirone exerts inhibitory effects on psilocybin-induced effects, presumably via 5-HT1A receptor activation, an interaction between 5-HT1A and 5-HT2A receptors, or both. The data suggest that the modulation of 5-HT1A receptor activity may be a useful target in the treatment of visual hallucinations in different psychiatric and neurological diseases. PMID:26875114

  8. Mutational analysis of the promoter and the coding region of the 5-HT1A gene

    Erdmann, J.; Noethen, M.M.; Shimron-Abarbanell, D. [Univ. of Bonn (Germany)] [and others

    1994-09-01

    Disturbances of serotonergic pathways have been implicated in many neuropsychiatric disorders. Serotonin (5HT) receptors can be subdivided into at least three major families (5HT1, 5HT2, and 5HT3). Five human 5HT1 receptor subtypes have been cloned, namely 1A, 1D{alpha}, 1D{beta}, 1E, and 1F. Of these, the 5HT1A receptor is the best characterized subtype. In the present study we sought to identify genetic variation in the 5HT1A receptor gene which through alteration of protein function or level of expression might contribute to the genetics of neuropsychiatric diseases. The coding region and the 5{prime} promoter region of the 5HT1A gene from 159 unrelated subjects (45 schizophrenic, 46 bipolar affective, and 43 patients with Tourette`s syndrome, as well as 25 controls) were analyzed using SSCA. SSCA revealed the presence of two mutations both located in the coding region of the 5HT1A receptor gene. The first mutation is a rare silent C{r_arrow}T substitution at nucleotide position 549. The second mutation is characterized by a base pair substitution (A{r_arrow}G) at the first position of codon 28 and results in an amino acid exchange (Ile{r_arrow}Val). Since Val28 was found only in a single schizophrenic patient and in none of the other patients or controls, we decided to extend our samples and to use a restriction assay for screening a further 74 schizophrenic, 95 bipolar affective, and 49 patients with Tourette`s syndrome, as well as 185 controls, for the presence of the mutation. In total, the mutation was found in 2 schizophrenic patients, in 3 bipolars, in 1 Tourette patient, and in 5 controls. To our knowledge the Ile-28-Val substitution reported here is the first natural occuring molecular variant which has been identified for a serotonin receptor so far.

  9. 远位触液神经元5-HT1A受体在大鼠神经病理性痛中的作用%Role of 5-HT1A receptor in distal cerebrospinal fluid-contacting neurons in neuropathic pain in rats

    张崧; 朱品; 郭建荣; 张励才

    2011-01-01

    目的 评价远位触液神经元5-羟色胺1A(5-HT1A)受体在大鼠神经病理性痛中的作用.方法 雄性SD大鼠40只,体重230~270 g,采用随机数字表法,将其随机分为4组(n=10):假手术组(S组)、神经病理性痛组(NP组)、二甲基亚砜组(DMSO组)和8-羟基-2-(双-正丙胺基)-四氢萘满组(8-OH-DPAT组).采用坐骨神经慢性压迫法(CCI制备大鼠神经病理性痛模型,S组仅暴露坐骨神经,但不结扎.CCI后第7天,8-OH-DPAT组和DMSO组向远位触液神经元分别缓慢注射5-HT1A受体特异性激动剂8-OH-DPAT或DMSO 1 μl,5 min内注射完毕.分别于CCI前(T0)、CCI后第7天(T1)和给药后3、6 h(T2,3)时,测定缩足潜伏期(PWL)和缩足阈值(PWT).于给药后6 h时处死大鼠,取脑组织,采用免疫荧光标记法检测远位触液核神经元5-HT1A受体的表达.结果 与S组比较,NP组、DMSO组和8-OH-DPAT组T1时PWL缩短,PWT降低(P<0.01);与DMSO组比较,8-OH-DPAT组T2和T3时PWL延长,PWT升高(P<0.01).与S组比较,NP组和DMSO组5-HT1A受体表达下调(P<0.01);与NP组和DMSO组比较,8-OH-DPAT组5-HT1A.受体表达上调(P<0.01);NP组和DMSO组间5-HT1A受体表达比较差异无统计学意义(P>0.05).结论 远位触液神经元5-HT1A受体参与了大鼠神经病理性痛的调控.%Objective To evaluate the role of 5-HT1A receptors in distal cerebrospinal fluid (CSF)-contacting neurons in neuropathic pain (NP) in rats. Methods Forty male SD rats weighing 230-270 g were randomly divided into 4 groups (n = 8 each): sham operation group (group S); NP group; dimethyl sulfoxide (DMSO) group and 8-OH-DPAT (a specific 5-HT1A receptor agonist) group. NP was induced by chronic constrictive injury (CCI) in groups NP, DMSO and 8-OH-DPAT. Four silk ligatures were placed on the sciatic nerve at 1 mm intervals . In group S, the sciatic nerve was exposed but not ligated. 8-OH-DPAT and DMSO 1 μl were injected into the region where most of CSF-contacting neurons are present over 5 min

  10. Synthesis and structure-affinity relationships of novel small molecule natural product derivatives capable of discriminating between serotonin 5-HT1A, 5-HT2A, 5-HT2C receptor subtypes

    Cummings, David F.; Canseco, Diana C.; Sheth, Pratikkumar; Johnson, James E.; Schetz, John A.

    2010-01-01

    Efforts to develop ligands that distinguish between clinically relevant 5-HT2A and 5-HT2C serotonin receptor subtypes have been challenging, because their sequences have high homology. Previous studies reported that a novel aplysinopsin belonging to a chemical class of natural products isolated from a marine sponge was selective for the 5-HT2C over the 5-HT2A receptor subtype. Our goal was to explore the 5-HT2A/2C receptor structure-affinity relationships of derivatives based on the aplysinop...

  11. Differential regulation of serotonin-1A receptor stimulated [35S]GTPγS binding in the dorsal raphe nucleus by citalopram and escitalopram

    Rossi, Dania V.; Burke, Teresa F.; Hensler, Julie G.

    2008-01-01

    The effect of chronic citalopram or escitalopram administration on 5-HT1A receptor function in the dorsal raphe nucleus was determined by measuring [35S]GTPγS binding stimulated by the 5-HT1A receptor agonist (R)-(+)-8-OH-DPAT (1nM-10μM). Although chronic administration of citalopram or escitalopram has been shown to desensitize somatodendritic 5-HT1A autoreceptors, we found that escitalopram treatment decreased the efficacy of 5-HT1A receptors to activate G-proteins, whereas citalopram treat...

  12. Orbitofrontal Cortex 5-HT1A Receptor Modulate Glutamate and GABA in Depression Induced by Chronic Unpredictable Mild Stress%应激性抑郁样行为发生中眶额叶5-HT1A受体对谷氨酸和γ-氨基丁酸的调节

    李江娜; 安书成; 李珍

    2015-01-01

    Stress response and depression have a crucial impact on modern society. Although the symptoms are well characterized, the molecular mechanisms underlying depression are largely unknown. Currently, the monoaminergic systems, especially serotonergic systems, have received the most attention in the research of depression. Accumulating evidence suggests that the glutamatergic and GABAergic system play an important role in the neurobiology and treatment of this disease. Multiple studies have shown that serotonin (5-HT) could modulate the neurotransmission of glutamic acid (Glu) and gamma-aminobutyric acid (GABA). The orbitofrontal cortex (OFC), which is involved in the pathophysiology and treatment of depression, plays a critical role in the control of higher brain functions and it mainly receives a dense 5-HT innervation from the dorsal raphe nucleus. There exist some 5-HT1A receptors on glutamatergic neurons and GABAergic neurons in the OFC. The purpose of this research was to elucidate the modulatory action of 5-HT1A receptor on the functions of Glu and GABA, which are the principal neurotransmitters mediating excitatory and inhibitory signals in the OFC respectively, in a well-established animal model of depression induced by chronic unpredictable mild stress (CUMS). We used CUMS in rat to mimic the core symptoms in human. Using the pharmacology approaches by microinjecting of 5-HT1A receptor agonist 8-OH-DPAT and its antagonist WAY100635 to the OFC, we detected behavioral changes by using behavior tests including sucrose preference test, open field test and tail suspension test. In addition, high-performance liquid chromatography (HPLC) was used to detect the level of neurotransmitters such as 5-HT, Glu and GABA in the OFC, respectively. CUMS group showed a variety of behavioral characteristics of depression, including a significant reduction in the sucrose preference, and locomotion, rearing and grooming in the open field test, and a significant increase in

  13. Effect of chronic rapid eye movement sleep deprivation on cognition and protein expression of brain 5-HT1A receptor in rats%慢性睡眠剥夺对大鼠学习记忆功能及不同脑区5-羟色胺1A受体蛋白表达的影响

    荣霏; 程滨; 温晓飒; 马文领

    2012-01-01

    Objective To investigate the effect of chronic rapid eye movement (REM) sleep deprivation on learning and memory function and the changes of 5-HT1A receptor protein expression in hippocampus, prefrontal cortex and hypothalamus in rats. Methods Adult male Sprague-Dawley rats were randomly divided into chronic REM sleep deprivation (CSD, n = 15), big platform treatment control (TC, n = 12) and blank control (BC, n = 4) groups after screening experiment. The sleep deprivation model was established by modified multiple platform method. Learning and memory functions were detected by Morris water maze and open field test before and after sleep deprivation. The effects of chronic REM sleep deprivation on 5-HT1A receptor protein expression in the hippocampus, prefrontal cortex and hypothalamus were analyzed by Western blotting analysis. Results Compared with BC and TC groups, the weight of the rats in CSD group was significantly decreased 3 days after sleep deprivation (all P0.05). Motion speed of the central region in CSD rats was significantly slower than that in TC rats 21 days after CSD (P<0.05). Compared with BC and TC groups, the protein expression of 5-HT1A receptor in the 3 encephalic regions significantly increased in CSD group 21 days after CSD (P<0. 05), especially in the hypothalamus (P<0. 01). Conclusion Chronic REM sleep deprivation can impair the learning and memory. 5-HT1A receptor may be involved in modulating the dysfunction.%目的 观察慢性快速眼动相(REM)睡眠剥夺对大鼠学习记忆能力以及海马、前额皮质、下丘脑5-羟色胺1A(5-HT1A)受体蛋白表达变化的影响.方法 成年雄性Sprague-Dawley大鼠经过筛选后随机分为空白对照组(BC组,4只)、大平台对照组(TC组,12只)和慢性睡眠剥夺(CSD)组(15只).采用改良多平台水环境方法建立大鼠慢性REM睡眠剥夺模型,利用Morris水迷宫、自主活动箱检测CSD后大鼠学习记忆功能变化,Western印迹法分析CSD对大鼠海

  14. Disruption of 5-HT1A function in adolescence but not early adulthood leads to sustained increases of anxiety.

    Garcia-Garcia, A L; Meng, Q; Richardson-Jones, J; Dranovsky, A; Leonardo, E D

    2016-05-01

    Current evidence suggests that anxiety disorders have developmental origins. Early insults to the circuits that sub-serve emotional regulation are thought to cause disease later in life. Evidence from studies in mice demonstrate that the serotonergic system in general, and serotonin 1A (5-HT1A) receptors in particular, are critical during the early postnatal period for the normal development of circuits that subserve anxious behavior. However, little is known about the role of serotonin signaling through 5-HT1A receptors between the emergence of normal anxiety behavior after weaning, and the mature adult phenotype. Here, we use both transgenic and pharmacological approaches in male mice, to identify a sensitive period for 5-HT1A function in the stabilization of circuits mediating anxious behavior during adolescence. Using a transgenic approach we show that suppression of 5-HT1A receptor expression beginning in early adolescence results in an anxiety-like phenotype in the open field test. We further demonstrate that treatment with the 5-HT1A antagonist WAY 100,635 between postnatal day (P)35 and P50, but not at later timepoints, results in altered anxiety in ethologically based conflict tests like the open field test and elevated plus maze. This change in anxiety behavior occurs without impacting behavior in the more depression-related sucrose preference test or forced swim test. The treatment with WAY 100,635 does not affect adult 5-HT1A expression levels, but leads to increased expression of the serotonin transporter in the raphe, along with enhanced serotonin levels in both the prefrontal cortex and raphe that correlate with the behavioral changes observed in adult mice. This work demonstrates that signaling through 5-HT1A receptors during adolescence (a time when pathological anxiety emerges), but not early adulthood, is critical in regulating anxiety setpoints. These data suggest the possibility that brief interventions in the serotonergic system during

  15. The 5-HT1A agonists 8-OH-DPAT, buspirone and ipsapirone attenuate stress-induced anorexia in rats.

    Dourish, C T; Kennett, G A; Curzon, G

    1987-01-01

    The effects of 5-HT agonists and antagonists, benzodiazepine anxiolytics and tricyclic antidepressants on restraint stress-induced anorexia in rats were examined. The selective 5-HT(1A) agonists 8-hydroxy-2-(di- n-propylamino)tetralin (8-OH-DPAT), buspirone and ipsapirone, when injected 2 h after the termination of stress, attenuated stress-induced anor exia and body weight loss. The effects of 8-OH-DPAT on stress-induced anorexia were blocked by the 5-HT(1A) antagonist spiperone but not by the 5-HT(2) antagonist ketanserin. The preferential 5-HT(1B) agonists RU-24969 and quipazine induced anorexia in unstressed rats and tended to supplement the anorectic effects of stress. The benzodiazepines chlordiazepoxide and diazepam and the 5-HT antagonist cyproheptadine had no effect on stress-induced anorexia, when given (like the 5-HT(1A) agonists) 2 h after the stress. Similarly, daily injection for 2 weeks of the tricyclic antidepressants desipramine and sertraline had no beneficial effect. The data suggest that 8-OH-DPAT, buspirone and ipsapirone attenuate stress-induced anorexia in rodents by a hyperphagic action on 5-HT(1A) receptors. PMID:22158750

  16. Augmentative effect of tetrandrine on pentobarbital hypnosis mediated by 5-HT1A and 5-HT2A/2C receptors in mice%5-HT1A和5-HT2A/2C受体在粉防己碱增强戊巴比妥钠睡眠中的介导作用

    杜楠; 王黎恩; 师晓荣; 崔翔宇; 崔素颖; 张帆; 张永鹤

    2008-01-01

    前期研究表明粉防己碱增强戊巴比妥钠诱导的催眠作用与5-HT系统相关.本研究采用戊巴比妥钠(45 mg/kg,协)诱导的小鼠翻正反射消失和恢复实验方法,对粉防己碱与不同5-HT受体在增强戊巴比妥钠诱导睡眠中的相互作用进行了探讨.结果表明粉防己碱分别与选择性5-HT1A受体拮抗剂p-MPPI(1 mg/kg,i.p.),选择性5-HT2A/2C受体拮抗剂ketanserin(1.5mg/kg,i.p.)合用可以显著增强戊巴比妥钠诱导的催眠作用.选择性5-HT1A受体激动剂8-OH-DPAT(0.1 mg/kg,s.c.)或5-HT2A/2C受体激动剂DOI(0.2 mg/kg.i.p.)能够显著减少戊巴比妥钠诱导的小鼠睡眠时间,而粉防己碱(60 mg/kg,i.p.)可以显著拮抗这种睡眠抑制作用.此结果提示,粉防己碱增强戊巴比妥钠诱导的催眠作用可能与5-HT1A受体和5-HT2A/2C受体有关.%It has been reported that augmentative effect of tetrandrine on pentobarbital hypnosis in mice may be related to sero-tonergic system. The present study was undertaken to investigate the interaction of tetrandrine and different 5-HT receptors on pentobarbital-induced sleep by using the loss-of-righting reflex method. The results showed that augmentative effect of tetrandrine on pentobarbital hypnosis in mice were potentiated by the p-MPPI (5-HT1A receptor antagonist) (1 mg/kg, i.p.) and ketanserin (5-HT2A/2C receptor antagonist) (1.5 mg/kg, i.p.), respectively. Pretreatment with either 8-OH-DPAT (5-HT1A receptor agonist)(0.1 mg/kg, s.c.) or DOI (5-HT2A/2C receptor agonist) (0.2 mg/kg, i.p.) significantly decreased pentobarbital-induced sleep time,and tetrandrine (60 mg/kg, i.g.) significantly reversed this effect. These results suggest that both the 5-HTtA and 5-HT2A/2C subfamily may be involved in the potentiating mechanism of tetrandrine's effects on pentobarbital hypnosis.

  17. Influence of intraventricular inj ection of 5,7-drhydroxytryptamine in 5-HT1A receptor sensitivity of pyramidal neurons in medial prefrontal cortex%脑室内注射5,7-双羟色胺对内侧前额叶皮层锥体神经元5-HT1 A受体敏感性的影响

    刘彦彤; 高捷; 王爽

    2014-01-01

    Objective To explore the influence of intraventricular injection of 5, 7-drhydroxytryptamine (5, 7-DHT)in 5-HT1A receptor sensitivity of medial prefrontal cortex pyramidal neurons in the rats,and to clarity the effect of 5-HT1A receptor on the eletronic response of pyramidal neurons.Methods 36 male SD rats were randomly divided into sham operation group (n=21)and 5,7-DHT lesion group (n=15).5,7-DHT was injected intraventricularly in the rats in 5,7-DHT lesion group,and the same dose saline was injected in the rats in sham operation group.The rats in two groups were intravenously injected with different doses(0.5-128.0μg·kg-1 )of 8-CH-DPAT.The firing rate of mPFC pyramidal neurons was recorded with extracellular electrophysioological examination.The rats in two groups were intravenously injected with WAY100635,the sensitivites of the rats to 8-OH-DPAT and WAY100635 in 5, 7-DHT lesion group were observed, and compared with sham operation group.Results The different doses (0.5-128.0μg·L-1 )of 8-OH-DDAT had an excitatory-inhibitory effect on the firing rate of mPFC pyamidal neurons in sham operation group;the neurons were excited when the doses of 8-OH-DPAT were 0.5-38.0μg·kg-1 ,and the firing rates were increased(P<0.05);the neurons were inhibited when the dose of 8-OH-DPAT was 128.0μg·kg-1 ,and the firing rate was decreased.The different doses(0.5-218.0μg·L-1 )of 8-OH-DPAT inhibited the elecctronic response of pyramidal neurons of the rats in 5,7-DHT lesion group in a dose-dependent manner (df=5,F=3.44,P=0.003),and the firing rates were reduced. WAY-100635 (50μg·kg-1 )reversed completely the inhibition of 8-OH-DPAT.Conclusion The sensitivity of 5-HT1A receptor of rat mPFC pyramidal neurons can be decreased by intraventricular injection of 5,7-DHT.%目的:探讨脑室内注射5,7-双羟色胺(5,7-DHT)对内侧前额叶皮层(mPFC)锥体神经元5-羟色胺-1A(5-HT1A)受体敏感性的影响,阐明5-HT1A受体对锥体神经元

  18. Apports de la TEP dans l'imagerie moléculaire des récepteurs sérotoninergiques 5-HT1A et 5-HT7

    Lemoine, Laëtitia

    2011-01-01

    The serotonergic system, implicated in several diseases of central nervous system, can be explored in vivo by PET imaging (positron emission tomography). The research and the preclinical validation of radiotracers that specifically target serotonin are crucial. In this work, we focused on two serotonin receptors for which we have developed molecular tools for functional imaging: (i) the 5-HT1A and (ii) the 5-HT7. (i) 5-HT1A receptors are among the serotonin receptors the best described at pre...

  19. Proopiomelanocortin but not vasopressin or renin-angiotensin system induces resuscitative effects of central 5-HT1A activation in haemorrhagic shock in rats.

    Sowa, P; Adamczyk-Sowa, M; Zwirska-Korczala, K; Pierzchala, K; Adamczyk, D; Paluch, Z; Misiolek, M

    2014-10-01

    The aim of this study was to determine the effectory mechanisms: vasopressin, renin-angiotensin system and proopiomelanocortin-derived peptides (POMC), partaking in the effects of serotonin through central serotonin 1A receptor (5-HT1A) receptors in haemorrhagic shock in rats. The study was conducted on male Wistar rats. All experimental procedures were carried out under full anaesthesia. The principal experiment included a 2 hour observation period in haemorrhagic shock. Drugs used - a selective 5-HT1A agonist 8-OH-DPAT (5 μg/5 μl); V1a receptor antagonist [β-mercapto-β, β-cyclo-pentamethylenepropionyl(1),O-me-Tyr(2),Arg(8)]AVP (10 μg/kg); angiotensin type I receptor antagonist (AT1) ZD7155 (0.5 mg/kg, i.v.); angiotensin-converting-enzyme inhibitor captopril (30 mg/kg, i.v.); melanocortin type 4 (MC4) receptor antagonist HS014 (5 μg, i.c.v.). There was no influence of ZD715, captopril or blocking of the V1a receptors on changes in the heart rate (HR), mean arterial pressure (MAP), peripheral blood flow or resistance caused by the central stimulation of 5-HT1A receptors (P≥0.05). However, selective blocking of central MC4 receptors caused a slight, but significant decrease in HR and MAP (Pvasopressin systems do not participate in these actions. PMID:25371525

  20. 何首乌的抗抑郁作用及其对海马5HT1A受体表达和神经细胞发生的影响%Anti-depression effect of Heshouwu (Radix Polygoni Muotiflori) and its influences on expression of hippocampus 5HT1A receptor and neurogenesis

    畅洪昇; 鲁艺; 王伟明; 李丽娜; 孙文燕; 王伟; 王庆国

    2012-01-01

    Objective To study the anti-depression effect and mechanism of Heshouwu {Radix Polygoni Muotiflori), a medicinal with the actions of nourishing blood and tonifying liver. Methods The rat and mouse models of depression were established by using bounding combining chronic unpredictable mild stress. The anti-depression effect of Heshouwu was evaluated through open field test and sucrose preference degree detection. The expression of 5HT1A was analyzed by using RT-PCR technique. New neurons were labeled through the intraperitoneal injection of Brdu, and neurogenesis in brain tissue was detected by applying ELISA. Results Heshouwu (2 g/kg) improved the horizontal movement and sucrose preference degree (P <0. 05), and increased the expression of hippocampus 5HT1A mRNA in chronic stress rats. Heshouwu (2. 85 g/kg) increased the content of brain Brdu in chronic stress mice (P <0.01). All above effects of Heshouwu were similar to those of fluoxetine. Conclusion Heshouwu can relieve the depression behaviors of chronic stress animals, and the mechanism may be related to that it can improve 5HT neuron transmission and axoneuron proliferation. The therapy of nourishing blood and tonifying liver and related medicinal and formulas is important in the treatment of depression.%目的 研究养血补肝药物何首乌的抗抑郁作用和机制.方法 采用束缚联合慢性不可预知温和应激大鼠、小鼠抑郁模型,通过敞箱行为和蔗糖水偏嗜度测试评价何首乌的抗抑郁药效作用.通过RT-PCR技术分析海马5HT1A基因表达,通过腹腔注射溴脱氧核苷尿嘧啶(Brdu)标记新生神经细胞,并以酶联免疫(ELISA)检测分析脑组织神经细胞发生.结果 何首乌(2 g/kg)增加了慢性应激大鼠的水平运动、蔗糖水偏嗜度(P<0.05),以及海马5HT1AmRNA表达(P<0.01).何首乌(2.85 g/kg)增加了慢性应激小鼠脑组织中Brdu含量(P<0.01),以上作用与氟西汀相似.结论 何首乌可以改善慢性应激动物

  1. Effect of prenatal stress on memory, nicotine withdrawal and 5HT1A expression in raphe nuclei of adult rats.

    Said, N; Lakehayli, S; El Khachibi, M; El Ouahli, M; Nadifi, S; Hakkou, F; Tazi, A

    2015-06-01

    Maternal distress has often been associated with cognitive deficiencies and drug abuse in rats. This study examined these behavioral effects in offspring of mothers stressed during gestation. To this end, pregnant dams were subjected to daily electric foot shocks during the last 10 days of pregnancy. We measured litter parameters and body weights of the descendants after weaning (21 days) and at adulthood (80 days). Afterwards, prenatally stressed and control rats' performances in the novel object recognition test were compared in order to evaluate their memory while others underwent the Water consumption test to assess the nicotine withdrawal intensity after perinatal manipulations. Meanwhile, another set of rats were sacrificed and 5HT1A receptors' mRNA expression was measured in the raphe nuclei by quantitative Real Time PCR. We noticed no significant influence of maternal stress on litter size and body weight right after weaning. However, control rats were heavier than the stressed rats in adulthood. The results also showed a significant decrease in the recognition score in rats stressed in utero compared to the controls. Moreover, a heightened anxiety symptom was observed in the prenatally stressed offspring following nicotine withdrawal. Additionally, the Real Time PCR method revealed that prenatal stress induced a significant decrease in 5HT1A receptors' levels in the raphe nuclei. Nicotine had a similar effect on these receptors' expression in both nicotine-treated control and prenatally stressed groups. Taken together, these findings suggest that the cognitive functions and drug dependence can be triggered by early adverse events in rats. PMID:25896010

  2. Role of Hippocampal 5-HT1A Receptor and Its Modulation to NMDA Receptor and AMPA Receptor in Depression Induced by Chronic Unpredictable Mild Stress%应激性抑郁样行为发生中海马5-羟色胺1A受体的作用及其对NMDA受体和AMPA受体的调节

    问黎敏; 安书成; 刘慧

    2012-01-01

    为探讨慢性不可预见性温和应激(chronic unpredictable mild stress,CUMS)诱发抑郁样行为发生中海马5-羟色胺1A受体(5-hydroxytryptamine receptor 1A,5-HT1AR)表达与作用,及其对谷氨酸N-甲基-D-天冬氨酸(N-methyl-D-aspartic acid,NMDA)受体和α-氨基羟甲基异恶唑丙酸(α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid,AMPA)受体的影响.通过建立CUMS动物模型,给应激抑郁模型大鼠海马微量注射5-HT1A受体激动剂、给正常大鼠海马微量注射5-HT1A受体拮抗剂,测量大鼠体重变化率,并采用糖水偏爱测试、旷场实验和悬尾实验等方法对大鼠进行行为学检测,运用Western blot和ELISA方法检测大鼠海马组织中5-HT1AR和NMDAR和AMPAR的关键亚基的表达以及磷酸化水平.结果显示,与对照组相比,CUMS组大鼠表现出抑郁样行为,海马5-HT1AR、AMPA受体的GluR2/3亚基表达及磷酸化明显降低,NMDA受体的NR1和NR2B亚基表达及磷酸化显著增加;正常大鼠海马微量注射5-HT1A受体拮抗剂WAY100635,动物行为学表现及AMPA受体、NMDA受体表达及磷酸化水平均与CUMS组相同;注射5-HT1A受体激动剂8-OH-DPAT能逆转应激诱导的上述改变.以上结果表明,CUMS诱发抑郁榉行为与海马5-HT1AR表达下降,AMPAR表达量及磷酸化水平降低,NMDAR表达量及磷酸化水平升高有关.5-HT通过5-HT1AR产生抗抑郁作用.5-HT1AR激动剂抗抑郁作用与降低NMDAR表达量及磷酸化水平,提高AMPAR表达量及磷酸化水平密切相关.%Stressors markedly influence central neurochemical and hormonal processes and thus play a pivotal role in the occurrence of depressive illnesses. As the center for stress response and the potential target for stressfulprovocation, the hippocampus is becoming a focus in depression research. Although a large number of behavioral paradigms have been proposed as animal models of depression, only a few are considered potentially useful research tools with

  3. An approach for serotonin depletion in pigs: effects on serotonin receptor binding

    Ettrup, Anders; Kornum, Birgitte R; Weikop, Pia; Knudsen, Gitte M

    2011-01-01

    CPA caused average decreases in 5-HT concentrations of 61% ± 14% and 66% ± 16%, respectively, and a substantial loss of 5-HT immunostaining was seen throughout the brain. The serotonin depletion significantly increased 5-HT₄ receptor binding in nucleus accumbens, but did not alter 5-HT(1A) and 5-HT(2A...

  4. An approach for serotonin depletion in pigs: effects on serotonin receptor binding

    Ettrup, Anders; Kornum, Birgitte R; Weikop, Pia; Knudsen, Gitte M

    2011-01-01

    CPA caused average decreases in 5-HT concentrations of 61% ± 14% and 66% ± 16%, respectively, and a substantial loss of 5-HT immunostaining was seen throughout the brain. The serotonin depletion significantly increased 5-HT4 receptor binding in nucleus accumbens, but did not alter 5-HT(1A) and 5-HT(2A...

  5. Serotonin type-1A receptor imaging in depression

    Regional 5-hydroxytryptamine1A (5-HT1A) receptor binding potential (BP) of depressed subjects with primary, recurrent, familial mood disorders was compared to that of healthy controls by using positron emission tomography and [carbonyl-11C]WAY-100635 {[11C]N-(2-(4-(2-methoxyphenyl)-1-piperazin-1-yl)ethyl)-N-(2-pyridyl) cyclohexanecarboxamide}. The mean 5-HT1A receptor BP was reduced 42% in the midbrain raphe and 25-33% in limbic and neocortical areas in the mesiotemporal, occipital, and parietal cortex. The magnitude of these abnormalities was most prominent in bipolar depressives and unipolar depressives who had bipolar relatives. These abnormal reductions in 5-HT1A receptor BP are consistent with in vivo evidence that 5-HT1A receptor sensitivity is reduced in major depressive disorder and postmortem data showing a widespread deficit of 5-HT1A receptor expression in primary mood disorders

  6. Neuroticism and serotonin 5-HT1A receptors in healthy subjects

    Hirvonen, Jussi; Tuominen, Lauri; Någren, Kjell; Hietala, Jarmo

    2015-01-01

    Neuroticism is a personality trait associated with vulnerability for mood and anxiety disorders. Serotonergic mechanisms likely contribute to neuroticism. Serotonin 5-HT1A receptors are altered in mood and anxiety disorders, but whether 5-HT1A receptors are associated with neuroticism in healthy...... subjects is unclear. We measured brain serotonin 5-HT1A receptor in 34 healthy subjects in vivo using positron emission tomography (PET) and [carbonyl-(11)C]WAY-100635. Binding potential (BPP) was determined using the golden standard of kinetic compartmental modeling using arterial blood samples and...... radiometabolite determination. Personality traits were assessed using the Karolinska Scales of Personality. We found a strong negative association between serotonin 5-HT1A receptor BPP and neuroticism. That is, individuals with high neuroticism tended to have lower 5-HT1A receptor binding than individuals with...

  7. Pinpointing brainstem mechanisms responsible for autonomic dysfunction in Rett syndrome: therapeutic perspectives for 5-HT1A agonists.

    Abdala, Ana P; Bissonnette, John M; Newman-Tancredi, Adrian

    2014-01-01

    Rett syndrome is a neurological disorder caused by loss of function of methyl-CpG-binding protein 2 (MeCP2). Reduced function of this ubiquitous transcriptional regulator has a devastating effect on the central nervous system. One of the most severe and life-threatening presentations of this syndrome is brainstem dysfunction, which results in autonomic disturbances such as breathing deficits, typified by episodes of breathing cessation intercalated with episodes of hyperventilation or irregular breathing. Defects in numerous neurotransmitter systems have been observed in Rett syndrome both in animal models and patients. Here we dedicate special attention to serotonin due to its role in promoting regular breathing, increasing vagal tone, regulating mood, alleviating Parkinsonian-like symptoms and potential for therapeutic translation. A promising new symptomatic strategy currently focuses on regulation of serotonergic function using highly selective serotonin type 1A (5-HT1A) "biased agonists." We address this newly emerging therapy for respiratory brainstem dysfunction and challenges for translation with a holistic perspective of Rett syndrome, considering potential mood and motor effects. PMID:24910619

  8. Changes in 5-HT2A-mediated behavior and 5-HT2A- and 5-HT1A receptor binding and expression in conditional brain-derived neurotrophic factor knock-out mice

    Klein, A B; Santini, M A; Aznar, S;

    2010-01-01

    Changes in brain-derived neurotrophic factor (BDNF) expression have been implicated in the etiology of psychiatric disorders. To investigate pathological mechanisms elicited by perturbed BDNF signaling, we examined mutant mice with central depletion of BDNF (BDNF(2L/2LCk-cre)). A severe impairmen...

  9. The association between romantic relationship status and 5-HT1A gene in young adults.

    Liu, Jinting; Gong, Pingyuan; Zhou, Xiaolin

    2014-01-01

    What factors determine whether or not a young adult will fall in love? Sociological surveys and psychological studies have shown that non-genetic factors, such as socioeconomic status, external appearance, and personality attributes, are crucial components in romantic relationship formation. Here we demonstrate that genetic variants also contribute to romantic relationship formation. As love-related behaviors are associated with serotonin levels in the brain, this study investigated to what extent a polymorphism (C-1019G, rs6295) of 5-HT1A gene is related to relationship status in 579 Chinese Han people. We found that 50.4% of individuals with the CC genotype and 39.0% with CG/GG genotype were in romantic relationship. Logistic regression analysis indicated that the C-1019G polymorphism was significantly associated with the odds of being single both before and after controlling for socioeconomic status, external appearance, religious beliefs, parenting style, and depressive symptoms. These findings provide, for the first time, direct evidence for the genetic contribution to romantic relationship formation. PMID:25412229

  10. Higher density of serotonin-1A receptors in the hippocampus and cerebral cortex of alcohol-preferring P rats

    Saturable [3H]-80HDPAT binding to 5HT-1A receptors in membranes prepared from hippocampus and frontal cerebral cortex of alcohol-preferring (P) rats and of alcohol-nonpreferring (NP) rats has been compared. The Bmax values or densities of recognition sites for 5HT-1A receptors in both brain areas of the P rats are 38 and 44 percent lower in the P rats than in the NP rats. The corresponding KD values are 38 and 44 percent lower in the P rats than in the NP rats, indicating higher affinities of the recognition sites for the 5HT-1A receptors in hippocampus and cerebral cortex of the P rats. These findings indicate either an enrichment of 5HT-1A receptor density during selective breeding for alcohol preference or an upregulation of 5HT-1A receptors of 5HT found in these brain areas of P rats as compared with the NP rats

  11. 5-HT1A receptors modulate small-conductance Ca2+-activated K+ channels

    Grunnet, Morten; Jespersen, Thomas; Perrier, Jean-François

    2004-01-01

    the ion channel. To investigate the physiological relevance of this pathway, we characterized the mAHP present after action potentials in spinal motoneurons recorded in a slice preparation from the lumbar spinal cord of the adult turtle. By performing current and voltage clamp recordings, we showed...

  12. Behavioral and Neuroendocrine Response to Psychosocial Stress in Male Rats : The Effects of the 5-HT 1A Agonist lpsapirone

    Korte, S. Mechiel; Smit, Jenneke; Bouws, Gerdien A.H.; Koolhaas, Jaap M.; Bohus, Béla

    1990-01-01

    The effect of the 5-HT 1A agonist ipsapirone on the behavior, plasma catecholamine, and corticosterone levels was studied in male Wistar rats during the psychosocial stress of confrontation with a confined dominant opponent 24 hr after defeat. The effect of the drug was also studied during a predefe

  13. Elevated Serotonin 1A Binding in Remitted Major Depressive Disorder: Evidence for a Trait Biological Abnormality

    Miller, Jeffrey M.; Brennan, Kathleen G.; R. Todd Ogden; Oquendo, Maria A.; Sullivan, Gregory M.; John Mann, J; Parsey, Ramin V.

    2009-01-01

    Background Several biological abnormalities in major depressive disorder (MDD) persist during episode remission, including altered serotonin neurotransmission, and may reflect underlying pathophysiology. We previously described elevated brain serotonin 1A (5-HT1A) receptor binding in antidepressant-naïve subjects with MDD within a major depressive episode (MDE) compared to healthy controls using positron emission tomography (PET). In the current study, we measured 5-HT1A receptor binding in u...

  14. Tandospirone, a 5-HT1A partial agonist is effective in treating anorexia nervosa: a case series

    Okita, Kyoji; Shiina, Akihiro; Nakazato, Michiko; Iyo, Masaomi

    2013-01-01

    This case report details the therapeutic effects of tandospirone on two patients with anorexia nervosa, one with the restricting subtype (ANR), and another with the binge-eating/purging subtype (ANBP). A 22-year-old female patient with ANR and a 23-year-old female patient with ANBP were treated successfully with the 5-HT1A partial agonist tandospirone. After treatment, not only did both patients gain weight, they also showed improved scores on the Eating Disorder Examination Questionnaire. In...

  15. 5-HT2A and mGlu2 receptor binding levels are related to differences in impulsive behavior in the Roman Low- (RLA) and High- (RHA) avoidance rat strains

    Klein, A B; Ultved, L; Adamsen, D;

    2014-01-01

    serotonin transporter (SERT), 5-HT(2A) and 5-HT(1A) receptor binding using highly specific radioligands ((3)H-escitalopram, (3)H-MDL100907 and (3)H-WAY100635) and mGlu2/3 receptor binding ((3)H-LY341495) using receptor autoradiography in fronto-cortical sections from RLA-I (n=8) and RHA-I (n=8) male rats...

  16. The effect of urapidil, an alpha-1 adrenoceptor antagonist and a 5-HT1A agonist, on the vascular tone of the porcine coronary and pulmonary arteries, the rat aorta and the human pulmonary artery.

    Bopp, Claire; Auger, Cyril; Diemunsch, Pierre; Schini-Kerth, Valérie

    2016-05-15

    Urapidil (Eupressyl(®)) an antihypertensive drug acting as an α1 antagonist and a 5-HT1A agonist, may be of special interest in the treatment of hypertension associated with preeclamptic toxaemia and hypoxia-induced pulmonary arterial vasoconstriction. However, the effect of urapidil on vascular tone has been poorly investigated. Vascular reactivity was evaluated using pulmonary and coronary arteries from 36 pigs, aortae from 22 rats and 9 human pulmonary artery samples suspended in organ chambers. Concentration-relaxation curves either to urapidil, 5-HT, or the 5-HT1A receptor agonist 8-OH-DPAT were constructed after pre-contraction of rings. Pig pulmonary and coronary artery rings were contracted with U46619, a thromboxane mimetic, rat aortic rings with either endothelin-1 or phenylephrine, and human pulmonary artery rings with U46619 or phenylephrine. Urapidil markedly inhibited phenylephrine-induced contractions in rat aortic rings with and without endothelium with a more pronounced effect observed in rings without endothelium. Both 5-HT and 8-OH-DPAT failed to induce relaxation in rat aortic rings with an intact endothelium. 5-HT, but not urapidil and 8-OH-DPAT, induced a concentration-dependent relaxation in the porcine coronary and pulmonary artery rings with an intact endothelium (P<0.05). 5-HT and phenylephrine but not urapidil caused concentration-dependent contractions in human pulmonary artery rings. The present findings, while confirming that urapidil is a potent inhibitor of α1-adrenoceptor-induced contraction, do not support the role of 5-HT1A receptor activation in the control of the vascular tone of the different types of arteries tested in response to urapidil. In addition, they indicate that urapidil seems to preferentially target arteries with endothelial dysfunction. PMID:26957055

  17. Application of highly sensitive UPLC-MS to determine biodistribution at tracer doses: validation with the 5-HT1A ligand [18F]FPWAY

    High-sensitivity and high-resolution LC/MS instrumentation has been applied in positron emission tomography (PET) radiopharmaceutical development to provide quantitative measurement of the mass of radiotracers extracted from tissues of rats. We employed the highly sensitive Waters Q-TOF premier MS coupled with an Acquity UPLC system to demonstrate that LC-MS can generate ex vivo biodistribution data for PET 5-HT1A ligand FPWAY without the need to radiolabel. For the biodistribution studies, we injected rats with [18F]FPWAY containing various amounts of nonradioactive FPWAY. At the end of the allotted time, the animals were killed and six regions of brain and plasma from each animal were processed for quantitative measurement of parent compound concentration by LC-MS. These data were then converted to the differential uptake ratio DUR (%ID/g*body weight/100) and the brain tissue-specific binding ratio to allow direct comparison with data obtained by gamma counting of the coinjected radioactive [18F]FPWAY. The DUR and the brain tissue-specific binding ratio calculated using the LC-MS method were highly correlated to the values obtained by standard radioactivity measurements of [18F]FPWAY. In conclusion, there was significant concordance between the LC/MS and radioactivity method in determination of DUR and the specific binding ratio in the rat brain. This concordance indicated that high-sensitivity LC/MS is an indispensable tool in evaluating the quantity of administered chemical in tissue as part of the development of new molecular imaging probes.

  18. Characterization of 5-HT1D receptor binding sites in post-mortem human brain cortex.

    Martial, J; de Montigny, C; Cecyre, D; Quirion, R

    1991-01-01

    The present study provides further evidence for the presence of serotonin1D (5-HT1D) receptors in post-mortem human brain. Receptor binding parameters in temporal cortex homogenates were assessed using [3H]5-HT in the presence of 100 nM 8-OH-DPAT, 1 microM propranolol and 1 microM mesulergine to prevent labelling of the 5-HT1A, 5-HT1B and 5-HT1C sites, respectively. Under these conditions, [3H]5-HT apparently bound to a class of high affinity (Kd = 5.0 +/- 1.0 nM) low capacity (Bmax = 96 +/- ...

  19. Synthesis and structure-activity relationships of a new model of arylpiperazines. Part 7: Study of the influence of lipophilic factors at the terminal amide fragment on 5-HT(1A) affinity/selectivity.

    López-Rodríguez, María L; Ayala, David; Viso, Alma; Benhamú, Bellinda; de La Pradilla, Roberto Fernández; Zarza, Fernando; Ramos, José A

    2004-03-15

    The influence of lipophilic factors at the amide fragment of a new series of (+/-)-7a-alkyl-2-[4-(4-arylpiperazin-1-yl)butyl]-1,3-dioxoperhydropyrrolo[1,2-c]imidazoles 2 and of (+/-)-7a-alkyl-2-[(4-arylpiperazin-1-yl)methyl]-1,3-dioxoperhydropyrrolo[1,2-c]imidazoles 3 has been studied. Variations of logP have been carried out by introducing different hydrocarbonated substituents (R(1)) at the position 7a of the bicyclohydantoin, namely the non-pharmacophoric part. All the new compounds exhibit high potency for the 5-HT(1A) receptor; however, affinities for the alpha(1) receptor are high for compounds 2a-l while compounds 3a-f are selective over this adrenergic receptor. On the other hand, differences in logP do not notably affect the K(i) values for the above receptors. PMID:15018929

  20. Management of skin cancer by agonists of 5-HT1A and antagonists of 5-HT2A receptors

    Menezes, Ana Catarina da Silva Fernandes Saraiva de

    2015-01-01

    Tese de mestrado, Ciências Biofarmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2015 A pele é o maior órgão humano e apresenta funções importantes quer a nível neuroendócrino, quer imunológico. A presença de um análogo do eixo hipotalâmico-hipofisário-adrenal na pele permite reagir a fatores externos de stress e modular as funções da mesma, tais como a melanogénese. A serotonina (5-hidroxitriptamina, 5-HT) é um neuromodelador importante que atua como fator de crescimento no can...

  1. Adaptations in pre- and postsynaptic 5-HT1A receptor function and cocaine supersensitivity in serotonin transporter knockout rats.

    Homberg, J.R.; Boer, SF De; Raaso, H.S.; Olivier, J.D.A.; Verheul, M.; Ronken, E.; Cools, A.R.; Ellenbroek, B.A.; Schoffelmeer, A.N.; Schuren, L.J. van der; Vries, TJ De; Cuppen, E.

    2008-01-01

    RATIONALE: While individual differences in vulnerability to psychostimulants have been largely attributed to dopaminergic neurotransmission, the role of serotonin is not fully understood. OBJECTIVES: To study the rewarding and motivational properties of cocaine in the serotonin transporter knockout

  2. Adaptations in pre- and postsynaptic 5-HT(1A) receptor function and cocaine supersensitivity in serotonin transporter knockout rats

    Homberg, Judith R; De Boer, Sietse F; Raasø, Halfdan S; Olivier, Jocelien D A; Verheul, Mark; Ronken, Eric; Cools, Alexander R; Ellenbroek, Bart A; Schoffelmeer, Anton N M; Vanderschuren, Louk J M J; De Vries, Taco J; Cuppen, Edwin

    2008-01-01

    RATIONALE: While individual differences in vulnerability to psychostimulants have been largely attributed to dopaminergic neurotransmission, the role of serotonin is not fully understood. OBJECTIVES: To study the rewarding and motivational properties of cocaine in the serotonin transporter knockout

  3. Effect of 5-HT1A receptor-mediated serotonin augmentation on Fos immunoreactivity in rat brain

    Jongsma, ME; Sebens, JB; Bosker, FJ; Korf, J

    2002-01-01

    The consequences of pharmacologically evoked augmented serotonin (5-hydroxytryptamine, 5-HT) release on neuronal activity in the brain, as reflected by the cellular expression of the immediate early gene c-fos, were studied. Wistar rats were treated with saline, the 5-HT reuptake inhibitor citalopra

  4. Larger adaptive response of 5-HT1A autoreceptors to chronic fluoxetine in a mouse model of depression than in healthy mice

    N.FROGER; E.PALAZZO; T.RENOIR; M.MELFORT; N.BARDEN; M.HAMON; L.LANFUMEY

    2004-01-01

    Vulnerability to major depressive disorders, in particular depression, is often associated with both hypoactivity of the central serotoninergic (5-HT) system and hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis. Extensive studies in normal healthy rodents showed that chronic treatment with SSRI antidepressants produced a marked functional desensitization of somatodendritic 5-HT1A autoreceptors, and this adaptive change has been claimed to play a key role in the therapeutic action of

  5. The serotonin-1A receptor distribution in healthy men and women measured by PET and [carbonyl-11C]WAY-100635

    The higher prevalence rates of depression and anxiety disorders in women compared to men have been associated with sexual dimorphisms in the serotonergic system. The present positron emission tomography (PET) study investigated the influence of sex on the major inhibitory serotonergic receptor subtype, the serotonin-1A (5-HT1A) receptor. Sixteen healthy women and 16 healthy men were measured using PET and the highly specific radioligand [carbonyl-11C]WAY-100635. Effects of age or gonadal hormones were excluded by restricting the inclusion criteria to young adults and by controlling for menstrual cycle phase. The 5-HT1A receptor BPND was quantified using (1) the 'gold standard' manual delineation approach with ten regions of interest (ROIs) and (2) a newly developed delineation method using a PET template normalized to the Montreal Neurologic Institute space with 45 ROIs based on automated anatomical labeling. The 5-HT1A receptor BPND was found equally distributed in men and women applying both the manual delineation method and the automated delineation approach. Women had lower mean BPND values in every region investigated, with a borderline significant sex difference in the hypothalamus (p=0.012, uncorrected). There was a high intersubject variability of the 5-HT1A receptor BPND within both sexes compared to the small mean differences between men and women. To conclude, when measured in the follicular phase, women do not differ from men in the 5-HT1A receptor binding. To explain the higher prevalence of affective disorders in women, further studies are needed to evaluate the relationship between hormonal status and the 5-HT1A receptor expression. (orig.)

  6. GH4ZD10 cells expressing rat 5-HT1A receptors coupled to adenylyl cyclase are a model for the postsynaptic receptors in the rat hippocampus.

    Fowler, C J; Ahlgren, P. C.; Brännström, G

    1992-01-01

    1. Vasoactive intestinal polypeptide (VIP) stimulated adenosine 3':5'-cyclic monophosphate (cyclic AMP) production by cultured GH4ZD10 cells with an EC50 value of about 7 nM. The extracellularly recovered cyclic AMP predominated, and was reduced by co-incubation with 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT) and 5-hydroxytryptamine (5-HT), whereas dopamine (0.1-30 microM) did not reduce VIP-stimulated cyclic AMP production. 2. The responses to 5-HT and 8-OH-DPAT were blocked by (-)...

  7. Augmentation with a 5-HT1A but not a 5-HT1B receptor antagonist critically depends on the dose of citalopram

    Cremers, TIFH; Liao, Y; Bosker, FJ; den Boer, JA; Westerink, BHC; Wikstrom, HV

    2000-01-01

    Pharmacokinetic and pharmacodynamic parameters of the selective serotonin reuptake inhibitor 1-(3-dimethylaminopropyl)-1-(4-nuorophenyl)-5-phtalancarbonitril (citalopram) were determined in order to find optimal conditions for augmentation of its effect on extracellular serotonin [5-hydroxytryptamin

  8. 5-HT1A Receptor Null Mutant Mice Responding Under a Differential-Reinforcement-of-Low-Rate 72-Second Schedule of Reinforcement

    Scott-McKean, Jonah J.; Wenger, Galen R.; Tecott, Laurence H.; Costa, Alberto C.S.

    2008-01-01

    Over the last two decades, our ever-increasing ability to manipulate the mouse genome has resulted in a variety of genetically defined mouse models of depression and other psychiatric and neurological disorders. However, it is still the case that some relevant rodent models for depression and antidepressant action have been validated experimentally in rats only and not in mice. An important example of such models is the operant model of antidepressant action known as differential-reinforcemen...

  9. 5-HT1A and 5-HT1B receptor agonists and aggression: A pharmacological challenge of the serotonin deficiency hypothesis

    de Boer, SF; Koolhaas, JM; Koolhaas, Jaap M.

    2005-01-01

    More than any other brain neurotransmitter system, the indolamine serotonin (5-HT) has been linked to aggression in a wide and diverse range of species, including humans. The nature of this linkage, however, is not simple and it has proven difficult to unravel the precise role of this amine in the predisposition for and execution of aggressive behavior. The dogmatic view that 5-HT inhibits aggression has dominated both pharmacological research strategies to develop specific and effective nove...

  10. Potentiation of 5-methoxy-N,N-dimethyltryptamine-induced hyperthermia by harmaline and the involvement of activation of 5-HT1A and 5-HT2A receptors

    Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2015-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are serotonin (5-HT) analogs often abused together, which alters thermoregulation that may indicate the severity of serotonin toxicity. Our recent studies have revealed that co-administration of monoamine oxidase inhibitor harmaline leads to greater and prolonged exposure to 5-HT agonist 5-MeO-DMT that might be influenced by cytochrome P450 2D6 (CYP2D6) status. This study was to define the effects of harmaline and 5-MeO-DMT on thermor...

  11. Citrus aurantium L. essential oil exhibits anxiolytic-like activity mediated by 5-HT1A-receptors and reduces cholesterol after repeated oral treatment

    Costa, Celso A R A; Cury, Thaís C; Cassettari, Bruna O; Regina K. Takahira; Flório, Jorge C; Costa, Mirtes

    2013-01-01

    Background The current treatments for anxiety disorders and depression have multiple adverse effects in addition to a delayed onset of action, which has prompted efforts to find new substances with potential activity in these disorders. Citrus aurantium was chosen based on ethnopharmacological data because traditional medicine refers to the Citrus genus as useful in diminishing the symptoms of anxiety or insomnia, and C. aurantium has more recently been proposed as an adjuvant for antidepress...

  12. A linear combination of pharmacophore hypotheses as a new tool in search of new active compounds--an application for 5-HT1A receptor ligands.

    Dawid Warszycki

    Full Text Available This study explores a new approach to pharmacophore screening involving the use of an optimized linear combination of models instead of a single hypothesis. The implementation and evaluation of the developed methodology are performed for a complete known chemical space of 5-HT1AR ligands (3616 active compounds with K i < 100 nM acquired from the ChEMBL database. Clusters generated from three different methods were the basis for the individual pharmacophore hypotheses, which were assembled into optimal combinations to maximize the different coefficients, namely, MCC, accuracy and recall, to measure the screening performance. Various factors that influence filtering efficiency, including clustering methods, the composition of test sets (random, the most diverse and cluster population-dependent and hit mode (the compound must fit at least one or two models from a final combination were investigated. This method outmatched both single hypothesis and random linear combination approaches.

  13. Development of novel mixed ligand technetium complexes (3 + 1 combination) for imaging central neural system receptors

    A series of mixed ligand oxotechnetium-99m complexes carrying the 1-(2-methoxyphenyl) piperazine moiety has been synthesized. For structural characterization, and for in vitro binding assays, the analogous oxorhenium or oxotechnetium-99 complexes were prepared. As demonstrated by appropriate competition binding tests in rat hippocampal preparations, all oxorhenium analogues showed affinity for the 5-HT1A receptor binding sites with 50% inhibitory concentration values in the nanomolar range (IC50=6-106nM). All 99mTcO[SN(R)S]/[S] complexes showed a significant brain uptake in rats at 2 min post-injection (0.24-1.31 dose/organ). The regional distribution is inhomogeneous but the ratio between areas rich and poor in 5-HT1A receptor was not high. Structural modifications to this system may further improve the biological profile of these compounds and eventually provide efficient 99mTc receptor imaging agents. (author)

  14. Establishment of Radiolabelling Method for the Development of Neurodegenerative Disease Imaging Agent Using 5-HT{sub 1A} Subtype of Receptor Anatagonist

    Choi, Sun Ju; Choi, Sang Mu; Kim, On Hee; Hong, Young Don; Park, Kyung Bae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2005-07-01

    The 5-HT1A subtype of receptors for the neurotransmitter serotonin is predominantly located in the limbic forebrain. And it is involved in the modulation of emotion and the function of the hypothalamus. Since 5-HT1A receptors are implicated in the pathogenesis of anxiety, depression, hallucinogenic behaviour, motion sickness and eating disorders, they are an important target for drug therapy and diagnosis of diseases. Serotonin is synthesized from the amino acid L-tryptophan by sequential hydroxylation and decarboxylation. It is stored in presynaptic vesicles and released from nerve terminals during neuronal firing. One of the best-characterised binding sites for serotonin is the 5-HT1A receptor. This is mainly due to the relatively early discovery of a selective ligand, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) for this subpopulation. Thus, many researchers have tried to develop a radioligand capable of assessing in vivo changes in 5-HT1A receptors in depressed subjects, people with anxiety disorders, patients with Alzheimer's disease and schizophrenics. In present study, we studied the radioligands which would play a role in visualization and quantification of this important neuroreceptor for single-photon emission tomography (SPET)

  15. On the existence and function of galanin receptor heteromers in the Central Nervous System

    Kjell eFuxe

    2012-10-01

    Full Text Available Galanin receptor (GalR subtypes1-3 linked to central galanin neurons may form heteromers with each other and other types of G protein coupled receptors (GPCRs in the Central Nervous System (CNS. These heteromers may be one molecular mechanism for galanin peptides and their N-terminal fragments (gal 1-15 to modulate the function of different types of glia-neuronal networks in the CNS, especially the emotional and the cardiovascular networks. GalR-5-HT1A heteromers likely exist with antagonistic GalR-5-HT1A receptor-receptor interactions in the ascending midbrain raphe 5-HT neuron systems and their target regions. They represent a novel target for antidepressant drugs. Evidence is given for the existence of GalR1-5-HT1A heteromers in cellular models with transinhibition of the protomer signaling. A GalR1-GalR2 heteromer is proposed to be a galanin N-terminal fragment preferring receptor (1-15 in the CNS. Furthermore, a GalR1-GalR2-5-HT1A heterotrimer is postulated to explain why only galanin (1-15 but not galanin (1-29 can antagonistically modulate the 5-HT1A receptors in the dorsal hippocampus rich in gal fragment binding sites. The results underline a putative role of different types of GalR-5-HT1A heteroreceptor complexes in depression. GalR antagonists may also have therapeutic actions in depression by blocking the antagonistic GalR-NPYY1 receptor interactions in putative GalR-NPYY1 receptor heteromers in the CNS resulting in increases in NPYY1 transmission and antidepressant effects. In contrast the galanin fragment receptor (a postulated GalR1-GalR2 heteromer appears to be linked to the NPYY2 receptor enhancing the affinity of the NPYY2 binding sites in a putative GalR1-GalR2-NPYY2 heterotrimer. Finally, putative GalR-α2-adrenoreceptor heteromers with antagonistic receptor-receptor interactions may be a widespread mechanism in the CNS for integration of galanin and noradrenaline signals also of likely relevance for depression.

  16. Receptor binding profiles and quantitative structure-affinity relationships of some 5-substituted-N,N-diallyltryptamines.

    Cozzi, Nicholas V; Daley, Paul F

    2016-02-01

    N,N-Diallyltryptamine (DALT) and 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) are two tryptamines synthesized and tested by Alexander Shulgin. In self-experiments, 5-MeO-DALT was reported to be psychoactive in the 12-20mg range, while the unsubstituted compound DALT had few discernible effects in the 42-80 mg range. Recently, 5-MeO-DALT has been used in nonmedical settings for its psychoactive effects, but these effects have been poorly characterized and little is known of its pharmacological properties. We extended the work of Shulgin by synthesizing additional 5-substituted-DALTs. We then compared them to DALT and 5-MeO-DALT for their binding affinities at 45 cloned receptors and transporter proteins. Based on in vitro binding affinity, we identified 27 potential receptor targets for the 5-substituted-DALT compounds. Five of the DALT compounds had affinity in the 10-80 nM range for serotonin 5-HT1A and 5-HT2B receptors, while the affinity of DALT itself at 5-HT1A receptors was slightly lower at 100 nM. Among the 5-HT2 subtypes, the weakest affinity was at 5-HT2A receptors, spanning 250-730 nM. Five of the DALT compounds had affinity in the 50-400 nM range for serotonin 5-HT1D, 5-HT6, and 5-HT7 receptors; again, it was the unsubstituted DALT that had the weakest affinity at all three subtypes. The test drugs had even weaker affinity for 5-HT1B, 5-HT1E, and 5-HT5A subtypes and little or no affinity for the 5-HT3 subtype. These compounds also had generally nanomolar affinities for adrenergic α2A, α2B, and α2C receptors, sigma receptors σ1 and σ2, histamine H1 receptors, and norepinephrine and serotonin uptake transporters. They also bound to other targets in the nanomolar-to-low micromolar range. Based on these binding results, it is likely that multiple serotonin receptors, as well as several nonserotonergic sites are important for the psychoactive effects of DALT drugs. To learn whether any quantitative structure-affinity relationships existed, we evaluated

  17. Base neurobiologique du rôle des récepteurs 5-HT1A dans le mode d'action des antidépresseurs sérotoninergiques

    Gardier, A. M.; Jacquot, C.; Artigas, Francesc

    1995-01-01

    [FR]Les inhibiteurs de recapture sélectifs de la sérotonine (IRSS) bloquent l'activité du transporteur de la 5-hydroxy-tryptamine (5-HT) dépendante du sodium ; ils augmentent ainsi la concentration des mono-amines dans la fente synaptique. Le long délai (deux à quatre semaines) pour que les propriétés antidépressives se manifestent correspondrait au temps nécessaire à la désensibilisation fonctionnelle des autorécepteurs 5-HT1A des noyaux du raphé. La mesure des concentrations cérébrales extr...

  18. Clozapine functions through the prefrontal cortex serotonin 1A receptor to heighten neuronal activity via calmodulin kinase II-NMDA receptor interactions.

    Purkayastha, Sudarshana; Ford, Jason; Kanjilal, Baishali; Diallo, Souleymane; Del Rosario Inigo, Joseph; Neuwirth, Lorenz; El Idrissi, Abdeslem; Ahmed, Zaghloul; Wieraszko, Andrzej; Azmitia, Efrain C; Banerjee, Probal

    2012-02-01

    Aberrant dopamine release in the prefrontal cortex (PFC) is believed to underlie schizophrenia, but the mechanistic pathway through which a widely used antipsychotic, clozapine (Clz), evokes neurotransmitter-releasing electrical stimulation is unclear. We analyzed Clz-evoked regulation of neuronal activity in the PFC by stimulating axons in layers IV and V and recording the electrical effect in the post-synaptic pyramidal cells of layers II and III. We observed a Clz-evoked increase in population spike (PS), which was mediated by serotonin 1A receptor (5-HT(1A)-R), phospholipase Cβ, and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). Immunoblotting demonstrated that the Clz-activation of CaMKII was 5-HT(1A)-R-mediated. Intriguingly, the NMDA receptor (NMDA-R) antagonist (±)2-amino-5-phosphonovaleric acid (APV) eliminated the Clz-mediated increase in PS, suggesting that the 5-HT(1A)-R, NMDA-R and CaMKII form a synergistic triad, which boosts excitatory post-synaptic potential (EPSP), thereby enhancing PS. In corroboration, Clz as well as NMDA augmented field EPSP (fEPSP), and WAY100635 (a 5-HT(1A)-R antagonist), APV, and a CaMKII inhibitor eliminated this increase. As previously shown, CaMKII binds to the NMDA-R 2B (NR2B) subunit to become constitutively active, thereby inducing α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor recruitment to the post-synaptic membrane and an increase in fEPSP. Co-immunoprecipitation demonstrated that Clz potentiates interactions among CaMKII, NR2B, and 5-HT(1A)-R, possibly in the membrane rafts of the post-synaptic density (PSD), because pretreatment with methyl-β-cyclodextrin (MCD), an agent that disrupts rafts, inhibited both co-immunoprecipitation as well as fEPSP. In summary, Clz functions in the PFC by orchestrating a synergism among 5-HT(1A)-R, CaMKII, and NMDA-R, which augments excitability in the PFC neurons of layers II/III. PMID:22044428

  19. Determination of optimal acquisition time of [18F]FCWAY PET for imaging serotonin 1A receptors in the healthy male subjects

    The purpose of this research is to find optimal acquisition time point of [18F]FCWAY PET for the assessment of serotonin 1A receptor (5-HT1A) density. To achieve this goal, we examined the specific-to-nonspecific ratios in various brain regions. The cerebellum has very few 5-HT1A receptors in the brain, so we set this region as the reference tissue. As a result, specific-to-nonspecific binding ratios in the frontal, temporal cortex and the hippocampus were steadily increased at 90 min after injection and remained stable at 120 min. In addition, the binding ratio of the late time was significantly higher than that of the previous time points. From these results, we recommend that 90 min p.i. is a better single time point for the analysis rather than previous time points for assessing [18F]FCWAY binding to 5-HT1A receptors. - Highlights: • For routine clinical study, PET protocol should be conducted on a single time point with short imaging acquisition. • The specific-to-nonspecific ratios in the various brain regions were calculated. • Optimal [18F]FCWAY PET acquisition time point was proposed

  20. Radioligand Binding at Muscarinic Receptors

    El-Fakahany, E. E.; Jakubík, Jan

    New York: Springer, 2016 - (Mysliveček, J.; Jakubík, J.), s. 37-68. (Neuromethods. 107). ISBN 978-1-4939-2857-6 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : muscarinic acetylcholine receptors * radioligand binding Subject RIV: ED - Physiology

  1. 5-Hydroxytryptamine 1A and 2B serotonin receptors in neurite outgrowth: involvement of early growth response protein 1.

    Anelli, Tonino; Cardarelli, Silvia; Ori, Michela; Nardi, Irma; Biagioni, Stefano; Poiana, Giancarlo

    2013-01-01

    Neurotransmitters play important roles in neurogenesis; in particular, acetylcholine and serotonin may regulate neurite elongation. Acetylcholine may also activate transcription factors such as early growth response protein 1 (EGR-1), which plays a role in neurite extension. N18TG2 neuroblastoma cells (which do not produce neurotransmitters and constitutively express muscarinic acetylcholine receptors) were transfected with constructs containing the cDNA for choline acetyltransferase, 5-hydroxytryptamine 1A (5-HT1A) and 5-HT2B serotonin receptors to study acetylcholine and serotonin interplay in neurite outgrowth. 5-HT1A receptor stimulation causes a decrease in EGR-1 levels and inhibition of neurite outgrowth; 5-HT2B stimulation, however, has no effect. Muscarinic cholinergic stimulation, on the other end, increases EGR-1 levels and fiber outgrowth. Inhibition of EGR-1 binding reduces fiber outgrowth activity. When both cholinergic and 5-HT1A receptors are stimulated, fiber outgrowth is restored; therefore, acetylcholine counterbalances the inhibitory effect of serotonin on neurite outgrowth. These results suggest that EGR-1 plays a role in the interplay of acetylcholine and serotonin in the regulation of neurite extension during development. PMID:24158140

  2. Acute and chronic effects of citalopram on postsynaptic 5-hydroxytryptamine(1A) receptor-mediated feedback : a microdialysis study in the amygdala

    Bosker, FJ; Cremers, TIFH; Jongsma, ME; Westerink, BHC; Wikstrom, VH; den Boer, JA

    2001-01-01

    Microdialysis was used to assess the involvement of postsynaptic 5-hydroxytryptamine(1A) (5-HT1A) receptors in the regulation of extracellular 5-HT in the amygdala. Local infusion of the 5-HT1A receptor agonist flesinoxan (0.3, 1, 3 muM) for 30 min into the amygdala maximally decreased 5-HT to 50% o

  3. Glucocorticoid receptor transformation and DNA binding

    The overall goal is to probe the mechanism whereby glucocorticoid receptors are transformed from a non-DNA-binding form to their active DNA-binding form. The author has examined the effect of an endogenous inhibitor purified from rat liver cytosol on receptor binding to DNA. The inhibitor binds to transformed receptors in whole cytosol and prevent their binding to DNA. He also examined the role of sulfhydryl groups in determining the DNA binding activity of the transformed receptor and in determining the transformation process. Treatment of rat liver cytosol containing temperature-transformed, [3H]dexamethasone-bound receptors at 00C with the sulfhydryl modifying reagent methyl methanethiosulfonate inhibits the DNA-binding activity of the receptor, and DNA-binding activity is restored after addition of dithiothreitol. In addition, he has examined the relationship between receptor phosphorylation and DNA binding. Untransformed receptor complexes purified from cytosol prepared from mouse L cells grown in medium containing [32P]orthophosphate contain two components, a 100 k-Da and a 90-kDa subunit, both of which are phosphoproteins. On transformation, the receptor dissociates from the 90-kDa protein. Transformation of the complex under cell free conditions does not result in a dephosphorylation of the 100-kDa steroid-binding protein. Transformed receptor that has been bound to DNA and purified by monoclonal antibody is still in a phosphorylated form. These results suggest that dephosphorylation is not required for receptor binding to DNA

  4. Prior Multiple Ethanol Withdrawals Enhance Stress-Induced Anxiety-Like Behavior: Inhibition by CRF1- and Benzodiazepine-Receptor Antagonists and a 5-HT1a-Receptor Agonist

    Breese, George R.; Overstreet, David H.; KNAPP, DARIN J.; Navarro, Montserrat

    2005-01-01

    Repeated withdrawals from chronic ethanol induce a persistent adaptive change. Further, stress substitutes for the initial two withdrawals of a multiple-withdrawal protocol to sensitize rats to withdrawal-induced anxiety-like behavior (‘anxiety’). Therefore, it was tested whether the persistent adaptation induced by multiple-withdrawal exposures allows stress to elicit anxiety after a period of abstinence. Social interaction was used to assess the degree of anxiety induced by 45 min of restra...

  5. Depressive behavior and alterations in receptors for dopamine and 5-hydroxytryptamine in the brain of the senescence accelerated mouse (SAM)-P10.

    Onodera, T; Watanabe, R; Tha, K K; Hayashi, Y; Murayama, T; Okuma, Y; Ono, C; Oketani, Y; Hosokawa, M; Nomura, Y

    2000-08-01

    The senescence accelerated mouse (SAM) is known as a murine model of aging. SAM consists of senescence accelerated-prone mouse (SAMP) and senescence accelerated-resistant mouse (SAMR). Previous studies reported that SAMP10 exhibits age-related learning impairments and behavioral depression in a tail suspension test after 7 months. We investigated the changes in emotional behavior in a forced swimming test and in receptors for dopamine and 5-hydroxytryptamine (5-HT) in SAMP10. SAMP10 at 8 months showed an increase of immobility in the test compared with SAMR1. Treatment with desipramine (25 mg/kg, i.p., 3 days) in SAMP10 caused a decrease in immobility. In the cortex from SAMP10, [3H]quinpirole binding to D2/D3 dopamine receptors increased significantly compared with control SAMR1. In the hippocampus from SAMP10, [3H]8-hydroxy DPAT binding to 5-HT1A receptor increased. In midbrains from SAMP10, bindings of [3H]quinpirole and [3H]8-hydroxy DPAT increased. [3H]SCH23390 binding to D1/D5 receptors and [3H]ketanserin binding to 5-HT2 receptor in brain regions examined in SAMP10 were similar to those in SAMR1. The present findings represent the first neurochemical evidence of an increase of D2/D3 and 5-HT1A receptors in SAMP10. SAMP10 may be a useful model of aging associated depressive behavior. PMID:11001177

  6. Intrathecal 5-methoxy-N,N-dimethyltryptamine in mice modulates 5-HT1 and 5-HT3 receptors.

    Alhaider, A A; Hamon, M; Wilcox, G L

    1993-11-01

    The antinociceptive effects of intrathecally administered 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a potent 5-HT receptor agonist, were studied in three behavioral tests in mice: the tail-flick test and the intrathecal substance P and N-methyl-D-aspartic acid (NMDA) assays. Intrathecal administration of 5-MeO-DMT (4.6-92 nmol/mouse) produced a significant prolongation of the tail-flick latency. This action was blocked by 5-HT3 and gamma-aminobutyric acidA (GABAA) receptor antagonists but not by 5-HT2, 5-HT1A, 5-HT1B or 5-HT1S receptor antagonists. Binding studies indicated that 5-MeO-DMT had very low affinity for 5-HT3 receptors. 5-MeO-DMT inhibited biting behavior while increasing scratching behavior induced by intrathecally administered substance P. The inhibition of biting behavior was antagonized by intrathecal co-administration of 5-HT1B and GABAA receptor antagonists while 5-HT1A, 5-HT1S, 5-HT2 and 5-HT3 receptor antagonists had no effect. 5-MeO-DMT-enhanced scratching behavior was inhibited by all the antagonists used except ketanserin and bicuculline, suggesting the involvement of 5-HT1A, 5-HT1B, 5-HT1S, 5-HT3 and GABAA receptors. NMDA-induced biting behavior was inhibited by 5-MeO-DMT pretreatment; this action was antagonized by 5-HT1B, 5-HT3 and GABAA receptor antagonists. The involvement of these receptors in 5-MeO-DMT action suggests that it may promote release of 5-HT (5-hydroxytryptamine, serotonin). PMID:7507056

  7. Impact of receptor clustering on ligand binding

    Caré Bertrand R

    2011-03-01

    Full Text Available Abstract Background Cellular response to changes in the concentration of different chemical species in the extracellular medium is induced by ligand binding to dedicated transmembrane receptors. Receptor density, distribution, and clustering may be key spatial features that influence effective and proper physical and biochemical cellular responses to many regulatory signals. Classical equations describing this kind of binding kinetics assume the distributions of interacting species to be homogeneous, neglecting by doing so the impact of clustering. As there is experimental evidence that receptors tend to group in clusters inside membrane domains, we investigated the effects of receptor clustering on cellular receptor ligand binding. Results We implemented a model of receptor binding using a Monte-Carlo algorithm to simulate ligand diffusion and binding. In some simple cases, analytic solutions for binding equilibrium of ligand on clusters of receptors are provided, and supported by simulation results. Our simulations show that the so-called "apparent" affinity of the ligand for the receptor decreases with clustering although the microscopic affinity remains constant. Conclusions Changing membrane receptors clustering could be a simple mechanism that allows cells to change and adapt its affinity/sensitivity toward a given stimulus.

  8. Binding characteristics of swine erythrocyte insulin receptors

    Crossbred gilts had 8.8 +/- 1.1% maximum binding of [125I]insulin to insulin receptors on erythrocytes. The number of insulin-binding sites per cell was 137 +/- 19, with a binding affinity ranging from 7.4 X 10(7)M-1 to 11.2 X 10(7)M-1 and mean of 8.8 X 10(7)M-1. Pregnant sows had a significant increase in maximum binding due to an increase in number of receptor sites per cell. Lactating sows fed a high-fiber diet and a low-fiber diet did not develop a significant difference in maximum binding of insulin. Sows fed the low-fiber diet had a significantly higher number of binding sites and a significantly lower binding affinity than did sows fed a high-fiber diet. Receptor-binding affinity was lower in the low-fiber diet group than in cycling gilts, whereas data from sows fed the high-fiber diet did not differ from data for cycling gilts. Data from this study indicated that insulin receptors of swine erythrocytes have binding characteristics similar to those in other species. Pregnancy and diet will alter insulin receptor binding in swine

  9. 5-Hydroxytryptamine 1A receptors in the dorsomedial hypothalamus connected to dorsal raphe nucleus inputs modulate defensive behaviours and mediate innate fear-induced antinociception.

    Biagioni, Audrey Franceschi; de Oliveira, Rithiele Cristina; de Oliveira, Ricardo; da Silva, Juliana Almeida; dos Anjos-Garcia, Tayllon; Roncon, Camila Marroni; Corrado, Alexandre Pinto; Zangrossi, Hélio; Coimbra, Norberto Cysne

    2016-03-01

    The dorsal raphe nucleus (DRN) is an important brainstem source of 5-hydroxytryptamine (5-HT), and 5-HT plays a key role in the regulation of panic attacks. The aim of the present study was to determine whether 5-HT1A receptor-containing neurons in the medial hypothalamus (MH) receive neural projections from DRN and to then determine the role of this neural substrate in defensive responses. The neurotracer biotinylated dextran amine (BDA) was iontophoretically microinjected into the DRN, and immunohistochemical approaches were then used to identify 5HT1A receptor-labelled neurons in the MH. Moreover, the effects of pre-treatment of the dorsomedial hypothalamus (DMH) with 8-OH-DPAT and WAY-100635, a 5-HT1A receptor agonist and antagonist, respectively, followed by local microinjections of bicuculline, a GABAA receptor antagonist, were investigated. We found that there are many projections from the DRN to the perifornical lateral hypothalamus (PeFLH) but also to DMH and ventromedial (VMH) nuclei, reaching 5HT1A receptor-labelled perikarya. DMH GABAA receptor blockade elicited defensive responses that were followed by antinociception. DMH treatment with 8-OH-DPAT decreased escape responses, which strongly suggests that the 5-HT1A receptor modulates the defensive responses. However, DMH treatment with WAY-100635 failed to alter bicuculline-induced defensive responses, suggesting that 5-HT exerts a phasic influence on 5-HT1A DMH neurons. The activation of the inhibitory 5-HT1A receptor had no effect on antinociception. However, blockade of the 5-HT1A receptor decreased fear-induced antinociception. The present data suggest that the ascending pathways from the DRN to the DMH modulate panic-like defensive behaviours and mediate antinociceptive phenomenon by recruiting 5-HT1A receptor in the MH. PMID:26749090

  10. Receptor binding studies of the living heart

    Receptors form a class of intrinsic membrane proteins (or glycoproteins) defined by the high affinity and specificity with which they bind ligands. Many receptors are associated directly or indirectly with membrane ion channels that open or close after a conformational change of the receptor induced by the binding of the neurotransmitter. Changes in number and/or affinity of cardiac neurotransmitter receptors have been associated with myocardial ischemia and infarction, congestive heart failure, and cardiomyopathy as well as diabetes or thyroid-induced heart muscle disease. These alterations of cardiac receptors have been demonstrated in vitro on membrane homogenates from samples collected mainly during surgery or postmortem. The disadvantage of these in vitro binding techniques is that receptors lose their natural environment and their relationships with the other components of the tissue

  11. The role of the serotonergic system and the effects of antidepressants during brain development examined using in vivo PET imaging and in vitro receptor binding

    Shrestha, Stal Saurav

    2014-01-01

    Serotonin (5-HT) and the serotonergic system, which includes the serotonin transporter (SERT) and the two G protein-coupled 5-HT1A and 5-HT1B receptors, are implicated in the pathophysiology and treatment of several neuropsychiatric disorders including major depressive disorder (MDD) and anxiety. Two classes of antidepressants—selective serotonin reuptake inhibitors (SSRIs), which block SERT, and tricyclic antidepressants (TCAs), which block several monoamine transporters...

  12. Spacer conformation in biologically active molecules. Part 2. Structure and conformation of 4-[2-(diphenylmethylamino)ethyl]-1-(2-methoxyphenyl) piperazine and its diphenylmethoxy analog—potential 5-HT 1A receptor ligands

    Karolak-Wojciechowska, J.; Fruziński, A.; Czylkowski, R.; Paluchowska, M. H.; Mokrosz, M. J.

    2003-09-01

    As a part of studies on biologically active molecule structures with aliphatic linking chain, the structures of 4-[2-diphenylmethylamino)ethyl]-1-(2-methoxyphenyl)piperazine dihydrochloride ( 1) and 4-[2-diphenylmethoxy)ethyl]-1-(2-methoxyphenyl)piperazine fumarate ( 2) have been reported. In both compounds, four atomic non-all-carbons linking chains (N)C-C-X-C are present. The conformation of that linking spacer depends on the nature of the X-atom. The preferred conformation for chain with XNH has been found to be fully extended while for that with XO—the bend one. It was confirmed by conformational calculations (strain energy distribution and random search) and crystallographic data, including statistics from CCDC.

  13. Oxygen isoteres of hydroxy-di-n-propylaminotetralines. Syntheses of racemic monomethoxy and monohydroxy-3-(di-n-[3H-propyl] amino) chromanes: new radioligands for serotonine 5-HT1A and dopamine D2 receptor sites labelling

    Condensation of monomethoxy salicylaldehydes: 4a-d with nitroethanol gave methoxy-3-nitro-2H chromanes 5a-d which were reduced with LAH into methoxy-3-amino chromanes 6a-d. Two syntheses of 2-hydroxy-6-methoxy-benzal-dehyde: 4a were described. N-alkylations of 6a-d were carried out a/ by Borch procedure b/ by n-propylation with propyl iodide in presence of bases c/ by allylation in presence of bases. Methoxy-3-(diallyl-amino) chromanes: 13a-d were catalytically reduced with hydrogen (Pd/C in methanol) into mixtures of methoxy-3 (di-n-propylamino) chromanes 2a-d and methoxy-3- (n-proplylamino) chromanes resulting from the hydrogenolysis of one allyl group. Methoxy-3-dialkylamino chromanes 2a-d and 13a were O-demethylated either by boiling 48% or by BBr3 in CH2Cl2. Catalytic hydrogenation with tritium of precursors 13a-d and 15a in methanol in presence of 10% PdC gave [3H]-5.OH-DPAC: 3a; [3H] 5.OMe-DPAC: 2a and the isomers: 2b-2d which were purified by HPLC, analyzed by reversed HPLC, 3H-NMR, M.S. (spec. radioactivity: 37.2-80 Ci/mMole. Radiochemical purity: 98.3-99.6%). (author)

  14. Binding of Glutamate to the Umami Receptor

    Lopez Cacales, J.; Oliviera Costa, S.; de Groot, B.; Walters, D

    2010-01-01

    Abstract The umami taste receptor is a heterodimer composed of two members of the T1R taste receptor family: T1R1 and T1R3. It detects glutamate in humans, and is a more general amino acid detector in other species. We have constructed homology models of the ligand binding domains of the human umami receptor (based on crystallographic structures of the metabotropic glutamate receptor of the central nervous system). We have carried out molecular dynamics simulations of the ligand bi...

  15. GABAA receptors, but not dopamine, serotonin or NMDA receptors, are increased in the frontal cortex from schizophrenic subjects

    Full text: Having shown changed 5HT2A receptor density in the frontal cortex (FC) from schizophrenic subjects (1) we now report on further studies of the molecular neuroanatomy of the FC in schizophrenia. We used in situ radioligand binding and autoradiography to measure the density of [3H]8OH-DPAT (1 nM) binding (5HT1A receptors) and [3H]GR113808 (2.4nM) binding (5HT4 receptors) in Brodmann's areas (BA) 8, 9 and 10 from 10 schizophrenic and 10 controls subjects. In addition, [3H]muscimol (100 nM) binding (GABAA receptors), [3H]TCP (20nM) binding (NMDA receptors), [3H]SCH 23390 (3nM) binding (DA D1like receptors) and [3H]YM-09151-2 (4nM) binding (DA D2-like receptors) was measured in BA 9 from 17 schizophrenic and 17 control subjects. Subjects were matched for age and sex and the post-mortem interval for tissue collection did not differ. There was a significant increase (18%) in the density of GABAA receptors in BA 9 from subjects with schizophrenia (p<0.05) with no change in NMDA, dopamine or serotonin receptors. These data support the hypothesis that there are selective changes in neurotransmitter receptors in the FC of subjects with schizophrenia. It is not yet clear if such changes contribute to the pathology of the illness. Copyright (1998) Australian Neuroscience Society

  16. Receptor binding studies of soft anticholinergic agents

    Huang, Fenglei; Buchwald, Peter; Browne, Clinton E.; Farag, Hassan H.; Wu, Wnei-Mei; Ji, Fubao; Hochhaus, Guenther; Bodor, Nicholas

    2001-01-01

    Receptor binding studies were performed on 24 soft anticholinergic agents and 5 conventional anticholinergic agents using 4 cloned human muscarinic receptor subtypes. The measured pKi values of the soft anticholinergic agents ranged from 6.5 to 9.5, with the majority being in the range of 7.5 to 8.5. Strong correlation was observed between the pKis determined here and the pA2 values measured earlier in guinea pig ileum contraction assays. The corresponding correlation coefficients (r2) were 0...

  17. Contribution of non-genetic factors to dopamine and serotonin receptor availability in the adult human brain

    Borg, J; Cervenka, S; Kuja-Halkola, R; Matheson, G J; Jönsson, E G; Lichtenstein, P; Henningsson, S; Ichimiya, T; Larsson, H; Stenkrona, P; Halldin, C; Farde, L

    2016-01-01

    and environmental factors, respectively, on dopaminergic and serotonergic markers in the living human brain. Eleven monozygotic and 10 dizygotic healthy male twin pairs were examined with PET and [(11)C]raclopride binding to the D2- and D3-dopamine receptor and [(11)C]WAY100635 binding to the......The dopamine (DA) and serotonin (5-HT) neurotransmission systems are of fundamental importance for normal brain function and serve as targets for treatment of major neuropsychiatric disorders. Despite central interest for these neurotransmission systems in psychiatry research, little is known about...... binding and a major contribution of environmental factors (pairwise shared and unique individual; 0.70-0.75) on neocortical 5-HT1A receptor binding. Our findings indicate that individual variation in neuroreceptor availability in the adult brain is the end point of a nature-nurture interplay, and call for...

  18. Functional Selectivity and Antidepressant Activity of Serotonin 1A Receptor Ligands

    Zdzisław Chilmonczyk

    2015-08-01

    Full Text Available Serotonin (5-HT is a monoamine neurotransmitter that plays an important role in physiological functions. 5-HT has been implicated in sleep, feeding, sexual behavior, temperature regulation, pain, and cognition as well as in pathological states including disorders connected to mood, anxiety, psychosis and pain. 5-HT1A receptors have for a long time been considered as an interesting target for the action of antidepressant drugs. It was postulated that postsynaptic 5-HT1A agonists could form a new class of antidepressant drugs, and mixed 5-HT1A receptor ligands/serotonin transporter (SERT inhibitors seem to possess an interesting pharmacological profile. It should, however, be noted that 5-HT1A receptors can activate several different biochemical pathways and signal through both G protein-dependent and G protein-independent pathways. The variables that affect the multiplicity of 5-HT1A receptor signaling pathways would thus result from the summation of effects specific to the host cell milieu. Moreover, receptor trafficking appears different at pre- and postsynaptic sites. It should also be noted that the 5-HT1A receptor cooperates with other signal transduction systems (like the 5-HT1B or 5-HT2A/2B/2C receptors, the GABAergic and the glutaminergic systems, which also contribute to its antidepressant and/or anxiolytic activity. Thus identifying brain specific molecular targets for 5-HT1A receptor ligands may result in a better targeting, raising a hope for more effective medicines for various pathologies.

  19. The excitability and rhythm of medullary respiratory neurons in the cat are altered by the serotonin receptor agonist 5-methoxy-N,N, dimethyltryptamine.

    Lalley, P M

    1994-06-13

    5-Methoxy-N,N-dimethyltryptamine (5-MeODMT) is an indolealkylamine which has agonist activity at 5HT receptors. In the present investigation, 5-MeODMT had two types of effects on medullary respiratory neurons of the cat. Iontophoretic administration or i.v. doses (43 +/- 8.9 micrograms/kg) of 5-MeODMT hyperpolarized respiratory neurons and severely reduced action potential discharges. Cinanserin, a 5HT-2/1 c receptor antagonist, when injected i.v. reduced the inhibition produced by i.v. injection of 5-MeODMT. Iontophoresis of cinanserin did not antagonize inhibition produced by iontophoresis of 5-MeODMT or 5-HT. The depression of respiratory discharge by i.v. injection of 5-MeODMT is attributed to presynaptic effects (network depression) and post-synaptic activation of 5HT-1A receptors on respiratory neurons. 5-MeODMT (27 +/- 2.78 micrograms/kg i.v.) also increased discharge frequency of inspiratory and expiratory neurons. Inspiratory neuron discharges were briefer and expiratory neuron discharges occurred earlier in relation to phrenic nerve activity. It is suggested that the effects of the smaller doses are due to binding of 5-MeODMT to 5HT-1A receptors on early inspiratory neurons of the medulla. PMID:7922531

  20. Two cases of mild serotonin toxicity via 5-hydroxytryptamine 1A receptor stimulation

    Nakayama H

    2014-02-01

    Full Text Available Hiroto Nakayama,1,* Sumiyo Umeda,2,* Masashi Nibuya,3 Takeshi Terao,4 Koichi Nisijima,5 Soichiro Nomura3 1Yamaguchi Prefecture Mental Health Medical Center, Yamaguchi, Japan; 2Department of Psychiatry, NTT West Osaka Hospital, Osaka, Japan; 3Department of Psychiatry, National Defense Medical College, Saitama, Japan; 4Department of Neuropsychiatry, Oita University Faculty of Medicine, Oita, Japan; 5Department of Psychiatry, Jichi University School of Medicine, Tochigi, Japan  *These authors contributed equally to this work Abstract: We propose the possibility of 5-hydroxytryptamine (5-HT1A receptor involvement in mild serotonin toxicity. A 64-year-old woman who experienced hallucinations was treated with perospirone (8 mg/day. She also complained of depressed mood and was prescribed paroxetine (10 mg/day. She exhibited finger tremors, sweating, coarse shivering, hyperactive knee jerks, vomiting, diarrhea, tachycardia, and psychomotor agitation. After the discontinuation of paroxetine and perospirone, the symptoms disappeared. Another 81-year-old woman, who experienced delusions, was treated with perospirone (8 mg/day. Depressive symptoms appeared and paroxetine (10 mg/day was added. She exhibited tachycardia, finger tremors, anxiety, agitation, and hyperactive knee jerks. The symptoms disappeared after the cessation of paroxetine and perospirone. Recently, the effectiveness of coadministrating 5-HT1A agonistic psychotropics with selective serotonin reuptake inhibitors (SSRIs has been reported, and SSRIs with 5-HT1A agonistic activity have been newly approved in the treatment of depression. Perospirone is a serotonin–dopamine antagonist and agonistic on the 5-HT1A receptors. Animal studies have indicated that mild serotonin excess induces low body temperature through 5-HT1A, whereas severe serotonin excess induces high body temperature through 5-HT2A activation. Therefore, it could be hypothesized that mild serotonin excess induces side effects

  1. Drosophila insulin-producing cells are differentially modulated by serotonin and octopamine receptors and affect social behavior.

    Jiangnan Luo

    Full Text Available A set of 14 insulin-producing cells (IPCs in the Drosophila brain produces three insulin-like peptides (DILP2, 3 and 5. Activity in IPCs and release of DILPs is nutrient dependent and controlled by multiple factors such as fat body-derived proteins, neurotransmitters, and neuropeptides. Two monoamine receptors, the octopamine receptor OAMB and the serotonin receptor 5-HT1A, are expressed by the IPCs. These receptors may act antagonistically on adenylate cyclase. Here we investigate the action of the two receptors on activity in and output from the IPCs. Knockdown of OAMB by targeted RNAi led to elevated Dilp3 transcript levels in the brain, whereas 5-HT1A knockdown resulted in increases of Dilp2 and 5. OAMB-RNAi in IPCs leads to extended survival of starved flies and increased food intake, whereas 5-HT1A-RNAi produces the opposite phenotypes. However, knockdown of either OAMB or 5-HT1A in IPCs both lead to increased resistance to oxidative stress. In assays of carbohydrate levels we found that 5-HT1A knockdown in IPCs resulted in elevated hemolymph glucose, body glycogen and body trehalose levels, while no effects were seen after OAMB knockdown. We also found that manipulations of the two receptors in IPCs affected male aggressive behavior in different ways and 5-HT1A-RNAi reduced courtship latency. Our observations suggest that activation of 5-HT1A and OAMB signaling in IPCs generates differential effects on Dilp transcription, fly physiology, metabolism and social interactions. However the findings do not support an antagonistic action of the two monoamines and their receptors in this particular system.

  2. Structural Analysis of Botulinum Neurotoxin Type G Receptor Binding

    Schmitt, John; Karalewitz, Andrew; Benefield, Desire A.; Mushrush, Darren J.; Pruitt, Rory N.; Spiller, Benjamin W.; Barbieri, Joseph T.; Lacy, D. Borden (Vanderbilt); (MCW)

    2010-10-19

    Botulinum neurotoxin (BoNT) binds peripheral neurons at the neuromuscular junction through a dual-receptor mechanism that includes interactions with ganglioside and protein receptors. The receptor identities vary depending on BoNT serotype (A-G). BoNT/B and BoNT/G bind the luminal domains of synaptotagmin I and II, homologous synaptic vesicle proteins. We observe conditions under which BoNT/B binds both Syt isoforms, but BoNT/G binds only SytI. Both serotypes bind ganglioside G{sub T1b}. The BoNT/G receptor-binding domain crystal structure provides a context for examining these binding interactions and a platform for understanding the physiological relevance of different Syt receptor isoforms in vivo.

  3. Bladder endothelin-1 receptor binding of bosentan and ambrisentan.

    Osano, Ayaka; Yokoyama, Yoshinari; Hayashi, Hideki; Itoh, Kunihiko; Okura, Takashi; Deguchi, Yoshiharu; Ito, Yoshihiko; Yamada, Shizuo

    2014-01-01

    The present study aimed to characterize bladder endothelin-1 (ET-1) receptor binding of clinically used ET-1 receptor antagonists by using [(125)I]ET-1. The inhibition of specific [(125)I]ET-1 binding was measured in the presence of ET-1 and its receptor antagonists. Specific binding of [(125)I]ET-1 in rat bladder was saturable and of high affinity, which characterized selective labeling of bladder ET-1 receptors. ET-1, bosentan, ambrisentan, and CI-1020 inhibited specific [(125)I]ET-1 binding in a concentration-dependent manner at nanomolar ranges of IC50. Nonlinear least squares regression analysis revealed the presence of high- and low-affinity ET-1 receptor sites for ambrisentan and CI-1020. Bosentan and ambrisentan significantly increased the dissociation constant for bladder [(125)I]ET-1 binding without affecting maximal number of binding sites (Bmax). Thus, bosentan and ambrisentan seem to bind to bladder ET-1 receptor in a competitive and reversible manner. Oral administration of bosentan caused a dose-dependent decrease in Bmax for bladder [(125)I]ET-1 binding, suggesting significant binding of bladder ET-1 receptors in vivo. A significant amount of pharmacologically relevant ET-1 receptors may exist in the bladder. These receptors may be implicated in the pathogenesis of lower urinary tract symptoms and may also be promising targets for the development of therapeutic agents. PMID:24389822

  4. [18F]altanserin binding to human 5HT2A receptors is unaltered after citalopram and pindolol challenge

    Pinborg, L. H.; Adams, K. H.; Yndsgaard, S; Hasselbalch, S. G.; Holm, S; Kristiansen, H; Paulson, Olaf B.; Knudsen, G. M.

    2004-01-01

    subjects as a constant infusion for 20 minutes. To reduce 5-HT1A-mediated autoinhibition of cortical 5-HT release, four of the seven subjects were pretreated with the partial 5-HT1A agonist pindolol for 3 days at an increasing oral dose (25 mg on the day of scanning). In each subject, the baseline...

  5. Synthesis and pharmacological evaluation of a new series of radiolabeled ligands for 5-HT7 receptor PET neuroimaging

    Introduction: The brain serotonin-7 receptor (5-HT7) is the most recently discovered serotonin receptor. It is targeted by several drug-candidates in psychopharmacology and neuropharmacology. In these fields, positron emission tomography (PET) is a molecular imaging modality offering great promise for accelerating the development process from preclinical discovery to clinical phases. We recently described fluorinated 5-HT7 radioligands, inspired by the structure of SB269970, the prototypical 5-HT7 antagonist. Although these results were promising, it appeared that the radiotracer-candidates suffered, among other drawbacks, from too low a 5-HT7 receptor affinity. Methods: In the present study, seven structural analogs of SB269970 were synthesized using design strategies aiming to improve their radiopharmacological properties. Their 5-HT7 binding properties were investigated by cellular functional assay. The nitro-precursors of the analogs were radiolabeled by [18 F-]nucleophilic substitution, and in vitro autoradiography was performed in rat brain, followed by in vivo microPET. Result: The chemical and radiochemical purity of the fluorine radiotracers was > 99% with specific activity in the 40–129 GBq/μmol range. The seven derivatives presented heterogeneous binding affinities toward 5-HT7 and 5-HT1A receptors. While [18 F]2F3P3 had promising characteristics in vitro, it showed poor brain penetration in vivo, partially reversed after pharmacological inhibition of P-glycoprotein. Conclusions: These results indicated that, while chemical modification of these series improved several radiotracer-candidates in terms of 5-HT7 receptor affinity and specificity toward 5-HT1A receptors, other physicochemical modulations would be required in order to increase brain penetration

  6. THE RECEPTOR BINDING AFFINITIES, ANTIPROGESTERONE AND ANTIGLUCOCORTICOID ACTIVITIES OF MIFEPRISTONE AND LILOPRISTONE

    LIUYong-Qiang; WUXi-Rui

    1989-01-01

    With radioligand binding assays, the receptor binding affmities of mifepristone and lilopristone to the rabbit uterus cytosol progesterone receptor and the rat fiver cytosol glucocorticoid receptor have been measured. The relative binding affinities ( RBA ) of

  7. Localization of CGRP receptor components and receptor binding sites in rhesus monkey brainstem

    Eftekhari, Sajedeh; Roberts, Rhonda; Chen, Tsing-Bau;

    2016-01-01

    -like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1), respectively. To define CGRP receptor binding sites, in vitro autoradiography was performed with [(3)H]MK-3207 (a CGRP receptor antagonist). CLR and RAMP1 mRNA and protein expression were detected in the pineal gland, medial mammillary...

  8. Characterization of pulmonary sigma receptors by radioligand binding.

    Lever, John R; Litton, Tyler P; Fergason-Cantrell, Emily A

    2015-09-01

    This study establishes the expression of appreciable populations of sites on mouse lung membranes that exhibit radioligand binding properties and pharmacology consistent with assignment as sigma1 and sigma2 receptors. Specific binding of the sigma1 receptor radioligand [(3)H](+)-pentazocine reached steady state within 6h at 37°C. Saturation studies revealed high affinity binding to a single class of sites (Kd 1.36±0.04nM; Bmax 967±11fmol/mg protein). Inhibition studies showed appropriate sigma1 receptor pharmacology, including higher affinity for (+)-N-allylnormetazocine with respect to the (-)-enantiomer, and positive allosteric modulation of dextromethorphan binding by phenytoin. Using [(3)H]1,3-di(2-tolyl)guanidine in the presence of (+)-pentazocine to assess sigma2 receptor binding, steady state was achieved within 2min at 25°C. Cold saturation studies revealed one high affinity, low capacity binding site (Kd 31.8±8.3nM; Bmax 921±228fmol/mg protein) that displayed sigma2 receptor pharmacology. A very low affinity, high capacity interaction also was observed that represents saturable, but not sigma receptor specific, binding. A panel of ligands showed rank order inhibition of radioligand binding appropriate for the sigma2 receptor, with ifenprodil displaying the highest apparent affinity. In vivo, dextromethorphan inhibited the specific binding of a radioiodinated sigma1 receptor ligand in lung with an ED50 of 1.2μmol/kg, a value near the recommended dosage for the drug as a cough suppressant. Overall, the present work provides a foundation for studies of drug interactions with pulmonary sigma1 and sigma2 receptors in vitro and in vivo. PMID:26004528

  9. 5-HT3-like receptors in the rat medial prefrontal cortex: an electrophysiological study.

    Ashby, C R; Minabe, Y; Edwards, E; Wang, R Y

    1991-06-01

    In this study, we have identified and characterized 5-HT3-like receptors in the rat medial prefrontal cortex (mPFc), an area with a moderate density of 5-HT3 binding sites, using the techniques of single unit recording and microiontophoresis. The microiontophoresis of the 5-HT3 receptor agonist 2-methylserotonin (2-Me-5HT), similar to the action of 5-HT, produced a current-dependent (10-80 nA) suppression of the firing rate of both spontaneously active and glutamate (GLU)-activated (quiescent) mPFc cells. Phenylbiguanide (PBG), another 5-HT3 receptor agonist, suppressed the firing rate of mPFc cells but was less effective compared to 2-Me-5HT. The continuous iontophoresis (10-20 min) of 1 M magnesium chloride markedly attenuated the suppressant effect produced by electrical stimulation of the ascending 5-HT pathway, but did not alter 2-Me-5HT's action, suggesting that the action of 2-Me-5HT is a direct one. The suppressant action of 2-Me-5HT on mPFc cells was blocked by a number of structurally diverse and selective 5-HT3 antagonists, with a rank order of effectiveness as follows: ICS 205930 = (+/-)-zacopride greater than granisetron = ondansetron = LY 278584 greater than MDL 72222. Furthermore, the intravenous administration of (+/-)-zacopride antagonized the action of 2-Me-5HT and PBG on mPFc cells. In contrast to the effects of the 5-HT3 receptors antagonists, other receptor antagonists such as metergoline (5-HT1A,1B,1C.2), (+/-)-pindolol (5-HT1A,1B, beta), SCH 23390 (5-HT1C.2, D1), l-sulpiride (D2) or SR 95103 (GABAA) failed to block 2-Me-5HT's action. These results combined suggest that 2-Me-5HT's suppressive action on mPFc cells is mediated directly by 5-HT3-like receptors. PMID:1679370

  10. Flavonoids with M1 Muscarinic Acetylcholine Receptor Binding Activity

    Meyyammai Swaminathan

    2014-06-01

    Full Text Available Muscarinic acetylcholine receptor-active compounds have potential for the treatment of Alzheimer’s disease. In this study, a series of natural and synthetic flavones and flavonols was assayed in vitro for their ability to inhibit radioligand binding at human cloned M1 muscarinic receptors. Several compounds were found to possess competitive binding affinity (Ki = 40–110 µM, comparable to that of acetylcholine (Ki = 59 µM. Despite the fact that these compounds lack a positively-charged ammonium group under physiological conditions, molecular modelling studies suggested that they bind to the orthosteric site of the receptor, mainly through non-polar interactions.

  11. Risperidone treatment increases CB1 receptor binding in rat brain

    Secher, Anna; Husum, Henriette; Holst, Birgitte;

    2010-01-01

    showed that risperidone treatment altered CB(1) receptor binding in the rat brain. Risperidone-induced adiposity and metabolic dysfunction in the clinic may be explained by increased CB(1) receptor density in brain regions involved in appetite and regulation of metabolic function....... positively correlated with visceral fat mass. Risperidone treatment increased CB(1) receptor binding in the arcuate nucleus (40%), hippocampus (25-30%) and amygdala (35%) without concurrent alterations in the CB(1) receptor mRNA. Risperidone treatment increased adiponectin mRNA. CONCLUSION: The present study...

  12. Characterisation of the melanocortin 4 receptor by radioligand binding

    The DNA encoding the human melanocortin 4 receptor was expressed in COS (CV-1 origin, Sv 40) cells and its radioligand binding properties was tested by using the [124I[(Nle4, D-Phe7) αmelanocyte stimulating hormone (MSH). The radioligand was found to bind to a single saturable site with a Kd of 3l84±0.57 nmol/l in the MC4 receptor expressing cells. The order of potency of a number of substance competing for the [1225I[[Nle4, D-Phe7[ αMSH binding was the following; [Nle4, D-Phe7[ α-MSH>[Nlee[-α-MSH>β-MSH>desacetyl-α-MSH >α-MSH>ACTH (1-39)>ACTH (4-10)>γ2-MSH. This order of potency is unique for the melanocortin 4 receptor when compared to our previously published data for the other melanocortin receptor subtypes. Most notably the melanocortin 4 receptor shows highest affinity for β-MSH, among the endogenous MSH-peptides. Furthermore the melanocortin 4 receptor shows very low affinity for the γ-MSH peptides. This distinguishes the melanocortin 4 receptor from the melanocortin 3 receptor, which is the other major central nervous system melanocortin-receptor, as melanocortin 3 receptor shows high affinity for γ-MSH. Our finding might indicate a specific role for β-MSH for the melanocortin 4 receptor. (au) 31 refs

  13. Noncovalent Interactions within a Synthetic Receptor Can Reinforce Guest Binding

    Rodriguez-Docampo, Zaida; Pascu, Sofia I.; Kubik, Stefan; Otto, Sijbren

    2006-01-01

    Structural and thermodynamic data are presented on the binding properties of anion receptors containing two covalently linked cyclopeptide subunits that bind sulfate and iodide anions with micromolar affinity in aqueous solution. A synchrotron X-ray crystal structure of the sulfate complex of one receptor revealed that the anion is bound between the peptide rings of the biscyclopeptide. Intimate intramolecular contacts between the nonpolar surfaces of the proline rings of the individual recep...

  14. Fluorescent Receptor Binding Assay for Detecting Ciguatoxins in Fish

    Hardison, D. Ransom; Holland, William C.; McCall, Jennifer R.; Bourdelais, Andrea J.; Baden, Daniel G.; Darius, H. Taiana; Chinain, Mireille; Tester, Patricia A.; Shea, Damian; Harold A. Flores Quintana; Morris, James A.; Litaker, R. Wayne

    2016-01-01

    Ciguatera fish poisoning is an illness suffered by > 50,000 people yearly after consumption of fish containing ciguatoxins (CTXs). One of the current methodologies to detect ciguatoxins in fish is a radiolabeled receptor binding assay (RBA(R)). However, the license requirements and regulations pertaining to radioisotope utilization can limit the applicability of the RBA(R) in certain labs. A fluorescence based receptor binding assay (RBA(F)) was developed to provide an alternative method of s...

  15. Sex Differences in Serotonin 1 Receptor Binding in Rat Brain

    Fischette, Christine T.; Biegon, Anat; McEwen, Bruce S.

    1983-10-01

    Male and female rats exhibit sex differences in binding by serotonin 1 receptors in discrete areas of the brain, some of which have been implicated in the control of ovulation and of gonadotropin release. The sex-specific changes in binding, which occur in response to the same hormonal (estrogenic) stimulus, are due to changes in the number of binding sites. Castration alone also affects the number of binding sites in certain areas. The results lead to the conclusion that peripheral hormones modulate binding by serotonin 1 receptors. The status of the serotonin receptor system may affect the reproductive capacity of an organism and may be related to sex-linked emotional disturbances in humans.

  16. Estradiol Binds to Insulin and Insulin Receptor Decreasing Insulin Binding in vitro

    RobertRoot-Bernstein

    2014-07-01

    Methods: Ultraviolet spectroscopy, capillary electrophoresis and NMR demonstrated estrogen binding to insulin and its receptor. Horse-radish peroxidase-linked insulin was used in an ELISA-like procedure to measure the effect of estradiol on binding of insulin to its receptor. Measurements: Binding constants for estrogens to insulin and the insulin receptor were determined by concentration-dependent spectral shifts. The effect of estradiol on insulin-HRP binding to its receptor was determined by shifts in the insulin binding curve. Main Results: Estradiol bound to insulin with a Kd of 12 x 10-9 M and to the insulin receptor with a Kd of 24 x 10-9 M, while other hormones had significantly less affinity. 200 nM estradiol shifted the binding curve of insulin to its receptor 0.8 log units to the right. Conclusions: Estradiol concentrations in many hyperestrogenemic syndromes are sufficient to interfere with insulin binding to its receptor producing significant insulin resistance.

  17. In Silico Investigation of the Neurotensin Receptor 1 Binding Site

    Lückmann, Michael; Holst, Birgitte; Schwartz, Thue W.;

    2016-01-01

    The neurotensin receptor 1 (NTSR1) belongs to the family of 7TM, G protein-coupled receptors, and is activated by the 13-amino-acid peptide neurotensin (NTS) that has been shown to play important roles in neurol. disorders and the promotion of cancer cells. Recently, a high-resoln. x-ray crystal...... structure of NTSR1 in complex with NTS8-13 has been detd., providing novel insights into peptide ligand recognition by 7TM receptors. SR48692, a potent and selective small mol. antagonist has previously been used extensively as a tool compd. to study NTSR1 receptor signaling properties. To investigate...... the binding mode of SR48692 and other small mol. compds. to NTSR1, we applied an Automated Ligand-guided Backbone Ensemble Receptor Optimization protocol (ALiBERO), taking receptor flexibility and ligand knowledge into account. Structurally overlapping binding poses for SR48692 and NTS8-13 were obsd., despite...

  18. The potential of a radiosensitive intracerebral probe to monitor F-18-MPPF binding in mouse hippocampus in vivo

    As mouse imaging has become more challenging in preclinical research, efforts have been made to develop dedicated PET systems. Although these systems are currently used for the study of Physio-pathologic murine models, they present some drawbacks for brain studies, including a low temporal resolution that limits the pharmacokinetic study of radiotracers. The aim of this study was to demonstrate the ability of a radiosensitive intracerebral probe to measure the binding of a radiotracer in the mouse brain in vivo. Methods: The potential of a probe 0.25 mm in diameter for pharmacokinetic studies was assessed.First, Monte Carlo simulations followed by experimental studies were used to evaluate the detection volume and sensitivity of the probe and its adequacy for the size of loci in the mouse brain. Second, ex vivo autoradiography of 5-hydroxytryptamine receptor 1A (5-HT1A) receptors in the mouse brain was performed with the PET radiotracer 2'-methoxy-phenyl-(N-2'-pyridinyl)-p-F-18-fluoro-benzamido-ethylpiperazine (F-18-MPPF). Finally, the binding kinetics of F-18-MPPF were measured in vivo in both the hippocampus and the cerebellum of mice. Results: Both the simulations and the experimental studies demonstrated the feasibility of using small probes to measure radioactive concentrations in specific regions of the mouse brain. Ex vivo autoradiography showed a heterogeneous distribution of F-18-MPPF consistent with the known distribution of 5-HT1A in the mouse brain. Finally, the time-activity curves obtained in vivo were reproducible and validated the capacity of the new probe to accurately measure F-18-MPPF kinetics in the mouse hippocampus. Conclusion: Our results demonstrate the ability of the tested radiosensitive intracerebral probe to monitor binding of PET radiotracers in anesthetized mice in vivo, with high temporal resolution suited for compartmental modeling. (authors)

  19. Fatty acid binding receptors in intestinal physiology and pathophysiology

    Kaemmerer, Elke; Plum, Patrick; Klaus, Christina; Weiskirchen, Ralf; Liedtke, Christian; Adolf, Maximilian; Schippers, Angela; Wagner, Norbert; Reinartz, Andrea; Gassler, Nikolaus

    2010-01-01

    Free fatty acids are essential dietary components and recognized as important molecules in the maintenance of cellular homeostasis. In the last decade, the molecular pathways for free fatty acid sensing in the gastrointestinal tract have been further elucidated by molecular identification and functional characterization of fatty acid binding receptors. These sensing molecules belong to the family of G protein-coupled receptors. In the intestine, four important receptors have been described so...

  20. σ1 Receptor Modulation of G-Protein-Coupled Receptor Signaling: Potentiation of Opioid Transduction Independent from Receptor Binding

    Kim, Felix J.; Kovalyshyn, Ivanka; Burgman, Maxim; Neilan, Claire; Chien, Chih-Cheng

    2010-01-01

    σ Ligands modulate opioid actions in vivo, with agonists diminishing morphine analgesia and antagonists enhancing the response. Using human BE(2)-C neuroblastoma cells that natively express opioid receptors and human embryonic kidney (HEK) cells transfected with a cloned μ opioid receptor, we now demonstrate a similar modulation of opioid function, as assessed by guanosine 5′-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding, by σ1 receptors. σ Ligands do not compete opioid receptor binding. Administered alone, neither σ agonists nor antagonists significantly stimulated [35S]GTPγS binding. Yet σ receptor selective antagonists, but not agonists, shifted the EC50 of opioid-induced stimulation of [35S]GTPγS binding by 3- to 10-fold to the left. This enhanced potency was seen without a change in the efficacy of the opioid, as assessed by the maximal stimulation of [35S]GTPγS binding. σ1 Receptors physically associate with μ opioid receptors, as shown by coimmunoprecipitation studies in transfected HEK cells, implying a direct interaction between the proteins. Thus, σ receptors modulate opioid transduction without influencing opioid receptor binding. RNA interference knockdown of σ1 in BE(2)-C cells also potentiated μ opioid-induced stimulation of [35S]GTPγS binding. These modulatory actions are not limited to μ and δ opioid receptors. In mouse brain membrane preparations, σ1-selective antagonists also potentiated both opioid receptor and muscarinic acetylcholine receptor-mediated stimulation of [35S]GTPγS binding, suggesting a broader role for σ receptors in modulating G-protein-coupled receptor signaling. PMID:20089882

  1. Sigma 1 receptor modulation of G-protein-coupled receptor signaling: potentiation of opioid transduction independent from receptor binding.

    Kim, Felix J; Kovalyshyn, Ivanka; Burgman, Maxim; Neilan, Claire; Chien, Chih-Cheng; Pasternak, Gavril W

    2010-04-01

    sigma Ligands modulate opioid actions in vivo, with agonists diminishing morphine analgesia and antagonists enhancing the response. Using human BE(2)-C neuroblastoma cells that natively express opioid receptors and human embryonic kidney (HEK) cells transfected with a cloned mu opioid receptor, we now demonstrate a similar modulation of opioid function, as assessed by guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTP gamma S) binding, by sigma(1) receptors. sigma Ligands do not compete opioid receptor binding. Administered alone, neither sigma agonists nor antagonists significantly stimulated [(35)S]GTP gamma S binding. Yet sigma receptor selective antagonists, but not agonists, shifted the EC(50) of opioid-induced stimulation of [(35)S]GTP gamma S binding by 3- to 10-fold to the left. This enhanced potency was seen without a change in the efficacy of the opioid, as assessed by the maximal stimulation of [(35)S]GTP gamma S binding. sigma(1) Receptors physically associate with mu opioid receptors, as shown by coimmunoprecipitation studies in transfected HEK cells, implying a direct interaction between the proteins. Thus, sigma receptors modulate opioid transduction without influencing opioid receptor binding. RNA interference knockdown of sigma(1) in BE(2)-C cells also potentiated mu opioid-induced stimulation of [(35)S]GTP gamma S binding. These modulatory actions are not limited to mu and delta opioid receptors. In mouse brain membrane preparations, sigma(1)-selective antagonists also potentiated both opioid receptor and muscarinic acetylcholine receptor-mediated stimulation of [(35)S]GTP gamma S binding, suggesting a broader role for sigma receptors in modulating G-protein-coupled receptor signaling. PMID:20089882

  2. Effect of desipramine on dopamine receptor binding in vivo

    Effect of desipramine on the in vivo binding of 3H-SCH23390 and 3H-N-methylspiperone (3H-NMSP) in mouse striatum was studied. The ratio of radioactivity in the striatum to that in the cerebellum at 15 min after i.v. injection of 3H-SCH23390 or 45 min after injection of 3H-NMSP were used as indices of dopamine D1 or D2 receptor binding in vivo, respectively. In vivo binding of D1 and D2 receptors was decreased in a dose-dependent manner by acute treatment with desipramine (DMI). A saturation experiment suggested that the DMI-induced reduction in the binding was mainly due to the decrease in the affinity of both receptors. No direct interactions between the dopamine receptors and DMI were observed in vitro by the addition of 1 mM of DMI into striatal homogenate. Other antidepressants such as imipramine, clomipramine, maprotiline and mianserin also decreased the binding of dopamine D1 and D2 receptors. The results indicated an important role of dopamine receptors in the pharmacological effect of antidepressants

  3. Modeling of ligand binding to dopamine D2 receptor

    Ostopovici-Halip Liliana

    2014-01-01

    Full Text Available The dopaminic receptors have been for long time the major targets for developing new small molecules with high affinity and selectivity to treat psychiatric disorders, neurodegeneration, drug abuse, and other therapeutic areas. In the absence of a 3D structure for the human D2 dopamine (HDD2 receptor, the efforts for discovery and design of new potential drugs rely on comparative models generation, docking and pharmacophore development studies. To get a better understanding of the HDD2 receptor binding site and the ligand-receptor interactions a homology model of HDD2 receptor based on the X-ray structure of β2-adrenergic receptor has been built and used to dock a set of partial agonists of HDD2 receptor. The main characteristics of the binding mode for the HDD2 partial agonists set are given by the ligand particular folding and a complex network of contacts represented by stacking interactions, salt bridge and hydrogen bond formation. The characterization of the partial agonist binding mode at HDD2 receptor provide the needed information to generate pharmacophore models which represent essential information in the future virtual screening studies in order to identify new potential HDD2 partial agonists.

  4. Characterisation of the melanocortin 4 receptor by radioligand binding

    Schioeth, H.B.; Wikberg, J.E.S. [Uppsala Univ., Dept. of Pharmaceutical Pharmacology, Uppsala (Sweden); Muceniece, R. [Inst. of Organic Synthesis, Lab. of Pharmacology, Riga (Latvia)

    1996-09-01

    The DNA encoding the human melanocortin 4 receptor was expressed in COS (CV-1 origin, Sv 40) cells and its radioligand binding properties was tested by using the [{sup 124}I](Nle{sup 4}, D-Phe{sup 7}) {alpha}melanocyte stimulating hormone (MSH). The radioligand was found to bind to a single saturable site with a K{sub d} of 3l84{+-}0.57 nmol/l in the MC4 receptor expressing cells. The order of potency of a number of substance competing for the [{sup 12}25I][Nle{sup 4}, D-Phe{sup 7}] {alpha}MSH binding was the following; [Nle{sup 4}, D-Phe{sup 7}] {alpha}-MSH>[Nle{sup e}]-{alpha}-MSH>{beta}-MSH>desacetyl-{alpha}-MSH >{alpha}-MSH>ACTH (1-39)>ACTH (4-10)>{gamma}2-MSH. This order of potency is unique for the melanocortin 4 receptor when compared to our previously published data for the other melanocortin receptor subtypes. Most notably the melanocortin 4 receptor shows highest affinity for {beta}-MSH, among the endogenous MSH-peptides. Furthermore the melanocortin 4 receptor shows very low affinity for the {gamma}-MSH peptides. This distinguishes the melanocortin 4 receptor from the melanocortin 3 receptor, which is the other major central nervous system melanocortin-receptor, as melanocortin 3 receptor shows high affinity for {gamma}-MSH. Our finding might indicate a specific role for {beta}-MSH for the melanocortin 4 receptor. (au) 31 refs.

  5. Estradiol Binds to Insulin and Insulin Receptor Decreasing Insulin Binding in vitro

    RobertRoot-Bernstein

    2014-01-01

    Rationale: Insulin resistance associated with hyperestrogenemias occurs in gestational diabetes mellitus, polycystic ovary syndrome, ovarian hyperstimulation syndrome, estrogen therapies, metabolic syndrome and obesity. The mechanism by which insulin and estrogen interact is unknown. We hypothesize that estrogen binds directly to insulin and the insulin receptor producing insulin resistance. Objectives: To determine the binding constants of steroid hormones to insulin, the insulin recepto...

  6. Coregulator Control of Androgen Receptor Action by a Novel Nuclear Receptor-Binding Motif

    Jehle, Katja; Cato, Laura; Neeb, Antje; Muhle-Goll, Claudia; Jung, Nicole; Smith, Emmanuel W.; Buzon, Victor; Carbó, Laia R.; Estébanez-Perpiñá, Eva; Schmitz, Katja; Fruk, Ljiljana; Luy, Burkhard; Chen, Yu; Cox, Marc B.; Bräse, Stefan

    2014-01-01

    The androgen receptor (AR) is a ligand-activated transcription factor that is essential for prostate cancer development. It is activated by androgens through its ligand-binding domain (LBD), which consists predominantly of 11 α-helices. Upon ligand binding, the last helix is reorganized to an agonist conformation termed activator function-2 (AF-2) for coactivator binding. Several coactivators bind to the AF-2 pocket through conserved LXXLL or FXXLF sequences to enhance the activity of the rec...

  7. Differential effect of glucocorticoid receptor antagonists on glucocorticoid receptor nuclear translocation and DNA binding

    Spiga, Francesca; Knight, David M; Droste, Susanne K; Conway-Campbell, Becky; Kershaw, Yvonne; MacSweeney, Cliona P; Thomson, Fiona J; Craighead, Mark; Peeters, Bernard WMM; Lightman, Stafford L

    2016-01-01

    The effects of RU486 and S-P, a more selective glucocorticoid receptor antagonist from Schering-Plough, were investigated on glucocorticoid receptor nuclear translocation and DNA binding. In the in vitro study, AtT20 cells were treated with vehicle or with RU486, S-P or corticosterone (3–300 nM) or co-treated with vehicle or glucocorticoid receptor antagonists (3–300 nM) and 30 nM corticosterone. Both glucocorticoid receptor antagonists induced glucocorticoid receptor nuclear translocation but only RU486 induced DNA binding. RU486 potentiated the effect of corticosterone on glucocorticoid receptor nuclear translocation and DNA binding, S-P inhibited corticosterone-induced glucocorticoid receptor nuclear translocation, but not glucocorticoid receptor-DNA binding. In the in vivo study, adrenalectomized rats were treated with vehicle, RU486 (20 mg/kg) and S-P (50 mg/kg) alone or in combination with corticosterone (3 mg/kg). RU486 induced glucocorticoid receptor nuclear translocation in the pituitary, hippocampus and prefrontal cortex and glucocorticoid receptor-DNA binding in the hippocampus, whereas no effect of S-P on glucocorticoid receptor nuclear translocation or DNA binding was observed in any of the areas analysed. These findings reveal differential effects of RU486 and S-P on areas involved in regulation of hypothalamic–pituitary–adrenal axis activity in vivo and they are important in light of the potential use of this class of compounds in the treatment of disorders associated with hyperactivity of the hypothalamic–pituitary–adrenal axis. PMID:20093322

  8. Binding Mode Prediction of Evodiamine within Vanilloid Receptor TRPV1

    Huaping Liang; Liangren Zhang; Wuzhuang Gong; Yanhui Zhang; Zhanli Wang; Lidan Sun; Hui Yu; Hongwei Jin

    2012-01-01

    Accurate assessment of the potential binding mode of drugs is crucial to computer-aided drug design paradigms. It has been reported that evodiamine acts as an agonist of the vanilloid receptor Transient receptor potential vanilloid-1 (TRPV1). However, the precise interaction between evodiamine and TRPV1 was still not fully understood. In this perspective, the homology models of TRPV1 were generated using the crystal structure of the voltage-dependent shaker family K

  9. Structural Allostery and Binding of the Transferring Receptor Complex

    Xu,G.; Liu, R.; Zak, O.; Aisen, P.; Chance, M.

    2005-01-01

    The structural allostery and binding interface for the human serum transferrin (Tf){center_dot}transferrin receptor (TfR) complex were identified using radiolytic footprinting and mass spectrometry. We have determined previously that the transferrin C-lobe binds to the receptor helical domain. In this study we examined the binding interactions of full-length transferrin with receptor and compared these data with a model of the complex derived from cryoelectron microscopy (cryo-EM) reconstructions. The footprinting results provide the following novel conclusions. First, we report characteristic oxidations of acidic residues in the C-lobe of native Tf and basic residues in the helical domain of TfR that were suppressed as a function of complex formation; this confirms ionic interactions between these protein segments as predicted by cryo-EM data and demonstrates a novel method for detecting ion pair interactions in the formation of macromolecular complexes. Second, the specific side-chain interactions between the C-lobe and N-lobe of transferrin and the corresponding interactions sites on the transferrin receptor predicted from cryo-EM were confirmed in solution. Last, the footprinting data revealed allosteric movements of the iron binding C- and N-lobes of Tf that sequester iron as a function of complex formation; these structural changes promote tighter binding of the metal ion and facilitate efficient ion transport during endocytosis.

  10. Radioiodination of chicken luteinizing hormone without affecting receptor binding potency

    By improving the currently used lactoperoxidase method, we were able to obtain radioiodinated chicken luteinizing hormone (LH) that shows high specific binding and low nonspecific binding to a crude plasma membrane fraction of testicular cells of the domestic fowl and the Japanese quail, and to the ovarian granulosa cells of the Japanese quail. The change we made from the original method consisted of (1) using chicken LH for radioiodination that was not only highly purified but also retained a high receptor binding potency; (2) controlling the level of incorporation of radioiodine into chicken LH molecules by employing a short reaction time and low temperature; and (3) fractionating radioiodinated chicken LH further by gel filtration using high-performance liquid chromatography. Specific radioactivity of the final 125I-labeled chicken LH preparation was 14 microCi/micrograms. When specific binding was 12-16%, nonspecific binding was as low as 2-4% in the gonadal receptors. 125I-Labeled chicken LH was displaced by chicken LH and ovine LH but not by chicken follicle-stimulating hormone. The equilibrium association constant of quail testicular receptor was 3.6 x 10(9) M-1. We concluded that chicken LH radioiodinated by the present method is useful for studies of avian LH receptors

  11. Development of prolactin receptor antagonists with reduced pH-dependence of receptor binding

    Hansen, Mathilde Johanne Kaas; Olsen, Johan Gotthardt; Bernichtein, Sophie;

    2011-01-01

    H than at physiological pH and since the extracellular environment around solid tumors often is acidic, it is desirable to develop antagonists that have improved binding affinity at low pH. The pK(a) value of a histidine side chain is ~6.8 making histidine residues obvious candidates for examination....... From evaluation of known molecular structures of human prolactin, of the prolactin receptor and of different complexes of the two, three histidine residues in the hormone-receptor binding site 1 were selected for mutational studies. We analyzed 10 variants by circular dichroism spectroscopy, affinity...... and thermodynamic characterization of receptor binding by isothermal titration calorimetry combined with in vitro bioactivity in living cells. Histidine residue 27 was recognized as a central hot spot for pH sensitivity and conservative substitutions at this site resulted in strong receptor binding at...

  12. Development of a homogeneous binding assay for histamine receptors.

    Crane, Kathy; Shih, Daw-Tsun

    2004-12-01

    Histamine is critically involved in a wide range of physiological and pathological processes through its actions at different receptors. Thus, histamine receptors have been actively pursued as therapeutic targets in the pharmaceutical industry for the treatment of a variety of diseases. There are currently four histamine receptors that have been cloned, all of which are G protein-coupled receptors. Studies from both academia and pharmaceutical companies have identified compounds that modulate the function of specific histamine receptors. These efforts led to the successful introduction of histamine H(1) and H(2) receptor antagonists for the treatment of allergy and excess gastric acid secretion, respectively. Histamine H(3) receptor ligands are currently under investigation for the treatment of obesity and neurological disorders. The recently identified histamine H(4) receptor is preferentially expressed in the immune tissues, suggesting a potential role in normal immune functions and possibly in the pathogenesis of inflammatory diseases. Even with the long history of histamine research and the important applications of histamine receptor ligands, assays to measure the affinity of compounds binding to histamine receptors are still routinely analyzed using a filtration assay, a very low-throughput assay involving washing and filtration steps. This article describes a simple, robust, and homogeneous binding assay based on the scintillation proximity assay (SPA) technology that provides results equivalent to those obtained using the more complex filtration assay. The SPA format is easily adapted to high-throughput screening because it is amenable to automation. In summary, this technique allows high-throughput screening of compounds against multiple histamine receptors and, thus, facilitates drug discovery efforts. PMID:15519569

  13. The Quantum Nature of Drug-Receptor Interactions: Deuteration Changes Binding Affinities for Histamine Receptor Ligands

    Repič, Matej; Zakšek, Maja; Kotnik, Kristina; Fijan, Estera; Mavri, Janez

    2016-01-01

    In this article we report a combined experimental and computational study concerning the effects of deuteration on the binding of histamine and two other histaminergic agonists to 3H-tiotidine-labeled histamine H2 receptor in neonatal rat astrocytes. Binding affinities were measured by displacing radiolabeled tiotidine from H2 receptor binding sites present on cultured neonatal rat astrocytes. Quantum-chemical calculations were performed by employing the empirical quantization of nuclear motion within a cluster model of the receptor binding site extracted from the homology model of the entire H2 receptor. Structure of H2 receptor built by homology modelling is attached in the supporting information (S1 Table) Experiments clearly demonstrate that deuteration affects the binding by increasing the affinity for histamine and reducing it for 2-methylhistamine, while basically leaving it unchanged for 4-methylhistamine. Ab initio quantum-chemical calculations on the cluster system extracted from the homology H2 model along with the implicit quantization of the acidic N–H and O–H bonds demonstrate that these changes in the binding can be rationalized by the altered strength of the hydrogen bonding upon deuteration known as the Ubbelohde effect. Our computational analysis also reveals a new mechanism of histamine binding, which underlines an important role of Tyr250 residue. The present work is, to our best knowledge, the first study of nuclear quantum effects on ligand receptor binding. The ligand H/D substitution is relevant for therapy in the context of perdeuterated and thus more stable drugs that are expected to enter therapeutic practice in the near future. Moreover, presented approach may contribute towards understanding receptor activation, while a distant goal remains in silico discrimination between agonists and antagonists based on the receptor structure. PMID:27159606

  14. The receptor binding domain of botulinum neurotoxin serotype C binds phosphoinositides.

    Zhang, Yanfeng; Varnum, Susan M

    2012-03-01

    Botulinum neurotoxins (BoNTs) are the most toxic proteins known for humans and animals with an extremely low LD(50) of ∼1 ng/kg. BoNTs generally require a protein and a ganglioside on the cell membrane surface for binding, which is known as a "dual receptor" mechanism for host intoxication. Recent studies have suggested that in addition to gangliosides, other membrane lipids such as phosphoinositides may be involved in the interactions with the receptor binding domain (HCR) of BoNTs for better membrane penetration. Using two independent lipid-binding assays, we tested the interactions of BoNT/C-HCR with lipids in vitro domain. BoNT/C-HCR was found to bind negatively charged phospholipids, preferentially phosphoinositides in both assays. Interactions with phosphoinositides may facilitate tighter binding between neuronal membranes and BoNT/C. PMID:22120109

  15. Whole-genome cartography of estrogen receptor alpha binding sites.

    Chin-Yo Lin

    2007-06-01

    Full Text Available Using a chromatin immunoprecipitation-paired end diTag cloning and sequencing strategy, we mapped estrogen receptor alpha (ERalpha binding sites in MCF-7 breast cancer cells. We identified 1,234 high confidence binding clusters of which 94% are projected to be bona fide ERalpha binding regions. Only 5% of the mapped estrogen receptor binding sites are located within 5 kb upstream of the transcriptional start sites of adjacent genes, regions containing the proximal promoters, whereas vast majority of the sites are mapped to intronic or distal locations (>5 kb from 5' and 3' ends of adjacent transcript, suggesting transcriptional regulatory mechanisms over significant physical distances. Of all the identified sites, 71% harbored putative full estrogen response elements (EREs, 25% bore ERE half sites, and only 4% had no recognizable ERE sequences. Genes in the vicinity of ERalpha binding sites were enriched for regulation by estradiol in MCF-7 cells, and their expression profiles in patient samples segregate ERalpha-positive from ERalpha-negative breast tumors. The expression dynamics of the genes adjacent to ERalpha binding sites suggest a direct induction of gene expression through binding to ERE-like sequences, whereas transcriptional repression by ERalpha appears to be through indirect mechanisms. Our analysis also indicates a number of candidate transcription factor binding sites adjacent to occupied EREs at frequencies much greater than by chance, including the previously reported FOXA1 sites, and demonstrate the potential involvement of one such putative adjacent factor, Sp1, in the global regulation of ERalpha target genes. Unexpectedly, we found that only 22%-24% of the bona fide human ERalpha binding sites were overlapping conserved regions in whole genome vertebrate alignments, which suggest limited conservation of functional binding sites. Taken together, this genome-scale analysis suggests complex but definable rules governing ERalpha

  16. DC-SIGN:binding receptors for hepatitis C virus

    王全楚; 冯志华; 聂青和; 周永兴

    2004-01-01

    Objective To review the recent developments in and research into binding receptors of hepatitis C virus (HCV) and especially the role of dendritic cell-specitic adhesion receptor (DC-SIGN) in HCV.Data sources Both Chinese- and English-languge literature was searched using MEDLINE (2000-2003) and the databank of Chinese-language literature (2000-2003).Study selection Relevant articles on DC-SIGN and HCV binding receptors in recent domestic and foreign literature were selected.Data extraction Data were mainly extracted from 40 articles which are listed in the references section of this review. Results DC-SIGN, a dendritic cell-specific adhesion receptor and a type Ⅱ transmembrane mannose-binding C-type lectin, is very important in the function of dendritic cells (DC), both in mediating na(I)ve T cell interactions through ICAM-3 and as a rolling receptor that mediates the DC-specific ICAM-2-dependent migration processes-It can be used by HCV and other viral and bacterial pathogens including human immunodeficiency virus (HIV), Ebola virus, CMV and Mycobacterium tuberculosis- to facilitate infection. Both DC-SIGN and DC-SIGNR can act either in cis, by concentrating virus on target cells, or in trans, by transmission of bound virus to a target cell expressing appropriate entry receptors. Recent report showed that DC-S IGN not only plays a role in entry into DC, HCV E2 interaction with DC-SIGN might also be detrimental to the interaction of DC with T cells during antigen presentation.Conclusions DC-SIGNs are high-affinity binding receptors for HCV.The clinical strategies that target DC-SIGN may be successful in restricting HCV dissemination and pathogenesis as well as directing the migration of DCs to manipulate appropriate immune responses in autoimmunity and tumorigenic situations.

  17. D-2 receptor binding in dopa-responsive dystonia

    Kunig, G; Leenders, KL; Antonini, A; Vontobel, P; Weindl, A; Meinck, HM

    1998-01-01

    We have studied dopamine D-2 receptor binding by [C-11]raclopride positron emission tomography in 14 patients with dopa-responsive dystonia (DRD). Data were compared with 16 levodopa-treated patients with Parkinson's disease (PD) and 26 healthy controls. The results revealed an elevated [C-11]raclop

  18. A behavioural and biochemical study in mice and rats of putative selective agonists and antagonists for 5-HT1 and 5-HT2 receptors.

    Goodwin, G. M.; Green, A R

    1985-01-01

    Radioligand binding techniques have demonstrated the existence of 5-hydroxytryptamine (5-HT) binding subtypes: 5-HT2, 5-HT1A and 5-HT1B. These techniques have also indicated that certain drugs appear to show sub-type specificity: 8-hydroxy-2-(di-n-propylamino)tetralin(8-OH-DPAT), a 5-HT1A agonist; 5-methoxy-3(1,2,3,6-tetrahydropyridin-4-yl)1-H indole (RU 24969), a 5-HT1B agonist; and ritanserin, a 5-HT2 antagonist. (-)-Propranolol is a 5-HT1 antagonist of uncertain sub-type specificity. An ex...

  19. Crystal structure of mouse coronavirus receptor-binding domain complexed with its murine receptor

    Peng, Guiqing; Sun, Dawei; Rajashankar, Kanagalaghatta R.; Qian, Zhaohui; Holmes, Kathryn V.; Li, Fang (Cornell); (UMM-MED); (Colorado)

    2011-09-28

    Coronaviruses have evolved diverse mechanisms to recognize different receptors for their cross-species transmission and host-range expansion. Mouse hepatitis coronavirus (MHV) uses the N-terminal domain (NTD) of its spike protein as its receptor-binding domain. Here we present the crystal structure of MHV NTD complexed with its receptor murine carcinoembryonic antigen-related cell adhesion molecule 1a (mCEACAM1a). Unexpectedly, MHV NTD contains a core structure that has the same {beta}-sandwich fold as human galectins (S-lectins) and additional structural motifs that bind to the N-terminal Ig-like domain of mCEACAM1a. Despite its galectin fold, MHV NTD does not bind sugars, but instead binds mCEACAM1a through exclusive protein-protein interactions. Critical contacts at the interface have been confirmed by mutagenesis, providing a structural basis for viral and host specificities of coronavirus/CEACAM1 interactions. Sugar-binding assays reveal that galectin-like NTDs of some coronaviruses such as human coronavirus OC43 and bovine coronavirus bind sugars. Structural analysis and mutagenesis localize the sugar-binding site in coronavirus NTDs to be above the {beta}-sandwich core. We propose that coronavirus NTDs originated from a host galectin and retained sugar-binding functions in some contemporary coronaviruses, but evolved new structural features in MHV for mCEACAM1a binding.

  20. Serotonin receptor subtype mediation of the interoceptive discriminative stimuli induced by 5-methoxy-N,N-dimethyltryptamine.

    Spencer, D G; Glaser, T; Traber, J

    1987-01-01

    Male Wistar rats were trained to discriminate the interoceptive effects of 5-methoxy-N,N-dimethyltryptamine (5-OMe-DMT; 1.25 mg/kg, IP) from saline in a two-lever operant chamber. Following discrimination learning, the following drugs (with ED50 dose in mg/kg IP) dose-dependently generalized: lysergic acid diethylamide (LSD, 0.04), 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.11), 6-methoxy-4-(dipropyl-amino)-1,3,4,5-tetrahydrobenz(c,d)indole hydrochloride (BAY R 1531, 0.15), 5-OMe-DMT itself (0.63), ipsapirone (TVX Q 7821, 2.7), and buspirone (3.8). The potencies of these drugs in generalization tests were best correlated with their binding affinities for the 5-HT1A serotonin receptor subtype (as measured by displacement of 3H-ipsapirone in the hippocampus). Drugs not, or only partially generalizing included quipazine, bufotenin, m-trifluoromethylphenylpiperazine (TFMPP), 5-methoxy-3(1,2,3,6-tetrahydropyridine-4-yl)-1H-indole succinate (RU 24969), citalopram, clomipramine, 1,4-dihydro-2,6-dimethyl-3-nitro-4(2-trifluoromethylphenyl)-pyridine-5- carboxylate (BAY K 8644), the buspirone metabolite 1-pyrimidinyl-piperazine (1-PP), methysergide, metergoline, and metitepine. Of the last three compounds with antagonistic activity at 5-HT receptors, as well as ketanserin, pizotifen, and ritanserin, only metitepine and pindolol could fully block the 5-OMe-DMT stimulus. Pizotifen blocked the generalization of quipazine fully, that of 5-OMe-DMT only partially, and that of ipsapirone not at all. These data indicate that the 5-HT1A receptor subtype is strongly involved in the transduction of the interoceptive discriminative stimuli induced by 5-OMe-DMT, with 5-HT2 agonism also playing a possible role. PMID:3122248

  1. Evidence for an intrinsic binding force between dodecaborate dianions and receptors with hydrophobic binding pockets.

    Warneke, Jonas; Jenne, Carsten; Bernarding, Johannes; Azov, Vladimir A; Plaumann, Markus

    2016-05-01

    A gas phase binding study revealed strong intrinsic intermolecular interactions between dianionic halogenated closo-dodecaborates [B12X12](2-) and several neutral organic receptors. Oxidation of a tetrathiafulvalene host allowed switching between two host-guest binding modes in a supramolecular complex. Complexes of β-cyclodextrin with [B12F12](2-) show remarkable stability in the gas phase and were successfully tested as carriers for the delivery of boron clusters into cancer cells. PMID:27087168

  2. Identification of novel viral receptors with cell line expressing viral receptor-binding protein.

    Mei, Mei; Ye, Jianqiang; Qin, Aijian; Wang, Lin; Hu, Xuming; Qian, Kun; Shao, Hongxia

    2015-01-01

    The viral cell receptors and infection can be blocked by the expression of the viral receptor-binding protein. Thus, the viral cell receptor is an attractive target for anti-viral strategies, and the identification of viral cell receptor is critical for better understanding and controlling viral disease. As a model system for viral entry and anti-retroviral approaches, avian sarcoma/leukosis virus (ASLV, including the A-J ten subgroups) has been studied intensively and many milestone discoveries have been achieved based on work with ASLV. Here, we used a DF1 cell line expressed viral receptor-binding protein to efficiently identify chicken Annexin A2 (chANXA2) as a novel receptor for retrovirus ALV-J (avian leukosis virus subgroup J). Our data demonstrate that antibodies or siRNA to chANXA2 significantly inhibited ALV-J infection and replication, and over-expression of chANXA2 permitted the entry of ALV-J into its non-permissible cells. Our findings have not only identified chANXA2 as a novel biomarker for anti-ALV-J, but also demonstrated that cell lines with the expression of viral receptor-binding protein could be as efficient tools for isolating functional receptors to identify novel anti-viral targets. PMID:25604889

  3. Interaction of chemokines with their receptors--from initial chemokine binding to receptor activating steps

    Thiele, Stefanie; Rosenkilde, Mette Marie

    2014-01-01

    The human chemokine system comprises 19 seven-transmembrane helix (7TM) receptors and 45 endogenous chemokines that often interact with each other in a promiscuous manner. Due to the chemokine system's primary function in leukocyte migration, it has a central role in immune homeostasis and...... interactions possibly occur, resulting in a multi-step process, as recently proposed for other 7TM receptors. Overall, the N-terminus of chemokine receptors is pivotal for binding of all chemokines. During receptor activation, differences between the two major chemokine subgroups occur, as CC-chemokines mainly...

  4. The effects of serotonin1A receptor on female mice body weight and food intake are associated with the differential expression of hypothalamic neuropeptides and the GABAA receptor.

    Butt, Isma; Hong, Andrew; Di, Jing; Aracena, Sonia; Banerjee, Probal; Shen, Chang-Hui

    2014-10-01

    Both common eating disorders anorexia nervosa and bulimia nervosa are characteristically diseases of women. To characterize the role of the 5-HT1A receptor (5-HT1A-R) in these eating disorders in females, we investigated the effect of saline or 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) treatment on feeding behavior and body weight in adult WT female mice and in adult 5-HT1A-R knockout (KO) female mice. Our results showed that KO female mice have lower food intake and body weight than WT female mice. Administration of 8-OH-DPAT decreased food intake but not body weight in WT female mice. Furthermore, qRT-PCR was employed to analyze the expression levels of neuropeptides, γ-aminobutyric acid A receptor subunit β (GABAA β subunits) and glutamic acid decarboxylase in the hypothalamic area. The results showed the difference in food intake between WT and KO mice was accompanied by differential expression of POMC, CART and GABAA β2, and the difference in body weight between WT and KO mice was associated with significantly different expression levels of CART and GABAA β2. As such, our data provide new insight into the role of 5-HT1A-R in both feeding behavior and the associated expression of neuropeptides and the GABAA receptor. PMID:25130282

  5. The intact urokinase receptor is required for efficient vitronectin binding

    Høyer-Hansen, G; Behrendt, N; Ploug, M; Danø, K; Preissner, K T

    1997-01-01

    -blotting experiments we found that vitronectin binds uPAR but not uPAR(2+3). In real-time biomolecular interaction analysis using recombinant, soluble uPAR (suPAR) both plasma and multimeric forms of vitronectin bound to intact, antibody-immobilized suPAR. Monoclonal antibodies against domain 1 of uPAR blocked su......PAR binding to vitronectin and vitronectin did not interact with suPAR(2+3). Both suPAR(2+3) and the isolated domain 1 failed to compete with the intact suPAR in binding to vitronectin. We therefore conclude that the intact receptor is required for efficient vitronectin binding....

  6. Receptor binding of biosynthetic human insulin on isolated pig hepatocytes

    Gammeltoft, S.

    Biosynthetic human insulin (BHI) and pancreatic human insulin were compared with respect to receptor binding in a heterologous assay system: displacement of pork A14-/sup 125/I-monoiodoinsulin from receptors on pig hepatocytes. The concentrations of human insulin giving half-maximal displacement were identical for both preparations, i.e., 0.5 nM. Their relative potency was 1.01 +/- 0.14 (SD, N . 5), suggesting that biosynthetic and pancreatic human insulin exert the same biologic activity.

  7. Receptor binding of biosynthetic human insulin on isolated pig hepatocytes

    Biosynthetic human insulin (BHI) and pancreatic human insulin were compared with respect to receptor binding in a heterologous assay system: displacement of pork A14-125I-monoiodoinsulin from receptors on pig hepatocytes. The concentrations of human insulin giving half-maximal displacement were identical for both preparations, i.e., 0.5 nM. Their relative potency was 1.01 +/- 0.14 (SD, N . 5), suggesting that biosynthetic and pancreatic human insulin exert the same biologic activity

  8. [Role of serotonin receptors in vascular tone in the pithed rat].

    Sánchez-López, Araceli; Centurión, David; Lozano-Cuenca, Jair; Muñoz-Islas, Enriqueta; Cobos-Puc, Luis E; Villalón, Carlos M

    2009-12-01

    Serotonin (5-hydroxytryptamine; 5-HT) has been shown to produce vascular sympatho-inhibition in a wide variety of isolated blood vessels by activation of prejunctional 5-HT1 receptors. After considering the mechanisms involved in modulating neuroeffector transmission, the present review analyzes the experimental findings identifying the pharmacological profile of the 5-HT receptors that inhibit the sympathetically-induced vasopressor responses in pithed rats. Thus, 5-HT-induced sympatho-inhibition has been shown to be: (i) unaffected by physiological saline or by the selective antagonists ritanserin (5-HT2), MDL72222 (5-HT3) or tropisetron (5-HT3/4); (ii) blocked by methysergide, a non-selective 5-HT1/2 receptor antagonist; and (iii) potently mimicked by 5-carboxamidotryptamine (5-CT), a non-selective 5-HT1 receptor agonist, as well as by the selective agonists 8-OH-DPAT (5-HT1A), indorenate (5-HT1A), CP93,129 (5-HT1B), and sumatriptan (5-HT1B/1D). These findings show the involvement of prejunctional 5-HT1 receptors. With the use of selective antagonists, it has been shown subsequently that the sympatho-inhibition induced by indorenate, CP93, 129, and sumatriptan was selectively antagonized by WAY100635 (5-HT1A), cyanopindolol (5-HT1A/1B), and GR127935 (5-HT1B/1D), respectively. These results demonstrate that the 5-HT1 receptors mediating sympatho-inhibition on the systemic vasculature of pithed rats resemble the pharmacological profile of the 5-HT1A, 5-HT1B, and 5-HT1D subtypes. PMID:20361490

  9. Mast cell expression of the serotonin1A receptor in guinea pig and human intestine.

    Wang, Guo-Du; Wang, Xi-Yu; Zou, Fei; Qu, Meihua; Liu, Sumei; Fei, Guijun; Xia, Yun; Needleman, Bradley J; Mikami, Dean J; Wood, Jackie D

    2013-05-15

    Serotonin [5-hydroxytryptamine (5-HT)] is released from enterochromaffin cells in the mucosa of the small intestine. We tested a hypothesis that elevation of 5-HT in the environment of enteric mast cells might degranulate the mast cells and release mediators that become paracrine signals to the enteric nervous system, spinal afferents, and secretory glands. Western blotting, immunofluorescence, ELISA, and pharmacological analysis were used to study expression of 5-HT receptors by mast cells in the small intestine and action of 5-HT to degranulate the mast cells and release histamine in guinea pig small intestine and segments of human jejunum discarded during Roux-en-Y gastric bypass surgeries. Mast cells in human and guinea pig preparations expressed the 5-HT1A receptor. ELISA detected spontaneous release of histamine in guinea pig and human preparations. The selective 5-HT1A receptor agonist 8-hydroxy-PIPAT evoked release of histamine. A selective 5-HT1A receptor antagonist, WAY-100135, suppressed stimulation of histamine release by 5-HT or 8-hydroxy-PIPAT. Mast cell-stabilizing drugs, doxantrazole and cromolyn sodium, suppressed the release of histamine evoked by 5-HT or 8-hydroxy-PIPAT in guinea pig and human preparations. Our results support the hypothesis that serotonergic degranulation of enteric mast cells and release of preformed mediators, including histamine, are mediated by the 5-HT1A serotonergic receptor. Association of 5-HT with the pathophysiology of functional gastrointestinal disorders (e.g., irritable bowel syndrome) underlies a question of whether selective 5-HT1A receptor antagonists might have therapeutic application in disorders of this nature. PMID:23518679

  10. (/sup 3/H)dihydroergotamine as a high-affinity, slowly dissociating radioligand for 5-HT1B binding sites in rat brain membranes: evidence for guanine nucleotide regulation of agonist affinity states

    Hamblin, M.W.; Ariani, K.; Adriaenssens, P.I.; Ciaranello, R.D.

    1987-12-01

    (/sup 3/H)Dihydroergotamine (DE) labels a population of binding sites in rat brain membranes with an affinity of approximately 70 pM in both hippocampus (maximal binding at saturation (Bmax) = 340 fmol/mg of protein) and cerebral cortex (Bmax = 250 fmol/mg of protein). Specific binding typically comprises about 97% of total binding at the Kd of the radioligand when nonspecific binding is determined in the presence of 100 nM unlabeled DE. Association kinetics at 37 degrees C are consistent with a uniform association rate constant for all sites labeled. Specific binding is completely reversible with addition of excess unlabeled DE, but dissociation does not proceed with simple first-order kinetics, suggesting the presence of more than one discrete binding site. Competition studies with selective drugs reveal alpha adrenergic, 5-HT1A and 5-HT1B components of (/sup 3/H)DE specific binding. When phentolamine (500 nM) is included to block alpha receptors and DPAT (100 nM) or spiroxatrine (500 nM) is included to block 5-HT1A receptors, specific binding is exclusively to sites with drug affinities characteristic of 5-HT1B receptors. Under these 5-HT1B-selective conditions, (/sup 3/H)DE binding is about 90% specific, with a Kd of about 50 to 60 pM and a Bmax of 96 fmol/mg of protein in hippocampus and 77 fmol/mg of protein in cortex. (/sup 3/H)DE binding to 5-HT1B sites is very slowly dissociable, with a T1/2 of greater than 2 h at 37 degrees C. 5-HT1B antagonists and DE itself yield competition curves at (/sup 3/H)DE-labeled 5-HT1B sites that are adequately fit assuming a single site in nonlinear regression analysis. Addition of 100 microM guanylyl 5'-imidodiphosphate appears to convert nearly all 5-HT1B sites to those having low affinity for agonists while having a much smaller effect on the binding of (/sup 3/H)DE.