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Sample records for benzodiazepine receptor activity

  1. Midazolam inhibits hippocampal long-term potentiation and learning through dual central and peripheral benzodiazepine receptor activation and neurosteroidogenesis

    OpenAIRE

    Tokuda, Kazuhiro; O’Dell, Kazuko A.; Izumi, Yukitoshi; Charles F. Zorumski

    2010-01-01

    Benzodiazepines (BDZs) enhance γ-aminobutyric acid-A (GABAA) receptor inhibition by direct actions on central BDZ receptors (CBRs). Although some BDZs also bind mitochondrial receptors (translocator protein 18kDa, TSPO) and promote the synthesis of GABA-enhancing neurosteroids, the role of neurosteroids in the clinical effects of BDZs is unknown. In rat hippocampal slices, we compared midazolam, an anesthetic BDZ with clonazepam, an anticonvulsant/anxiolytic BDZ that activates CBRs selectivel...

  2. Effect of peripheral benzodiazepine receptor ligands on lipopolysaccharide-induced tumor necrosis factor activity in thioglycolate-treated mice.

    OpenAIRE

    Matsumoto, T.; Ogata, M.; Koga, K.; Shigematsu, A

    1994-01-01

    To investigate the effect of peripheral and central benzodiazepine receptor ligands on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) activity in mouse macrophages, three types of ligands, 4'-chlorodiazepam (pure peripheral), midazolam (mixed), and clonazepam (pure central), were compared. Midazolam and 4'-chlorodiazepam significantly suppressed LPS (1-microgram/ml)-induced TNF activity in thioglycolate-elicited mouse macrophages. In every concentration examined (0.001 to 100 mi...

  3. Characterization of astrocytic and neuronal benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bender, A.S.

    1988-01-01

    Primary cultures of astrocytes and neurons express benzodiazepine receptors. Neuronal benzodiazepine receptors were of high-affinity, K{sub D} values were 7.5-43 nM and the densities of receptors (B{sub max}) were 924-4131 fmol/mg protein. Astrocytes posses a high-affinity benzodiazepine receptor, K{sub D} values were 6.6-13 nM. The B{sub max} values were 6,033-12,000 fmol/mg protein. The pharmacological profile of the neuronal benzodiazepine receptor was that of the central-type benzodiazepine receptor, where clonazepam has a high-affinity and Ro 5-4864 (4{prime}-chlorodiazepam) has a low-affinity. Whereas astrocytic benzoidazepine receptor was characteristic of the so called peripheral-type benzodiazepine receptors, which shows a high-affinity towards Ro 5-4863, and a low-affinity towards clonazepam. The astrocytic benzodiazepine receptors was functionally correlated with voltage dependent calcium channels, since dihydropyridines and benzodiazepines interacted with ({sup 3}H) diazepam and ({sup 3}H) nitrendipine receptors with the same rank order of potency, showing a statistically significant correlation. No such correlation was observed in neurons.

  4. Benzodiazepine receptor antagonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C

    2004-01-01

    Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy....

  5. Lysine and pipecolic acid and some of their derivatives show anticonvulsant activity, and stimulation of benzodiazepine receptor activity

    International Nuclear Information System (INIS)

    Benzodiazepines are one of the most widely prescribed drugs in the treatment of anxiety, epilepsy and muscle tension. The natural products lysine and pipecolic acid known to be present in the animal, plant and microorganism, have been shown to be anticonvulsant against pentetrazol (PTZ)-induced seizures in mice. Methyl and ethyl esters of L-lysine and the N-isopropanol derivative of pipecolic acid appear to increase the anticonvulsant potency of the parent compounds, presumably due to their increase in hydrophobicity. Lysine and pipecolic acid showed significant stimulation of specific [3H]flunitrazepam (FZ) binding to mouse brain membranes. This stimulation was enhanced by chloride ions and stereospecific with L-isomer having higher effect. The dose-dependent anticonvulsant activity of lysine and pipecolic acid, and their stimulation of [3H]FZ binding appear to be correlated. The antiepileptic activity lysine, pipecolic acid and their derivatives therefore may be mediated through the γ-aminobutyric acid-benzodiazepine receptor complex

  6. Antiplasmodial and GABA(A)-benzodiazepine receptor binding activities of five plants used in traditional medicine in Mali, West Africa.

    Science.gov (United States)

    Bah, Sekou; Jäger, Anna K; Adsersen, Anne; Diallo, Drissa; Paulsen, Berit Smestad

    2007-04-01

    Extracts of five medicinal plants: Boscia angustifolia, Cissus quadrangularis, Securidaca longipedunculata, Stylosanthes erecta and Trichilia emetica, used traditionally in Malian traditional medicine were screened for in vitro antiplasmodial activity and GABA(A)-benzodiazepine receptor binding activity. Four extracts showed significant antiplasmodial activities, with the dichloromethane extract of leaf of Securidaca longipedunculata being the most active (IC(50) of 7 microg/ml [95% CI: 5-9]). The dichloromethane extract of leaf of Trichilia emetica, in addition to its antiplasmodial activity (IC(50): 12 microg/ml [95% CI: 12-14]), exhibited a good binding activity to the GABA(A)-benzodiazepine receptor, while water and methanol extracts of the same plant did not show any activity. A strong GABA(A)-receptor complex binding activity was observed in the methanol extract of aerial part of Stylosanthes erecta. The results in this study justify some of the traditional indications of the plants investigated and may thus be candidates for Improved Traditional Medicines in Mali. PMID:17126508

  7. Functional characterization of the 1,5-benzodiazepine clobazam and its major active metabolite N-desmethylclobazam at human GABAA receptors expressed in Xenopus laevis oocytes

    DEFF Research Database (Denmark)

    Hammer, Harriet; Ebert, Bjarke; Jensen, Henrik S.; Jensen, Anders A.

    2015-01-01

    The 1,5-benzodiazepine clobazam is indicated for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome in patients 2 years of age or older in the United States, and for treatment of anxiety and various forms of epilepsy elsewhere. Clobazam has been reported to exhibit...... receptors. Interestingly, however, clobazam and especially N-desmethylclobazam were highly efficacious potentiators of α6β2δ receptor signaling. Although this activity component is unlikely to contribute to the in vivo effects of clobazam/N-desmethylclobazam, the 1,5-benzodiazepine could constitute an...

  8. Pharmacology of benzodiazepine receptors: an update.

    OpenAIRE

    Sieghart, W.

    1994-01-01

    Benzodiazepine receptors are allosteric modulatory sites on GABAA receptors. GABAA receptors are probably composed of five protein subunits, at least some of which belong to different subunit classes. So far six alpha-, four beta-, three gamma-, and delta- and two rho = p subunits of GABAA receptors have been identified. A large number of different subunit combinations, each of which will result in a GABAA receptor with distinct electrophysiological and pharmacological properties, are therefo...

  9. PK11195 binding to the peripheral benzodiazepine receptor as a marker of microglia activation in multiple sclerosis and experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Vowinckel, E; Reutens, D; Becher, B;

    1997-01-01

    Activated glial cells are implicated in regulating and effecting the immune response that occurs within the CNS as part of multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). The peripheral benzodiazepine receptor (PBR) is expressed in glial cells. We exa...

  10. Mitochondrial benzodiazepine receptors regulate steroid biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Mukhin, A.G.; Papadopoulos, V.; Costa, E.; Krueger, K.E. (Georgetown Univ. School of Medicine, Washington, DC (USA))

    1989-12-01

    Recent observations on the steroid synthetic capability within the brain open the possibility that benzodiazepines may influence steroid synthesis in nervous tissue through interactions with peripheral-type benzodiazepine recognition sites, which are highly expressed in steroidogenic cells and associated with the outer mitochondrial membrane. To examine this possibility nine molecules that exhibit a greater than 10,000-fold difference in their affinities for peripheral-type benzodiazepine binding sites were tested for their effects on a well-established steroidogenic model system, the Y-1 mouse adrenal tumor cell line. 4{prime}-Chlorodiazepam, PK 11195, and PK 14067 stimulated steroid production by 2-fold in Y-1 cells, whereas diazepam, flunitrazepam, zolpidem, and PK 14068 displayed a lower (1.2- to 1.5-fold) maximal stimulation. In contrast, clonazepam and flumazenil did not stimulate steroid synthesis. The potencies of these compounds to inhibit {sup 3}H-labeled PK 11195 binding to peripheral-type benzodiazepine recognition sites correlated with their potencies to stimulate steroid production. Similar findings were observed in bovine and rat adrenocortical cell preparations. These results suggest that ligands of the peripheral-type benzodiazepine recognition site acting on this mitochondrial receptor can enhance steroid production. This action may contribute specificity to the pharmacological profile of drugs preferentially acting on the benzodiazepine recognition site associated with the outer membrane of certain mitochondrial populations.

  11. Mitochondrial benzodiazepine receptors regulate steroid biosynthesis

    International Nuclear Information System (INIS)

    Recent observations on the steroid synthetic capability within the brain open the possibility that benzodiazepines may influence steroid synthesis in nervous tissue through interactions with peripheral-type benzodiazepine recognition sites, which are highly expressed in steroidogenic cells and associated with the outer mitochondrial membrane. To examine this possibility nine molecules that exhibit a greater than 10,000-fold difference in their affinities for peripheral-type benzodiazepine binding sites were tested for their effects on a well-established steroidogenic model system, the Y-1 mouse adrenal tumor cell line. 4'-Chlorodiazepam, PK 11195, and PK 14067 stimulated steroid production by 2-fold in Y-1 cells, whereas diazepam, flunitrazepam, zolpidem, and PK 14068 displayed a lower (1.2- to 1.5-fold) maximal stimulation. In contrast, clonazepam and flumazenil did not stimulate steroid synthesis. The potencies of these compounds to inhibit 3H-labeled PK 11195 binding to peripheral-type benzodiazepine recognition sites correlated with their potencies to stimulate steroid production. Similar findings were observed in bovine and rat adrenocortical cell preparations. These results suggest that ligands of the peripheral-type benzodiazepine recognition site acting on this mitochondrial receptor can enhance steroid production. This action may contribute specificity to the pharmacological profile of drugs preferentially acting on the benzodiazepine recognition site associated with the outer membrane of certain mitochondrial populations

  12. Modulation of cholinephosphotransferase activity in breast cancer cell lines by Ro5-4864, a peripheral benzodiazepine receptor agonist

    International Nuclear Information System (INIS)

    Changes in phospholipid and fatty acid profile are hallmarks of cancer progression. Increase in peripheral benzodiazepine receptor expression has been implicated in breast cancer. The benzodiazepine, Ro5-4864, increases cell proliferation in some breast cancer cell lines. Biosynthesis of phosphatidylcholine (PC) has been identified as a marker for cells proliferating at high rates. Cholinephosphotransferase (CPT) is the terminal enzyme for the de novo biosynthesis of PC. We have addressed here whether Ro5-4864 facilitates some cancer causing mechanisms in breast cancer. We report that cell proliferation increases exponentially in aggressive breast cancer cell lines 11-9-1-4 and BT-549 when treated with nanomolar concentrations of Ro5-4864. This increase is seen within 24 h of treatment, consistent with the cell doubling time in these cells. Ro5-4864 also upregulates c-fos expression in breast cancer cell lines 11-9-1-4 and BT-549, while expression in non-tumorigenic cell line MCF-12A was either basal or slightly downregulated. We further examined the expression of the CPT gene in breast cancer (11-9-1-4, BT-549) and non-tumorigenic cell lines (MCF-12A, MCF-12F). We found that the CPT gene is overexpressed in breast cancer cell lines compared to the non-tumorigenic cell lines. Furthermore, the activity of CPT in forming PC is increased in the breast cancer cell lines cultured for 24 h. Additionally, we examined the CPT activity in the presence of nanomolar concentrations of Ro5-4864. Biosynthesis of PC was increased in breast cancer cell lines upon treatment. We therefore propose that Ro5-4864 facilitates PC formation, a process important in membrane biogenesis for proliferating cells

  13. Functional characterization of the 1,5-benzodiazepine clobazam and its major active metabolite N-desmethylclobazam at human GABA(A) receptors expressed in Xenopus laevis oocytes.

    Science.gov (United States)

    Hammer, Harriet; Ebert, Bjarke; Jensen, Henrik Sindal; Jensen, Anders A

    2015-01-01

    The 1,5-benzodiazepine clobazam is indicated for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome in patients 2 years of age or older in the United States, and for treatment of anxiety and various forms of epilepsy elsewhere. Clobazam has been reported to exhibit different in vivo adverse effects and addiction liability profile than the classic 1,4-benzodiazepines. In this study, it was investigated whether the in vitro pharmacological properties of clobazam and its major active metabolite N-desmethylclobazam could explain some of these clinical differences. The functional properties of the two 1,5-benzodiazepines were characterized at the human γ-aminobutyric acid type A receptor (GABA(A)R) subtypes α1β2γ(2S), α2β2γ(2S), α3β2γ(2S), α5β2γ(2S) and α6β2δ expressed in Xenopus laevis oocytes by use of two-electrode voltage-clamp electrophysiology and compared to those exhibited by the 1,4-benzodiazepine clonazepam. All three compounds potentiated GABA EC20-evoked responses through the α(1,2,3,5)β2γ(2S) GABA(A)Rs in a reversible and concentration-dependent manner, with each displaying similar EC50 values at the four subtypes. Furthermore, the degrees of potentiation of the GABA EC20 currents through the four receptors mediated by saturating modulator concentrations did not differ substantially for any of the three benzodiazepines. The three compounds were substantially less potent (200-3900 fold) as positive allosteric modulators at the α6β2δ GABA(A)R than at the α(1,2,3,5)β2γ(2S) receptors. Interestingly, however, clobazam and especially N-desmethylclobazam were highly efficacious potentiators of α6β2δ receptor signaling. Although this activity component is unlikely to contribute to the in vivo effects of clobazam/N-desmethylclobazam, the 1,5-benzodiazepine could constitute an interesting lead for novel modulators targeting this low-affinity binding site in GABAARs. In conclusion, the non-selective modulation

  14. Pentameric ligand-gated ion channel ELIC is activated by GABA and modulated by benzodiazepines

    OpenAIRE

    Spurny, R.; Ramerstorfer, J.; Price, K; Brams, M.; M. Ernst; Nury, H.; Verheij, M.; Legrand, P.; Bertrand, D.; Bertrand, S.; Dougherty, D A; de Esch, I. J. P.; Corringer, P.-J.; Sieghart, W.; Lummis, S. C. R.

    2012-01-01

    GABA_A receptors are pentameric ligand-gated ion channels involved in fast inhibitory neurotransmission and are allosterically modulated by the anxiolytic, anticonvulsant, and sedative-hypnotic benzodiazepines. Here we show that the prokaryotic homolog ELIC also is activated by GABA and is modulated by benzodiazepines with effects comparable to those at GABA_A receptors. Crystal structures reveal important features of GABA recognition and indicate that benzodiazepines, depending on their conc...

  15. Repeated swim stress alters brain benzodiazepine receptors measured in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Weizman, R.; Weizman, A.; Kook, K.A.; Vocci, F.; Deutsch, S.I.; Paul, S.M.

    1989-06-01

    The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of (/sup 3/H)Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in (14C)iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress (an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures), although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results.

  16. Repeated swim stress alters brain benzodiazepine receptors measured in vivo

    International Nuclear Information System (INIS)

    The effects of repeated swim stress on brain benzodiazepine receptors were examined in the mouse using both an in vivo and in vitro binding method. Specific in vivo binding of [3H]Ro15-1788 to benzodiazepine receptors was decreased in the hippocampus, cerebral cortex, hypothalamus, midbrain and striatum after repeated swim stress (7 consecutive days of daily swim stress) when compared to nonstressed mice. In vivo benzodiazepine receptor binding was unaltered after repeated swim stress in the cerebellum and pons medulla. The stress-induced reduction in in vivo benzodiazepine receptor binding did not appear to be due to altered cerebral blood flow or to an alteration in benzodiazepine metabolism or biodistribution because there was no difference in [14C]iodoantipyrine distribution or whole brain concentrations of clonazepam after repeated swim stress. Saturation binding experiments revealed a change in both apparent maximal binding capacity and affinity after repeated swim stress. Moreover, a reduction in clonazepam's anticonvulsant potency was also observed after repeated swim stress [an increase in the ED50 dose for protection against pentylenetetrazol-induced seizures], although there was no difference in pentylenetetrazol-induced seizure threshold between the two groups. In contrast to the results obtained in vivo, no change in benzodiazepine receptor binding kinetics was observed using the in vitro binding method. These data suggest that environmental stress can alter the binding parameters of the benzodiazepine receptor and that the in vivo and in vitro binding methods can yield substantially different results

  17. Imaging of a glioma using peripheral benzodiazepine receptor ligands

    Energy Technology Data Exchange (ETDEWEB)

    Starosta-Rubinstein, S.; Ciliax, B.J.; Penney, J.B.; McKeever, P.; Young, A.B.

    1987-02-01

    Two types of benzodiazepine receptors have been demonstrated in mammalian tissues, one which is localized on neuronal elements in brain and the other, on glial cells and in peripheral tissues such as kidney. In vivo administration of /sup 3/H-labeled PK 11195 (1-(2-chlorophenyl-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide) or (/sup 3/H)flunitrazepam with 5 mg of clonazepam per kg to rats with intracranial C6 gliomas resulted in high levels of tritiated-drug binding to the tumor as shown by quantitative autoradiography. Pharmacological studies indicated that the bound drugs labeled the peripheral benzodiazepine binding site. Binding to the peripheral benzodiazepine site was confirmed primarily to malignant cells with little binding to adjacent normal brain tissue or to necrotic tissue. Tumor cell binding was completely inhibited by preadministration of the peripheral benzodiazepine blocking agent PK 11195 at 5 mg/kg. The centrally selective benzodiazepine ligand clonazepam had no effect on PK 11195 binding to the tumor cells. When binding to other tumor cell lines grown in nude mice and nude athymic rats was evaluated, little or no peripheral benzodiazepine binding was detected on human pheochromocytoma (RN1) and neuroblastoma (SK-N-MC, SK-N-SH) tumor cells, respectively. However, high densities of peripheral benzodiazepine binding sites were observed on tumors derived from a human glioma cell line (ATCC HTB 14, U-87 MG). The presence of high concentrations of specific peripheral benzodiazepine receptors on glial tumors suggests that human primary central nervous system tumors could be imaged and diagnosed using peripheral benzodiazepine ligands labeled with positron- or gamma-emitting isotopes.

  18. Imaging of a glioma using peripheral benzodiazepine receptor ligands

    International Nuclear Information System (INIS)

    Two types of benzodiazepine receptors have been demonstrated in mammalian tissues, one which is localized on neuronal elements in brain and the other, on glial cells and in peripheral tissues such as kidney. In vivo administration of 3H-labeled PK 11195 [1-(2-chlorophenyl-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide] or [3H]flunitrazepam with 5 mg of clonazepam per kg to rats with intracranial C6 gliomas resulted in high levels of tritiated-drug binding to the tumor as shown by quantitative autoradiography. Pharmacological studies indicated that the bound drugs labeled the peripheral benzodiazepine binding site. Binding to the peripheral benzodiazepine site was confirmed primarily to malignant cells with little binding to adjacent normal brain tissue or to necrotic tissue. Tumor cell binding was completely inhibited by preadministration of the peripheral benzodiazepine blocking agent PK 11195 at 5 mg/kg. The centrally selective benzodiazepine ligand clonazepam had no effect on PK 11195 binding to the tumor cells. When binding to other tumor cell lines grown in nude mice and nude athymic rats was evaluated, little or no peripheral benzodiazepine binding was detected on human pheochromocytoma (RN1) and neuroblastoma (SK-N-MC, SK-N-SH) tumor cells, respectively. However, high densities of peripheral benzodiazepine binding sites were observed on tumors derived from a human glioma cell line (ATCC HTB 14, U-87 MG). The presence of high concentrations of specific peripheral benzodiazepine receptors on glial tumors suggests that human primary central nervous system tumors could be imaged and diagnosed using peripheral benzodiazepine ligands labeled with positron- or gamma-emitting isotopes

  19. Chronic caffeine or theophylline exposure reduces gamma-aminobutyric acid/benzodiazepine receptor site interactions.

    Science.gov (United States)

    Roca, D J; Schiller, G D; Farb, D H

    1988-05-01

    Methylxanthines, such as caffeine and theophylline, are adenosine receptor antagonists that exert dramatic effects upon the behavior of vertebrate animals by increasing attentiveness, anxiety, and convulsive activity. Benzodiazepines, such as flunitrazepam, generally exert behavioral effects that are opposite to those of methylxanthines. We report the finding that chronic exposure of embryonic brain neurons to caffeine or theophylline reduces the ability of gamma-aminobutyric acid (GABA) to potentiate the binding of [3H]flunitrazepam to the GABA/benzodiazepine receptor. This theophylline-induced "uncoupling" of GABA- and benzodiazepine-binding site allosteric interactions is blocked by chloroadenosine, an adenosine receptor agonist, indicating that the chronic effects of theophylline are mediated by a site that resembles an adenosine receptor. We speculate that adverse central nervous system effects of long-term exposure to methylxanthines such as in caffeine-containing beverages or theophylline-containing medications may be exerted by a cell-mediated modification of the GABAA receptor. PMID:2835648

  20. Benzodiazepine receptor antagonists for acute and chronic hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Kjaergard, L L; Gluud, C

    2001-01-01

    The pathogenesis of hepatic encephalopathy is unknown. It has been suggested that liver failure leads to the accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition which may progress to coma. Several trials have assessed benzodiazepine receptor...

  1. Benzodiazepines

    Science.gov (United States)

    ... longer duration of action are utilized to treat insomnia in patients with daytime anxiety. These benzodiazepines ... of abuse Abuse is frequently associated with adolescents and young adults who take the drug orally or crush it ...

  2. Functional characterization of the 1,5-benzodiazepine clobazam and its major active metabolite N-desmethylclobazam at human GABAA receptors expressed in Xenopus laevis oocytes

    DEFF Research Database (Denmark)

    Hammer, Harriet; Ebert, Bjarke; Jensen, Henrik S.;

    2015-01-01

    different in vivo adverse effects and addiction liability profile than the classic 1,4-benzodiazepines. In this study, it was investigated whether the in vitro pharmacological properties of clobazam and its major active metabolite N-desmethylclobazam could explain some of these clinical differences...

  3. In vivo imaging of microglial activation using a peripheral benzodiazepine receptor ligand. [11C]PK-11195 and animal PET following ethanol injury in rat striatum

    International Nuclear Information System (INIS)

    To investigate whether [11C]PK-11195, a specific peripheral benzodiazepine receptors (PBRs) ligand for positron emission tomography (PET), can show activated microglia in a rat brain injury model. On day 1, ethanol was injected into the rat's right striatum (ST) using a stereotaxic operative procedure. On day 3, head magnetic resonance imaging (MRI) scans for surgically treated rats were performed to evaluate ethanol injury morphologically. On day 4, dynamic PET scans (17 injured rats and 7 non-injured controls) were performed for 60 min with an animal PET scanner under chloral hydrate anesthesia following a bolus injection of [11C]PK-11195 through tail vein. Because PBRs are present throughout the brain, there is no suitable receptor-free reference region. The reference tissue model may not be applicable because of low target to back-ground ratio for low affinity of [11C]PK-11195 to PBRs. We evaluated the PBRs binding with regions of interest (ROIs)-based approach to estimate total distribution volume (V). We used an integral from 0 min to 60 min (V60) as an estimate of V. On the coronal PET image, ROIs were placed on bilateral ST. Differences in right/left ST V60 ratios between lesioned and unlesioned control rats were compared using unpaired t tests. Immunohistochemical staining was performed for confirming the presence of activated microglia following decapitation on the PET experiment day. The right/left ST V60 ratios in lesioned rats (1.07±0.08) were significantly higher than those in unlesioned control rats (1.00±0.06, P11C]PK-11195 PET imaging would be a useful tool for evaluating microglial activation in a rat brain injury model. (author)

  4. Pharmacological actions of Y-24180, a new specific antagonist of platelet activating factor (PAF): II. Interactions with PAF and benzodiazepine receptors.

    Science.gov (United States)

    Takehara, S; Mikashima, H; Muramoto, Y; Terasawa, M; Setoguchi, M; Tahara, T

    1990-12-01

    The inhibitory effect of Y-24180, 4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H-t hieno [3,2-f][1,2,4]triazolo [4,3-a][1,4]diazepine, on platelet activating factor (PAF)-induced platelet aggregation and the specific binding of 3H-PAF to platelets was compared with other thienodiazepine derivatives, WEB 2086 and etizolam. Y-24180 inhibited PAF-induced rabbit platelet aggregation in vitro (IC50 3.84 nM), but had little effect on adenosine diphosphate- or arachidonic acid-induced aggregation. WEB 2086 and etizolam also showed an inhibitory effect of PAF-induced aggregation (IC50 values are 456 and 6730 nM, respectively). In PAF-induced human platelet aggregation, Y-24180 (IC50 0.84 nM) was more potent than WEB 2086 (IC50 4.21 nM) and etizolam (IC50 998 nM). Y-24180, WEB 2086 and etizolam displaced 3H-PAF binding from the washed-platelets of rabbits with an IC50 value of 3.50, 9.35 and 29.5 nM, respectively. In rabbits, pretreatment with Y-24180 and WEB 2086 antagonized PAF-induced platelet aggregation dose-dependently. The significant inhibitory effect of Y-24180 (1 mg/kg, p.o.) lasted 72 hr after a single dose oral administration. WEB 2086 (10 mg/kg, p.o.) also antagonized the ex vivo response induced by PAF 1 hr after administration, but no significant effect was observed 3 hr after administration. Y-24180 displaced 3H-diazepam binding from the synaptosomal membranes of rat cerebral cortex with a Ki value of 3.68 microM. The affinity of Y-24180 for benzodiazepine(BZP) receptors was lower than those of WEB 2086 and etizolam and was about 1000 times lower than that for PAF receptors in platelets. PMID:1965554

  5. Imaging of a glioma using peripheral benzodiazepine receptor ligands.

    OpenAIRE

    Starosta-Rubinstein, S; Ciliax, B J; Penney, J B; McKeever, P; Young, A B

    1987-01-01

    Two types of benzodiazepine receptors have been demonstrated in mammalian tissues, one which is localized on neuronal elements in brain and the other, on glial cells and in peripheral tissues such as kidney. In vivo administration of 3H-labeled PK 11195 [1-(2-chlorophenyl-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide] or [3H]flunitrazepam with 5 mg of clonazepam per kg to rats with intracranial C6 gliomas resulted in high levels of tritiated-drug binding to the tumor as shown by quan...

  6. The benzodiazepine/GABA receptor complex during severe ethanol intoxication and withdrawal in the rat

    International Nuclear Information System (INIS)

    The benzodiazepine/GABA (gammaaminobutyric acid) receptor complex was investigated during severe ethanol intoxication and withdrawal in the rat. The intragastric intubation technique was used to establish physical ethanol dependence in the animals. Cerebral cortex from male Wistar rats was studied 1) after 31/2 days of severe ethanol intoxication, 2) during the ethanol withdrawal reaction and 3) in a control group. The effect of GABA-ergic activation by muscimol and THIP (4,5,6,7-tetrahydroisoxazole(5,4-c)pyridin-3-01) on 3H-diazepam binding was unchanged during ethanol intoxication and withdrawal, as was the affinity constant (Ksub(D)) and the maximal number of binding sites (Bsub(max)) for 3H-flunitrazepam. In conclusion, the benzodiazepine/GABA receptor complex is unlikely to play any causual part in physical ethanol dependence. (author)

  7. Purification of high affinity benzodiazepine receptor binding site fragments from rat brain

    International Nuclear Information System (INIS)

    In central nervous system benzodiazepine recognition sites occur on neuronal cell surfaces as one member of a multireceptor complex, including recognition sites for benzodiazepines, gamma aminobutyric acid (GABA), barbiturates and a chloride ionophore. During photoaffinity labelling, the benzodiazepine agonist, 3H-flunitrazepam, is irreversibly bound to central benzodiazepine high affinity recognition sites in the presence of ultraviolet light. In these studies a 3H-flunitrazepam radiolabel was used to track the isolation and purification of high affinity agonist binding site fragments from membrane-bound benzodiazepine receptor in rat brain. The authors present a method for limited proteolysis of 3H-flunitrazepam photoaffinity labeled rat brain membranes, generating photolabeled benzodiazepine receptor fragments containing the agonist binding site. Using trypsin chymotrypsin A4, or a combination of these two proteases, they have demonstrated the extent and time course for partial digestion of benzodiazepine receptor, yielding photolabeled receptor binding site fragments. These photolabeled receptor fragments have been further purified on the basis of size, using ultrafiltration, gel permeation chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) as well as on the basis of hydrophobicity, using a high performance liquid chromatography (HPLC) precolumn, several HPLC elution schemes, and two different HPLC column types. Using these procedures, they have purified three photolabeled benzodiazepine receptor fragments containing the agonist binding site which appear to have a molecular weight of less than 2000 daltons each

  8. Physiology and physiopathology of central type Benzodiazepine receptors: Study in the monkey and in human brain using positron emission tomography

    International Nuclear Information System (INIS)

    A new non-invasive technique that allows to study in a living subject central type benzodiazepine receptors is developed. A combined approach is applied using a specific positron-emitting radiotracer for the in vivo labelling of the receptors and positron emission tomography allowing, by external detection, a quantitative determination of tissue radioactivity. The radioligand used for the in vivo labelling of benzodiazepine receptors is the antagonist RO 15-1788 labelled with carbon 11. The various stages of the study are described: in vivo characterization in the monkey of central type benzodiazepine receptors; characterization of central type benzodiazepine receptors in human brain using selective molecules for the BZ1 benzodiazepine subclass; demonstration of the heterogeneity of central type benzodiazepine receptors in the brain; study of pathological alteration of benzodiazepine receptors in experimental epilepsy

  9. Benzodiazepine receptor binding in vivo with (/sup 3/)-Ro 15-1788

    Energy Technology Data Exchange (ETDEWEB)

    Goeders, N.E.; Kuhar, M.J.

    1985-07-29

    In vivo benzodiazepine receptor binding has generally been studied by ex vivo techniques. In this investigation, the authors identify the conditions where (/sup 3/H)-Ro 15-1788 labels benzodiazepine receptors by true in vivo binding, i.e. where workable specific to nonspecific ratios are obtained in intact tissues without homogenization or washing. (/sup 3/H)-Flunitrazepam and (/sup 3/H)-clonazepam did not exhibit useful in vivo receptor binding. 39 references, 5 figures, 1 table.

  10. Benzodiazepine receptor binding in vivo with [3]-Ro 15-1788

    International Nuclear Information System (INIS)

    In vivo benzodiazepine receptor binding has generally been studied by ex vivo techniques. In this investigation, the authors identify the conditions where [3H]-Ro 15-1788 labels benzodiazepine receptors by true in vivo binding, i.e. where workable specific to nonspecific ratios are obtained in intact tissues without homogenization or washing. [3H]-Flunitrazepam and [3H]-clonazepam did not exhibit useful in vivo receptor binding. 39 references, 5 figures, 1 table

  11. Platelet peripheral benzodiazepine receptors are decreased in Parkinson's disease

    International Nuclear Information System (INIS)

    Peripheral benzodiazepine (BDZ) receptors are located in a variety of tissues, including platelets, in the nuclear and/or mitochondrial membranes. The authors studied the density of peripheral BDZ receptors in platelets of 10 de novo Parkinson's disease (PD) patients, 18 PD patients treated with a levodopa/carbidopa combination, and in 15 healthy subjects matched for sex and age. The binding assay was conducted using [3H]PK 11195, a specific ligand for peripheral BDZ receptors. A significant decrease in the density of [3H]PK 11195 binding sites has been observed in PD patients with respect to controls but not between de novo and treated PD patients. No correlation has been found between the decrease in density of [3H]PK 11195 binding sites in platelets and either the duration or severity of PD. Peripheral BDZ receptors are implicated in the regulation of mitochondrial respiratory function. Thus, their decrease in PD might parallel the abnormalities in mitochondrial function recently found in this neurologic disease

  12. Autoradiographic localization of benzodiazepine receptors in the rat kidney

    Energy Technology Data Exchange (ETDEWEB)

    Beaumont, K.; Healy, D.P.; Fanestil, D.D.

    1984-11-01

    The localization of benzodiazepine (BZD) receptors in the rat kidney was studied by autoradiography after in vitro labeling of kidney slices with flunitrazepam. The affinity, density, and rank order of displacement of (/sup 3/H)-flunitrazepam by several BZDs (RO 5-4864 > diazepam > clonazepam) demonstrated that binding was to BZD receptors of the peripheral type. In autoradiograms obtained with tritium-sensitive film, a high density of silver grains was obtained in the outer medulla, with lower densities in the cortex. Binding was absent from the inner medulla (papilla). In higher resolution autoradiograms obtained with an emulsion-coated cover slip procedure, silver grains were seen to be concentrated over a tubular element in both outer medulla and cortex, identifiable by morphology and distribution as the thick ascending limb of the loop of Henle and the distal convoluted tubule. The identity of the labeled tubules was confirmed by immunofluorescent localization in adjacent slices of Tamm-Horsfall protein, a specific marker for these segments of tubules. Investigation of the effects of peripherally specific BZDs such as RO 5-4864 on distal tubule function is indicated.

  13. Autoradiographic localization of benzodiazepine receptors in the rat kidney

    International Nuclear Information System (INIS)

    The localization of benzodiazepine (BZD) receptors in the rat kidney was studied by autoradiography after in vitro labeling of kidney slices with flunitrazepam. The affinity, density, and rank order of displacement of [3H]-flunitrazepam by several BZDs (RO 5-4864 > diazepam > clonazepam) demonstrated that binding was to BZD receptors of the peripheral type. In autoradiograms obtained with tritium-sensitive film, a high density of silver grains was obtained in the outer medulla, with lower densities in the cortex. Binding was absent from the inner medulla (papilla). In higher resolution autoradiograms obtained with an emulsion-coated cover slip procedure, silver grains were seen to be concentrated over a tubular element in both outer medulla and cortex, identifiable by morphology and distribution as the thick ascending limb of the loop of Henle and the distal convoluted tubule. The identity of the labeled tubules was confirmed by immunofluorescent localization in adjacent slices of Tamm-Horsfall protein, a specific marker for these segments of tubules. Investigation of the effects of peripherally specific BZDs such as RO 5-4864 on distal tubule function is indicated

  14. Effect of chronic (-)-nicotine treatment on rat cerebral benzodiazepine receptors

    International Nuclear Information System (INIS)

    The purpose of this study was to clarify the effect of (-)-nicotine on cerebral benzodiazepine receptors (BzR) with radiotracer methods. The effect of (-)-nicotine on BzR was examined in in vitro studies using chronic (-)-nicotine-treated rats using 3H-diazepam. The in vitro radioreceptor assay showed a 14% increase in the maximum number of binding sites of BzR in chronic (-)-nicotine-treated rats in comparison with the control rats. Moreover, a convenient in vivo uptake index of 125I-iomazenil was calculated and a higher uptake of the radioactivity was observed in the chronic (-)-nicotine-treated group than in the control group. Although further studies of the mechanism of (-)-nicotine on such BzR changes are required, an increase in the amount of BzR in the cerebral cortex was found in rats that underwent chronic (-)-nicotine treatment, and this result contributed to the understanding of the effects of (-)-nicotine and smoking on neural functions

  15. Synthesis and Anticonvulsant Activity of Various Mannich and Schiff Bases of 1,5-Benzodiazepines

    Directory of Open Access Journals (Sweden)

    Surendra N. Pandeya

    2012-01-01

    Full Text Available Benzodiazepines have a various behavioral effects in addition to their anxiolytic action. There is every reason to believe that the BZ/GABA receptor complex is involved in these effects, since GABAmimetic manipulations modify the effect of BZ in tests of convulsive activity, motor function, and appetitive behavior. 1,5-Benzodiazepines are biologically important molecules and are extensively used clinically as analgesic, hypnotic, sedative, and antidepressive agents. Hence, 1,5-Benzodiazepines were synthesized by condensation of o-phenylenediamine and ketones, for example, cyclohexanone and acetone in presence of sulfated zirconia (catalyst. Mannich bases were synthesized with acetophenone, p-nitroacetophenone, p-chloroacetophenone, and formaldehyde. Schiff bases were synthesized using Mannich base of 1,5-benzodiazepines with p-chloroaniline and p-chlorophenylsemicarbazide in the presence of glacial acetic acid. All the synthesized compounds were characterized by 1H NMR and IR spectral analyses. All the synthesized derivatives were evaluated at the dose of 30 mg/kg b.w for anticonvulsant activity by isoniazid induced convulsion model, and the compounds NBZD-3 and NBZD-8 were found to be the most active among all compounds. Among all the synthesized derivatives, compounds NBZD-13 and NBZD-17 were found to be the most active among all compounds using thiosemicarbazide induced model. Although NBZD-8, NBZD-10, and NBZD-18 are the compounds which had shown good anticonvulsant activity and have an advantage over that, they were not sedative.

  16. Soman- or kainic acid-induced convulsions decrease muscarinic receptors but not benzodiazepine receptors

    International Nuclear Information System (INIS)

    [3H]Quinuclidinyl benzilate (QNB) binding to muscarinic receptors decreased in the rat forebrain after convulsions induced by a single dose of either soman, a potent inhibitor of acetylcholinesterase, or kainic acid, an excitotoxin. A Rosenthal plot revealed that the receptors decreased in number rather than affinity. When the soman-induced convulsions were blocked, the decrease in muscarinic receptors at 3 days was less extensive than when convulsions occurred and at 10 days they approached control levels in most of the brain areas. The most prominent decrements in QNB binding were in the piriform cortex where the decline in QNB binding is probably related to the extensive convulsion-associated neuropathology. The decrements in QNB binding after convulsions suggest that the convulsive state leads to a down-regulation of muscarinic receptors in some brain areas. In contrast to the decrease in QNB binding after convulsions, [3H]flunitrazepam binding to benzodiazepine receptors did not change even in the piriform cortex where the loss in muscarinic receptors was most prominent. Thus, it appears that those neuronal processes that bear muscarinic receptors are more vulnerable to convulsion-induced change than those with benzodiazepine receptors

  17. Effects of vitamin B-6 nutrition on benzodiazepine (BDZ) receptor binding in the developing rat brain

    International Nuclear Information System (INIS)

    A dietary deficiency of vitamin B-6 promotes seizure activity in neonatal animals and human infants. Previous studied have shown that neonatal vitamin B-6 deprivation results in reduced levels of brain gamma-aminobutyric acid (GABA) and increased binding at the GABA site of the GABA/BDZ receptor complex. Since the GABA and BDZ receptors are allosterically linked, this study was undertaken to determine if vitamin B-6 deprivation had an effect on BDZ receptor binding. Benzodiazepine receptor binding isotherms using 3H-flunitrazepam as ligand were performed in the presence and absence of 10 μM GABA. The results indicate a significant increase in the binding affinity (Kd) in the presence of GABA in cerebellar membranes from deficient rat pups at 14 days of age with no effect on receptor number (Bmax). By 28 days of age, the increase in Kd was no longer present. No change in Kd or Bmax was observed in cortical tissue from deficient animals at 14 or 28 days of age. Preliminary studies of GABA-enhancement of 3H-flunitrazepam binding indicate that vitamin B-6 deficiency also induces alterations in the ability of GABA to enhance BZD receptor binding. In summary, these results indicate that the effects of vitamin B-6 deprivation on BDZ receptor binding are region specific and age related

  18. Early ontogeny of the central benzodiazepine receptor in human embryos and fetuses

    Energy Technology Data Exchange (ETDEWEB)

    Hebebrand, J.; Hofmann, D.; Reichelt, R.; Schnarr, S.; Knapp, M.; Propping, P.; Foedisch, H.J.

    1988-01-01

    The early ontogeny of the central benzodiazepine receptor (BZR) was investigated in human embryos and fetuses between 7 and 26 weeks of gestation. Brain tissue was gained from terminated pregnancies or spontaneous abortions. Binding studies, which were performed with /sup 3/H-flunitrazepam (FNZ), revealed that specific benzodiazepine binding is already detectable at an embryonal age of 7 weeks post conception. Binding at this early stage can be displaced potently by clonazepam and the inverse agonist ..beta..-CCE. Additionally, /sup 3/H-FNZ binding is enhanced by GABA. Thus, benzodiazepine binding is of the central type. Receptor density increases steeply in whole brain between weeks 8 and 11 of gestation. In frontal cortex receptor density increases gradually between weeks 12 and 26 of gestation. No specific fetal disease entity (including trisomy 21) was consistently associated with exceptionally high or low B/sub max/-values.

  19. Early ontogeny of the central benzodiazepine receptor in human embryos and fetuses

    International Nuclear Information System (INIS)

    The early ontogeny of the central benzodiazepine receptor (BZR) was investigated in human embryos and fetuses between 7 and 26 weeks of gestation. Brain tissue was gained from terminated pregnancies or spontaneous abortions. Binding studies, which were performed with 3H-flunitrazepam (FNZ), revealed that specific benzodiazepine binding is already detectable at an embryonal age of 7 weeks post conception. Binding at this early stage can be displaced potently by clonazepam and the inverse agonist β-CCE. Additionally, 3H-FNZ binding is enhanced by GABA. Thus, benzodiazepine binding is of the central type. Receptor density increases steeply in whole brain between weeks 8 and 11 of gestation. In frontal cortex receptor density increases gradually between weeks 12 and 26 of gestation. No specific fetal disease entity (including trisomy 21) was consistently associated with exceptionally high or low B/sub max/-values

  20. Quantitative autoradiography of muscarinic and benzodiazepine receptors in the forebrain of the turtle, Pseudemys scripta

    International Nuclear Information System (INIS)

    The distribution of muscarinic and benzodiazepine receptors was investigated in the turtle forebrain by the technique of in vitro receptor autoradiography. Muscarinic binding sites were labeled with 1 nM 3H-quinuclidinyl benzilate (3H-QNB), and benzodiazepine sites were demonstrated with the aid of 1 nM 3H-flunitrazepam (3H-FLU). Autoradiograms generated on 3H-Ultrofilm apposed to tissue slices revealed regionally specific distributions of muscarinic and benzodiazepine binding sites that are comparable with those for mammalian brain. Dense benzodiazepine binding was found in the anterior olfactory nucleus, the lateral and dorsal cortices, and the dorsal ventricular ridge (DVR), a structure with no clear mammalian homologue. Muscarinic binding sites were most dense in the striatum, accumbens, DVR, lateral geniculate, and the anterior olfactory nucleus. Cortical binding sites were studied in greater detail by quantitative analysis of autoradiograms generated by using emulsion-coated coverslips. Laminar gradients of binding were observed that were specific for each radioligand; 3H-QNB sites were most dense in the inner molecular layer in all cortical regions, whereas 3H-FLU binding was generally most concentrated in the outer molecular layer and was least dense through all layers in the dorsomedial cortex. Because pyramidal cells are arranged in register in turtle cortex, the laminar patterns of receptor binding may reflect different receptor density gradients along pyramidal cell dendrites

  1. A Review of the Updated Pharmacophore for the Alpha 5 GABA(A Benzodiazepine Receptor Model

    Directory of Open Access Journals (Sweden)

    Terry Clayton

    2015-01-01

    Full Text Available An updated model of the GABA(A benzodiazepine receptor pharmacophore of the α5-BzR/GABA(A subtype has been constructed prompted by the synthesis of subtype selective ligands in light of the recent developments in both ligand synthesis, behavioral studies, and molecular modeling studies of the binding site itself. A number of BzR/GABA(A α5 subtype selective compounds were synthesized, notably α5-subtype selective inverse agonist PWZ-029 (1 which is active in enhancing cognition in both rodents and primates. In addition, a chiral positive allosteric modulator (PAM, SH-053-2′F-R-CH3 (2, has been shown to reverse the deleterious effects in the MAM-model of schizophrenia as well as alleviate constriction in airway smooth muscle. Presented here is an updated model of the pharmacophore for α5β2γ2 Bz/GABA(A receptors, including a rendering of PWZ-029 docked within the α5-binding pocket showing specific interactions of the molecule with the receptor. Differences in the included volume as compared to α1β2γ2, α2β2γ2, and α3β2γ2 will be illustrated for clarity. These new models enhance the ability to understand structural characteristics of ligands which act as agonists, antagonists, or inverse agonists at the Bz BS of GABA(A receptors.

  2. Binding of [3H]ethyl-β-carboline-3-carboxylate to brain benzodiazepine receptors

    International Nuclear Information System (INIS)

    It is reported that in contrast to the changes in affinity of [3H]benzodiazepines elicited by halide ions, barbiturates, and pyrazolopyridines, the apparent affinity of β-[3H]CCE (ethyl-β-carboline-3-carboxylate) is unaffected by these agents. Furthermore, Scatchard analysis of β-[3H]CCE binding to cerebral cortical and cerebellar membranes revealed a significantly greater number of binding sites than was observed with either [3H]diazepam or [3H]flunitazepam, suggesting that at low concentrations benzodiazepines selectively label a subpopulation of the receptors labelled with β-[3H]CCE. Alternatively, β-[3H]CCE may bind to sites that are distinct from those labelled with [3H]-benzodiazepines. (Auth.)

  3. Synthesis, structure and affinity of novel 3-alkoxy-1,2-dihydro-3H-1,4-benzodiazepin-2-ones for CNS central and peripheral benzodiazepine receptors.

    Science.gov (United States)

    Andronati, Sergey; Semenishyna, Ekaterina; Pavlovsky, Victor; Simonov, Yuriy; Makan, Svetlana; Boyko, Irina; Burenkova, Natalya; Gdaniec, Maria; Cardinael, Pascal; Bouillon, Jean-Philippe; Mazepa, Alexander

    2010-04-01

    A series of novel 3-alkoxy-1,2-dihydro-3H-1,4-benzodiazepin-2-ones (7-15) was synthesized and their in vitro affinity for both the central benzodiazepine receptor (CBR) and the peripheral benzodiazepine receptor (PBR) of rat brain was studied. Racemic mixture of 7-bromo-3-(2-methoxy)ethoxy-5-phenyl-1,2-dihydro-3H-1,4-benzodiazepin-2-one (13) was separated into enantiomers 14, 15 by chiral HPLC. Absolute configuration of R-enantiomer 15 was determined by the method of X-ray diffraction analysis. The affinity of S-enantiomer 14 for CBR ( IC50)=245 nM) is 20-fold higher than the affinity of R-enantiomer 15 (IC50)=4,930 nM). A high selectivity for CBR versus PBR (IC50) (PBR)>10,000 nM) was shown by all reported compounds. Compound 12 was revealed as a potent (IC50)=9 nM) and selective CBR ligand among the synthesized 3-alkoxy-1,2-dihydro-3H-1,4-benzodiazepin-2-ones. PMID:20061068

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-12-14

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

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

    International Nuclear Information System (INIS)

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

  6. Benzodiazepine receptor quantification in Huntington's disease with [123I]iomazenil and SPECT

    OpenAIRE

    Pinborg, L; Videbak, C; Hasselbalch, S; Sorensen, S.; Wagner, A; Paulson, O; Knudsen, G

    2001-01-01

    OBJECTIVES—Increasing evidence suggests that metabolic changes predate neuronal death in Huntington's disease and emission tomography methods (PET and SPECT) have shown changes in glucose consumption and receptor function in early and possibly even presymptomatic disease. Because the GABAA-benzodiazepine receptor complex (BZR) is expressed on virtually all cerebral neurons BZR density images may be used to detect neuronal death. In this study the regional cerebral [123...

  7. Biodistribution and dosimetry of [I-123]iodo-PK 11195 : a potential agent for SPET imaging of the peripheral benzodiazepine receptor

    NARCIS (Netherlands)

    Versijpt, J; Dumont, F; Thierens, H; Jansen, H; De Vos, F; Slegers, G; Santens, P; Dierckx, RA; Korf, J

    2000-01-01

    The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidneys and heart. In addition, the PER has been reported to reflect neuro-inflammatory damage by co-localisation with activated microglia. PK 11195 is a high-affinity ligand for the PER. The aim of this stud

  8. Benzodiazepine effect of {sup 125}I-iomazenil-benzodiazepine receptor binding and serum corticosterone level in a rat model

    Energy Technology Data Exchange (ETDEWEB)

    Fukumitsu, Nobuyoshi [Proton Medical Research Center, University of Tsukuba, Ibaragi, 305-8575 (Japan)]. E-mail: gzl13162@nifty.ne.jp; Ogi, Shigeyuki [Department of Radiology, Jikei University School of Medicine, Tokyo, 105-8461 (Japan); Uchiyama, Mayuki [Department of Radiology, Jikei University School of Medicine, Tokyo, 105-8461 (Japan); Mori, Yutaka [Department of Radiology, Jikei University School of Medicine, Tokyo, 105-8461 (Japan)

    2005-01-01

    To test the change in free or unoccupied benzodiazepine receptor (BZR) density in response to diazepam, we investigated {sup 125}I-iomazenil ({sup 125}I-IMZ) binding and serum corticosterone levels in a rat model. Wistar male rats, which received psychological stress using a communication box for 5 days, were divided into two groups according to the amount of administered diazepam: no diazepam [D (0)] group and 10 mg/kg per day [D (10)] group of 12 rats each. The standardized uptake value (SUV) of {sup 125}I-IMZ of the D (10) group were significantly lower (P<.05) than those of the D (0) group in the frontal, parietal and temporal cortices, globus pallidus, hippocampus, amygdala and hypothalamus. The serum corticosterone level ratio in the D (10) group was significantly lower than that in the D (0) group (P<.05). From the change in serum corticosterone levels, diazepam attenuated the psychological stress produced by the physical stress to animals in adjacent compartments. From the reduced binding of {sup 125}I-IMZ, it is clear that diazepam competed with endogenous ligand for the free BZR sites, and the frontal, parietal and temporal cortices, globus pallidus, hippocampus, amygdala and hypothalamus are important areas in which {sup 125}I-IMZ binding is strongly affected by administration of diazepam.

  9. Interactions of pyrethroid insecticides with GABAA and peripheral-type benzodiazepine receptors

    International Nuclear Information System (INIS)

    Pyrethroid insecticides are potent proconvulsants in the rat. All pyrethroids evincing proconvulsant activity elicited a similar 25-30% maximal reduction of seizure threshold. The Type II pyrethroids were the most potent proconvulsants with 1RαS, cis cypermethrin having an ED50 value of 6.3 nmol/kg. The proconvulsant activity of both Type I and Type II pyrenthroids was blocked by pretreatment with PK 11195, the peripheral-type benzodiazepine receptor (PTBR) antagonist. In contrast, phenytoin did not antagonize the proconvulsant activity of either deltamethrin or permethrin. Pyrethroids displaced the specific binding of [3H]Ro5-4864 to rat brain membranes with a significant correlation between the log EC50 values for their activities as proconvulsants and the log IC50 values for their inhibition of [3H]Ro5-4864 binding. Both Ro5-4864 and pyrethroid insecticides were found to influence specific [35S]TBPS binding in a GABA-dependent manner. PK 11195 and the Type II pyrethroid, deltamethrin antagonized the Ro5-4864-induced modulation of [35S]TBPS binding. Pyrethroid insecticides, Ro5-4864 and veratridine influenced GABA-gated 36Chloride influx. Moreover, the Type II pyrethroids elicited an increase in 36chloride influx in the absence of GABA-stimulation. Both of these actions were antagonized by PK 11195 and tetrodotoxin

  10. The GABA-A benzodiazepine receptor complex: Role of pet and spect in neurology and psychiatry

    International Nuclear Information System (INIS)

    Nuclear medicine imaging techniques such as positron emission tomography (PET) and single photon emission tomography (SPECT) for selective depiction of GABA-A-benzodiazepine receptor (GBZR) binding are complementary investigations in the diagnostic process of neurological and psychiatric disorders. This review summarizes the current knowledge about options and limitations of PET and SPECT for in vivo diagnostics in neurology and psychiatry. The growing importance of GBZR-imaging for the understanding of pathophysiology and pharmacological treatment in different psychiatric syndromes is discussed. (orig.)

  11. Possible interaction of fluoroquinolones with the benzodiazepine-GABAA-receptor complex.

    OpenAIRE

    Unseld, E; Ziegler, G.; Gemeinhardt, A; Janssen, U.; Klotz, U

    1990-01-01

    1. The possible involvement of the benzodiazepine (BZD)-GABAA-receptor complex in mediating CNS stimulatory effects of fluoroquinolones was tested in vitro, in a binding inhibition assay and in vivo, in a clinical drug interaction study using electro-encephalogram (EEG) monitoring. 2. The specific binding of [3H]-flunitrazepam to rat synaptic brain membranes was inhibited by various fluoroquinolones in a concentration-dependent manner. 3. Ofloxacin had CNS-stimulating effects as revealed by t...

  12. Isotopically labelled benzodiazepines

    International Nuclear Information System (INIS)

    This paper reports on the benzodiazepines which are a class of therapeutic agents. Improvements in the analytical methodology in the areas of biochemistry and pharmacology were significant, particularly in the application of chromatographic and spectroscopic techniques. In addition, the discovery and subsequent development of tritium and carbon-14 as an analytical tool in the biological sciences were essentially post-world war II phenomena. Thus, as these new chemical entities were found to be biologically active, they could be prepared in labeled form for metabolic study, biological half-life determination (pharmacokinetics), tissue distribution study, etc. This use of tracer methodology has been liberally applied to the benzodiazepines and also more recently to the study of receptor-ligand interactions, in which tritium, carbon-11 or fluorine-18 isotopes have been used. The history of benzodiazepines as medicinal agents is indeed an interesting one; an integral part of that history is their use in just about every conceivable labeled form

  13. GABA/benzodiazepine receptor complex in long-sleep and short-sleep mice

    Energy Technology Data Exchange (ETDEWEB)

    Marley, R.J.

    1987-01-01

    LS mice are more sensitive to benzodiazepine-induced anesthesia; however, the two lines do not differ in their hypothermic response to flurazepam. SS mice are more resistant to 3-mercaptopropionic acid-induced seizures and more sensitive to the anticonvulsant effects of benzodiazepines. The various correlates of GABA and benzodiazepine actions probably are the results of different mechanisms of action and/or differential regional control. Bicuculline competition for /sup 3/H-GABA binding sites is greater in SS cerebellar tissue and /sup 3/H-flunitrazepam binding is greater in the mid-brain region of LS mice. GABA enhancement of /sup 3/H-flunitrazepma binding is greater in SS mice. Ethanol also enhances /sup 3/H-flunitrazepam binding and increases the levels of /sup 3/H-flunitrazepam binding above those observed for GABA. Using correlational techniques on data from LS and SS mice and several inbred mouse strains, it was demonstrated that a positive relationship exists between the degree of receptor coupling within the GABA receptor complex and the degree of resistance to seizures.

  14. GABA/benzodiazepine receptor complex in long-sleep and short-sleep mice

    International Nuclear Information System (INIS)

    LS mice are more sensitive to benzodiazepine-induced anesthesia; however, the two lines do not differ in their hypothermic response to flurazepam. SS mice are more resistant to 3-mercaptopropionic acid-induced seizures and more sensitive to the anticonvulsant effects of benzodiazepines. The various correlates of GABA and benzodiazepine actions probably are the results of different mechanisms of action and/or differential regional control. Bicuculline competition for 3H-GABA binding sites is greater in SS cerebellar tissue and 3H-flunitrazepam binding is greater in the mid-brain region of LS mice. GABA enhancement of 3H-flunitrazepma binding is greater in SS mice. Ethanol also enhances 3H-flunitrazepam binding and increases the levels of 3H-flunitrazepam binding above those observed for GABA. Using correlational techniques on data from LS and SS mice and several inbred mouse strains, it was demonstrated that a positive relationship exists between the degree of receptor coupling within the GABA receptor complex and the degree of resistance to seizures

  15. Antianxiety and antidepressant-like effects of AC-5216, a novel mitochondrial benzodiazepine receptor ligand

    OpenAIRE

    Kita, Atsuko; Kohayakawa, Hitoshi; Kinoshita, Tomoko; Ochi, Yoshiaki; Nakamichi, Keiko; Kurumiya, Satoshi; Furukawa, Kiyoshi; Oka, Makoto

    2004-01-01

    We investigated the ability of N-benzyl-N-ethyl-2-(7,8-dihydro-7-methyl-8-oxo-2-phenyl-9H-purin-9-yl)acetamide (AC-5216), a novel mitochondrial benzodiazepine receptor (MBR) ligand, to produce anti-anxiety and antidepressant-like effects in various animal models.AC-5216 showed high affinity for MBRs prepared from rat whole brain (Ki 0.297 nM), rat glioma cells (IC50 3.04 nM) and human glioma cells (IC50 2.73 nM), but only negligible affinity for the other main receptors including central benz...

  16. Studies of peripheral benzodiazepine receptors in mussels: comparison between a polluted and a nonpolluted site.

    Science.gov (United States)

    Betti, Laura; Giannaccini, Gino; Nigro, Marco; Dianda, Sabina; Gremigni, Vittorio; Lucacchini, Antonio

    2003-01-01

    The aim of this study was to investigate the peripheral benzodiazepine receptors in soft tissue membranes of the mussel Mytilus galloprovincialis from both polluted and nonpolluted seawater populations, using a radioligand specific for this receptor, [3H]PK11195. Mussels were dissected into four body parts--mantle, gills, digestive gland, and muscles-to determine the distribution of tissue-specific peripheral benzodiazepine receptors (PBRs). The specific binding was saturable and reversible. A statistically significant increase (muscle, 537% and mantle, 201%, as absolute percentages) in the maximal number of binding sites (B(max)) was found in mussels from the polluted site, compared with mussels from the nonpolluted site. By contrast, the value of the dissociation constant (K(d)) at equilibrium does not show a statistically significant variation between the two groups. In competitive experiments of the compounds clonazepam, flumazenil, flunitrazepam, Ro5-4864, PK11195, and protoporphyrin IX, only PK11195 and protoporphyrin IX displaced [3H]PK11195 specifically bound to soft tissue membranes, revealing that the binding sites of peripheral benzodiazepine receptors of mussels have pharmacological properties comparable to those of low vertebrates such as trout. M. galloprovincialis was also tested as an indicator of heavy metal exposure, and metal accumulation in the digestive gland was measured by atomic absorption spectrophotometry (AAS). The contents of Pb, Mn, and Zn in mussels collected off the polluted site were higher than those in mussels from the nonpolluted site. These data suggest that PBRs are present in the soft tissues of the mussel M. galloprovincialis. Here we report preliminary evidence of biochemical alterations in mussels from the polluted site. PMID:12547633

  17. In vivo study of drug interaction with brain benzodiazepine receptor

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, O.; Shinotoh, H.; Ito, T.; Suzuki, K.; Hashimoto, K.; Yamasaki, T.

    1985-05-01

    The possibility of direct estimation of in vivo Bz receptor occupancy in brain was evaluated using C-11, or H-3-flumazepil (Ro15-1788). In animal experiments, 1 ..mu..Ci of H-3-Ro15-1788 was injected at 0.5 or 20 hr after i.v. injection of various dosage of clonazepam. Then radioactivity in cerebral cortex, cerebellum and blood at 5 min. after injection of the tracer was compared. Competitive inhibition of in vivo binding was clearly observed when clonazepam was pretreated at 0.5 hr before injection of the tracer. On the other hand, brain radioactivity was increased when clonazepam was administered at 20 hr before injection of the tracer. This increase in binding of H-3-Ro15-1788 might be caused by rebound of Bz receptor function by treatment with Bz agonist, and this rebound may have an important role in physiological function. Clinical investigation concerning drug interaction with brain Bz receptor was performed in normal volunteer and patients with neurological disorders. The distribution of C-11-Ro15-1788 in the brain of patients chronically treated with clonazepam were significantly heterogeneous. However, cerebral blood flow estimated with N-13 NH3 of these patients were normal.

  18. In vivo study of drug interaction with brain benzodiazepine receptor

    International Nuclear Information System (INIS)

    The possibility of direct estimation of in vivo Bz receptor occupancy in brain was evaluated using C-11, or H-3-flumazepil (Ro15-1788). In animal experiments, 1 μCi of H-3-Ro15-1788 was injected at 0.5 or 20 hr after i.v. injection of various dosage of clonazepam. Then radioactivity in cerebral cortex, cerebellum and blood at 5 min. after injection of the tracer was compared. Competitive inhibition of in vivo binding was clearly observed when clonazepam was pretreated at 0.5 hr before injection of the tracer. On the other hand, brain radioactivity was increased when clonazepam was administered at 20 hr before injection of the tracer. This increase in binding of H-3-Ro15-1788 might be caused by rebound of Bz receptor function by treatment with Bz agonist, and this rebound may have an important role in physiological function. Clinical investigation concerning drug interaction with brain Bz receptor was performed in normal volunteer and patients with neurological disorders. The distribution of C-11-Ro15-1788 in the brain of patients chronically treated with clonazepam were significantly heterogeneous. However, cerebral blood flow estimated with N-13 NH3 of these patients were normal

  19. Application of gamma-aminobutyric acid type A-benzodiazepine receptor imaging for study of neuropsychiatric disorders

    International Nuclear Information System (INIS)

    Gamma-aminobutyric acid type A-benzodiazepine receptors are heterogeneous polypeptide pentamers widely spread in the central nervous system on the neuron membrane. Different subunit combinations educe various neuro-inhibitory pharmacological effects such as sedative, hypnosis, anticonvulsion and anxiolysis. PET can be utilized to study the binding of the receptors in vivo. PET radioligands of gamma-aminobutyric acid type A-benzodiazepine receptors can be classified into 3 types: antagonists,agonists and reverse agonists, of which antagonist radiotracer 11C-flumazenil is the most commonly applied in epilepsy, anxiety disorders, depression, vegetative state,addiction and other neuro-psychiatric disorders. (authors)

  20. Synthesis of a Benzodiazepine-derived Rhodium NHC Complex by C-H Bond Activation

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, Roberg G.; Gribble, Jr., Michael W.; Ellman, Jonathan A.

    2008-01-30

    The synthesis and characterization of a Rh(I)-NHC complex generated by C-H activation of 1,4-benzodiazepine heterocycle are reported. This complex constitutes a rare example of a carbene tautomer of a 1,4-benzodiazepine aldimine stabilized by transition metal coordination and demonstrates the ability of the catalytically relevant RhCl(PCy{sub 3}){sub 2} fragment to induce NHC-forming tautomerization of heterocycles possessing a single carbene-stabilizing heteroatom. Implications for the synthesis of benzodiazepines and related pharmacophores via C-H functionalization are discussed.

  1. Further characterization of benzodiazepine receptor differences in long-sleep and short-sleep mice

    International Nuclear Information System (INIS)

    Molecular and conformational characteristics of benzodiazepine (BZ) receptors in cortex and cerebellum from long-sleep and mice were investigated using heat inactivation and beta-carboline competition techniques. To investigate differences in the allosteric coupling between GABA and BZ receptors, the protection of BZ receptors from heat inactivation, by GABA, was also evaluated. The two genotypes do not differ in the affinity or number of BZ receptors in the cortex or cerebellum. They do, however, appear to differ in the molecular structure and/or regulation of the conformational state of the receptor in the cortex, as indicated by a greater sensitivity of LS mice to both heat inactivation and beta-carboline competition of 3H-flunitrazepam (FNZ) binding in this region. Evidence for differences in the nature of coupling between GABA and BZ receptors is provided by the finding in that in both regions, GABA protected BZ receptors from inactivation to a greater degree in LS mice. The relationship between these differences and the multiplicity of expression of BZ receptors is discussed

  2. Further characterization of benzodiazepine receptor differences in long-sleep and short-sleep mice

    Energy Technology Data Exchange (ETDEWEB)

    Marley, R.J.; Stinchcomb, A.; Wehner, J.M.

    1988-01-01

    Molecular and conformational characteristics of benzodiazepine (BZ) receptors in cortex and cerebellum from long-sleep and mice were investigated using heat inactivation and beta-carboline competition techniques. To investigate differences in the allosteric coupling between GABA and BZ receptors, the protection of BZ receptors from heat inactivation, by GABA, was also evaluated. The two genotypes do not differ in the affinity or number of BZ receptors in the cortex or cerebellum. They do, however, appear to differ in the molecular structure and/or regulation of the conformational state of the receptor in the cortex, as indicated by a greater sensitivity of LS mice to both heat inactivation and beta-carboline competition of /sup 3/H-flunitrazepam (FNZ) binding in this region. Evidence for differences in the nature of coupling between GABA and BZ receptors is provided by the finding in that in both regions, GABA protected BZ receptors from inactivation to a greater degree in LS mice. The relationship between these differences and the multiplicity of expression of BZ receptors is discussed.

  3. Radiosynthesis and initial evaluation of [18F]-FEPPA for PET imaging of peripheral benzodiazepine receptors

    International Nuclear Information System (INIS)

    Introduction: A novel [18F]-radiolabelled phenoxyanilide, [18F]-FEPPA, has been synthesized and evaluated, in vitro and ex vivo, as a potential positron emission tomography imaging agent for the peripheral benzodiazepine receptor (PBR). Methods: [18F]-FEPPA and two other radiotracers for imaging PBR, namely [11C]-PBR28 and [11C]-PBR28-d3, were synthesised and evaluated in vitro and ex vivo as potential PBR imaging agents. Results: [18F]-FEPPA is efficiently prepared in one step from its tosylate precursor and [18F]-fluoride in high radiochemical yields and at high specific activity. FEPPA displayed a Ki of 0.07 nM for PBR in rat mitochondrial membrane preparations and a suitable lipophilicity for brain penetration (log P of 2.99 at pH 7.4). Upon intravenous injection into rats, [18F]-FEPPA showed moderate brain uptake [standard uptake value (SUV) of 0.6 at 5 min] and a slow washout (SUV of 0.35 after 60 min). Highest uptake of radioactivity was seen in the hypothalamus and olfactory bulb, regions previously reported to be enriched in PBR in rat brain. Analysis of plasma and brain extracts demonstrated that [18F]-FEPPA was rapidly metabolized, but no lipophilic metabolites were observed in either preparation and only 5% radioactive metabolites were present in brain tissue extracts. Blocking studies to determine the extent of specific binding of [18F]-FEPPA in rat brain were problematic due to large perturbations in circulating radiotracer and the lack of a reference region. Conclusions: Further evaluation of the potential of [18F]-FEPPA will require the employment of rigorous kinetic models and/or appropriate animal models

  4. Modulation of acetylcholine release from rat striatal slices by the GABA/benzodiazepine receptor complex

    Energy Technology Data Exchange (ETDEWEB)

    Supavilai, P.; Karobath, M.

    1985-02-04

    GABA, THIP and muscimol enhance spontaneous and inhibit electrically induced release of tritium labelled compounds from rat striatal slices which have been pre-labelled with /sup 3/H-choline. Baclofen is inactive in this model. Muscimol can inhibit electrically induced release of tritiated material by approximately 75% with half maximal effects at 2 ..mu..M. The response to muscimol can be blocked by the GABA antagonists bicuculline methobromide, picrotoxin, anisatin, R 5135 and CPTBO (cyclopentylbicyclophosphate). Drugs which act on the benzodiazepine receptor (BR) require the presence of muscimol to be effective and they modulate the effects of muscimol in a bidirectional manner. Thus BR agonists enhance and inverse BR agonists attenuate the inhibitory effects of muscimol on electrically induced release. Ro15-1788, a BR antagonist, does not modulate the inhibitory effects of muscimol but antagonizes the actions of clonazepam, a BR agonist, and of DMCM, an inverse BR agonist. These results demonstrate that a GABA/benzodiazepine receptor complex can modulate acetylcholine release from rat striatal slices in vitro. 24 references, 3 figures, 5 table.

  5. Modulation of acetylcholine release from rat striatal slices by the GABA/benzodiazepine receptor complex

    International Nuclear Information System (INIS)

    GABA, THIP and muscimol enhance spontaneous and inhibit electrically induced release of tritium labelled compounds from rat striatal slices which have been pre-labelled with 3H-choline. Baclofen is inactive in this model. Muscimol can inhibit electrically induced release of tritiated material by approximately 75% with half maximal effects at 2 μM. The response to muscimol can be blocked by the GABA antagonists bicuculline methobromide, picrotoxin, anisatin, R 5135 and CPTBO (cyclopentylbicyclophosphate). Drugs which act on the benzodiazepine receptor (BR) require the presence of muscimol to be effective and they modulate the effects of muscimol in a bidirectional manner. Thus BR agonists enhance and inverse BR agonists attenuate the inhibitory effects of muscimol on electrically induced release. Ro15-1788, a BR antagonist, does not modulate the inhibitory effects of muscimol but antagonizes the actions of clonazepam, a BR agonist, and of DMCM, an inverse BR agonist. These results demonstrate that a GABA/benzodiazepine receptor complex can modulate acetylcholine release from rat striatal slices in vitro. 24 references, 3 figures, 5 table

  6. Synthesis, characterisation, stereochemistry and antimicrobial activity of 5 -piperazino- and 5-morpholinoacetyl-2,2,4-trimethyl-1, 5-benzodiazepines

    Indian Academy of Sciences (India)

    S Ponnuswamy; A Akila; D Deepa Rajakumari; V Shreevidhyaa Suressh; G Usha

    2015-11-01

    Three 1,5-benzodiazepines viz., 5-chloroacetyl-, 5-piperazinoacetyl- and N5 -morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepines have been synthesized. The structural characterisation and the conformational preferences of the compounds have been carried out using IR, 1D and 2D NMR spectral data. The NMR spectral data show that the -acetyltetrahydro-1,5-benzodiazepines prefer to exist in boat conformation with exo orientation of >C=O at 5 position in the solution state. The X-ray crystal structure of 5-morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepine also supports boat conformation in the solid state. The antimicrobial activity for -acetyltetrahydro-1,5-benzodiazepines have been carried out. -morpholinoacetyl-2,2,4-trimethyl-1H-1,5-benzodiazepine demonstrated better antibacterial and antifungal activities.

  7. [3H]Clonazepam, like [3H]flunitrazepam, is a photoaffinity label for the central type of benzodiazepine receptors

    International Nuclear Information System (INIS)

    [3H]Clonazepam, like [3H]flunitrazepam, is irreversibly bound to membrane proteins of brain tissue when exposed to UV light. In polyacrylamide gel electrophoresis followed by fluorography, the same pattern of photolabelled proteins was obtained in cerebellum and in hippocampus when either [3H]clonazepam or [3H]flunitrazepam was used as photoaffinity label. Since [3H]clonazepam does not interact with the peripheral type of benzodiazepine binding site present in the brain, these results confirm previous evidence that the proteins photolabelled with [3H]flunitrazepam are associated with the central type of benzodiazepine receptor. (Auth.)

  8. The expression of peripheral benzodiazepine receptors in human skin: the relationship with epidermal cell differentiation.

    Science.gov (United States)

    Stoebner, P E; Carayon, P; Penarier, G; Fréchin, N; Barnéon, G; Casellas, P; Cano, J P; Meynadier, J; Meunier, L

    1999-06-01

    The peripheral benzodiazepine receptor (PBR) is a protein of mitochondrial outer membranes utilizing porphyrins as endogenous ligands. PBR is part of a heteromeric receptor complex involved in the formation of mitochondrial permeability transition pores and in the early events of apoptosis. PBR may function as an oxygen-dependent signal generator; recent data indicate that these receptors may preserve the mitochondria of haematopoietic cell lines from damage caused by oxygen radicals. To identify PBRs in human skin, we used a specific monoclonal antibody directed against the C-terminus fragment of the human receptor. PBR immunoreactivity was found in keratinocytes, Langerhans cells, hair follicles and dermal vascular endothelial cells. Interestingly, confocal microscopic examination of skin sections revealed that PBR expression was strongly upregulated in the superficial differentiated layers of the epidermis. Ultrastructurally, PBRs were distributed throughout the cytoplasm but were selectively expressed on the mitochondrial membranes of epidermal cells. The elevated level of PBRs in the spinous layer was not associated with an increased number of mitochondria nor with an increased amount of mRNA as assessed by in situ hybridization on microautoradiographed skin sections. The present work provides, for the first time, evidence of PBR immunoreactivity in human skin. This mitochondrial receptor may modulate apoptosis in the epidermis; its increased expression in differentiated epidermal layers may represent a novel mechanism of natural skin protection against free radical damage generated by ultraviolet exposure. PMID:10354064

  9. Benzodiazepine receptor distribution and cerebral blood flow in early blindness. A PET study

    International Nuclear Information System (INIS)

    We studied benzodiazepine receptor (BZR) distribution, which is thought to be affected by neuronal density in the cerebral cortex, and CBF using [11C]flumazenil and [15O]water PET in early blind (EB) and in blindfold sighted control (SC) subjects. PET images were co-registered to the subject's MRI. Using SPM96, MRI images were normalized in the Talairach and Tournoux coordinate system, and accordingly MRI-registered PET images were spatially normalized. Statistical parametric maps were computed on a voxel-by-voxel basis, using the general linear model. CBF for EB was significantly larger in the Brodmann area 17 and 18, especially anterior area, than that for SC, while there was no significant difference in BZR distribution. Our BZR data suggest that the amount of neurons do not change due to early visual deprivation in the visual cortex, in spite of high CBF in visual cortex of EB subjects. (author)

  10. Systematic review of modulators of benzodiazepine receptors in irritable bowel syndrome:Is there hope?

    Institute of Scientific and Technical Information of China (English)

    Pooneh Salari; Mohammad Abdollahi

    2011-01-01

    Several drugs are used in the treatment of irritable bowel syndrome (IBS) but all have side effects and variable efficacy.Considering the role of the gut-brain axis,immune,neural,and endocrine pathways in the patho-genesis of IBS and possible beneficial effects of ben-zodiazepines (BZD) in this axis,the present systematic review focuses on the efficacy of BZD receptor modulators in human IBS.For the years 1966 to February 2011,all literature was searched for any articles on the use of BZD receptor modulators and IBS.After thorough evaluation and omission of duplicate data,10 out of 69 articles were included.BZD receptor modulators can be helpful,especially in the diarrhea-dominant form of IBS,by affecting the inflammatory,neural,and psychologic pathways,however,controversies still exist.Recently,a new BZD receptor modulator,dextofisopam was synthesized and studied in human subjects,but the studies are limited to phase II b clinical trials.None of the existing trials considered the neuroimmunomodulatory effectof BZDs in IBS,but bearing in mind the concentration-dependent effect of BZDs on cytokines and cell proliferation,future studies using pharmacodynamic and pharmacokinetic approaches are highly recommended.

  11. Modulation of radioligand binding to the GABA(A)-benzodiazepine receptor complex by a new component from Cyperus rotundus.

    Science.gov (United States)

    Ha, Jeoung-Hee; Lee, Kwang-Youn; Choi, Hyoung-Chul; Cho, Jungsook; Kang, Byung-Soo; Lim, Jae-Chul; Lee, Dong-Ung

    2002-01-01

    Four sesquiterpenes, beta-selinene, isocurcumenol, nootkatone and aristolone and one triterpene, oleanolic acid were isolated from the ethylacetate fraction of the rhizomes of Cyperus rotundus and tested for their ability to modulate gamma-aminobutyric acid (GABA(A))-benzodiazepine receptor function by radioligand binding assays using rat cerebrocortical membranes. Among these compounds, only isocurcumenol, one of the newly identified constituents of this plant, was found to inhibit [3H]Ro15-1788 binding and enhance [3H]flunitrazepam binding in the presence of GABA. These results suggest that isocurcumenol may serve as a benzodiazepine receptor agonist and allosterically modulate GABAergic neurotransmission via enhancement of endogenous receptor ligand binding. PMID:11824542

  12. SPECT imaging of GABAA/benzodiazepine receptors and cerebral perfusion in mild cognitive impairment

    International Nuclear Information System (INIS)

    The involvement of neocortical and limbic GABAA/benzodiazepine (BZD) receptors in Alzheimer's disease (AD) is controversial and mainly reported in advanced stages. The status of these receptors in the very early stages of AD is unclear and has not been explored in vivo. Our aims were to investigate in vivo the integrity of cerebral cortical GABAA/BZD receptors in subjects with amnestic mild cognitive impairment (MCI) and to compare possible receptor changes to those in cerebral perfusion. [123I]Iomazenil and [99mTc]HMPAO SPECT images were acquired in 16 patients with amnestic MCI and in 14 normal elderly control subjects (only [123I]iomazenil imaging in 5, only [99mTc]HMPAO imaging in 4, and both [123I]iomazenil and [99mTc]HMPAO imaging in 5). Region of interest (ROI) analysis and voxel-based analysis were performed with cerebellar normalization. Neither ROI analysis nor voxel-based analysis showed significant [123I]iomazenil binding changes in MCI patients compared to control subjects, either as a whole group or when considering only those patients with MCI that converted to AD within 2 years of clinical follow-up. In contrast, the ROI analysis revealed significant hypoperfusion of the precuneus and posterior cingulate cortex in the whole group of MCI patients and in MCI converters as compared to control subjects. Voxel-based analysis showed similar results. These results indicate that in the very early stages of AD, neocortical and limbic neurons/synapses expressing GABAA/BZD receptors are essentially preserved. They suggest that in MCI patients functional changes precede neuronal/synaptic loss in neocortical posterior regions and that [99mTc]HMPAO rCBF imaging is more sensitive than [123I]iomazenil GABAA/BZD receptor imaging in detecting prodromal AD. (orig.)

  13. Chronic brief restraint decreases in vivo binding of benzodiazepine receptor ligand to mouse brain.

    Science.gov (United States)

    Mosaddeghi, M; Burke, T F; Moerschbaecher, J M

    1993-01-01

    This study examines the effects of chronic brief restraint on in vivo benzodiazepine (BZD) receptor binding in mouse brain. Three groups of mice were used. Mice in group 1 were neither restrained nor injected (ACUTE control). Mice in group 2 were restrained for 5-6 s by grabbing the back skin and holding the subject upside-down at a 45 degrees angle as if to be injected (CHRONIC SHAM control) for 7 d. Mice in group 3 (CHRONIC SALINE) received daily single intraperitoneal (ip) injections of saline (5 mL/kg) for 7 d. On d 8 BZD receptors were labeled in vivo by administration of 3 microCi [3H]flumazenil (ip). The levels of ligand bound in vivo to cerebral cortex (CX), cerebellum (CB), brain stem (BS), striatum (ST), hippocampus (HP), and hypothalamus (HY) were determined. Results indicated that the level of binding was significantly (p stress produces a decrease in BZD receptor binding sites. PMID:8385464

  14. Single dose efficacy evaluation of two partial benzodiazepine receptor agonists in photosensitive epilepsy patients: A placebo-controlled pilot study.

    Science.gov (United States)

    Kasteleijn-Nolst Trenité, Dorothée G A; Groenwold, Rolf H H; Schmidt, Bernd; Löscher, Wolfgang

    2016-05-01

    Benzodiazepines (BZDs) are highly effective to suppress various types of seizures; however, their clinical use is limited due to adverse effects and tolerance and dependence liability. Drugs that act only as partial agonists at the BZD recognition site (initially termed "BZD receptor") of the GABAA receptor chloride ionophore complex or exhibit a GABAA receptor subtype-selectivity are thought to have advantages vs. full agonists such as diazepam and most other clinically used BZDs in that such compounds have less adverse effects and reduced or absent tolerance and dependence liability. One of such compounds, abecarnil, has been clinically evaluated as a novel anxiolytic drug, but, despite its potent preclinical anti-seizure activity, it has not yet been evaluated in patients with epilepsy. In the present proof-of-concept study, we performed a within-subject placebo-controlled, single oral dose study of abecarnil in patients with photosensitive epilepsy. Flumazenil, which is generally considered a BZD receptor antagonist, but has slight partial agonistic properties, was used for comparison. In total, 12 patients were enrolled in this study. Abecarnil, 5 or 10mg, completely abolished the photo-paroxysmal EEG response, while flumazenil, 30, 60 or 100mg, was less effective. The anti-epileptic effect of abecarnil was significantly different from both placebo and flumazenil. Sedative adverse effects were observed after abecarnil but not flumazenil. The study substantiates previous pre-clinical experiments that abecarnil exerts pronounced anti-seizure activity. Epilepsy is often associated with anxiety, so that the anxiolytic activity of abecarnil would be an added advantage when using this compound in epilepsy patients. PMID:26921854

  15. Quantification of human brain benzodiazepine receptors using [{sup 18}F]fluoroethylflumazenil: a first report in volunteers and epileptic patients

    Energy Technology Data Exchange (ETDEWEB)

    Leveque, Philippe [Unite de Tomographie par Positrons, Universite Catholique de Louvain, Louvain-la-Neuve (Belgium); Unite de Chimie Pharmaceutique et de Radiopharmacie, CMFA/REMA, Universite Catholique de Louvain, 73-40 Avenue Mounier, 1200, Bruxelles (Belgium); Sanabria-Bohorquez, Sandra [Imaging Research, Merck Research Laboratories, West Point, Philadelphia (United States); Bol, Anne; Volder, Anne de; Labar, Daniel [Unite de Tomographie par Positrons, Universite Catholique de Louvain, Louvain-la-Neuve (Belgium); Rijckevorsel, K. van [Service de Neurologie, Cliniques Universitaires Saint-Luc, Bruxelles (Belgium); Gallez, Bernard [Unite de Chimie Pharmaceutique et de Radiopharmacie, CMFA/REMA, Universite Catholique de Louvain, 73-40 Avenue Mounier, 1200, Bruxelles (Belgium); Unite de Resonance Magnetique Biomedicale, Universite Catholique de Louvain, Bruxelles (Belgium)

    2003-12-01

    Fluorine-18 fluoroethylflumazenil ([{sup 18}F]FEF) is a tracer for central benzodiazepine (BZ) receptors which is proposed as an alternative to carbon-11 flumazenil for in vivo imaging using positron emission tomography (PET) in humans. In this study, [{sup 18}F]FEF kinetic data were acquired using a 60-min two-injection protocol on three normal subjects and two patients suffering from mesiotemporal epilepsy as demonstrated by abnormal magnetic resonance imaging and [{sup 18}F]fluorodeoxyglucose positron emission tomography. First, a tracer bolus injection was performed and [{sup 18}F]FEF rapidly distributed in the brain according to the known BZ receptor distribution. Thirty minutes later a displacement injection of 0.01 mg/kg of unlabelled flumazenil was performed. Activity was rapidly displaced from all BZ receptor regions demonstrating the specific binding of [{sup 18}F]FEF. No displacement was observed in the pons. Plasma input function was obtained from arterial blood sampling, and metabolite analysis was performed by high-performance liquid chromatography. Metabolite quantification revealed a fast decrease in tracer plasma concentration, such that at 5 min post injection about 70% of the total radioactivity in plasma corresponded to [{sup 18}F]FEF, reaching 24% at 30 min post injection. The interactions between [{sup 18}F]FEF and BZ receptors were described using linear compartmental models with plasma input and reference tissue approaches. Binding potential values were in agreement with the known distribution of BZ receptors in human brain. Finally, in two patients with mesiotemporal sclerosis, reduced uptake of [{sup 18}F]FEF was clearly observed in the implicated left hippocampus. (orig.)

  16. [11C]vinpocetine: a prospective peripheral benzodiazepine receptor ligand for primate PET studies.

    Science.gov (United States)

    Gulyás, Balázs; Halldin, Christer; Vas, Adám; Banati, Richard B; Shchukin, Evgeny; Finnema, Sjoerd; Tarkainen, Jari; Tihanyi, Károly; Szilágyi, Géza; Farde, Lars

    2005-03-15

    Vinpocetine, a synthetic derivative of the Vinca minor alkaloid vincamine, is a widely used drug in neurological practice. We tested the hypothesis that vinpocetine binds to peripheral benzodiazepine binding sites (PBBS) and is therefore a potential ligand of PBBS. Positron emission tomography (PET) measurements in two cynomolgous monkeys showed that pretreatment with vinpocetine markedly reduced the brain uptake of [11C]PK11195, a known PBBS radioligand. On the other hand, whereas pretreatment with PK11195 increased the brain uptake of [11C]vinpocetine due to the blockade of PBBS in the periphery, it significantly reduced the binding potential (BP) values of [11C]vinpocetine in the whole brain and in individual brain structures to PK11195. These findings indicate that, whereas the two ligands have different affinities to PBBS, vinpocetine is a potent ligand of PBBS, which in turn suggests that the pharmacological activity of vinpocetine may involve the regulation of glial functions. PMID:15760643

  17. Synthesis and evaluation of [{sup 123}I] ligands for the study of the peripheral benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Mattner, F.; Katsifis, A.; Mardon, K.; Papazian, V.; Najdovski, L.; Dikic, B. [Australian Nuclear Science and technology Organisation, Lucas Heights, Sydney, NSW (Australia). Radiopharmaceuticals Division

    1998-06-01

    Full text: The peripheral benzodiazepine receptors (PBR), are distinct from the central benzodiazepine receptors in their pharmacology and subcellular location. PBR`s are predominantly found in the peripheral organs such as kidney, heart, adrenal cortex, as well as in the glial cells in the brain. PBR`s have been implicated in the control of cell proliferation and differentiation and shown to display increased levels in a variety of malignant tumours. Increased levels of PBR`s have also been implicated in a variety of neurodegenerative disorders. We have prepared and evaluated [{sup 123}I]N`N`-dimethyl-6-methyl-(4`iodophenyl) midazo[l,2-a]pyridine-3-acetamide (1), [{sup 123}I]N`N`-diethyl-6-chloro-(4`iodophenyl) imidazo[l,2-a]pyridine-3-acetamide (2) and [{sup 123}l]3-benzoimidomethyl-2- (4`-t-butylphenyl)-6-iodoimidazo[1,2-b]pyridazine (3) as potential probes for the study of the PBR`s in oncology and neurodegeneration using SPECT. The iodine-123 analogues 1 and 2 were prepared by iododestannylation with Na {sup 123}I in the presence of chloramine-T and HCI. Compound 3 was prepared from the bromo precursor with Na {sup 123}I using Cu{sup +} assisted halogen exchange. In vivo biodistribution of all three compounds in rodents indicated high uptake in tissues with known PBR sites. Pre-treatment of the rats with PK 11195, Ro 5-4864 and the cold material reduced significantly the uptake of activity in organs expressing the PBR`s. Other drugs including flumazenil and haloperidol, did not significantly reduce the uptake of activity in these organs. Metabolite studies on 1 and 2 indicated high in vivo stability, however significant deiodination in vivo was observed for 3. In conclusion, ligands 1, 2 and 3 indicated high and selective in vivo uptake in organs expressing the PBR whereas ligand 3 had reduced in vivo stability. Compounds 1 and 2 are therefore suitable candidates for further development as ligands for the study of the PBR`s using SPECT

  18. Maternal Characteristics of Women Exposed to Hypnotic Benzodiazepine Receptor Agonist during Pregnancy

    Directory of Open Access Journals (Sweden)

    Bjarke Askaa

    2014-01-01

    Full Text Available Background. There is little knowledge regarding the characteristics of women treated with hypnotic benzodiazepine receptor agonists (HBRAs during pregnancy. In this large Danish cohort study, we characterize women exposed to HBRA during pregnancy. We determined changes in prevalence of HBRA use from 1997 to 2010 and exposure to HBRAs in relation to pregnancy. Methods. We performed a retrospective cohort study including 911,017 pregnant women in the period from 1997 to 2010. Information was retrieved from The Danish Birth Registry and The Registry of Medicinal Product Statistics to identify pregnant women redeeming a prescription of HBRAs. Results. We identified 2,552 women exposed to HBRAs during pregnancy, increasing from 0.18% in 1997 to 0.23% in 2010. Compared to unexposed women, exposed women were characterized by being older, with higher BMI, in their third or fourth parity, of lower income and education level, more frequently smokers, and more likely to be comedicated with antipsychotic, anxiolytic, or antidepressant drugs (P<0.0001. Conclusion. Women using HBRAs during their pregnancy differ from unexposed women in socioeconomic factors and were more likely to receive comedication. The consumption of HBRAs was reduced during pregnancy compared to before conception.

  19. 125I-iomazenil-benzodiazepine receptor binding during psychological stress in rats

    International Nuclear Information System (INIS)

    We investigated the changes in 125I-iomazenil (125I-IMZ) benzodiazepine receptor (BZR) binding with psychological stress in a rat model. Six male Wistar rats were placed under psychological stress for 1 hour by using a communication box. No physical stress was not received. 1.85 MBq of 125I-IMZ was injected into the lateral tail vein and the rat was killed 3 hours later. Twenty-micormeter-thick sections of the brain were collected and % injected dose per body weight (% ID/BW) of eleven regions (frontal, parietal, temporal, occipital cortices, caudate putamen, accumubens nuclei, globus pallidus, amygdala, thalamus, hippocampus and hypothalamus) were calculated by autoradiography. The %ID/BW of rats which were placed under psychological stress was compared with that of 6 control rats. The %ID/BW of rats which were placed under psychological stress diffusely tended to show a reduction in 125I-IMZ-BZR binding. A significant decrease in BZR binding was observed in the hippocampus of the rats which were placed under psychological stress. 125I-IMZ-BZR binding tended to decrease throughout the brain. (author)

  20. Gamma-aminobutyric acid-modulated benzodiazepine binding sites in bacteria

    International Nuclear Information System (INIS)

    Benzodiazepine binding sites, which were once considered to exist only in higher vertebrates, are here demonstrated in the bacteria E. coli. The bacterial [3H]diazepam binding sites are modulated by GABA; the modulation is dose dependent and is reduced at high concentrations. The most potent competitors of E.Coli [3H]diazepam binding are those that are active in displacing [3H]benzodiazepines from vertebrate peripheral benzodiazepine binding sites. These vertebrate sites are not modulated by GABA, in contrast to vertebrate neuronal benzodiazepine binding sites. The E.coli benzodiazepine binding sites therefore differ from both classes of vertebrate benzodiazepine binding sites; however the ligand spectrum and GABA-modulatory properties of the E.coli sites are similar to those found in insects. This intermediate type of receptor in lower species suggests a precursor for at least one class of vertebrate benzodiazepine binding sites may have existed

  1. Tryptic mapping and membrane topology of the benzodiazepine receptor alpha-subunit

    Energy Technology Data Exchange (ETDEWEB)

    Lentes, K.U.; Venter, J.C.

    1986-05-01

    Rat brain membrane benzodiazepine receptors (BZR) were photoaffinity labelled specifically (in presence or absence of 6 ..mu..M clonazepam) with 10 nM /sup 3/H-flunitrazepam (FNZ). Digestion of the FNZ-labelled, membrane-bound BZR with 200 ..mu..g trypsin/mg membrane protein yielded H/sub 2/O-soluble BZR-fragments of molecular mass (M/sub r/) 34, 31, 28, 24, 21, 18, 16, 12, 10 and 7kDa. Because the 34kDa-peptide is the largest fragment containing a FNZ-binding site they conclude that this represents the extracellular domain of the BZR. In the remaining pellet two labelled peptides with M/sub r/ of 44kDa and 28kDa were found that required the use of detergents for their solubilization; they therefore contain the membrane anchoring domain. Digestion of the 0.5% Na-deoxycholate solubilized, intact BZR (M/sub r/ 51kDa) resulted in the same tryptic pattern as the membrane form of the receptor plus two larger fragments of M/sub r/ 45kDa and 40kDa. Arrangement of all tryptic fragments with reference to the FNZ binding site reveals a membrane topology of the BZR alpha-subunit with 67% (34kDa) for the extracellular domain, 21% (11kDa) for the membrane anchoring domain and 12% (6kDa) for a putative cytoplasmic domain. The overlap between some of the labelled fragments suggest that the BZ binding site must be located near the membrane surface of the extracellular domain.

  2. Tryptic mapping and membrane topology of the benzodiazepine receptor alpha-subunit

    International Nuclear Information System (INIS)

    Rat brain membrane benzodiazepine receptors (BZR) were photoaffinity labelled specifically (in presence or absence of 6 μM clonazepam) with 10 nM 3H-flunitrazepam (FNZ). Digestion of the FNZ-labelled, membrane-bound BZR with 200 μg trypsin/mg membrane protein yielded H2O-soluble BZR-fragments of molecular mass (M/sub r/) 34, 31, 28, 24, 21, 18, 16, 12, 10 and 7kDa. Because the 34kDa-peptide is the largest fragment containing a FNZ-binding site they conclude that this represents the extracellular domain of the BZR. In the remaining pellet two labelled peptides with M/sub r/ of 44kDa and 28kDa were found that required the use of detergents for their solubilization; they therefore contain the membrane anchoring domain. Digestion of the 0.5% Na-deoxycholate solubilized, intact BZR (M/sub r/ 51kDa) resulted in the same tryptic pattern as the membrane form of the receptor plus two larger fragments of M/sub r/ 45kDa and 40kDa. Arrangement of all tryptic fragments with reference to the FNZ binding site reveals a membrane topology of the BZR alpha-subunit with 67% (34kDa) for the extracellular domain, 21% (11kDa) for the membrane anchoring domain and 12% (6kDa) for a putative cytoplasmic domain. The overlap between some of the labelled fragments suggest that the BZ binding site must be located near the membrane surface of the extracellular domain

  3. Apparent target size of rat brain benzodiazepine receptor, acetylcholinesterase, and pyruvate kinase is highly influenced by experimental conditions

    International Nuclear Information System (INIS)

    Radiation inactivation is a method to determine the apparent target size of molecules. In this report we examined whether radiation inactivation of various enzymes and brain receptors is influenced by the preparation of samples preceding irradiation. The apparent target sizes of endogenous acetylcholinesterase and pyruvate kinase from rat brain and from rabbit muscle and benzodiazepine receptor from rat brain were investigated in some detail. In addition the target sizes of alcohol dehydrogenase (from yeast and horse liver), beta-galactosidase (from Escherichia coli), lactate dehydrogenase (endogenous from rat brain), and 5-HT2 receptors, acetylcholine muscarine receptors, and [35S] butyl bicyclophosphorothionate tertiary binding sites from rat brain were determined. The results show that apparent target sizes are highly influenced by the procedure applied for sample preparation before irradiation. The data indicate that irradiation of frozen whole tissue as opposed to lyophilized tissue or frozen tissue homogenates will estimate the smallest and most relevant functional target size of a receptor or an enzyme

  4. Alterations in in-vivo benzodiazepine-receptor binding of C-11-Ro15-1788 (flumazepil)

    International Nuclear Information System (INIS)

    Alterations of the central benzodiazepine - receptor function caused by the change of physiological or psychological conditions, were recognized in both animal and human studies. Before the human study, animal experiments using tritiated Ro15-1788 were carried out. The stress was produced by forcing the mice to swim in a water-basin at 160C for 5 min. Within 3 min after the forced swimming, the tracer was injected. Brain radioactivities in stress-loaded mice increased over a period of 15 min after the intra-venous injection of tracers, while brain activities of carrier-added tracer decreased. In human study, approximately 5 mCi of C-11-Ro15-1788, which specific activity is 0.3-1.0 Ci/μmol, were intravenously injected to each case. Measurements of the brain activity were performed using positron-CT, with blood sample collection. 31 human studies were performed on. Cerebral cortex time activity curves in several volunteers in nervous and stressful state, showed the same pattern to that in the stress-loaded animal experiment. It is important that the significant different time course of cerebral activity after the injection of labelled Ro15-1788, was observed in stressful state, compared with control, in both human and animal study. From these results, it will be concluded the positron CT study using /sup 11/C-Ro15-1788 will become a new technic to detect the change of psychological conditions in human brain and to diagnose some kind of neuropsychiatric disease

  5. Affinity of 3-acyl substituted 4-quinolones at the benzodiazepine site of GABAA receptors

    DEFF Research Database (Denmark)

    Lager, Erik; Nilsson, Jakob; Nielsen, Elsebet Østergaard;

    2008-01-01

    The finding that alkyl 1,4-dihydro-4-oxoquinoline-3-carboxylate and N-alkyl-1,4-dihydro-4-oxoquinoline-3-carboxamide derivatives may be high-affinity ligands at the benzodiazepine binding site of the GABA(A) receptor, prompted a study of 3-acyl-1,4-dihydro-4-oxoquinoline (3-acyl-4-quinolones). In......- and a gamma-subunit in the GABA(A) receptor, selected compounds were tested on the alpha(1)beta(2)gamma(2s), alpha(2)beta(2)gamma(2s) and alpha(3)beta(2)gamma(2s) GABA(A) receptor subtypes. The 3-acyl-4-quinolones display various degrees of selectivity for alpha(1)- versus alpha(2)- and alpha(3...

  6. Decrease in benzodiazepine receptor binding in a patient with Angelman syndrome detected by iodine-123 iomazenil and single-photon emission tomography

    International Nuclear Information System (INIS)

    A receptor mapping technique using iodine-123 iomazenil and single-photon emission tomography (SPET) was employed to examine benzodiazepine receptor binding in a patient with Angelman syndrome (AS). AS is characterized by developmental delay, seizures, inappropriate laughter and ataxic movement. In this entity there is a cytogenic deletion of the proximal long arm of chromosome 15q11-q13, where the gene encoding the GABAA receptor β3 subunit (GABRB3) is located. Since the benzodiazepine receptor is constructed as a receptor-ionophore complex that contains the GABAA receptor, it is a suitable marker for GABA-ergic synapsis. To determine whether benzodiazepine receptor density, which indirectly indicates changes in GABAA receptor density, is altered in the brain in patients with AS, we investigated a 27-year-old woman with AS using 123I-iomazenil and SPET. Receptor density was quantitatively assessed by measuring the binding potential using a simplified method. Regional cerebral blood flow was also measured with N-isopropyl-p-123 iodoamphetamine. We demonstrated that benzodiazepiine receptor density is severely decreased in the cerebellum, and mildly decreased in the frontal and temporal cortices and basal ganglia, a result which is considered to indicate decreased GABAA receptor density in these regions. Although the deletion of GABRB3 was not observed in the present study, we indirectly demonstrated the disturbance of inhibitory neurotransmission mediated by the GABAA receptor in the investigated patient. 123I-iomazenil with SPET was useful to map benzodiazepine receptors, which indicate GABAA receptor distribution and their density. (orig.)

  7. Radiosynthesis and initial evaluation of [{sup 18}F]-FEPPA for PET imaging of peripheral benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Alan A. [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8 (Canada)], E-mail: alan.wilson@camhpet.ca; Garcia, Armando; Parkes, Jun [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); McCormick, Patrick [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Institute of Medical Science, University of Toronto, Toronto, Ontario, M5S 1A8 (Canada); Stephenson, Karin A. [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Houle, Sylvain; Vasdev, Neil [PET Centre, Centre for Addiction and Mental Health, Toronto, Ontario, M5T 1R8 (Canada); Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8 (Canada)

    2008-04-15

    Introduction: A novel [{sup 18}F]-radiolabelled phenoxyanilide, [{sup 18}F]-FEPPA, has been synthesized and evaluated, in vitro and ex vivo, as a potential positron emission tomography imaging agent for the peripheral benzodiazepine receptor (PBR). Methods: [{sup 18}F]-FEPPA and two other radiotracers for imaging PBR, namely [{sup 11}C]-PBR28 and [{sup 11}C]-PBR28-d3, were synthesised and evaluated in vitro and ex vivo as potential PBR imaging agents. Results: [{sup 18}F]-FEPPA is efficiently prepared in one step from its tosylate precursor and [{sup 18}F]-fluoride in high radiochemical yields and at high specific activity. FEPPA displayed a K{sub i} of 0.07 nM for PBR in rat mitochondrial membrane preparations and a suitable lipophilicity for brain penetration (log P of 2.99 at pH 7.4). Upon intravenous injection into rats, [{sup 18}F]-FEPPA showed moderate brain uptake [standard uptake value (SUV) of 0.6 at 5 min] and a slow washout (SUV of 0.35 after 60 min). Highest uptake of radioactivity was seen in the hypothalamus and olfactory bulb, regions previously reported to be enriched in PBR in rat brain. Analysis of plasma and brain extracts demonstrated that [{sup 18}F]-FEPPA was rapidly metabolized, but no lipophilic metabolites were observed in either preparation and only 5% radioactive metabolites were present in brain tissue extracts. Blocking studies to determine the extent of specific binding of [{sup 18}F]-FEPPA in rat brain were problematic due to large perturbations in circulating radiotracer and the lack of a reference region. Conclusions: Further evaluation of the potential of [{sup 18}F]-FEPPA will require the employment of rigorous kinetic models and/or appropriate animal models.

  8. Stress-related changes of benzodiazepine binding inhibitory activity (B.B.I.A.) in humans.

    Science.gov (United States)

    Marazziti, D; Michelini, S; Giannaccini, G; Martini, C; Castrogiovanni, P; Cassano, G B; Lucacchini, A

    1990-01-01

    The presence of benzodiazepine binding inhibitory activity (B.B.I.A.) in sera from 44 psychiatric patients and from 14 healthy volunteers, prompted us to investigate whether or not this activity underwent changes in stressful situations. We measured the inhibitory units (IU) of deproteinized sera of 12 subjects, immediately before and 2 weeks after sitting for a difficult university exam. Our results showed significantly higher IU values (i.e., higher B.B.I.A. concentrations) in the samples taken just before the exam. This preliminary finding clearly suggests the involvement of B.B.I.A. in anxiety mechanisms. PMID:2362542

  9. [Benzodiazepine and nonbenzodiazepine hypnotics].

    Science.gov (United States)

    Nakamura, Masaki; Inoue, Yuichi

    2015-06-01

    The prevalence of insomnia shows an age-associated increase. Especially, persons with age over 60 years frequently suffer from arousal during sleep and early-morning awakening. The reason of this phenomenon can be explained by age-related change in sleepwake regulation, comorbid diseases and psycho-social status. Benzodiazepine derivatives and benzodiazepine agonists have been widely used for treatment of insomnia. These GABA-A receptor agonist hypnotics have sedative effect, possibly causing various adverse events, i.e. falls and hip fracture, anterograde amnesia, next morning hangover especially in the elderly. When making a choice of treatment drugs for the elderly, low dose benzodiazepine hypnotics with relatively high Ω1-selectivity, and newer hypnotics including melatonic receptor agonist or orexin receptor antagonist can become important candidates considering their comorbid diseases or drug interaction with other medications. PMID:26065134

  10. {sup 125}I-iomazenil - benzodiazepine receptor binding and serum corticosterone level during psychological stress in a rat model

    Energy Technology Data Exchange (ETDEWEB)

    Fukumitsu, Nobuyoshi E-mail: GZL13162@nifty.ne.jp; Ogi, Shigeyuki; Uchiyama, Mayuki; Mori, Yutaka

    2004-02-01

    To test the hypothesis that benzodiazepine receptor density decreases in response to stress, we correlated {sup 125}I-iomazenil ({sup 125}I-IMZ) binding with serum corticosterone levels in a rat model. Wistar male rats were divided into four groups; control group (CON, 10 rats), no physical or psychological stress; and one-, three-, and five-day stress groups of 12 rats each (1-DAY, 3-DAY, and 5-DAY, respectively), receiving psychological stress for the given number of days. Psychological stress were given to rats with a communication box. The standardized uptake value (SUV) of {sup 125}I-iomazenil of the 3-DAY and 5-DAY showed that {sup 125}I-iomazenil - benzodiazepine receptor binding was significantly reduced in the cortices, accumbens nuclei, amygdala and caudate putamen (p<0.05). Serum corticosterone level ratio appeared to be slightly elevated in 3-DAY and 5-DAY, although this elevation was not significant. These data suggest that {sup 125}I-IMZ is a useful radioligand to reflect received stress and its binding in the cortices, accumbens nuclei, amygdala and caudate putamen is strongly affected by psychological stress.

  11. Molecular mechanisms of benzodiazepine-induced down-regulation of GABAA receptor alpha 1 subunit protein in rat cerebellar granule cells.

    OpenAIRE

    Brown, M. J.; Bristow, D. R.

    1996-01-01

    1. Chronic benzodiazepine treatment of rat cerebellar granule cells induced a transient down-regulation of the gamma-aminobutyric acidA (GABAA) receptor alpha 1 subunit protein, that was dose-dependent (1 nM-1 microM) and prevented by the benzodiazepine antagonist flumazenil (1 microM). After 2 days of treatment with 1 microM flunitrazepam the alpha 1 subunit protein was reduced by 41% compared to untreated cells, which returned to, and remained at, control cell levels from 4-12 days of treat...

  12. (/sup 3/H)Clonazepam, like (/sup 3/H)flunitrazepam, is a photoaffinity label for the central type of benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Sieghart, W. (Vienna Univ. (Austria)); Moehler, H. (Hoffmann-La Roche (F.) and Co., Basel (Switzerland))

    1982-06-16

    (/sup 3/H)Clonazepam, like (/sup 3/H)flunitrazepam, is irreversibly bound to membrane proteins of brain tissue when exposed to UV light. In polyacrylamide gel electrophoresis followed by fluorography, the same pattern of photolabelled proteins was obtained in cerebellum and in hippocampus when either (/sup 3/H)clonazepam or (/sup 3/H)flunitrazepam was used as photoaffinity label. Since (/sup 3/H)clonazepam does not interact with the peripheral type of benzodiazepine binding site present in the brain, these results confirm previous evidence that the proteins photolabelled with (/sup 3/H)flunitrazepam are associated with the central type of benzodiazepine receptor.

  13. Characterisation of the contribution of the GABA-benzodiazepine α1 receptor subtype to [11C]Ro15-4513 PET images

    Science.gov (United States)

    Myers, James FM; Rosso, Lula; Watson, Ben J; Wilson, Sue J; Kalk, Nicola J; Clementi, Nicoletta; Brooks, David J; Nutt, David J; Turkheimer, Federico E; Lingford-Hughes, Anne R

    2012-01-01

    This positron emission tomography (PET) study aimed to further define selectivity of [11C]Ro15-4513 binding to the GABARα5 relative to the GABARα1 benzodiazepine receptor subtype. The impact of zolpidem, a GABARα1-selective agonist, on [11C]Ro15-4513, which shows selectivity for GABARα5, and the nonselective benzodiazepine ligand [11C]flumazenil binding was assessed in humans. Compartmental modelling of the kinetics of [11C]Ro15-4513 time-activity curves was used to describe distribution volume (VT) differences in regions populated by different GABA receptor subtypes. Those with low α5 were best fitted by one-tissue compartment models; and those with high α5 required a more complex model. The heterogeneity between brain regions suggested spectral analysis as a more appropriate method to quantify binding as it does not a priori specify compartments. Spectral analysis revealed that zolpidem caused a significant VT decrease (∼10%) in [11C]flumazenil, but no decrease in [11C]Ro15-4513 binding. Further analysis of [11C]Ro15-4513 kinetics revealed additional frequency components present in regions containing both α1 and α5 subtypes compared with those containing only α1. Zolpidem reduced one component (mean±s.d.: 71%±41%), presumed to reflect α1-subtype binding, but not another (13%±22%), presumed to reflect α5. The proposed method for [11C]Ro15-4513 analysis may allow more accurate selective binding assays and estimation of drug occupancy for other nonselective ligands. PMID:22214903

  14. Effects of LiCl/pilocarpine-induced status epilepticus on rat brain mu and benzodiazepine receptor binding: Regional and ontogenetic studies

    Czech Academy of Sciences Publication Activity Database

    Rocha, L.; Suchomelová, Lucie; Mareš, Pavel; Kubová, Hana

    2007-01-01

    Roč. 1181, - (2007), s. 104-117. ISSN 0006-8993 R&D Projects: GA MŠk(CZ) LC554; GA ČR GA304/05/2582 Grant ostatní: CONACyT(MX) 45943-M Institutional research plan: CEZ:AV0Z50110509 Keywords : benzodiazepine receptor * µ receptor binding * status epilepticus Subject RIV: ED - Physiology Impact factor: 2.218, year: 2007

  15. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, J.; Kuriyama, K. (Kyoto Prefectural Univ. of Medicine (Japan))

    1990-05-01

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited (3H)flunitrazepam binding to benzodiazepine receptor, but not (3H)muscimol binding to GABAA receptor as well as t-(3H)butylbicycloorthobenzoate (( 3H) TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively (3H) flunitrazepam binding. On the other hand, the binding of beta-(3H)CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated (3H)muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-(3H)CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for (3H)flunitrazepam, (3H)muscimol and (3H)TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested.

  16. Functional modulation of cerebral gamma-aminobutyric acidA receptor/benzodiazepine receptor/chloride ion channel complex with ethyl beta-carboline-3-carboxylate: Presence of independent binding site for ethyl beta-carboline-3-carboxylate

    International Nuclear Information System (INIS)

    Effect of ethyl beta-carboline-3-carboxylate (beta-CCE) on the function of gamma-aminobutyric acid (GABA)A receptor/benzodiazepine receptor/chloride ion channel complex was studied. Beta-CCE noncompetitively and competitively inhibited [3H]flunitrazepam binding to benzodiazepine receptor, but not [3H]muscimol binding to GABAA receptor as well as t-[3H]butylbicycloorthobenzoate [( 3H] TBOB) binding to chloride ion channel, in particulate fraction of the mouse brain. Ro15-1788 also inhibited competitively [3H] flunitrazepam binding. On the other hand, the binding of beta-[3H]CCE was inhibited noncompetitively and competitively by clonazepam and competitively by Ro15-1788. In agreement with these results, benzodiazepines-stimulated [3H]muscimol binding was antagonized by beta-CCE and Ro15-1788. Gel column chromatography for the solubilized fraction from cerebral particulate fraction by 0.2% sodium deoxycholate (DOC-Na) in the presence of 1 M KCl indicated that beta-[3H]CCE binding site was eluted in the same fraction (molecular weight, 250,000) as the binding sites for [3H]flunitrazepam, [3H]muscimol and [3H]TBOB. GABA-stimulated 36Cl- influx into membrane vesicles prepared from the bovine cerebral cortex was stimulated and attenuated by flunitrazepam and beta-CCE, respectively. These effects of flunitrazepam and beta-CCE on the GABA-stimulated 36Cl- influx were antagonized by Ro15-1788. The present results suggest that the binding site for beta-CCE, which resides on GABAA receptor/benzodiazepine receptor/chloride ion channel complex, may be different from that for benzodiazepine. Possible roles of beta-CCE binding site in the allosteric inhibitions on benzodiazepine binding site as well as on the functional coupling between chloride ion channel and GABAA receptor are also suggested

  17. Benzodiazepines: rat pinealocyte binding sites and augmentation of norepinephrine-stimulated N-acetyltransferase activity

    Energy Technology Data Exchange (ETDEWEB)

    Matthew, E.; Parfitt, A.G.; Sugden, D.; Engelhardt, D.L.; Zimmerman, E.A.; Klein, D.C.

    1984-02-01

    Studies of (/sup 3/H)diazepam binding to intact rat pineal cells were carried out in tissue culture preparations. The binding was saturable, reversible and proportional to the number of cells used. Scatchard analysis resulted in a linear plot (Kd . 23 nM, maximum binding sites (Bmax) . 1.56 pmol/mg of protein for cells in monolayer culture; Kd . 7 nM, Bmax . 1.3 pmol/mg of protein for cells in suspension culture). Inhibition constants (Ki) for clonazepam (500 nM), flunitrazepam (38 nM) and Ro-5-4864 (5 nM) indicated that the binding sites were probably of the ''peripheral'' type. In addition, the effects of diazepam on norepinephrine-stimulated N-acetyltransferase (NAT) activity were studied in organ culture and dissociated cell culture. Diazepam (10-50 microM) both prolonged and increased the magnitude of the norepinephrine-induced increase in NAT activity but did not affect the initial rate of rise of enzyme activity. The effect was dose-dependent and was also seen with clonazepam, flunitrazepam and Ro-5-4864, but not with Ro-15-1788. Diazepam, by itself, at these concentrations, had no effect on NAT, but enzyme activity was increased by higher concentrations (0.1-1 mM). Although a relationship between the (/sup 3/H)diazepam binding sites described here and the effect of benzodiazepines on NAT cannot be established from these studies, the data suggest that the benzodiazepines may alter melatonin levels through their action on NAT.

  18. Benzodiazepines: rat pinealocyte binding sites and augmentation of norepinephrine-stimulated N-acetyltransferase activity

    International Nuclear Information System (INIS)

    Studies of [3H]diazepam binding to intact rat pineal cells were carried out in tissue culture preparations. The binding was saturable, reversible and proportional to the number of cells used. Scatchard analysis resulted in a linear plot [Kd . 23 nM, maximum binding sites (Bmax) . 1.56 pmol/mg of protein for cells in monolayer culture; Kd . 7 nM, Bmax . 1.3 pmol/mg of protein for cells in suspension culture]. Inhibition constants (Ki) for clonazepam (500 nM), flunitrazepam (38 nM) and Ro-5-4864 (5 nM) indicated that the binding sites were probably of the ''peripheral'' type. In addition, the effects of diazepam on norepinephrine-stimulated N-acetyltransferase (NAT) activity were studied in organ culture and dissociated cell culture. Diazepam (10-50 microM) both prolonged and increased the magnitude of the norepinephrine-induced increase in NAT activity but did not affect the initial rate of rise of enzyme activity. The effect was dose-dependent and was also seen with clonazepam, flunitrazepam and Ro-5-4864, but not with Ro-15-1788. Diazepam, by itself, at these concentrations, had no effect on NAT, but enzyme activity was increased by higher concentrations (0.1-1 mM). Although a relationship between the [3H]diazepam binding sites described here and the effect of benzodiazepines on NAT cannot be established from these studies, the data suggest that the benzodiazepines may alter melatonin levels through their action on NAT

  19. SPECT imaging of GABA{sub A}/benzodiazepine receptors and cerebral perfusion in mild cognitive impairment

    Energy Technology Data Exchange (ETDEWEB)

    Pappata, Sabina; Varrone, Andrea; Vicidomini, Caterina; Sansone, Valeria; Comerci, Marco; Panico, Maria Rosaria; Quarantelli, Mario [CNR, Institute of Biostructure and Bioimaging, Naples (Italy); Milan, Graziella; De Falco, Caterina; Lore, Elisa; Postiglione, Alfredo [University ' ' Federico II' ' , Department of Clinical and Experimental Medicine, Naples (Italy); Iavarone, Alessandro [Neurologic and Stroke Unit, CTO Hospital, Naples (Italy); Salvatore, Marco [CNR, Institute of Biostructure and Bioimaging, Naples (Italy); University ' ' Federico II' ' , Department of Biomorphological and Functional Sciences, Naples (Italy)

    2010-06-15

    The involvement of neocortical and limbic GABA{sub A}/benzodiazepine (BZD) receptors in Alzheimer's disease (AD) is controversial and mainly reported in advanced stages. The status of these receptors in the very early stages of AD is unclear and has not been explored in vivo. Our aims were to investigate in vivo the integrity of cerebral cortical GABA{sub A}/BZD receptors in subjects with amnestic mild cognitive impairment (MCI) and to compare possible receptor changes to those in cerebral perfusion. [{sup 123}I]Iomazenil and [{sup 99m}Tc]HMPAO SPECT images were acquired in 16 patients with amnestic MCI and in 14 normal elderly control subjects (only [{sup 123}I]iomazenil imaging in 5, only [{sup 99m}Tc]HMPAO imaging in 4, and both [{sup 123}I]iomazenil and [{sup 99m}Tc]HMPAO imaging in 5). Region of interest (ROI) analysis and voxel-based analysis were performed with cerebellar normalization. Neither ROI analysis nor voxel-based analysis showed significant [{sup 123}I]iomazenil binding changes in MCI patients compared to control subjects, either as a whole group or when considering only those patients with MCI that converted to AD within 2 years of clinical follow-up. In contrast, the ROI analysis revealed significant hypoperfusion of the precuneus and posterior cingulate cortex in the whole group of MCI patients and in MCI converters as compared to control subjects. Voxel-based analysis showed similar results. These results indicate that in the very early stages of AD, neocortical and limbic neurons/synapses expressing GABA{sub A}/BZD receptors are essentially preserved. They suggest that in MCI patients functional changes precede neuronal/synaptic loss in neocortical posterior regions and that [{sup 99m}Tc]HMPAO rCBF imaging is more sensitive than [{sup 123}I]iomazenil GABA{sub A}/BZD receptor imaging in detecting prodromal AD. (orig.)

  20. Development of 123I-labelled NNC 13-8241 as a radioligand for SPECT visualization of benzodiazepine receptor binding

    International Nuclear Information System (INIS)

    [125I]- and [123I]NNC 13-8241 were prepared from the trimethyltin precursor and radioactive iodide using the chloramine-T method. The total radiochemical yields of [125I]- and [123I]NNC 13-8241 were 60-70% and 40-50% respectively, with radiochemical purity higher than 98%. In binding studies with [125I]NNC 13-8241 in rats in vitro and in vivo a high uptake of radioactivity was demonstrated in brain regions known to have a high density of benzodiazepine (BZ) receptors such as the occipital and frontal cortex. SPECT examination with [123I]NNC 13-8241 in a Cynomolgus monkey demonstrated a high uptake of radioactivity in the occipital and frontal cortex. After displacement with flumazenil radioactivity in these brain regions was reduced to the level of a central region including the pons. Four hours after injection about 80% of the radioactivity in monkey plasma represented unchanged radioligand. This low degree of metabolism indicates that NNC 13-8241 is metabolically more stable than the radioligands hitherto developed for imaging of BZ-receptors in the primate brain

  1. Alterations of benzodiazepine receptor binding potential in anxiety and somatoform disorders measured by 123I-iomazenil SPECT

    International Nuclear Information System (INIS)

    123I-iomazenil (IMZ), a newly developed radioligand which acts on benzodiazepine receptors (BZR) as a partial inverse agonist, made it possible to evaluate the function of central BZR by single photon emission tomography (SPECT). To examine the alterations of the binding potential (BP) in the anxiety state, 123I-IMZ SPECT was performed in five patients with anxiety and somatoform disorders, and five epileptic patients without anxiety symptoms served as a reference. The BP of BZR was determined by using a table look-up procedure based on a three-compartment, two-parameter model in the bilateral superior frontal, inferior frontal, temporal, parietal, occipital, and cerebellar cortex. The mean BP of patients with anxiety and somatoform disorders was significantly decreased in the superior frontal, temporal, and parietal cortex, in comparison with that of epileptic patients. A significant correlation was observed between the anxiety levels scored on the Hamilton anxiety scale and BP in the right temporal cortex and left superior frontal cortex. These changes in BZR revealed by SPECT suggest the usefulness of 123I-IMZ SPECT to objectively evaluate anxiety levels in patients with anxiety symptoms. (author)

  2. Experiment K-6-18. Study of muscarinic and gaba (benzodiazepine) receptors in the sensory-motor cortex, hippcampus and spinal code

    Science.gov (United States)

    Daunton, N.; Damelio, F.; Krasnov, I.

    1990-01-01

    Frontal lobe samples of rat brains flown aboard Cosmos 1887 were processed for the study of muscarinic (cholinergic) and GABA (benzodiazepine) receptors and for immunocytochemical localization of the neurotransmitter gamma-aminobutyric acid (GABA) and glial fibrillary acidic protein (GFAP). Although radioactive labeling of both muscarinic cholinergic and GABA (benzodiazepine) receptors proved to be successful with the techniques employed, distinct receptor localization of individual laminae of the frontal neocortex was not possible since the sampling of the area was different in the various groups of animals. In spite of efforts made for proper orientation and regional identification of laminae, it was found that a densitometric (quantitation of autoradiograms) analysis of the tissue did not contribute to the final interpretation of the effects of weightlessness on these receptors. As to the immunocytochemical studies the use of both markers, GFAP and GABA antiserum, confirmed the suitability of the techniques for use in frozen material. However, similar problems to those encountered in the receptor studies prevented an adequate interpretation of the effects of micro-G exposure on the localization and distribution of GABA and GFAP. This study did, however, confirm the feasibility of investigating neurotransmitters and their receptors in future space flight experiments.

  3. Human locus coeruleus neurons express the GABAA receptor γ2 subunit gene and produce benzodiazepine binding

    OpenAIRE

    Hellsten, Kati S.; Sinkkonen, Saku T.; Hyde, Thomas M.; Kleinman, Joel E.; Särkioja, Terttu; Maksimow, Anu; Uusi-Oukari, Mikko; Korpi, Esa R.

    2010-01-01

    Noradrenergic neurons of the locus coeruleus project throughout the cerebral cortex and multiple subcortical structures. Alterations in the locus coeruleus firing are associated with vigilance states and with fear and anxiety disorders. Brain ionotropic type A receptors for γ-aminobutyric acid (GABA) serve as targets for anxiolytic and sedative drugs, and play an essential regulatory role in the locus coeruleus. GABAA receptors are composed of a variable array of subunits forming heteropentam...

  4. Different effects of long-term haloperidol administration on GABA/sub A/ and benzodiazepine receptors in various parts of the brain

    International Nuclear Information System (INIS)

    The data described in this paper are evidence that long-term administration of haloperidol has an opposite effect on the density of GABA/sub A/ and benzodiazepine receptors in the fore- and hindbrain. These changes are reflected at the molecular level as reversal of behavioral effect of the GABA/sub A/ agonist muscimol and the benzodiazepine agonist Ro15-1788. By means of parallel behavioral tests, binding of 3H-muscimol in the fore- and hindbrain of rats was investigated in experiments in vitro. 3H-flunitrazepam binding experiments were carried out in vivo on mice. Parallel with reversal of the behavioral effects of muscimol and Ro15-1788, the number of binding sites both for 3H-muscimol and for 3H-flunitrazepam in the forebrain was reduced; in the hindbrain the opposite process took place

  5. The 1,4-benzodiazepine Ro5-4864 (4-chlorodiazepam) suppresses multiple pro-inflammatory mast cell effector functions

    OpenAIRE

    Yousefi, Omid Sascha; Wilhelm, Thomas; Maschke-Neuß, Karin; Kuhny, Marcel; Martin, Christian; Molderings, Gerhard J; Kratz, Felix; Hildenbrand, Bernd; Huber, Michael

    2013-01-01

    Activation of mast cells (MCs) can be achieved by the high-affinity receptor for IgE (FcεRI) as well as by additional receptors such as the lipopolysaccharide (LPS) receptor and the receptor tyrosine kinase Kit (stem cell factor [SCF] receptor). Thus, pharmacological interventions which stabilize MCs in response to different receptors would be preferable in diseases with pathological systemic MC activation such as systemic mastocytosis. 1,4-Benzodiazepines (BDZs) have been reported to suppres...

  6. Biodistribution and dosimetry of [123I]iodo-Pk 11195: a potential agent for SPET imaging of the peripheral benzodiazepine receptor

    International Nuclear Information System (INIS)

    The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidneys and heart. In addition, the PBR has been reported to reflect neuro-inflammatory damage by co-localisation with activated microglia. PK 11195 is a high-affinity ligand for the PBR. The aim of this study was to investigate in humans the biodistribution and dosimetry of [123I]iodo-PK 11195, a potential single-photon emission tomography tracer for the PBR. Five healthy volunteers were injected with 112 MBq of [123I]iodo-PK 11195. Sequential whole-body scans were performed up to 72 h post injection. Multiple blood samples were taken, and urine was collected to measure the fraction voided by the renal system. Decay-corrected regions of interest of the whole-body images were analysed, and geometric mean count rates were used to determine organ activity. Organ absorbed doses and effective dose were calculated using the MIRD method. [123I]iodo-PK 11195 was rapidly cleared from the blood, mainly by the hepatobiliary system. Approximately 22% was voided in urine after 48 h. Average organ residence times were 0.74, 0.44 and 0.29 h for the liver, upper large intestine and lower large intestine, respectively. The testes received the highest dose, 109.4 μGy/MBq. All other organs investigated received doses of less than 50 μGy/MBq. The effective dose was 40.3 μSv/MBq. In conclusion, [123I]iodo-PK 11195 is a suitable agent for the visualisation of the PBR and indirectly for the imaging of neuro-inflammatory lesions. Taking into account the radiation burden of 7.46 mSv following an administration of 185 MBq, a [123I]iodo-PK 11195 investigation has to be considered an ICRP risk category IIb investigation. (orig.)

  7. Biodistribution and dosimetry of [{sup 123}I]iodo-Pk 11195: a potential agent for SPET imaging of the peripheral benzodiazepine receptor

    Energy Technology Data Exchange (ETDEWEB)

    Versijpt, J. [Groningen Univ. Hospital (Netherlands). Dept. of Biological Psychiatry; Div. of Nuclear Medicine, Ghent Univ. Hospital (Belgium); Dumont, F.; Vos, F. de; Slegers, G. [Dept. of Radiopharmacy, Ghent Univ. (Belgium); Thierens, H. [Dept. of Biomedical Physics and Radiation Protection, Ghent Univ. (Belgium); Jansen, H.; Dierckx, R.A. [Div. of Nuclear Medicine, Ghent Univ. Hospital (Belgium); Santens, P. [Dept. of Neurology, Ghent Univ. Hospital (Belgium); Korf, J. [Groningen Univ. Hospital (Netherlands). Dept. of Biological Psychiatry

    2000-09-01

    The highest concentrations of the peripheral benzodiazepine receptor (PBR) are found in the kidneys and heart. In addition, the PBR has been reported to reflect neuro-inflammatory damage by co-localisation with activated microglia. PK 11195 is a high-affinity ligand for the PBR. The aim of this study was to investigate in humans the biodistribution and dosimetry of [{sup 123}I]iodo-PK 11195, a potential single-photon emission tomography tracer for the PBR. Five healthy volunteers were injected with 112 MBq of [{sup 123}I]iodo-PK 11195. Sequential whole-body scans were performed up to 72 h post injection. Multiple blood samples were taken, and urine was collected to measure the fraction voided by the renal system. Decay-corrected regions of interest of the whole-body images were analysed, and geometric mean count rates were used to determine organ activity. Organ absorbed doses and effective dose were calculated using the MIRD method. [{sup 123}I]iodo-PK 11195 was rapidly cleared from the blood, mainly by the hepatobiliary system. Approximately 22% was voided in urine after 48 h. Average organ residence times were 0.74, 0.44 and 0.29 h for the liver, upper large intestine and lower large intestine, respectively. The testes received the highest dose, 109.4 {mu}Gy/MBq. All other organs investigated received doses of less than 50 {mu}Gy/MBq. The effective dose was 40.3 {mu}Sv/MBq. In conclusion, [{sup 123}I]iodo-PK 11195 is a suitable agent for the visualisation of the PBR and indirectly for the imaging of neuro-inflammatory lesions. Taking into account the radiation burden of 7.46 mSv following an administration of 185 MBq, a [{sup 123}I]iodo-PK 11195 investigation has to be considered an ICRP risk category IIb investigation. (orig.)

  8. Midazolam ameliorates the behavior deficits of a rat posttraumatic stress disorder model through dual 18 kDa translocator protein and central benzodiazepine receptor and neurosteroidogenesis.

    Directory of Open Access Journals (Sweden)

    Yu-Liang Miao

    Full Text Available Post-traumatic stress disorder (PTSD is a debilitating anxiety disorder that may develop after an individual has experienced or witnessed a severe traumatic event. It has been shown that the 18 kDa translocator protein (TSPO may be correlated with PTSD and that the TSPO ligand improved the behavioral deficits in a mouse model of PTSD. Midazolam, a ligand for TSPO and central benzodiazepine receptor (CBR, induces anxiolytic- and anti-depressant-like effects in animal models. The present study aimed to determine whether midazolam ameliorates PTSD behavior in rats as assessed by the single prolonged stress (SPS model. The SPS rats received daily Sertraline (Ser (15 mg/kg, i.p. [corrected] and midazolam (0.125, 0.25, 0.5, and 1 mg/kg, i.p. [corrected] during the exposure to SPS and behavioral assessments, which included the open field (OF test, the contextual fear paradigm (CFP, and the elevated plus-maze (EPM. The results showed that, like Ser (15 mg/kg, i.p. [corrected], midazolam (0.25 and 0.5 mg/kg, i.p. [corrected] significantly reversed the behavioral deficiencies of the SPS rats, including PTSD-associated freezing and anxiety-like behavior but not the effects on spontaneous locomotor activity. In addition, the anti-PTSD effects of midazolam (0.5 mg/kg, i.p. [corrected] were antagonized by the TSPO antagonist PK11195 (3 mg/kg, i.p., the CBR antagonist flumazenil (15 mg/kg, i.p. [corrected] and the inhibitor of steroidogenic enzymes finasteride (30 mg/kg, i.p. [corrected], which by themselves had no effect on PTSD-associated freezing and anxiety-like behavior. In summary, this study demonstrated that midazolam improves the behavioral deficits in the SPS model through dual TSPO and CBR and neurosteroidogenesis.

  9. Evaluation of a radiolabelled peripheral benzodiazepine receptor ligand in the central nervous system inflammation of experimental autoimmune encephalomyelitis: a possible probe for imaging multiple sclerosis

    International Nuclear Information System (INIS)

    Peripheral benzodiazepine receptors (PBRs) are upregulated on macrophages and activated microglia, and radioligands for the PBRs can be used to detect in vivo neuroinflammatory changes in a variety of neurological insults, including multiple sclerosis. Substituted 2-phenyl imidazopyridine-3-acetamides with high affinity and selectivity for PBRs have been prepared that are suitable for radiolabelling with a number of positron emission tomography and single-photon emission computed tomography (SPECT) isotopes. In this investigation, the newly developed high-affinity PBR ligand 6-chloro-2-(4'-iodophenyl)-3-(N,N-diethyl)imidazo [1,2-a]pyridine-3-acetamide, or CLINDE, was radiolabelled with123I and its biodistribution in the central nervous system (CNS) of rats with experimental autoimmune encephalomyelitis (EAE) evaluated. EAE was induced in male Lewis rats by injection of an emulsion of myelin basic protein and incomplete Freund's adjuvant containing Mycobacterium butyricum. Biodistribution studies with123I-CLINDE were undertaken on EAE rats exhibiting different clinical disease severity and compared with results in controls. Disease severity was confirmed by histopathology in the spinal cord of rats. The relationship between inflammatory lesions and PBR ligand binding was investigated using ex vivo autoradiography and immunohistochemistry on rats with various clinical scores. 123I-CLINDE uptake was enhanced in the CNS of all rats exhibiting EAE when compared to controls. Binding reflected the ascending nature of EAE inflammation, with lumbar/sacral cord > thoracic cord > cervical cord > medulla. The amount of ligand binding also reflected the clinical severity of disease. Ex vivo autoradiography and immunohistochemistry revealed a good spatial correspondence between radioligand signal and foci of inflammation and in particular ED-1+ cells representing macrophages and microglia. These results demonstrate the ability of 123I-CLINDE to measure in vivo inflammatory

  10. PET and SPECT in medically non-refractory complex partial seizures. Temporal asymmetries of glucose consumption, Benzodiazepine receptor density

    International Nuclear Information System (INIS)

    Aim: In contrast to medically refractory complex partial seizures (CPS), only limited knowledge exists on cerebral perfusion and metabolism in medically non-refractory CPS. The aim of this study was to investigate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGlc), regional cerebral blood flow (rCBF), and regional cerebral benzodiazepine receptor density (BRD) in this group of patients. Methods: The study included 49 patients with medically non-refractory cryptogenic CPS (age: 36.0±16.1 years). rCMRGlc was studied with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD with I-123-iomazenil-SPECT (IMZ). All studies were performed interictally and within four weeks in each patient. Duration of epilepsy ranged from 0.1 to 42 years (median 4.0 years). SPECT was performed with the triple-headed SPECT camera Multispect 3, PET with the PET camera ECAT EXACT 47. Using linear profiles, glucose consumption, as well as uptake of ECD and IMZ, were measured in four temporal regions of interest (ROIs), and asymmetry indices were calculated (ASY). The results were compared to 95% confidence intervals determined in control subjects. Results: Thirty-five of the 49 (71%) patients had at least one significantly elevated ASY; temporal rCMRGlc was asymmetrical in 41% of the patients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of all three variables, two of temporal rCMRGlc and BRD, three of temporal rCMRGlc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGlc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. Conclusion: The majority of patients with medically non-refractory CPS have focal abnormalities of blood flow and metabolism in their temporal lobe. In this group of patients, FDG-PET demonstrates abnormalities with the highest frequency of the three modalities studied, followed by IMZ

  11. Research Progress in Physical Dependence of Benzodiazepine-type Drugs and Receptor Mechanism%苯二氮(艹卓)类药物的躯体依赖及受体机制研究进展

    Institute of Scientific and Technical Information of China (English)

    王丽华

    2011-01-01

    Prolonged use of benzodiazepines can lead to physical dependence. The diverse behavioral effects of benzodiazepines may reflect the actions on different subtypes of GABAA receptors. Benzodiazepine action appears to be determined by the presence of particular ct subunits. But a complex picture is emerging with respect to abuse of benzodiazepines and the roles of different GABAA receptor subtypes. Recent researches suggest an interaction with all GABAA receptor subtypes is required for physical dependence of benzodiazepines. This article reviews physical dependence of benzodiazepine and mediating GABAA receptor subunits.%苯二氮(艹卓)类药物的长期使用会使患者产生躯体依赖.不同的苯二氮(艹卓)类药物的行为效应可能由不同的GABAA受体亚单位介导.苯二氮(艹卓)类药物主要作用于特定的α亚单位.然而,苯二氮艹 卓类药物的滥用和不同的GABAA受体亚单位所起的作用之间却是复杂的.研究表明,苯二氮(艹卓)类药物躯体依赖的发生需要所有GABAA受体亚单位的相互作用.现重点介绍国内外有关苯二氮(艹卓)类药物的躯体依赖的产生,GABAA受体亚单位介导的苯二氮(艹卓)类药物的躯体依赖等研究情况.

  12. PET and SPECT in medically non-refractory complex partial seizures. Temporal asymmetries of glucose consumption, Benzodiazepine receptor density

    Energy Technology Data Exchange (ETDEWEB)

    Matheja, P.; Kuwert, T.; Wolf, K.; Schober, O. [Muenster Univ. (Germany). Kliniken und Polikliniken fuer Nuklearmedizin; Stodieck, S.R.G.; Diehl, B.; Ringelstein, E.B. [Muenster Univ. (Germany). Klinik fuer Neurologie; Schuierer, G. [Muenster Univ. (Germany). Inst. fuer Klinische Radiologie

    1998-12-31

    Aim: In contrast to medically refractory complex partial seizures (CPS), only limited knowledge exists on cerebral perfusion and metabolism in medically non-refractory CPS. The aim of this study was to investigate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGlc), regional cerebral blood flow (rCBF), and regional cerebral benzodiazepine receptor density (BRD) in this group of patients. Methods: The study included 49 patients with medically non-refractory cryptogenic CPS (age: 36.0{+-}16.1 years). rCMRGlc was studied with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD with I-123-iomazenil-SPECT (IMZ). All studies were performed interictally and within four weeks in each patient. Duration of epilepsy ranged from 0.1 to 42 years (median 4.0 years). SPECT was performed with the triple-headed SPECT camera Multispect 3, PET with the PET camera ECAT EXACT 47. Using linear profiles, glucose consumption, as well as uptake of ECD and IMZ, were measured in four temporal regions of interest (ROIs), and asymmetry indices were calculated (ASY). The results were compared to 95% confidence intervals determined in control subjects. Results: Thirty-five of the 49 (71%) patients had at least one significantly elevated ASY; temporal rCMRGlc was asymmetrical in 41% of the patients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of all three variables, two of temporal rCMRGlc and BRD, three of temporal rCMRGlc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGlc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. Conclusion: The majority of patients with medically non-refractory CPS have focal abnormalities of blood flow and metabolism in their temporal lobe. In this group of patients, FDG-PET demonstrates abnormalities with the highest frequency of the three modalities studied, followed by

  13. Benzodiazepine receptor and cerebral blood flow in early Alzheimer's disease. SPECT study using 123I-Iomazenil and 123I-IMP

    International Nuclear Information System (INIS)

    This study was designed to investigate benzodiazepine receptors (BZR) and cerebral blood flow (CBF) in patients with early Alzheimer's disease. Imaging of BZR and measurement of CBF were performed by SPECT using 123I-Iomazenil (IMZ) and 123I-IMP respectively, in seven patients with early Alzheimer's disease and five patients with unilateral left cerebral infarction as controls. The values for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with cerebral infarction were adopted as control values. In patients with Alzheimer's disease, the CBF (ratio to cerebellum) decreased significantly in the frontal cortex and the parietal cortex compared with the control values. There was no significant difference in late IMZ SPECT counts (ratio to cerebellum) and washout (the ratio of late-to-early IMZ SPECT counts) between patients with Alzheimer's disease and the controls. However, the late IMZ SPECT counts and washout decreased in one patient with moderate dementia. There was a significant correlation between the severity of dementia and the late IMZ SPECT counts in the temporal cortex and the parietal cortex. These results suggest that benzodiazepine binding sites are relatively well preserved in patients with early Alzheimer's disease, and reduction of the CBF is caused by neuronal dysfunction rather than by neuronal loss. IMZ SPECT study is useful and necessary for clarifying the pathophysiological state in Alzheimer's disease. (author)

  14. Benzodiazepine receptor and cerebral blood flow in early Alzheimer`s disease. SPECT study using {sup 123}I-Iomazenil and {sup 123}I-IMP

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Shin; Koshi, Yasuhiko; Komiyama, Tasuku; Sakayori, Osamu; Komaba, Yuichi; Ohyama, Masashi; Mishina, Masahiro; Tsuganesawa, Toshikazu; Terashi, Akiro [Nippon Medical School, Tokyo (Japan). First Hospital

    1996-01-01

    This study was designed to investigate benzodiazepine receptors (BZR) and cerebral blood flow (CBF) in patients with early Alzheimer`s disease. Imaging of BZR and measurement of CBF were performed by SPECT using {sup 123}I-Iomazenil (IMZ) and {sup 123}I-IMP respectively, in seven patients with early Alzheimer`s disease and five patients with unilateral left cerebral infarction as controls. The values for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with cerebral infarction were adopted as control values. In patients with Alzheimer`s disease, the CBF (ratio to cerebellum) decreased significantly in the frontal cortex and the parietal cortex compared with the control values. There was no significant difference in late IMZ SPECT counts (ratio to cerebellum) and washout (the ratio of late-to-early IMZ SPECT counts) between patients with Alzheimer`s disease and the controls. However, the late IMZ SPECT counts and washout decreased in one patient with moderate dementia. There was a significant correlation between the severity of dementia and the late IMZ SPECT counts in the temporal cortex and the parietal cortex. These results suggest that benzodiazepine binding sites are relatively well preserved in patients with early Alzheimer`s disease, and reduction of the CBF is caused by neuronal dysfunction rather than by neuronal loss. IMZ SPECT study is useful and necessary for clarifying the pathophysiological state in Alzheimer`s disease. (author).

  15. Studies on 'carrier-free' radiohalogenation of receptor-binding 1,4-benzodiazepines with 18F, 75Br and 123I

    International Nuclear Information System (INIS)

    The aim of this study was to label suitable benzodiazepine derivatives with the short-lived radionuclides F-18, Br-75 and I-123 in order to map the receptor areas of these compounds in-vivo by emission tomography. Selective labelling of the diazepines in the 7th position was achieved starting from the nitro compound and then carrying out reduction, diazotization and dediazotization via triazene decomposition. Greatest radio-chemical yields were achieved with the bromium derivative. This compound was tested with success in clinical trials. A detailed discussion is presented on the choice of diazapines, the reaction conditions and the analytical methods used. In view of the short half-lives of the halogens, the synthesis could be completed within an hour. (PW)

  16. Increased expression of mitochondrial benzodiazepine receptors following low-level light treatment facilitates enhanced protoporphyrin IX production in glioma-derived cells in vitro

    Science.gov (United States)

    Bisland, S. K.; Hassanali, N. S.; Johnson, C.; Wilson, B. C.

    2007-02-01

    This study investigates whether low level light treatment (LLLT) can enhance the expression of Peripheral-type mitochondrial benzodiazepine receptors (PBRs) on the glioma-derived tumour cell line, CNS-1, and by doing so promote the synthesis of protoporphyrin IX (PpIX) and increase the photodynamic therapy (PDT)-induced cell kill using 5-aminolevulinic acid (ALA). The endogenous photosensitizer, (PpIX) and related metabolites including coproporphyrin III are known to traffic via the PBRs on the outer mitochondrial membrane on their passage into or out of the mitochondria. Astrocyte-derived cells within the brain express PBRs, while neurons express the central-type of benzodiazepine receptor. CNS-1 cells were exposed to a range of differing low-level light protocols immediately prior to PDT. LLLT involved using broad-spectrum light or monochromatic laser light specific to 635 or 905 nm wavelength. Cells (5μ10 5) were exposed to a range of LLLT doses (0, 1 or 5 J/cm2) using a fixed intensity of 10 mW/cm2 and subsequently harvested for cell viability, immunofluorescence or western blot analysis of PBR expression. The amount of PpIX within the cells was determined using chemical extraction techniques. Results confirm the induction of PBR following LLLT is dependent on the dose and wavelength of light used. Broadspectrum light provided the greatest cell kill following PDT, although LLLT with 635 nm or 905 nm also increased cell kill as compared to PDT alone. All LLLT regimens increased PBR expression compared to controls with corresponding increases in PpIX production. These data suggest that by selectively increasing PBR expression in tumour cells, LLLT may facilitate enhanced cell kill using ALA-PDT without damaging surrounding normal brain.

  17. Using [(11)C]Ro15 4513 PET to characterise GABA-benzodiazepine receptors in opiate addiction: Similarities and differences with alcoholism.

    Science.gov (United States)

    Lingford-Hughes, Anne; Myers, James; Watson, Ben; Reid, Alastair G; Kalk, Nicola; Feeney, Adrian; Hammers, Alexander; Riaño-Barros, Daniela A; McGinnity, Colm J; Taylor, Lindsay G; Rosso, Lula; Brooks, David J; Turkheimer, Federico; Nutt, David J

    2016-05-15

    The importance of the GABA-benzodiazepine receptor complex and its subtypes are increasingly recognised in addiction. Using the α1/α5 benzodiazepine receptor PET radioligand [(11)C]Ro15 4513, we previously showed reduced binding in the nucleus accumbens and hippocampus in abstinent alcohol dependence. We proposed that reduced [(11)C]Ro15 4513 binding in the nucleus accumbens was a marker of addiction whilst the reduction in hippocampus and positive relationship with memory was a consequence of chronic alcohol abuse. To examine this further we assessed [(11)C]Ro15 4513 binding in another addiction, opiate dependence, and used spectral analysis to estimate contributions of α1 and α5 subtypes to [(11)C]Ro15 4513 binding in opiate and previously acquired alcohol-dependent groups. Opiate substitute maintained opiate-dependent men (n=12) underwent an [(11)C]Ro15 4513 PET scan and compared with matched healthy controls (n=13). We found a significant reduction in [(11)C]Ro15 4513 binding in the nucleus accumbens in the opiate-dependent compared with the healthy control group. There was no relationship between [(11)C]Ro15 4513 binding in the hippocampus with memory. We found that reduced [(11)C]Ro15 4513 binding was associated with reduced α5 but not α1 subtypes in the opiate-dependent group. This was also seen in an alcohol-dependent group where an association between memory performance and [(11)C]Ro15 4513 binding was primarily driven by α5 and not α1 subtype. We suggest that reduced α5 levels in the nucleus accumbens are associated with addiction since we have now shown this in dependence to two pharmacologically different substances, alcohol and opiates. PMID:26876472

  18. Using [11C]Ro15 4513 PET to characterise GABA-benzodiazepine receptors in opiate addiction: Similarities and differences with alcoholism

    Science.gov (United States)

    Lingford-Hughes, Anne; Myers, James; Watson, Ben; Reid, Alastair G.; Kalk, Nicola; Feeney, Adrian; Hammers, Alexander; Riaño-Barros, Daniela A.; McGinnity, Colm J.; Taylor, Lindsay G.; Rosso, Lula; Brooks, David J.; Turkheimer, Federico; Nutt, David J.

    2016-01-01

    The importance of the GABA-benzodiazepine receptor complex and its subtypes are increasingly recognised in addiction. Using the α1/α5 benzodiazepine receptor PET radioligand [11C]Ro15 4513, we previously showed reduced binding in the nucleus accumbens and hippocampus in abstinent alcohol dependence. We proposed that reduced [11C]Ro15 4513 binding in the nucleus accumbens was a marker of addiction whilst the reduction in hippocampus and positive relationship with memory was a consequence of chronic alcohol abuse. To examine this further we assessed [11C]Ro15 4513 binding in another addiction, opiate dependence, and used spectral analysis to estimate contributions of α1 and α5 subtypes to [11C]Ro15 4513 binding in opiate and previously acquired alcohol-dependent groups. Opiate substitute maintained opiate-dependent men (n = 12) underwent an [11C]Ro15 4513 PET scan and compared with matched healthy controls (n = 13). We found a significant reduction in [11C]Ro15 4513 binding in the nucleus accumbens in the opiate-dependent compared with the healthy control group. There was no relationship between [11C]Ro15 4513 binding in the hippocampus with memory. We found that reduced [11C]Ro15 4513 binding was associated with reduced α5 but not α1 subtypes in the opiate-dependent group. This was also seen in an alcohol-dependent group where an association between memory performance and [11C]Ro15 4513 binding was primarily driven by α5 and not α1 subtype. We suggest that reduced α5 levels in the nucleus accumbens are associated with addiction since we have now shown this in dependence to two pharmacologically different substances, alcohol and opiates. PMID:26876472

  19. Evaluation of a radiolabelled peripheral benzodiazepine receptor ligand in the central nervous system inflammation of experimental autoimmune encephalomyelitis: a possible probe for imaging multiple sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Mattner, F.; Katsifis, A.; Ballantyne, P. [ANSTO, Radiopharmaceuticals Division, Lucas Heights (Australia); Staykova, M.; Willenborg, D.O. [Australian National University Medical School, The Canberra Hospital, Neurosciences Research Unit, Woden, Canberra (Australia)

    2005-04-01

    Peripheral benzodiazepine receptors (PBRs) are upregulated on macrophages and activated microglia, and radioligands for the PBRs can be used to detect in vivo neuroinflammatory changes in a variety of neurological insults, including multiple sclerosis. Substituted 2-phenyl imidazopyridine-3-acetamides with high affinity and selectivity for PBRs have been prepared that are suitable for radiolabelling with a number of positron emission tomography and single-photon emission computed tomography (SPECT) isotopes. In this investigation, the newly developed high-affinity PBR ligand 6-chloro-2-(4'-iodophenyl)-3-(N,N-diethyl)imidazo[1,2-a]pyridine-3-acetamide, or CLINDE, was radiolabelled with{sup 123}I and its biodistribution in the central nervous system (CNS) of rats with experimental autoimmune encephalomyelitis (EAE) evaluated. EAE was induced in male Lewis rats by injection of an emulsion of myelin basic protein and incomplete Freund's adjuvant containing Mycobacterium butyricum. Biodistribution studies with{sup 123}I-CLINDE were undertaken on EAE rats exhibiting different clinical disease severity and compared with results in controls. Disease severity was confirmed by histopathology in the spinal cord of rats. The relationship between inflammatory lesions and PBR ligand binding was investigated using ex vivo autoradiography and immunohistochemistry on rats with various clinical scores. {sup 123}I-CLINDE uptake was enhanced in the CNS of all rats exhibiting EAE when compared to controls. Binding reflected the ascending nature of EAE inflammation, with lumbar/sacral cord > thoracic cord > cervical cord > medulla. The amount of ligand binding also reflected the clinical severity of disease. Ex vivo autoradiography and immunohistochemistry revealed a good spatial correspondence between radioligand signal and foci of inflammation and in particular ED-1{sup +} cells representing macrophages and microglia. These results demonstrate the ability of {sup 123}I

  20. Effects of benzodiazepines and non-benzodiazepine compounds on the GABA-induced response in frog isolated sensory neurones.

    OpenAIRE

    Yakushiji, T; Fukuda, T.; Oyama, Y.; Akaike, N.

    1989-01-01

    1. The effects of benzodiazepines and non-benzodiazepine compounds on the gamma-aminobutyric acid (GABA)-induced chloride current (ICl) were studied in frog isolated sensory neurones by use of a concentration-jump (termed 'concentration-clamp') technique, under single-electrode voltage-clamp conditions. The drugs used were classified into four categories as follows: full benzodiazepine receptor agonists (diazepam, clonazepam, nitrazepam, midazolam, clotiazepam and etizolam), partial agonists ...

  1. Benzodiazepine-induced intestinal motor disturbances in rats: mediation by omega 2 (BZ2) sites on capsaicin-sensitive afferent neurones.

    OpenAIRE

    Bonnafous, C; Scatton, B; BUÉNO, L.

    1994-01-01

    1. The central and peripheral effects of the omega (benzodiazepine) site ligands, clonazepam, alpidem, zolpidem, triazolam, flumazenil, ethyl beta carboline-3-carboxylate (beta-CCE) and N-methyl beta carboline-3-carboxylate (beta-CCM) on intestinal myoelectrical activity were evaluated in conscious rats, chronically fitted with Nichrome electrodes implanted on the duodenum and jejunum. The localization of the omega (benzodiazepine) receptors involved in these effects was evaluated by use of s...

  2. GABA receptor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Doo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABA{sub A}-receptor that allows chloride to pass through a ligand gated ion channel and GABA{sub B}-receptor that uses G-proteins for signaling. The GABA{sub A}-receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABA{sub A}-receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with {sup 11}C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, {sup 18}F-fluoroflumazenil (FFMZ) has been developed to overcome {sup 11}C's short half-life. {sup 18}F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '1{sup 1}C-FMZ PET instead of {sup 18}F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABA{sub A} receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas.

  3. GABA receptor imaging

    International Nuclear Information System (INIS)

    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABAA-receptor that allows chloride to pass through a ligand gated ion channel and GABAB-receptor that uses G-proteins for signaling. The GABAA-receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABAA-receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with 11C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, 18F-fluoroflumazenil (FFMZ) has been developed to overcome 11C's short half-life. 18F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '11C-FMZ PET instead of 18F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABAA receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas

  4. Polyethylene glycol(PEG-400): An efficient and recyclable reaction medium for the synthesis of novel 1,5-benzodiazepines and their antimicrobial activity

    Institute of Scientific and Technical Information of China (English)

    Shankaraiah G. Konda; Baseer M. Shaikh; Sanjay A. Chavan; Bhaskar S. Dawane

    2011-01-01

    A new series of imidazole-containing 1,5-benzodiazepines have been synthesized by the condensation of chalcones with ophenylenediamine using piperidine in polyethylene glycol(PEG-400)as an efficient and green reaction solvent.The advantages of this protocol are environmental friendliness,easy work-up,high yields,mild reaction condition and avoidance of expensive catalyst.Furthermore,newly synthesized compounds were evaluated for their antimicrobial activity.

  5. Triton X-100 inhibits agonist-induced currents and suppresses benzodiazepine modulation of GABA(A) receptors in Xenopus oocytes

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Ebert, Bjarke; Klaerke, Dan;

    2009-01-01

    effects on gramicidin channel A appearance rate and lifetime in artificial lipid bilayers. In the present study, the pharmacological action of Triton-X 100 on GABA(A) receptors expressed in Xenopus laevis oocytes was examined. Triton-X 100 inhibited GABA(A) alpha(1)beta(3)gamma(2S) receptor currents in a...

  6. Effects of protein restriction, melatonin administration, and short daylength on brain benzodiazepine receptors in prepubertal male rats

    International Nuclear Information System (INIS)

    The possibility that there are changes in brain benzodiazepine binding sites controlled by photoperiod was investigated in two strains of male rats. The hypothesis was tested by 3H-diazepam binding studies in various brain regions of prepubertal rats maintained in 14 or 10 h of light or treated with late-afternoon injections of melatonin (50 micrograms/day). Protein restriction was applied during the experiment to sensitize the animals to the treatments. Under the conditions employed, rats kept in short daylength throughout or kept on long photoperiod and given late-afternoon melatonin injections showed evidence of delayed puberty (seminal vesicle, ventral prostate, and testis weight decreased by 45%, 55%, and 60% respectively, compared to control rats). Binding measurements were made 1 h before and 2 and 5 h after the onset of darkness in the pubertal (42-day-old) or experimentally prepubertal rats. In the rats of the Porton strain (for which protein restriction was obligatory for the gonadal response) there was no consistent treatment or time effects on specific binding of 3H-diazepam to washed membranes of the hypothalamus, midbrain, or striatum. Similarly, there were no differences in the stimulation of 3H-diazepam binding by 100 microM GABA or the inhibition of binding by 50 microM N-acetyl 5 methoxy kynurenamine. By contrast, in Wistar rats, specific binding to midbrain membranes was reduced 5 h after dark compared to 2 h (37% saline; 20% melatonin) and the extent of stimulation by GABA in the hypothalamus was increased 5 h after darkness (35.6% to 46.7% saline; 37.4% to 50% melatonin). Melatonin treatment resulted in significantly higher specific binding in the hypothalamus 2 h after dark (10%, control fed; 20%, protein restricted) but reduced the GABA induced stimulation of binding in the midbrain (35.5% to 25%, control fed; 33.7% to 23.5%, protein restricted)

  7. Different sensitivities to competitive inhibition of benzodiazepine receptor binding of {sup 11}C-iomazenil and {sup 11}C-flumazenil in rhesus monkey brain

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Osamu; Hosoi, Rie; Kobayashi, Kaoru [Osaka Univ., Suita (Japan). Medical School; Itoh, Takashi; Gee, A.; Suzuki, Kazutoshi

    2001-04-01

    The in vivo binding kinetics of {sup 11}C-iomazenil were compared with those of {sup 11}C-flumazenil binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either {sup 11}C-iomazenil or {sup 11}C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0, 5 and 20 {mu}g/kg). The regional distribution of {sup 11}C-iomazenil in the brain was similar to that of {sup 11}C-flumazenil, but the sensitivity of {sup 11}C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of {sup 11}C-flumazenil binding. A significant reduction in {sup 11}C-flumazenil binding in the cerebral cortex was observed with 20 {mu}g/kg of flumazenil, whereas a relatively smaller inhibition of {sup 11}C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that {sup 11}C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain. (author)

  8. Assessment of cerebral benzodiazepine receptor distribution in anxiety disorders by 123I-iomazenil-SPECT. Comparison to cerebral perfusion scintigraphy by 123I-IMP

    International Nuclear Information System (INIS)

    123I-Iomazenil (123I-IMZ) and 123I-IMP imaging were performed in 5 patients with anxiety disorder (PAD) and 6 normal volunteers (NV). On 123I-IMZ delayed imaging, the 2 PAD showed abnormally decreased findings. In anxiety disorder, decreased accumulation on 123I-IMZ delayed images was seen in left hippocampus and parahippocampal gyrus in one patient, in right frontal and temporal lobe and left occipital pole in the other. Compared with NV, PAD had lower 123I-IMZ uptake on delayed image in right upper and left lower frontal cortices, indicating the involvement of the benzodiazepine receptor complex in anxiety disorder. Compared with grading for anxiety disorder with Hamilton anxiety scale (HAS) and delayed to early count ratios of 123I-IMZ, negative correlation (R123I-IMP image, positive correlation (R>0.7) was recognized in the hippocampus, the parahippocampal gyrus, the lower outer temporal cortex and the lower frontal cortex. (author)

  9. Different sensitivities to competitive inhibition of benzodiazepine receptor binding of 11C-iomazenil and 11C-flumazenil in rhesus monkey brain

    International Nuclear Information System (INIS)

    The in vivo binding kinetics of 11C-iomazenil were compared with those of 11C-flumazenil binding in rhesus monkey brain. The monkey was anesthetized with ketamine and intravenously injected with either 11C-iomazenil or 11C-flumazenil in combination with the coadministration of different doses of non-radioactive flumazenil (0, 5 and 20 μg/kg). The regional distribution of 11C-iomazenil in the brain was similar to that of 11C-flumazenil, but the sensitivity of 11C-iomazenil binding to competitive inhibition by non-radioactive flumazenil was much less than that of 11C-flumazenil binding. A significant reduction in 11C-flumazenil binding in the cerebral cortex was observed with 20 μg/kg of flumazenil, whereas a relatively smaller inhibition of 11C-iomazenil binding in the same region was observed with the same dose of flumazenil. These results suggest that 11C-flumazenil may be a superior radiotracer for estimating benzodiazepine receptor occupancy in the intact brain. (author)

  10. [Analysis of the binding capacity of the benzodiazepine site of gabaa receptor in mice C57BL/6 and BALB/C pretreated with anxiolytics].

    Science.gov (United States)

    Iarkova, M A

    2011-01-01

    The level of specific 3H-flunitrazepam binding in synaptosomal membranes of C57BL/6 and BALB/c mice brain underwent to the stress of different types has been studied. Mild stress (Elevated Plus Maze) was shown to induce the decrease of benzodiazepine binding in BALB/c mice only, while the strong one (Exposure to a predator) was revealed to cause this decrease in both strains. Behavioral effects of different non-benzodiazepine drugs possessing anxiolytic properties (Afobazol, Ladasten and Noopept) was accompanied with the normalization of the level of benzodiazepine reception, reduced by the stress of both modalities. PMID:22232906

  11. The 18 kDa translocator protein (peripheral benzodiazepine receptor expression in the bone of normal, osteoprotegerin or low calcium diet treated mice.

    Directory of Open Access Journals (Sweden)

    Winnie Wai-Ying Kam

    Full Text Available The presence of the translocator protein (TSPO, previously named as the mitochondrial or peripheral benzodiazepine receptor, in bone cells was studied in vitro and in situ using RT-qPCR, and receptor autoradiography using the selective TSPO ligand PK11195.In vitro, the TSPO is highly expressed in osteoblastic and osteoclastic cells.In situ, constitutive expression of TSPO is found in bone marrow and trabecular bone, e.g., spongiosa. Mice with a reduction of bone turnover induced by a 4-day treatment of osteoprotegerin reduces [(3H]PK11195 binding in the spongiosa (320±128 Bq x mg(-1, 499±106 Bq x mg(-1 in saline-treated controls. In contrast, mice with an increase in bone turnover caused by a 4-day low calcium diet increases [(3H]PK11195 binding in the spongiosa (615±90 Bq x mg(-1. Further, our study includes technical feasibility data on [(18F]fluoride microPET imaging of rodent bone with altered turnover. Despite [(18F]fluoride having high uptake, the in vivo signal differences were small. Using a phantom model, we describe the spillover effect and partial volume loss that affect the quantitative microPET imaging of the small bone structures in experimental mouse models. In summary, we demonstrate the expression of TSPO in small rodent bone tissues, including osteoblasts and osteoclasts. A trend increase in TSPO expression was observed in the spongiosa from low to high bone turnover conditions. However, despite the potential utility of TSPO expression as an in vivo biomarker of bone turnover in experimental rodent models, our small animal PET imaging data using [(18F]fluoride show that even under the condition of a good biological signal-to-noise ratio and high tracer uptake, the currently achievable instrument sensitivity and spatial resolution is unlikely to be sufficient to detect subtle differences in small structures, such as mouse bone.

  12. Bioassay-guided isolation of apigenin with GABA-benzodiazepine activity from Tanacetum parthenium

    DEFF Research Database (Denmark)

    Jäger, Anna Katharina; Krydsfeldt, Katrine; Rasmussen, Hasse Bonde

    2009-01-01

    Extracts of Tanacetum parthenium are used in the prophylactic treatment of migraine and have also been used in Danish folk medicine for the treatment of epilepsy. An ethanol extract of T. parthenium showed high affinity for the GABA(A)-benzodiazepine site. An ethanol extract of T. parthenium was ...

  13. Benzodiazepines: Sedation and Agitation.

    Science.gov (United States)

    Gallagher, Catherine

    2016-01-01

    Dental anxiety is common and frequently poses a barrier to necessary dental treatment. The increasing availability of conscious sedation in dental practice has made treatment much more accessible for anxious patients. At present, benzodiazepines are the most commonly used drugs in sedation practice and provide a pleasant experience for most, but not all, patients. An understanding of the mechanism of action of benzodiazepines should inform our practice and deepen our understanding of why and how sedation may fail. CPD/CLINICAL RELEVANCE: As an increasing number of dentists provide sedation for their patients an update on benzodiazepines is timely. PMID:27024905

  14. AC-3933, a benzodiazepine partial inverse agonist, improves memory performance in MK-801-induced amnesia mouse model.

    Science.gov (United States)

    Hashimoto, Takashi; Iwamura, Yoshihiro

    2016-05-01

    AC-3933, a novel benzodiazepine receptor partial inverse agonist, is a drug candidate for cognitive disorders including Alzheimer's disease. We have previously reported that AC-3933 enhances acetylcholine release in the rat hippocampus and ameliorates scopolamine-induced memory impairment and age-related cognitive decline in both rats and mice. In this study, we further evaluated the procognitive effect of AC-3933 on memory impairment induced by MK-801, an N-methyl-d-aspartate receptor antagonist, in mice. Unlike the acetylcholinesterase inhibitor donepezil and the benzodiazepine receptor inverse agonist FG-7142, oral administration of AC-3933 significantly ameliorated MK-801-induced memory impairment in the Y-maze test and in the object location test. Interestingly, the procognitive effects of AC-3933 on MK-801-induced memory impairment were not affected by the benzodiazepine receptor antagonist flumazenil, although this was not the case for the beneficial effects of AC-3933 on scopolamine-induced memory deficit. Moreover, the onset of AC-3933 ameliorating effect on scopolamine- or MK-801-induced memory impairment was different in the Y-maze test. Taken together, these results indicate that AC-3933 improves memory deficits caused by both cholinergic and glutamatergic hypofunction and suggest that the ameliorating effect of AC-3933 on MK-801-induced memory impairment is mediated by a mechanism other than inverse activation of the benzodiazepine receptor. PMID:26946254

  15. Benzodiazepine poisoning in elderly

    Directory of Open Access Journals (Sweden)

    Perković-Vukčević Nataša

    2016-01-01

    Full Text Available Background/Aim. Benzodiazepines are among the most frequently ingested drugs in self-poisonings. Elderly may be at greater risk compared with younger individuals due to impaired metabolism and increased sensitivity to benzodiazepines. The aim of this study was to assess toxicity of benzodiazepines in elderly attempted suicide. Methods. A retrospective study of consecutive presentations to hospital after self-poisoning with benzodiazepines was done. Collected data consisted of patient's characteristics (age, gender, benzodiazepine ingested with its blood concentrations at admission, clinical findings including vital signs and Glasgow coma score, routine blood chemistry, complications of poisoning, details of management, length of hospital stay and outcome. According the age, patients are classified as young (15-40-year old, middle aged (41-65-year old and elderly (older than 65. Results. During a 2-year observational period 387 patients were admitted because of pure benzodiazepine poisoning. The most frequently ingested drug was bromazepam, the second was diazepam. The incidence of coma was significantly higher, and the length of hospital stay significantly longer in elderly. Respiratory failure and aspiration pneumonia occurred more frequently in old age. Also, flumazenil was more frequently required in the group of elderly patients. Conclusion. Massive benzodiazepines overdose in elderly may be associated with a significant morbidity, including deep coma with aspiration pneumonia, respiratory failure, and even death. Flumazenil is indicated more often to reduce CNS depression and prevent complications of prolonged unconsciousness, but supportive treatment and proper airway management of comatose patients is the mainstay of the treatment of acute benzodiazepine poisoning.

  16. Adverse effects of benzodiazepines

    OpenAIRE

    Claire Gudex

    1990-01-01

    The growing realisation that the benzodiazepines have potential for causing serious harm has caused concern due to their wide and common use. This has stimulated interest in the costs and benefits of their use. This paper is a review of the adverse effects of benzodiazepines, and concentrates on four areas of particular concern: drug dependence which the consequent withdrawal symptoms; psychological effects while on the drugs; use by the elderly’ and tolerance to the drug effects. Although th...

  17. Strategy for improved [11C]DAA1106 radiosynthesis and in vivo peripheral benzodiazepine receptor imaging using microPET, evaluation of [11C]DAA1106

    International Nuclear Information System (INIS)

    Introduction: The peripheral benzodiazepine receptor (PBR) has shown considerable potential as a clinical marker of neuroinflammation and tumour progression. [11C]DAA1106 ([11C]N-(2,5-dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)-acetamide) is a promising positron emission tomography (PET) radioligand for imaging PBRs. Methods: A four-step synthetic route was devised to prepare DAA1123, the precursor for [11C]DAA1106. Two robust, high yielding methods for radiosynthesis based on [11C]-O-methylation of DAA1123 were developed and implemented on a nuclear interface methylation module, producing [11C]DAA1106 with up to 25% radiochemical yields at end-of-synthesis based on [11C]CH3I trapped. Evaluation of [11C]DAA1106 for in vivo imaging was performed in a rabbit model with microPET, and the presence of PBR receptor in the target organ was further corroborated by immunohistochemistry. Results: The standard solution method produced 2.6-5.2 GBq (n=19) of [11C]DAA1106, whilst the captive solvent method produced 1.6-6.3 GBq (n=10) of [11C]DAA1106. Radiochemical purities obtained were 99% and specific radioactivity at end-of-synthesis was up to 200 GBq/μmol for both methods. Based on radiochemical product, shorter preparation times and simplicity of synthesis, the captive solvent method was chosen for routine productions of [11C]DAA1106. In vivo microPET [11C]DAA1106 scans of rabbit kidney demonstrated high levels of binding in the cortex. The subsequent introduction of nonradioactive DAA1106 (0.2 μmol) produced considerable displacement of the radioactive signal in this region. The presence of PBR in kidney cortex was further corroborated by immunohistochemistry. Conclusions: A robust, high yielding captive solvent method of [11C]DAA1106 production was developed which enabled efficacious in vivo imaging of PBR expressing tissues in an animal model

  18. Gamma-aminobutyric acid and benzodiazepine receptor changes induced by unilateral 6-hydroxydopamine lesions of the medial forebrain bundle

    Energy Technology Data Exchange (ETDEWEB)

    Pan, H.S.; Penney, J.B.; Young, A.B.

    1985-11-01

    Quantitative autoradiography was used to ascertain alterations in (TH)muscimol, (TH)flunitrazepam (FLU), (TH)naloxone, (TH)D-alanine-D-leucine-enkephalin (DADL), and (TH)spiroperidol binding in basal ganglia 1 week, 4 weeks, and 5 months after unilateral 6-hydroxydopamine lesions of the medial forebrain bundle (MFB) in the rat. At 1 and 4 weeks following lesions, (TH)spiroperidol binding increased 33% in striatum. At 5 months, (TH)spiroperidol was only nonsignificantly increased above control. At 1 week, (TH)muscimol binding decreased 39% in ipsilateral globus pallidus (GP), but increased 41% and 11% in entopeduncular nucleus (EPN) and substantia nigra pars reticulata (SNr), respectively. At 4 weeks, (TH)muscimol binding was reduced 19% in striatum and 44% in GP and remained enhanced by 32% in both EPN and SNr. These changes in (TH)muscimol binding persisted at 5 months. (TH)FLU binding was altered in the same direction as (TH)muscimol binding; however, changes were slower in onset and became significant (and remained so) only at 4 weeks after lesions. Decreases in (TH)naloxone and (TH)DADL binding were seen in striatum, GP, EPN, and SNr. Scatchard analyses revealed that only receptor numbers were altered. This study provides biochemical evidence for differential regulation of striatal GABAergic output to GP and EPN/SNr.

  19. Comparison of benzodiazepine receptor SPECT and 18F-FDG PET using a coincidence detection camera in patients with temporal lobe epilepsy: preliminary results

    International Nuclear Information System (INIS)

    Full text: The aim of this preliminary study was to compare the results of benzodiazepine receptor (BDR) SPECT using 123I-Iomazenil with those of 18F-FDG (FDG) PET obtained on a double-headed gamma camera with a coincidence detection system in patients with temporal lobe epilepsy (TLE). We evaluated 6 patients (4 female, 2 male; age range 26-54 years, average 43.5 years) with therapy-refractory TLE due to mesiotemporal sclerosis or other focal brain anomalies. To delineate the epileptogenic zone, clinical evaluation, ictal and interictal surface EEG using the international 10-20 system, brain MRI, interictal CBF SPECT using 99mTc-ECD, BDR SPECT and FDG coincidence PET were performed. The CBF SPECT, BDR SPECT and coincidence PET scans were viewed independently by 2 observers considering the regional cerebral blood flow, BDR density and FDG uptake asymmetry in the temporal lobe visually as none (0), low (1), moderate (2) and high (3). Ictal and interictal EEG recordings located the epileptogenic focus in all patients in the temporal region. Both the BDR SPECT and the FDG coincidence PET located the epileptogenic focus correctly in circumscribed areas of the temporal lobe in all patients, whereas brain MRI revealed focal anomalies only in 5 of 6 cases . The lateralization to the right (n=4) and left hemisphere (n=2) by interictal CBF SPECT, BDR SPECT and FDG coincidence PET corresponded to the EEG findings in all patients. The visual consideration of the asymmetry revealed a slightly but not statistically significant higher value for the FDG coincidence PET (observer 1: mean 2.333, SD 0.516; observer 2: mean 2.000, SD 0.632) than for the BDR SPECT (observer 1: mean 1.667, SD 1.033; observer 2: mean 1.833, SD 0.753). Visual consideration of the interictal CBF SPECT revealed mean values of 2.000 for both observers. The inter-observer variability was higher in the BDR SPECT than in the FDG coincidence PET and the interictal CBF SPECT, but the difference was not

  20. Pharmacologically induced long QT type 2 can be rescued by activation of IKs with benzodiazepine R-L3 in isolated guinea pig cardiomyocytes

    DEFF Research Database (Denmark)

    Nissen, Jakob Dahl; Diness, Jonas Goldin; Diness, Thomas Goldin; Hansen, Rie Schultz; Grunnet, Morten; Jespersen, Thomas

    2009-01-01

    The ionic current responsible for terminating the action potential (AP), and thereby in part determining the AP duration (APD), is the potassium current (IK), consisting of primarily two components: a rapidly (IKr) and a slowly (IKs) activating delayed rectifier potassium current. The aim of this...... study was to evaluate potential antiarrhythmic effects of compound induced IKs activation using the benzodiazepine L-364,373 (R-L3). Ventricular myocytes from guinea pigs were isolated and whole-cell current clamping was performed at 35 degrees C. It was found that 1 microM R-L3 significantly reduced...... increase in repolarizing capacity was seen with 1 microM R-L3, as more complete repolarization of the AP was achieved before EADs could be elicited. Finally, a functional demonstration of the repolarization reserve revealed that increased IKs can counteract a pharmacologically reduced IKr. In conclusion...

  1. Benzodiazepine Synthesis and Rapid Toxicity Assay

    Science.gov (United States)

    Fletcher, James T.; Boriraj, Grit

    2010-01-01

    A second-year organic chemistry laboratory experiment to introduce students to general concepts of medicinal chemistry is described. Within a single three-hour time window, students experience the synthesis of a biologically active small molecule and the assaying of its biological toxicity. Benzodiazepine rings are commonly found in antidepressant…

  2. GABA-B receptor activation and conflict behavior

    Energy Technology Data Exchange (ETDEWEB)

    Ketelaars, C.E.J.; Bollen, E.L.; Rigter, H.; Bruinvels, J.

    1988-01-01

    Baclofen and oxazepam enhance extinction of conflict behavior in the Geller-Seifter test while baclofen and diazepam release punished behavior in Vogel's conflict test. In order to investigate the possibility that the effect of the selective GABA-B receptor agonist baclofen is mediated indirectly via the GABA-A/benzodiazepine receptor complex, the effect of pretreatment of rats with baclofen on (/sup 3/H)-diazepam binding to washed and unwashed cortical and cerebellar membranes of rats has been studied. Baclofen pretreatment increase Bmax in washed cerebellar membranes when bicuculline was present in the incubation mixture. No effect was seen in cortical membranes. The present results render it unlikely that the effect of baclofen on extinction of conflict behavior and punished drinking is mediated via the GABA-A/benzodiazepine receptor complex. 50 references, 1 figure, 4 tables.

  3. GABA-B receptor activation and conflict behavior

    International Nuclear Information System (INIS)

    Baclofen and oxazepam enhance extinction of conflict behavior in the Geller-Seifter test while baclofen and diazepam release punished behavior in Vogel's conflict test. In order to investigate the possibility that the effect of the selective GABA-B receptor agonist baclofen is mediated indirectly via the GABA-A/benzodiazepine receptor complex, the effect of pretreatment of rats with baclofen on [3H]-diazepam binding to washed and unwashed cortical and cerebellar membranes of rats has been studied. Baclofen pretreatment increase Bmax in washed cerebellar membranes when bicuculline was present in the incubation mixture. No effect was seen in cortical membranes. The present results render it unlikely that the effect of baclofen on extinction of conflict behavior and punished drinking is mediated via the GABA-A/benzodiazepine receptor complex. 50 references, 1 figure, 4 tables

  4. High density of benzodiazepine binding sites in the substantia innominata of the rat

    Energy Technology Data Exchange (ETDEWEB)

    Sarter, M.; Schneider, H.H.

    1988-07-01

    In order to study the neuronal basis of the pharmacological interactions between benzodiazepine receptor ligands and cortical cholinergic turnover, we examined the regional distribution of specific benzodiazepine binding sites using in vitro autoradiography. In the basal forebrain, the substantia innominata contained a high density of (/sup 3/H)lormetazepam (LMZ) binding sites (Bmax = 277 fmol/mg tissue; Kd = 0.55 nM). The label could be displaced by diazepam (IC50 = 100 nM), the benzodiazepine receptor antagonist beta-carboline ZK 93426 (45 nM) and the partial inverse agonist beta-carboline FG 7142 (540 nM). It is hypothesized that the amnesic effects of benzodiazepine receptor agonists are exerted through benzodiazepine receptors which are situated on cholinergic neurons in the substantia innominata and are involved in a tonic inhibition of cortical acetylcholine release. The benzodiazepine receptor antagonist ZK 93426 may exert its nootropic effects via benzodiazepine receptors in the substantia innominata and, consequently, by disinhibiting cortical acetylcholine release.

  5. Inhibition of human immunodeficiency virus type 1 Tat-dependent activation of translation in Xenopus oocytes by the benzodiazepine Ro24-7429 requires trans-activation response element loop sequences.

    OpenAIRE

    Braddock, M; Cannon, P; Muckenthaler, M; Kingsman, A J; Kingsman, S M

    1994-01-01

    Two benzodiazepine compounds, [7-chloro-5-(2-pyrryl)-3H-1,4 benzodiazapin-2-(H)-one] (Ro5-3335) and [7-chloro-5-(1H-pyrrol-2-yl)-3H-benzo[e] [1,4] diazepin-2-yl]- methylamine (Ro24-7429), inhibit human immunodeficiency virus type 1 (HIV-1) replication via a specific effect on the function of the transactivator protein, Tat. To gain further insight into the mechanism of action of these compounds, we have tested their effects in an alternative assay for Tat activation in Xenopus oocytes. In thi...

  6. Discontinuing benzodiazepines: best practices.

    Science.gov (United States)

    Guaiana, G; Barbui, C

    2016-06-01

    In July 2015, the Canadian Agency for Drugs and Technologies in Health (CADTH) released a Rapid Response report summary, with a critical appraisal, on discontinuation strategies for patients with long-term benzodiazepines (BDZ) use. The CADTH document is a review of the literature. It includes studies whose intervention is BDZ discontinuation. Also, clinical guidelines, systematic reviews and meta-analyses are included. What emerges from the CADTH guidelines is that the best strategy remains gradual tapering of BDZ with little evidence for the use of adjunctive medications. The results show that simple interventions such as discontinuation letters from clinicians, self-help information and support in general, added to gradual tapering may be associated with a two- to three-fold higher chance of successful withdrawal, compared with treatment as usual. We suggest possible implications for day-to-day clinical practice. PMID:26818890

  7. Mechanism for the activation of glutamate receptors

    Science.gov (United States)

    Scientists at the NIH have used a technique called cryo-electron microscopy to determine a molecular mechanism for the activation and desensitization of ionotropic glutamate receptors, a prominent class of neurotransmitter receptors in the brain and spina

  8. Effects of benzodiazepines and non-benzodiazepine compounds on the GABA-induced response in frog isolated sensory neurones.

    Science.gov (United States)

    Yakushiji, T; Fukuda, T; Oyama, Y; Akaike, N

    1989-11-01

    1. The effects of benzodiazepines and non-benzodiazepine compounds on the gamma-aminobutyric acid (GABA)-induced chloride current (ICl) were studied in frog isolated sensory neurones by use of a concentration-jump (termed 'concentration-clamp') technique, under single-electrode voltage-clamp conditions. The drugs used were classified into four categories as follows: full benzodiazepine receptor agonists (diazepam, clonazepam, nitrazepam, midazolam, clotiazepam and etizolam), partial agonists (CL 218,872, Ro 16-6028, Ro 17-1812 and Ro 23-0364), inverse agonists (Ro 15-3505, FG 7142 and beta-CCE) and a benzodiazepine receptor antagonist, Ro 15-1788 (flumazenil). 2. All full agonists at concentrations of 3 x 10(-6) M or less increased dose-dependently the peak amplitude of ICl elicited by 3 x 10(-6) M GABA to twice to three times larger than the control. However, no further augmentation of the GABA response was observed at concentrations of 1 x 10(-5) M or higher. Partial agonists also showed a dose-dependent augmentation of the GABA response at concentrations ranging from 3 x 10(-8) M to 3 x 10(-5) M, but their efficacies of augmentation of the GABA response were only about half or less of those of full agonists. Of the inverse agonists, beta-CCE had a unique dose-dependent effect on the GABA response. Beta-CCE reduced dose-dependently the GABA response at concentrations of less than 3 x 10(-6) M, but augmented it at concentrations of 3 x 10(-5) M and 6 x 10(-5) M. The inverse agonists reduced dose-dependently the GABA response. The benzodiazepine antagonist, flumazenil, slightly augmented the GABA response at concentrations between 3 x 10 7M and 3 x 10 5 M. 3. These results show clear differences in the effects on the GABA response between these four categories of compounds known to affect the benzodiazepine recognition site of the GABA/ benzodiazepine receptor-chloride channel complex. Our experimental system of frog isolated sensory neurones and a 'concentration

  9. Use and abuse of benzodiazepines*

    OpenAIRE

    1983-01-01

    Benzodiazepines are widely used for the treatment of anxiety, insomnia, and certain neuromuscular and convulsive disorders. However, their widespread availability has given rise to fears that they are over-prescribed. The problem is compounded by the fact that there is no universal agreement among medical practitioners as to the clinical indications warranting the use of these drugs. Although most industrialized countries exercise control over the sale and manufacture of benzodiazepines, many...

  10. The peripheral benzodiazepine receptor ligand PK11195 binds with high affinity to the acute phase reactant α1-acid glycoprotein: implications for the use of the ligand as a CNS inflammatory marker

    International Nuclear Information System (INIS)

    The peripheral benzodiazepine receptor ligand PK11195 has been used as an in vivo marker of neuroinflammation in positron emission tomography studies in man. One of the methodological issues surrounding the use of the ligand in these studies is the highly variable kinetic behavior of [11C]PK11195 in plasma. We therefore undertook a study to measure the binding of [3H]PK11195 to whole human blood and found a low level of binding to blood cells but extensive binding to plasma proteins. Binding assays using [3H]PK11195 and purified human plasma proteins demonstrated a strong binding to α1-acid glycoprotein (AGP) and a much weaker interaction with albumin. Immunodepletion of AGP from plasma resulted in the loss of plasma [3H]PK11195 binding demonstrating: (i) the specificity of the interaction and (ii) that AGP is the major plasma protein to which PK11195 binds with high affinity. PK11195 was able to displace fluorescein-dexamethasone from AGP with IC50 of 11C]PK11195 to the brain parenchyma in diseases with blood brain barrier breakdown. Finally, local synthesis of AGP at the site of brain injury may contribute the pattern of [11C]PK11195 binding observed in neuroinflammatory diseases

  11. NMDA Receptor Activation by Spontaneous Glutamatergic Neurotransmission

    OpenAIRE

    Espinosa, Felipe; Kavalali, Ege T.

    2009-01-01

    Under physiological conditions N-methyl-d-aspartate (NMDA) receptor activation requires coincidence of presynaptic glutamate release and postsynaptic depolarization due to the voltage-dependent block of these receptors by extracellular Mg2+. Therefore spontaneous neurotransmission in the absence of action potential firing is not expected to lead to significant NMDA receptor activation. Here we tested this assumption in layer IV neurons in neocortex at their resting membrane potential (approxi...

  12. Hormone activation of baculovirus expressed progesterone receptors.

    Science.gov (United States)

    Elliston, J F; Beekman, J M; Tsai, S Y; O'Malley, B W; Tsai, M J

    1992-03-15

    Human and chicken progesterone receptors (A form) were overproduced in a baculovirus expression system. These recombinant progesterone receptors were full-length bound progesterone specifically and were recognized by monoclonal antibodies, AB52 and PR22, specific for human and chicken progesterone receptor, respectively. In gel retardation studies, binding of recombinant human and chicken progesterone receptors to their progesterone response element (PRE) was specific and was enhanced in the presence of progesterone. Binding of human progesterone receptor to the PRE was also enhanced in the presence of the antiprogestin, RU486, but very little effect was observed in the presence of estradiol, dexamethasone, testosterone, and vitamin D. In our cell-free transcription system, human progesterone receptor induced transcription in a receptor-dependent and hormone-activable manner. Receptor-stimulated transcription required the presence of the PRE in the test template and could be specifically inhibited by excess PRE oligonucleotides. Furthermore, chicken progesterone receptor also induced in vitro transcription in a hormone-activable manner. These results demonstrate that steroid receptors overexpressed in a baculovirus expression system are functional and exhibit steroid-responsive binding and transcription. These observations support our present understanding of the mechanism of steroid receptor-regulated gene expression and provide a technological format for studies of the role of hormone and antihormone in altering gene expression. PMID:1544902

  13. NMDA receptor activation by spontaneous glutamatergic neurotransmission.

    Science.gov (United States)

    Espinosa, Felipe; Kavalali, Ege T

    2009-05-01

    Under physiological conditions N-methyl-D-aspartate (NMDA) receptor activation requires coincidence of presynaptic glutamate release and postsynaptic depolarization due to the voltage-dependent block of these receptors by extracellular Mg(2+). Therefore spontaneous neurotransmission in the absence of action potential firing is not expected to lead to significant NMDA receptor activation. Here we tested this assumption in layer IV neurons in neocortex at their resting membrane potential (approximately -67 mV). In long-duration stable recordings, we averaged a large number of miniature excitatory postsynaptic currents (mEPSCs, >100) before or after application of dl-2 amino 5-phosphonovaleric acid, a specific blocker of NMDA receptors. The difference between the two mEPSC waveforms showed that the NMDA current component comprises approximately 20% of the charge transfer during an average mEPSC detected at rest. Importantly, the contribution of the NMDA component was markedly enhanced at membrane potentials expected for the depolarized up states (approximately -50 mV) that cortical neurons show during slow oscillations in vivo. In addition, partial block of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor component of the mEPSCs did not cause a significant reduction in the NMDA component, indicating that potential AMPA receptor-driven local depolarizations did not drive NMDA receptor activity at rest. Collectively these results indicate that NMDA receptors significantly contribute to signaling at rest in the absence of dendritic depolarizations or concomitant AMPA receptor activity. PMID:19261712

  14. Modulation of benzodiazepine by lysine and pipecolic acid on pentylenetetrazol-induced seizures

    International Nuclear Information System (INIS)

    L-lysine and its metabolite pipecolic acid (PA) have been studied for their effects on pentylenetetrazol (PTZ)-induced seizures in mice. L-Lysine of L-Pa i.p. significantly increased clonic and tonic latencies in a dose-dependent manner against 90 mg/kg PTZ-induced seizures. L-Lysine but not L-Pa enhanced the anticonvulsant effect of diazepam (DZ). L-Pa i.c.v. showed a slight decrease in clonic latency; it did not enhance the antiseizure activity of DZ; it caused seizures at 0.6 mmol/kg. D-PA i.c.v. displayed an opposite effect compared to its L-isomer. The anticonvulsant effect of L-lysine in terms of increase in seizure latency and survival was even more amplified when tested with a submaximal PTZ concentration. L-Lysine showed an enhancement of specific 3H-flunitrazepam(FZ) binding to mouse brain membranes both in vitro an din vivo. The possibility of L-lysine acting as a modulator for the GABA/benzodiazepine receptors was demonstrated. Since L-PA showed enhancement of 3H-FZ binding only in vitro but not in vivo, the anticonvulsant effect of L-PA may not be linked to the GABA/benzodiazepine receptor

  15. Benzodiazepine receptor equilibrium constants for flumazenil and midazolam determined in humans with the single photon emission computer tomography tracer [123I]iomazenil

    DEFF Research Database (Denmark)

    Videbaek, C; Friberg, L; Holm, S;

    1993-01-01

    This study is based on the steady state method for the calculation of Kd values recently described by Lassen (J. Cereb. Blood Flow Metab. 12 (1992), 709), in which a constant infusion of the examined nonradioactive ligand is used with a bolus injection of tracer. Eight volunteers were examined...... cortical rim for flumazenil were 7.4, 10.0, 10.3 and 17.7 nmol/l plasma water and, for midazolam, 73, 76, 58 and 30 nmol/l plasma water. The variation exceeds random methodological error and is probably due to interindividual differences in receptor affinity. The Kd level of midazolam is considerably...

  16. Strategy for improved [{sup 11}C]DAA1106 radiosynthesis and in vivo peripheral benzodiazepine receptor imaging using microPET, evaluation of [{sup 11}C]DAA1106

    Energy Technology Data Exchange (ETDEWEB)

    Probst, Katrin C. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)]|[BHF Carotid Imaging Group, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)]. E-mail: kp296@wbic.cam.ac.uk; Izquierdo, David [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)]|[BHF Carotid Imaging Group, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Bird, Joseph L.E. [BHF Carotid Imaging Group, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)]|[Department of Medicine, Cardiovascular Medicine Division, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Brichard, Laurent; Franck, Dominic; Fryer, Tim D.; Clark, John C. [Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Davies, John R. [Cardiovascular Medicine Division, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Richards, Hugh K. [Neurology Unit, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Davenport, Anthony P. [Clinical Pharmacology Unit, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Weissberg, Peter L. [Cardiovascular Medicine Division, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom); Warburton, Elizabeth A. [BHF Carotid Imaging Group, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)]|[Department of Clinical Neurosciences, University of Cambridge, Addenbrooke' s Hospital, CB2 2QQ Cambridge (United Kingdom)

    2007-05-15

    Introduction: The peripheral benzodiazepine receptor (PBR) has shown considerable potential as a clinical marker of neuroinflammation and tumour progression. [{sup 11}C]DAA1106 ([{sup 11}C]N-(2,5-dimethoxybenzyl)-N-(5-fluoro-2-phenoxyphenyl)-acetamide) is a promising positron emission tomography (PET) radioligand for imaging PBRs. Methods: A four-step synthetic route was devised to prepare DAA1123, the precursor for [{sup 11}C]DAA1106. Two robust, high yielding methods for radiosynthesis based on [{sup 11}C]-O-methylation of DAA1123 were developed and implemented on a nuclear interface methylation module, producing [{sup 11}C]DAA1106 with up to 25% radiochemical yields at end-of-synthesis based on [{sup 11}C]CH{sub 3}I trapped. Evaluation of [{sup 11}C]DAA1106 for in vivo imaging was performed in a rabbit model with microPET, and the presence of PBR receptor in the target organ was further corroborated by immunohistochemistry. Results: The standard solution method produced 2.6-5.2 GBq (n=19) of [{sup 11}C]DAA1106, whilst the captive solvent method produced 1.6-6.3 GBq (n=10) of [{sup 11}C]DAA1106. Radiochemical purities obtained were 99% and specific radioactivity at end-of-synthesis was up to 200 GBq/{mu}mol for both methods. Based on radiochemical product, shorter preparation times and simplicity of synthesis, the captive solvent method was chosen for routine productions of [{sup 11}C]DAA1106. In vivo microPET [{sup 11}C]DAA1106 scans of rabbit kidney demonstrated high levels of binding in the cortex. The subsequent introduction of nonradioactive DAA1106 (0.2 {mu}mol) produced considerable displacement of the radioactive signal in this region. The presence of PBR in kidney cortex was further corroborated by immunohistochemistry. Conclusions: A robust, high yielding captive solvent method of [{sup 11}C]DAA1106 production was developed which enabled efficacious in vivo imaging of PBR expressing tissues in an animal model.

  17. New 3-, 8-disubstituted pyrazolo[5,1-c][1,2,4]benzotriazines useful for studying the interaction with the HBp-3 area (hydrogen bond point area) in the benzodiazepine site on the gamma-aminobutyric acid type A (GABAA) receptor

    OpenAIRE

    G. Guerrini; G. CICIANI; Bruni, F.; Selleri, S.; F. Melani; Daniele, S.; Martini, C; A. Costanzo

    2011-01-01

    The pharmacophoric model using ADLR procedure, based on pyrazolo[5,1-c][1,2,4]benzotriazine system, studied in our laboratory, allowed us to identify the essential interaction points (HBp-1, HBp-2, and Lp-1) and the important areas for affinity modulation (HBp-3 and Lp-2) for binding recognition at benzodiazepine (Bzs) site of GABAA receptors (GABAA-Rs). In this work ADLR method is used to rationalize the affinity data of 23 new compounds and to improve the knowledge on HBp-3 area...

  18. Experiment K-7-18: Effects of Spaceflight in the Muscle Adductor Longus of Rats Flown in the Soviet Biosatellite Cosmos 2044. Part 2; Quantitative Autoradiographic Analysis of Gaba (Benzodiazepine) and Muscarinic (Cholinergic) Receptors in the Forebrain of Rats Flown on Cosmos 2044

    Science.gov (United States)

    Wu, L.; Daunton, N. G.; Krasnov, I. B.; DAmelio, F.; Hyde, T. M.; Sigworth, S. K.

    1994-01-01

    Quantitative autoradiographic analysis of receptors for GABA and acetylcholine in the forebrain of rats flown on COSMOS 2044 was undertaken as part of a joint US-Soviet study to determine the effects of microgravity on the central nervous system, and in particular on the sensory and motor portions of the forebrain. Changes in binding of these receptors in tissue from animals exposed to microgravity would provide evidence for possible changes in neural processing as a result of exposure to microgravity. Tritium-labelled diazepam and Quinuclidinyl-benzilate (QNB) were used to visualize GABA (benzodiazepine) and muscarinic (cholinergic) receptors, respectively. The density of tritium-labelled radioligands bound to various regions in the forebrain of both flight and control animals were measured from autoradiograms. Data from rats flown in space and from ground-based control animals that were not exposed to microgravity were compared.

  19. Insights into structure-activity relationship of GABAA receptor modulating coumarins and furanocoumarins.

    Science.gov (United States)

    Singhuber, Judith; Baburin, Igor; Ecker, Gerhard F; Kopp, Brigitte; Hering, Steffen

    2011-10-01

    The coumarins imperatorin and osthole are known to exert anticonvulsant activity. We have therefore analyzed the modulation of GABA-induced chloride currents (I(GABA)) by a selection of 18 coumarin derivatives on recombinant α(1)β(2)γ(2S) GABA(A) receptors expressed in Xenopus laevis oocytes by means of the two-microelectrode voltage clamp technique. Osthole (EC(50)=14 ± 1 μM) and oxypeucedanin (EC(50)=25 ± 8 μM) displayed the highest efficiency with I(GABA) potentiation of 116 ± 4 % and 547 ± 56 %, respectively. I(GABA) enhancement by osthole and oxypeucedanin was not inhibited by flumazenil (1 μM) indicating an interaction with a binding site distinct from the benzodiazepine binding site. In general, prenyl residues are essential for the positive modulatory activity, while longer side chains or bulkier residues (e.g. geranyl residues) diminish I(GABA) modulation. Generation of a binary classification tree revealed the importance of polarisability, which is sufficient to distinguish actives from inactives. A 4-point pharmacophore model based on oxypeucedanin - comprising three hydrophobic and one aromatic feature - identified 6 out of 7 actives as hits. In summary, (oxy-)prenylated coumarin derivatives from natural origin represent new GABA(A) receptor modulators. PMID:21749864

  20. Androgen insensitivity syndrome: gonadal androgen receptor activity

    International Nuclear Information System (INIS)

    To determine whether abnormalities of the androgen receptor previously observed in skin fibroblasts from patients with androgen insensitivity syndrome also occur in the gonads of affected individuals, androgen receptor activity in the gonads of a patient with testicular feminization syndrome was investigated. Using conditions for optimal recovery of androgen receptor from human testes established by previous studies, we detected the presence of a high-affinity (dissociation constant . 3.2 X 10(-10) mol/L), low-capacity (4.2 X 10(-12) mol/mg DNA), androgen-binding protein when tritium-labeled R1881 was incubated at 4 degrees C with nuclear extracts from the gonads of control patients or from a patient with testicular feminization syndrome but not when incubated at 37 degrees C. Thus this patient has an androgen receptor with a temperature lability similar to that of receptors from normal persons

  1. Benzodiazepine metabolism: an analytical perspective.

    Science.gov (United States)

    Mandrioli, Roberto; Mercolini, Laura; Raggi, Maria Augusta

    2008-10-01

    Benzodiazepines are currently among the most frequently prescribed drugs all over the world. They act as anxiolytics, sedatives, hypnotics, amnesics, antiepileptics and muscle relaxants. Despite their common chemical scaffold, these drugs differ in their pharmacokinetic and metabolic properties. In particular, they are biotransformed by different cytochrome P450 isoforms and also by different UDP-glucuronosyltransferase subtypes. The most important studies on the metabolic characteristics of several 1,4-benzodiazepines, carried out from 1998 onwards, are reported and briefly discussed in this review. Moreover, the analytical methods related to these studies are also described and commented upon and their most important characteristics are highlighted. Most methods are based on liquid chromatography, which provides wide applicability and good analytical performance granting high precision, accuracy and feasibility. Mass spectrometry is gaining widespread acceptance, particularly if the matrix is very complex and variable, such as human or animal blood. However, spectrophotometric detection is still used for this purpose and can grant sufficient selectivity and sensitivity when coupled to suitable sample pre-treatment procedures. A monograph is included for each of the following benzodiazepines: alprazolam, bromazepam, brotizolam, clotiazepam, diazepam, etizolam, flunitrazepam, lorazepam, midazolam, oxazepam and triazolam. PMID:18855614

  2. Biased Signaling of Protease-activated Receptors

    OpenAIRE

    PeishenZhao; NigelWilliamBunnett

    2014-01-01

    In addition to their role in protein degradation and digestion, proteases can also function as hormone-like signaling molecules that regulate vital patho-physiological processes, including inflammation, hemostasis, pain and repair mechanisms. Certain proteases can signal to cells by cleaving protease-activated receptors (PARs), a family of four G protein-coupled receptors. PARs are expressed by almost all cell types, control important physiological and disease-relevant processes, and are an e...

  3. Identification, characterization, and developmental regulation of embryonic benzodiazepine binding sites

    International Nuclear Information System (INIS)

    We report the identification and characterization of 2 classes of benzodiazepine binding sites in the embryonic chick CNS. Binding was examined by competition and saturation binding experiments, using as radioligands 3H-flunitrazepam, a classical benzodiazepine anxiolytic, and 3H-Ro5-4864, a convulsant benzodiazepine. The results demonstrate that high-affinity (KD = 2.3 nM) 3H-flunitrazepam binding sites (site-A) are present by embryonic day 5 (Hamburger and Hamilton stage 27) and increase throughout development (Bmax = 0.3 and 1.3 pmol/mg protein in 7 and 20 d brain membranes, respectively). When 7 or 20 d brain membranes are photoaffinity-labeled with 3H-flunitrazepam and ultraviolet light, the radioactivity migrates as 2 bands on SDS-PAGE, consistent with Mrs of 48,000 and 51,000. GABA potentiates 3H-flunitrazepam binding at both 7 and 20 d of development, indicating that site-A is coupled to receptors for GABA early in development. Importantly, we have also identified a novel site (site-B) that binds classical benzodiazepine agonists with low affinity (micromolar) but displays high affinity for Ro5-4864 (KD = 41 nM). Site-B displays characteristics expected for a functional receptor, including stereospecificity and sensitivity to inactivation by heat and protease treatment. Saturation binding studies employing 3H-Ro5-4864 indicate that the levels of site-B are similar in 7 and 20 d brain (ca. 2.5 pmol/mg protein). The function of site-B is not known, but its preponderance in 7 d brain, relative to site-A, suggests that it might be important during early embryonic development

  4. ERK activation causes epilepsy by stimulating NMDA receptor activity

    OpenAIRE

    Nateri, Abdolrahman S.; Raivich, Gennadij; Gebhardt, Christine; Da Costa, Clive; Naumann, Heike; Vreugdenhil, Martin; Makwana, Milan; Brandner, Sebastian; Adams, Ralf H.; Jefferys, John G. R.; Kann, Oliver; Behrens, Axel

    2007-01-01

    The ERK MAPK signalling pathway is a highly conserved kinase cascade linking transmembrane receptors to downstream effector mechanisms. To investigate the function of ERK in neurons, a constitutively active form of MEK1 (caMEK1) was conditionally expressed in the murine brain, which resulted in ERK activation and caused spontaneous epileptic seizures. ERK activation stimulated phosphorylation of eukaryotic translation initiation factor 4E (eIF4E) and augmented NMDA receptor 2B (NR2B) protein ...

  5. Benzodiazepines and postoperative cognitive dysfunction in the elderly

    DEFF Research Database (Denmark)

    Rasmussen, L.S.; Steentoft, Anni; Rasmussen, H.; Kristensen, P.A.; Møller, J.T.

    1999-01-01

    hypnotics benzodiazepine,diazepam,age factor,anaesthesia,geriatric,psychological responses,postoperative......hypnotics benzodiazepine,diazepam,age factor,anaesthesia,geriatric,psychological responses,postoperative...

  6. Inhibition of benzodiazepine binding in vitro by amentoflavone, a constituent of various species of Hypericum.

    Science.gov (United States)

    Baureithel, K H; Büter, K B; Engesser, A; Burkard, W; Schaffner, W

    1997-06-01

    Flower extracts of Hypericum perforatum, Hypericum hirsutum, Hypericum patulum and Hypericum olympicum efficiently inhibited binding of [3H]flumazenil to rat brain benzodiazepine binding sites of the GABAA-receptor in vitro with IC50 values of 6.83, 6.97, 13.2 and 6.14 micrograms/ml, respectively. Single constituents of the extracts like hypericin, the flavones quercetin and luteolin, the glycosylated flavonoides rutin, hyperoside and quercitrin and the biflavone 13, II8-biapigenin did not inhibit binding up to concentrations of 1 microM. In contrast, amentoflavone revealed an IC50 = 14.9 +/- 1.9 nM on benzodiazepine binding in vitro. Comparative HPLC analyses of hypericin and amentoflavone in extracts of different Hypericum species revealed a possible correlation between the amentoflavone concentration and the inhibition of flumazenil binding. For hypericin no such correlation was observed. Our experimental data demonstrate that amentoflavone, in contrast to hypericin, presents a very active compound with regard to the inhibition of [3H]-flumazenil binding in vitro and thus might be involved in the antidepressant effects of Hypericum perforatum extracts. PMID:9204773

  7. NMDA receptor activity in neuropsychiatric disorders

    Directory of Open Access Journals (Sweden)

    ShaheenELakhan

    2013-06-01

    Full Text Available N-Methyl-D-aspartate (NMDA receptors play a variety of physiologic roles and their proper signaling is essential for cellular homeostasis. Any disruption in this pathway, leading to either enhanced or decreased activity, may result in the manifestation of neuropsychiatric pathologies such as schizophrenia, mood disorders, substance induced psychosis, Huntington's disease, Alzheimer's disease, and neuropsychiatric systemic lupus erythematosus. Here, we explore the notion that the overlap in activity of at least one biochemical pathway, the NMDA receptor pathway, may be the link to understanding the overlap in psychotic symptoms between diseases. This review intends to present a broad overview of those neuropsychiatric disorders for which alternations in NMDA receptor activity is prominent thus suggesting that continued direction of pharmaceutical intervention to this pathway may present a viable option for managing symptoms.

  8. Mechanism of FGF receptor dimerization and activation

    Science.gov (United States)

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise.

  9. Inhibition of human immunodeficiency virus type 1 Tat-dependent activation of translation in Xenopus oocytes by the benzodiazepine Ro24-7429 requires trans-activation response element loop sequences.

    Science.gov (United States)

    Braddock, M; Cannon, P; Muckenthaler, M; Kingsman, A J; Kingsman, S M

    1994-01-01

    Two benzodiazepine compounds, [7-chloro-5-(2-pyrryl)-3H-1,4 benzodiazapin-2-(H)-one] (Ro5-3335) and [7-chloro-5-(1H-pyrrol-2-yl)-3H-benzo[e] [1,4] diazepin-2-yl]- methylamine (Ro24-7429), inhibit human immunodeficiency virus type 1 (HIV-1) replication via a specific effect on the function of the transactivator protein, Tat. To gain further insight into the mechanism of action of these compounds, we have tested their effects in an alternative assay for Tat activation in Xenopus oocytes. In this system, translation of trans-activation response element (TAR)-containing RNA is activated by Tat. Both compounds specifically blocked activation of translation in a dose-dependent fashion, with Ro24-7429 showing the greater potency. In the Xenopus oocyte system, as in mammalian cells, mutation of the TAR loop sequences abolishes Tat action. However, it is possible to obtain TAR-specific, Tat-dependent activation of a target RNA with a mutation in the loop provided that this target is in large excess. This result has been interpreted as indicating that a negative factor has been titrated (M. Braddock, R. Powell, A.D. Blanchard, A.J. Kingsman, and S.M. Kingsman, FASEB J. 7:214-222, 1993). Interestingly Ro24-7429 was unable to inhibit the TAR-specific but loop sequence-independent mode of translational activation. This finding suggests that a specific loop-binding cellular factor may mediate the effects of this inhibitor of Tat action. Consistent with this notion, we could not detect any effect of Ro24-7429 on the efficiency of specific Tat binding to TAR in vitro. PMID:8254735

  10. Anxiolytic activity of adenosine receptor activation in mice.

    Science.gov (United States)

    Jain, N; Kemp, N; Adeyemo, O; Buchanan, P; Stone, T W

    1995-10-01

    1. Purine analogues have been examined for anxiolytic- and anxiogenic-like activity in mice, by use of the elevated plus-maze. 2. The selective A1 receptor agonist, N6-cyclopentyladenosine (CPA) had marked anxiolytic-like activity at 10 and 50 microg kg(-1), with no effect on locomotor performance at these doses. 3. The A1 selective adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (CPX) had no significant effect on anxiety-related measures or locomotor behaviour, but blocked the anxiolytic-like activity of CPA. The hydrophilic xanthine, 8-(p-sulphophenyl) theophylline did not prevent anxiolysis by CPA. 4. Caffeine had anxiogenic-like activity at 30 mg kg(-1) which was prevented by CPA at 50 micro kg(-1). 5. The A2 receptor agonist, N6-[2-(3,5-dimethoxyphenyl)-2(2-methylphenyl)-ethyl]adenosine (DPMA) had no effect on anxiety behaviour but depressed locomotor activity at the highest dose tested of 1 mg kg(-1). The A2 receptor antagonist, 1,3-dimethyl-l-propargylxanthine (DMPX) had no effect on anxiety-related measures or locomotion and did not modify the anxiolytic-like activity of CPA. 6. Administration of DPMA in combination with anxiolytic doses of CPA prevented the anxiolytic-like activity of the latter. 7. The results suggest that the selective activation of central A1 adenosine receptors induces anxiolytic-like behaviour, while the activation of A2 sites causes locomotor depression and reduces the effects of A1 receptor activation. The absence of any effect of CPX alone suggests that the receptors involved in modulating behaviour in the elevated plus-maze in mice are not activated tonically by endogenous adenosine. PMID:8640355

  11. Imaging of neuropsychiatric disorders. The usefulness of new brain receptor radiopharmaceuticals

    International Nuclear Information System (INIS)

    Until now, imaging of brain receptors have been only possible with positron emission tomography (PET), because there have been no high specific activity, high receptor affinity tracers available for clinical use with single photon emission tomography (SPECT). During the recent years fair number of new receptor ligands have been developed. For dopaminergic system there, are ligands for studying both presynaptic and postsynaptic sites, benzodiazepine receptors can be imaged with high quality ligands and also serotonergic receptors can be imaged. Very intensive work is underway for developing muscarinic receptor ligands, as well as for many other brain receptors

  12. CERAPP: Collaborative estrogen receptor activity prediction project

    DEFF Research Database (Denmark)

    Mansouri, Kamel; Abdelaziz, Ahmed; Rybacka, Aleksandra;

    2016-01-01

    Background: Humans are exposed to thousands of man-made chemicals in the environment. Some chemicals mimic natural endocrine hormones and, thus, have the potential to be endocrine disruptors. Most of these chemicals have never been tested for their ability to interact with the estrogen receptor (ER......). Risk assessors need tools to prioritize chemicals for evaluation in costly in vivo tests, for instance, within the U.S. EPA Endocrine Disruptor Screening Program. oBjectives: We describe a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) and...

  13. Spongian diterpenoids inhibit androgen receptor activity

    OpenAIRE

    Yang, Yu Chi; Labros G Meimetis; Tien, Amy H; Mawji, Nasrin R.; Carr, Gavin; Wang, Jun; Andersen, Raymond J.; Sadar, Marianne D.

    2013-01-01

    Androgen receptor (AR) is a ligand-activated transcription factor and a validated drug target for all stages of prostate cancer. Antiandrogens compete with physiological ligands for AR ligand-binding domain (LBD). High-throughput screening of a marine natural product library for small molecules that inhibit AR transcriptional activity yielded the furanoditerpenoid spongia-13(16),-14-dien-19-oic acid, designated terpene 1 (T1). Characterization of T1 and the structurally related semi-synthetic...

  14. Synthesis and carbon-11-labeling of p-MeO-SSR180575, a novel indoleacetamide-based candidate for PET imaging of the peripheral benzodiazepine receptor (TSPO 18 kDa)

    International Nuclear Information System (INIS)

    Complete text of publication follows: Objectives: The 3-iso-quinolinecarboxamide [11C]PK11195, despite its low brain uptake and high level of nonspecific binding, is still the most widely used PET-radioligand for the in vivo imaging of the peripheral benzodiazepine receptor (PBR or TSPO 18 kDa). Several new PBR radioligands are currently developed to replace [11C]PK11195, e.g the pyrazolo[1, 5-a]pyrimidine-acetamides [11C]DPA-713 and [18F]DPA-714, the imidazo[1, 2-a]pyridine-acetamides [11C]CLINME and [18F]PBR111 and the N-benzyl-N-(2-phenoxy-aryl)- acetamides [11C]PBR28 and [18F]FEDAA1106. Another attractive newly identified chemical class of structures are the indole-acetamides and notably compounds derived from the lead compound SSR180575. Herein are reported the synthesis and the labelling with the positron-emitter carbon-11 (half-life: 20.38 min) of a novel derivative of SSR180575, bearing a para methoxy function on its phenyl ring. Methods: p-MeO-SSR180575 (1) was synthesized from commercially available 4-chloro-2-nitrotoluene in 10 steps. O-demethylation, performed with a boron tribromide solution in dichloromethane at low temperature, afforded the free phenol derivative 2. Carbon-11 labeling of p-MeO-SSR180575 (1) was performed using a TRACERLab FX-C Pro synthesizer (GEMS) and comprised (1) trapping of [11C]MeOTf at -10 C in acetone (0.3 mL) containing the nor-derivative 2 (O-demethylated, 0.6-0.9 mg) and aq. 3N NaOH (8 μL); (2) heating at 110 C for 2 min; (3) concentration to dryness and taking up the residue in 1.0 mL of the HPLC mobile phase; (4) purification using semi-preparative reversed-phase HPLC (Waters Symmetry C-18 - eluent: CH3CN / H2O / TFA: 50 / 50 / 0.1 (v:v:v) - flow rate: 5 mL/min - detection at 254 nm) and (5) SepPakR Plus C-18-based formulation for i.v. injection. Results: p-MeO-SSR180575 (1) was obtained in 10% overall yield. The tricky and low-yielding step in our approach was the pyridazine ring formation reaction that proceeded

  15. Fatty acids activate a chimera of the clofibric acid-activated receptor and the glucocorticoid receptor.

    OpenAIRE

    Göttlicher, M; Widmark, E; Q. Li; Gustafsson, J.A.

    1992-01-01

    Peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643 have been shown to activate PPAR (peroxisome proliferator-activated receptor), a member of the steroid nuclear receptor superfamily. We have cloned the cDNA from the rat that is homologous to that from the mouse [Issemann, I. & Green, S. (1990) Nature (London) 347, 645-650], which encodes a 97% similar protein with a particularly well-conserved putative ligand-binding domain. To search for physiologically occurring acti...

  16. Human Receptor Activation by Aroclor 1260, a Polychlorinated Biphenyl Mixture

    OpenAIRE

    Wahlang, Banrida; Falkner, K. Cameron; Clair, Heather B.; Al-Eryani, Laila; Prough, Russell A.; States, J. Christopher; Coslo, Denise M.; Omiecinski, Curtis J.; Cave, Matthew C.

    2014-01-01

    Polychlorinated biphenyls (PCBs) are persistent environmental toxicants, present in 100% of U.S. adults and dose-dependently associated with obesity and non-alcoholic fatty liver disease (NAFLD). PCBs are predicted to interact with receptors previously implicated in xenobiotic/energy metabolism and NAFLD. These receptors include the aryl hydrocarbon receptor (AhR), pregnane xenobiotic receptor (PXR), constitutive androstane receptor (CAR), peroxisome proliferator-activated receptors (PPARs), ...

  17. RELAXIN ACTIVATES PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR GAMMA

    OpenAIRE

    Singh, Sudhir; Bennett, Robert G

    2009-01-01

    Relaxin is a polypeptide hormone that triggers multiple signaling pathways through its receptor RXFP1. Many of relaxin’s functions, including vascular and antifibrotic effects, are similar to those induced by activation of PPARγ. In this study, we tested the hypothesis that relaxin signaling through RXFP1 would activate PPARγ activity. In cells overexpressing RXFP1 (HEK-RXFP1), relaxin increased transcriptional activity through a PPAR response element (PPRE) in a concentration-dependent manne...

  18. Flavonoids as GABAA receptor ligands: the whole story?

    Science.gov (United States)

    Wasowski, Cristina; Marder, Mariel

    2012-01-01

    Benzodiazepines are the most widely prescribed class of psychoactive drugs in current therapeutic use, despite the important unwanted side effects that they produce, such as sedation, myorelaxation, ataxia, amnesia, and ethanol and barbiturate potentiation and tolerance. They exert their therapeutic effects via binding to the benzodiazepine binding site of gamma-aminobutyric acid (GABA) type A receptors, and allosterically modulating the chloride flux through the ion channel complex. First isolated from plants used as tranquilizers in folkloric medicine, some natural flavonoids have been shown to possess selective affinity for the benzodiazepine binding site with a broad spectrum of central nervous system effects. Since the initial search for alternative benzodiazepine ligands amongst the flavonoids, a list of successful synthetic derivatives has been generated with enhanced activities. This review provides an update on research developments that have established the activity of natural and synthetic flavonoids on GABA type A receptors. Flavonoids are prominent drugs in the treatment of mental disorders, and can also be used as tools to study modulatory sites at GABA type A receptors and to develop GABA type A selective agents further.

  19. Anxiolytic activity of adenosine receptor activation in mice.

    OpenAIRE

    Jain, N; Kemp, N; Adeyemo, O; Buchanan, P.; Stone, T W

    1995-01-01

    1. Purine analogues have been examined for anxiolytic- and anxiogenic-like activity in mice, by use of the elevated plus-maze. 2. The selective A1 receptor agonist, N6-cyclopentyladenosine (CPA) had marked anxiolytic-like activity at 10 and 50 microg kg(-1), with no effect on locomotor performance at these doses. 3. The A1 selective adenosine receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (CPX) had no significant effect on anxiety-related measures or locomotor behaviour, but blocked ...

  20. Relaxin Family Peptide Receptor 1 (RXFP1) Activation Stimulates the Peroxisome Proliferator-Activated Receptor Gamma

    OpenAIRE

    Singh, Sudhir; Bennett, Robert G

    2009-01-01

    Relaxin (Rlx) has antifibrotic effects in a number of tissues. Many of these effects are similar to those induced by the activators of peroxisome proliferator-activated receptor γ (PPARγ), raising the possibility that a mechanism for Rlx’s antifibrotic effects may involve activation of the PPARγ pathway. This study investigates the effect of Rlx on PPARs and their mechanism of upregulation. It shows that Rlx stimulates ligand-independent PPAR activation in a dose-dependent manner. The combine...

  1. Monoclonal antibodies to the human insulin receptor that activate glucose transport but not insulin receptor kinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Forsayeth, J.R.; Caro, J.F.; Sinha, M.K.; Maddux, B.A.; Goldfine, I.D.

    1987-05-01

    Three mouse monoclonal antibodies were produced that reacted with the ..cap alpha.. subunit of the human insulin receptor. All three both immunoprecipitated /sup 125/I-labeled insulin receptors from IM-9 lymphocytes and competitively inhibited /sup 125/I-labeled insulin binding to its receptor. Unlike insulin, the antibodies failed to stimulate receptor autophosphorylation in both intact IM-9 lymphocytes and purified human placental insulin receptors. Moreover, unlike insulin, the antibodies failed to stimulate receptor-mediated phosphorylation of exogenous substrates. However, like insulin, two of the three antibodies stimulated glucose transport in isolated human adipocytes. One antibody, on a molar basis, was as potent as insulin. These studies indicate, therefore, that monoclonal antibodies to the insulin receptor can mimic a major function of insulin without activating receptor kinase activity. They also raise the possibility that certain actions of insulin such as stimulation of glucose transport may not require the activation of receptor kinase activity.

  2. Monoclonal antibodies to the human insulin receptor that activate glucose transport but not insulin receptor kinase activity

    International Nuclear Information System (INIS)

    Three mouse monoclonal antibodies were produced that reacted with the α subunit of the human insulin receptor. All three both immunoprecipitated 125I-labeled insulin receptors from IM-9 lymphocytes and competitively inhibited 125I-labeled insulin binding to its receptor. Unlike insulin, the antibodies failed to stimulate receptor autophosphorylation in both intact IM-9 lymphocytes and purified human placental insulin receptors. Moreover, unlike insulin, the antibodies failed to stimulate receptor-mediated phosphorylation of exogenous substrates. However, like insulin, two of the three antibodies stimulated glucose transport in isolated human adipocytes. One antibody, on a molar basis, was as potent as insulin. These studies indicate, therefore, that monoclonal antibodies to the insulin receptor can mimic a major function of insulin without activating receptor kinase activity. They also raise the possibility that certain actions of insulin such as stimulation of glucose transport may not require the activation of receptor kinase activity

  3. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH2, respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  4. Quantifying Agonist Activity at G Protein-coupled Receptors

    OpenAIRE

    Ehlert, Frederick J.; Suga, Hinako; Griffin, Michael T.

    2011-01-01

    When an agonist activates a population of G protein-coupled receptors (GPCRs), it elicits a signaling pathway that culminates in the response of the cell or tissue. This process can be analyzed at the level of a single receptor, a population of receptors, or a downstream response. Here we describe how to analyze the downstream response to obtain an estimate of the agonist affinity constant for the active state of single receptors.

  5. Chronic use of benzodiazepines among older adults

    Directory of Open Access Journals (Sweden)

    Jussara Mendonça Alvarenga

    2014-12-01

    Full Text Available OBJECTIVE To analyze the perception of and motivation for the chronic use of benzodiazepine among older adults. METHODS A qualitative study was conducted on 22 older adults living in Bambuí, MG, Southeastern Brazil, who were taking benzodiazepines and had the clinical and cognitive ability to respond to interview questions. The collected data were analyzed on the basis of the “signs, meanings, and actions” model. RESULTS The main reasons pointed out for the use of benzodiazepines were “nervousness”, “sleep problems”, and “worry” due to family and financial problems, everyday problems, and existential difficulties. None of the interviewees said that they used benzodiazepines in a dose higher than that recommended or had been warned by health professionals about any risks of their continuous use. Different strategies were used to obtain the prescription for the medication, and any physician would prescribe it, indicating that a bond was established with the drug and not with the health professional or healthcare service. Obtaining and consuming the medication turned into a crucial issue because benzodiazepine assumes the status of an essential food, which leads users to not think but sleep. It causes a feeling of relief from their problems such as awareness of human finitude and fragility, existential difficulties, and family problems. CONCLUSIONS Benzodiazepine assumes the characteristics of polyvalence among older adults, which extrapolate specific clinical indications, and of essentiality to deal with life’s problems in old age. Although it relieves the “nerves”, the chronic use of benzodiazepines buffers suffering and prevents older adults from going through the suffering. This shows important difficulties in the organization and planning of strategies that are necessary for minimizing the chronic use in this population.

  6. Chronic use of benzodiazepines among older adults.

    Science.gov (United States)

    Alvarenga, Jussara Mendonça; Giacomin, Karla Cristina; Loyola Filho, Antônio Ignácio de; Uchoa, Elizabeth; Firmo, Josélia Oliveira Araújo

    2014-12-01

    OBJECTIVE To analyze the perception of and motivation for the chronic use of benzodiazepine among older adults. METHODS A qualitative study was conducted on 22 older adults living in Bambuí, MG, Southeastern Brazil, who were taking benzodiazepines and had the clinical and cognitive ability to respond to interview questions. The collected data were analyzed on the basis of the "signs, meanings, and actions" model. RESULTS The main reasons pointed out for the use of benzodiazepines were "nervousness", "sleep problems", and "worry" due to family and financial problems, everyday problems, and existential difficulties. None of the interviewees said that they used benzodiazepines in a dose higher than that recommended or had been warned by health professionals about any risks of their continuous use. Different strategies were used to obtain the prescription for the medication, and any physician would prescribe it, indicating that a bond was established with the drug and not with the health professional or healthcare service. Obtaining and consuming the medication turned into a crucial issue because benzodiazepine assumes the status of an essential food, which leads users to not think but sleep. It causes a feeling of relief from their problems such as awareness of human finitude and fragility, existential difficulties, and family problems. CONCLUSIONS Benzodiazepine assumes the characteristics of polyvalence among older adults, which extrapolate specific clinical indications, and of essentiality to deal with life's problems in old age. Although it relieves the "nerves", the chronic use of benzodiazepines buffers suffering and prevents older adults from going through the suffering. This shows important difficulties in the organization and planning of strategies that are necessary for minimizing the chronic use in this population. PMID:26039388

  7. Cannabinoids go nuclear: evidence for activation of peroxisome proliferator-activated receptors

    OpenAIRE

    O'Sullivan, S E

    2007-01-01

    Cannabinoids act at two classical cannabinoid receptors (CB1 and CB2), a 7TM orphan receptor and the transmitter-gated channel transient receptor potential vanilloid type-1 receptor. Recent evidence also points to cannabinoids acting at members of the nuclear receptor family, peroxisome proliferator-activated receptors (PPARs, with three subtypes α, β (δ) and γ), which regulate cell differentiation and lipid metabolism. Much evidence now suggests that endocannabinoids are natural activators o...

  8. Model for growth hormone receptor activation based on subunit rotation within a receptor dimer

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard J.; Adams, Julian J.; Pelekanos, Rebecca A.; Wan, Yu; McKinstry, William J.; Palethorpe, Kathryn; Seeber, Ruth M.; Monks, Thea A.; Eidne, Karin A.; Parker, Michael W.; Waters, Michael J. (UWA); (St. Vincent); (Queensland)

    2010-07-13

    Growth hormone is believed to activate the growth hormone receptor (GHR) by dimerizing two identical receptor subunits, leading to activation of JAK2 kinase associated with the cytoplasmic domain. However, we have reported previously that dimerization alone is insufficient to activate full-length GHR. By comparing the crystal structure of the liganded and unliganded human GHR extracellular domain, we show here that there is no substantial change in its conformation on ligand binding. However, the receptor can be activated by rotation without ligand by inserting a defined number of alanine residues within the transmembrane domain. Fluorescence resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET) and coimmunoprecipitation studies suggest that receptor subunits undergo specific transmembrane interactions independent of hormone binding. We propose an activation mechanism involving a relative rotation of subunits within a dimeric receptor as a result of asymmetric placement of the receptor-binding sites on the ligand.

  9. Thyroid hormone receptor β mutants: Dominant negative regulators of peroxisome proliferator-activated receptor γ action

    OpenAIRE

    Araki, Osamu; Ying, Hao; Furuya, Fumihiko; Zhu, Xuguang; Cheng, Sheue-yann

    2005-01-01

    Thyroid hormone (T3) and peroxisome proliferators have overlapping metabolic effects in the maintenance of lipid homeostasis. Their actions are mediated by their respective receptors: thyroid hormone receptors (TR) and peroxisome proliferator-activated receptors (PPAR). We recently found that a dominantly negative TRβ mutant (PV) that causes a genetic disease, resistance to thyroid hormone, acts to repress the ligand (troglitazone)-mediated transcriptional activity of PPARγ in cultured thyroi...

  10. The insulin receptor C-terminus is involved in regulation of the receptor kinase activity.

    Science.gov (United States)

    Kaliman, P; Baron, V; Alengrin, F; Takata, Y; Webster, N J; Olefsky, J M; Van Obberghen, E

    1993-09-21

    During the insulin receptor activation process, ligand binding and autophosphorylation induce two distinct conformational changes in the C-terminal domain of the receptor beta-subunit. To analyze the role of this domain and the involvement of the C-terminal autophosphorylation sites (Tyr1316 and Tyr1322) in receptor activation, we used (i) antipeptide antibodies against three different C-terminal sequences (1270-1281, 1294-1317, and 1309-1326) and (ii) an insulin receptor mutant (Y/F2) where Tyr1316 and Tyr1322 have been replaced by Phe. We show that the autophosphorylation-induced C-terminal conformational change is preserved in the Y/F2 receptor, indicating that this change is not induced by phosphorylation of the C-terminal sites but most likely by phosphorylation of the major sites in the kinase domain (Tyr1146, Tyr1150, and Tyr1151). Binding of antipeptide antibodies to the C-terminal domain modulated (activated or inhibited) both mutant and wild-type receptor-mediated phosphorylation of poly(Glu/Tyr). In contrast to the wild-type receptor, Y/F2 exhibited the same C-terminal configuration before and after insulin binding, evidencing that mutation of Tyr1316 and Tyr1322 introduced conformational changes in the C-terminus. Finally, the mutant receptor was 2-fold more active than the wild-type receptor for poly(Glu/Tyr) phosphorylation. In conclusion, the whole C-terminal region of the insulin receptor beta-subunit is likely to exert a regulatory influence on the receptor kinase activity. Perturbations of the C-terminal region, such as binding of antipeptides or mutation of Tyr1316 and Tyr1322, provoke alterations at the receptor kinase level, leading to activation or inhibition of the enzymic activity. PMID:7690586

  11. The WSXWS motif in cytokine receptors is a molecular switch involved in receptor activation

    DEFF Research Database (Denmark)

    Dagil, Robert; Knudsen, Maiken J.; Olsen, Johan Gotthardt;

    2012-01-01

    The prolactin receptor (PRLR) is activated by binding of prolactin in a 2:1 complex, but the activation mechanism is poorly understood. PRLR has a conserved WSXWS motif generic to cytokine class I receptors. We have determined the nuclear magnetic resonance solution structure of the membrane prox...

  12. Benzodiazepine pathways in the chronically ill

    NARCIS (Netherlands)

    Van Hulten, Rolf; Heerdink, Eibert R.; Bakker, Albert; Leufkens, Hubert G.

    1999-01-01

    The association between patterns of use of benzodiazepines and chronic somatic morbidity was examined by applying the Chronic Disease Score (CDS). In the only pharmacy in a Dutch community, 6921 patients with data available covering a 10-year period (1983-1992) were included. In 1992, two-thirds of

  13. Activation of glucocorticoid receptors increases 5-HT2A receptor levels

    DEFF Research Database (Denmark)

    Trajkovska, Viktorija; Kirkegaard, Lisbeth; Krey, Gesa; Marcussen, Anders Bue; Thomsen, Morten Skøtt; Chourbaji, Sabine; Brandwein, Christiane; Ridder, Stephanie; Halldin, Christer; Gass, Peter; Knudsen, Gitte M; Aznar, Susana

    2009-01-01

    Major depression is associated with both dysregulation of the hypothalamic pituitary adrenal axis and serotonergic deficiency, not the least of the 5-HT2A receptor. However, how these phenomena are linked to each other, and whether a low 5-HT2A receptor level is a state or a trait marker of...... depression is unknown. In mice with altered glucocorticoid receptor (GR) expression we investigated 5-HT2A receptor levels by Western blot and 3H-MDL100907 receptor binding. Serotonin fibre density was analyzed by stereological quantification of serotonin transporter immunopositive fibers. To establish an...... effect of GR activation on 5-HT2A levels, mature organotypic hippocampal cultures were exposed to corticosterone with or without GR antagonist mifepristone and mineralocorticoid receptor (MR) antagonist spironolactone. In GR under-expressing mice, hippocampal 5-HT2A receptor protein levels were decreased...

  14. Baclofen in the short-term maintenance treatment of benzodiazepine dependence

    OpenAIRE

    Lekhansh Shukla; Arun Kandasamy; Muralidharan Kesavan; Vivek Benegal

    2014-01-01

    Benzodiazepine (BZD) dependence is a significant public health problem. Apart from the long-term tapering doses of BZD, no others drugs are available for the maintenance treatment of BZD dependence. Baclofen has been used in alcohol and other drug dependence as long-term anti-craving agent. Since alcohol and BZD act through the GABA receptor, we attempted to study the effect of Baclofen as maintenance treatment in a series of five cases with BZD dependence.

  15. Baclofen in the short-term maintenance treatment of benzodiazepine dependence

    Directory of Open Access Journals (Sweden)

    Lekhansh Shukla

    2014-01-01

    Full Text Available Benzodiazepine (BZD dependence is a significant public health problem. Apart from the long-term tapering doses of BZD, no others drugs are available for the maintenance treatment of BZD dependence. Baclofen has been used in alcohol and other drug dependence as long-term anti-craving agent. Since alcohol and BZD act through the GABA receptor, we attempted to study the effect of Baclofen as maintenance treatment in a series of five cases with BZD dependence.

  16. Cell death sensitization of leukemia cells by opioid receptor activation

    Science.gov (United States)

    Friesen, Claudia; Roscher, Mareike; Hormann, Inis; Fichtner, Iduna; Alt, Andreas; Hilger, Ralf A.; Debatin, Klaus-Michael; Miltner, Erich

    2013-01-01

    Cyclic AMP (cAMP) regulates a number of cellular processes and modulates cell death induction. cAMP levels are altered upon stimulation of specific G-protein-coupled receptors inhibiting or activating adenylyl cyclases. Opioid receptor stimulation can activate inhibitory Gi-proteins which in turn block adenylyl cyclase activity reducing cAMP. Opioids such as D,L-methadone induce cell death in leukemia cells. However, the mechanism how opioids trigger apoptosis and activate caspases in leukemia cells is not understood. In this study, we demonstrate that downregulation of cAMP induced by opioid receptor activation using the opioid D,L-methadone kills and sensitizes leukemia cells for doxorubicin treatment. Enhancing cAMP levels by blocking opioid-receptor signaling strongly reduced D,L-methadone-induced apoptosis, caspase activation and doxorubicin-sensitivity. Induction of cell death in leukemia cells by activation of opioid receptors using the opioid D,L-methadone depends on critical levels of opioid receptor expression on the cell surface. Doxorubicin increased opioid receptor expression in leukemia cells. In addition, the opioid D,L-methadone increased doxorubicin uptake and decreased doxorubicin efflux in leukemia cells, suggesting that the opioid D,L-methadone as well as doxorubicin mutually increase their cytotoxic potential. Furthermore, we found that opioid receptor activation using D,L-methadone alone or in addition to doxorubicin inhibits tumor growth significantly in vivo. These results demonstrate that opioid receptor activation via triggering the downregulation of cAMP induces apoptosis, activates caspases and sensitizes leukemia cells for doxorubicin treatment. Hence, opioid receptor activation seems to be a promising strategy to improve anticancer therapies. PMID:23633472

  17. Cocaine effects on mouse incentive-learning and human addiction are linked to α2 subunit-containing GABAA receptors

    Science.gov (United States)

    Dixon, Claire I.; Morris, Hannah V.; Breen, Gerome; Desrivieres, Sylvane; Jugurnauth, Sarah; Steiner, Rebecca C.; Vallada, Homero; Guindalini, Camila; Laranjeira, Ronaldo; Messas, Guilherme; Rosahl, Thomas W.; Atack, John R.; Peden, Dianne R.; Belelli, Delia; Lambert, Jeremy J.; King, Sarah L.; Schumann, Gunter; Stephens, David N.

    2010-01-01

    Because GABAA receptors containing α2 subunits are highly represented in areas of the brain, such as nucleus accumbens (NAcc), frontal cortex, and amygdala, regions intimately involved in signaling motivation and reward, we hypothesized that manipulations of this receptor subtype would influence processing of rewards. Voltage-clamp recordings from NAcc medium spiny neurons of mice with α2 gene deletion showed reduced synaptic GABAA receptor-mediated responses. Behaviorally, the deletion abolished cocaine’s ability to potentiate behaviors conditioned to rewards (conditioned reinforcement), and to support behavioral sensitization. In mice with a point mutation in the benzodiazepine binding pocket of α2-GABAA receptors (α2H101R), GABAergic neurotransmission in medium spiny neurons was identical to that of WT (i.e., the mutation was silent), but importantly, receptor function was now facilitated by the atypical benzodiazepine Ro 15-4513 (ethyl 8-amido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5-a] [1,4] benzodiazepine-3-carboxylate). In α2H101R, but not WT mice, Ro 15-4513 administered directly into the NAcc-stimulated locomotor activity, and when given systemically and repeatedly, induced behavioral sensitization. These data indicate that activation of α2−GABAA receptors (most likely in NAcc) is both necessary and sufficient for behavioral sensitization. Consistent with a role of these receptors in addiction, we found specific markers and haplotypes of the GABRA2 gene to be associated with human cocaine addiction. PMID:20133874

  18. Comparison of the activation kinetics of the M3 acetylcholine receptor and a constitutively active mutant receptor in living cells.

    Science.gov (United States)

    Hoffmann, Carsten; Nuber, Susanne; Zabel, Ulrike; Ziegler, Nicole; Winkler, Christiane; Hein, Peter; Berlot, Catherine H; Bünemann, Moritz; Lohse, Martin J

    2012-08-01

    Activation of G-protein-coupled receptors is the first step of the signaling cascade triggered by binding of an agonist. Here we compare the activation kinetics of the G(q)-coupled M(3) acetylcholine receptor (M(3)-AChR) with that of a constitutively active mutant receptor (M(3)-AChR-N514Y) using M(3)-AChR constructs that report receptor activation by changes in the fluorescence resonance energy transfer (FRET) signal. We observed a leftward shift in the concentration-dependent FRET response for acetylcholine and carbachol with M(3)-AChR-N514Y. Consistent with this result, at submaximal agonist concentrations, the activation kinetics of M(3)-AChR-N514Y were significantly faster, whereas at maximal agonist concentrations the kinetics of receptor activation were identical. Receptor deactivation was significantly faster with carbachol than with acetylcholine and was significantly delayed by the N514Y mutation. Receptor-G-protein interaction was measured by FRET between M(3)-AChR-yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP)-Gγ(2). Agonist-induced receptor-G-protein coupling was of a time scale similar to that of receptor activation. As observed for receptor deactivation, receptor-G-protein dissociation was slower for acetylcholine than that for carbachol. Acetylcholine-stimulated increases in receptor-G-protein coupling of M(3)-AChR-N514Y reached only 12% of that of M(3)-AChR and thus cannot be kinetically analyzed. G-protein activation was measured using YFP-tagged Gα(q) and CFP-tagged Gγ(2). Activation of G(q) was significantly slower than receptor activation and indistinguishable for the two agonists. However, G(q) deactivation was significantly prolonged for acetylcholine compared with that for carbachol. Consistent with decreased agonist-stimulated coupling to G(q), agonist-stimulated G(q) activation by M(3)-AChR-N514Y was not detected. Taken together, these results indicate that the N514Y mutation produces constitutive activation of M(3

  19. The Orphan Nuclear Receptor TR4 Is a Vitamin A-activated Nuclear Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X. Edward; Suino-Powell, Kelly M.; Xu, Yong; Chan, Cee-Wah; Tanabe, Osamu; Kruse, Schoen W.; Reynolds, Ross; Engel, James Douglas; Xu, H. Eric (Michigan-Med); (Van Andel)

    2015-11-30

    Testicular receptors 2 and 4 (TR2/4) constitute a subgroup of orphan nuclear receptors that play important roles in spermatogenesis, lipid and lipoprotein regulation, and the development of the central nervous system. Currently, little is known about the structural features and the ligand regulation of these receptors. Here we report the crystal structure of the ligand-free TR4 ligand binding domain, which reveals an autorepressed conformation. The ligand binding pocket of TR4 is filled by the C-terminal half of helix 10, and the cofactor binding site is occupied by the AF-2 helix, thus preventing ligand-independent activation of the receptor. However, TR4 exhibits constitutive transcriptional activity on multiple promoters, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, or ligand binding substantially reduce the transcriptional activity of this receptor. Importantly, both retinol and retinoic acid are able to promote TR4 to recruit coactivators and to activate a TR4-regulated reporter. These findings demonstrate that TR4 is a ligand-regulated nuclear receptor and suggest that retinoids might have a much wider regulatory role via activation of orphan receptors such as TR4.

  20. "Anxiolytic" and "anxiogenic" benzodiazepines and beta-carbolines: effects on aggressive and social behavior in rats and squirrel monkeys.

    Science.gov (United States)

    Weerts, E M; Tornatzky, W; Miczek, K A

    1993-01-01

    Ethopharmacological studies on the behavior of socially housed rats and squirrel monkeys were conducted to explore the role of the benzodiazepine GABAA-coupled ionophore receptor complex in aggressive and social interactions. Benzodiazepine receptor (BZR) antagonists, ZK 93426 (1-10 mg/kg) and flumazenil (3-10 mg/kg), the partial agonist, ZK 91296 (1-10 mg/kg) and the partial inverse agonists Ro 15-4513 (0.3-10 mg/kg), were administered to (1) squirrel monkeys prior to 1 h focal observations within established social groups or to (2) resident male rats before confrontations with a naive male intruder in their home cage for 5 min. Aggression was modified in a similar manner in both species, although squirrel monkeys were more sensitive to BZR challenges. Specifically, resident male rats showed dose dependent reductions in attack bites directed at intruder males that were significant at the highest dose of ZK 93426 (10 mg/kg). In squirrel monkeys, ZK 93426 (3 and 10 mg/kg) reduced aggressive grasps, threats and displays, as well as reducing the duration of being the target of aggression from untreated group members (1-10 mg/kg). The BZR partial agonist, ZK 91296 and the antagonist, flumazenil produced few effects on social behavior, low and high intensity aggression and motor activity in both species. Flumazenil (10-30 mg/kg) and ZK 91296 (10 mg/kg), but not ZK 93426, produced significant increases in foraging and feeding behaviors in squirrel monkeys. The hyperphagic effects of ZK 91296 and flumazenil, that are typical of BZR agonists compounds, were not observed in rats.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7870916

  1. The insulin receptor activation process involves localized conformational changes.

    Science.gov (United States)

    Baron, V; Kaliman, P; Gautier, N; Van Obberghen, E

    1992-11-15

    The molecular process by which insulin binding to the receptor alpha-subunit induces activation of the receptor beta-subunit with ensuing substrate phosphorylation remains unclear. In this study, we aimed at approaching this molecular mechanism of signal transduction and at delineating the cytoplasmic domains implied in this process. To do this, we used antipeptide antibodies to the following sequences of the receptor beta-subunit: (i) positions 962-972 in the juxtamembrane domain, (ii) positions 1247-1261 at the end of the kinase domain, and (iii) positions 1294-1317 and (iv) positions 1309-1326, both in the receptor C terminus. We have previously shown that insulin binding to its receptor induces a conformational change in the beta-subunit C terminus. Here, we demonstrate that receptor autophosphorylation induces an additional conformational change. This process appears to be distinct from the one produced by ligand binding and can be detected in at least three different beta-subunit regions: the juxtamembrane domain, the kinase domain, and the C terminus. Hence, the cytoplasmic part of the receptor beta-subunit appears to undergo an extended conformational change upon autophosphorylation. By contrast, the insulin-induced change does not affect the juxtamembrane domain 962-972 nor the kinase domain 1247-1261 and may be limited to the receptor C terminus. Further, we show that the hormone-dependent conformational change is maintained in a kinase-deficient receptor due to a mutation at lysine 1018. Therefore, during receptor activation, the ligand-induced change could precede ATP binding and receptor autophosphorylation. We propose that insulin binding leads to a transient receptor form that may allow ATP binding and, subsequently, autophosphorylation. The second conformational change could unmask substrate-binding sites and stabilize the receptor in an active conformation. PMID:1331080

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

    DEFF Research Database (Denmark)

    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...

  3. Chronic hyperammonemia induces tonic activation of NMDA receptors in cerebellum.

    Science.gov (United States)

    ElMlili, Nisrin; Boix, Jordi; Ahabrach, Hanan; Rodrigo, Regina; Errami, Mohammed; Felipo, Vicente

    2010-02-01

    Reduced function of the glutamate--nitric oxide (NO)--cGMP pathway is responsible for some cognitive alterations in rats with hyperammonemia and hepatic encephalopathy. Hyperammonemia impairs the pathway in cerebellum by increasing neuronal nitric oxide synthase (nNOS) phosphorylation in Ser847 by calcium-calmodulin-dependent protein kinase II (CaMKII), reducing nNOS activity, and by reducing nNOS amount in synaptic membranes, which reduces its activation following NMDA receptors activation. The reason for increased CaMKII activity in hyperammonemia remains unknown. We hypothesized that it would be as a result of increased tonic activation of NMDA receptors. The aims of this work were to assess: (i) whether tonic NMDA activation receptors is increased in cerebellum in chronic hyperammonemia in vivo; and (ii) whether this tonic activation is responsible for increased CaMKII activity and reduced activity of nNOS and of the glutamate--NO--cGMP pathway. Blocking NMDA receptors with MK-801 increases cGMP and NO metabolites in cerebellum in vivo and in slices from hyperammonemic rats. This is because of reduced phosphorylation and activity of CaMKII, leading to normalization of nNOS phosphorylation and activity. MK-801 also increases nNOS in synaptic membranes and reduces it in cytosol. This indicates that hyperammonemia increases tonic activation of NMDA receptors leading to reduced activity of nNOS and of the glutamate--NO--cGMP pathway. PMID:20002515

  4. Redefining the concept of protease-activated receptors: cathepsin S evokes itch via activation of Mrgprs

    OpenAIRE

    Reddy, Vemuri B.; Sun, Shuohao; Azimi, Ehsan; Elmariah, Sarina B.; Dong, Xinzhong; Lerner, Ethan A.

    2015-01-01

    Sensory neurons expressing Mas-related G protein coupled receptors (Mrgprs) mediate histamine-independent itch. We show that the cysteine protease cathepsin S activates MrgprC11 and evokes receptor-dependent scratching in mice. In contrast to its activation of conventional protease-activated receptors, cathepsin S mediated activation of MrgprC11 did not involve the generation of a tethered ligand. We demonstrate further that different cysteine proteases selectively activate specific mouse and...

  5. Human receptor activation by aroclor 1260, a polychlorinated biphenyl mixture.

    Science.gov (United States)

    Wahlang, Banrida; Falkner, K Cameron; Clair, Heather B; Al-Eryani, Laila; Prough, Russell A; States, J Christopher; Coslo, Denise M; Omiecinski, Curtis J; Cave, Matthew C

    2014-08-01

    Polychlorinated biphenyls (PCBs) are persistent environmental toxicants, present in 100% of U.S. adults and dose-dependently associated with obesity and non-alcoholic fatty liver disease (NAFLD). PCBs are predicted to interact with receptors previously implicated in xenobiotic/energy metabolism and NAFLD. These receptors include the aryl hydrocarbon receptor (AhR), pregnane xenobiotic receptor (PXR), constitutive androstane receptor (CAR), peroxisome proliferator-activated receptors (PPARs), liver-X-receptor (LXRα), and farnesoid-X-receptor (FXR). This study evaluates Aroclor 1260, a PCB mixture with congener composition mimicking that of human adipose tissue, and selected congeners, as potential ligands for these receptors utilizing human hepatoma-derived (HepG2) and primate-derived (COS-1) cell lines, and primary human hepatocytes. Aroclor 1260 (20 μg/ml) activated AhR, and PCB 126, a minor component, was a potent inducer. Aroclor 1260 activated PXR in a simple concentration-dependent manner at concentrations ≥10 μg/ml. Among the congeners tested, PCBs 138, 149, 151, 174, 183, 187, and 196 activated PXR. Aroclor 1260 activated CAR2 and CAR3 variants at lower concentrations and antagonize CAR2 activation by the CAR agonist, CITCO, at higher concentrations (≥20 μg/ml). Additionally, Aroclor 1260 induced CYP2B6 in primary hepatocytes. At subtoxic doses, Aroclor 1260 did not activate LXR or FXR and had no effect on LXR- or FXR-dependent induction by the agonists T0901317 or GW4064, respectively. Aroclor 1260 (20 μg/ml) suppressed PPARα activation by the agonist nafenopin, although none of the congeners tested demonstrated significant inhibition. The results suggest that Aroclor 1260 is a human AhR, PXR and CAR3 agonist, a mixed agonist/antagonist for CAR2, and an antagonist for human PPARα. PMID:24812009

  6. Tonic activation of presynaptic GABAB receptors on rat pallidosubthalamic terminals

    Institute of Scientific and Technical Information of China (English)

    Lei CHEN; Wing-ho YUNG

    2005-01-01

    Aim: The subthalamic nucleus plays a critical role in the regulation of movement,and abnormal activity of its neurons is associated with some basal ganglia motor symptoms. We examined the presence of functional presynaptic GABAB receptors on pallidosubthalamic terminals and tested whether they were tonically active in the in vitro subthalamic slices. Methods: Whole-cell patch-clamp recordings were applied to acutely prepared rat subthalamic nucleus slices. The effects of specific GABAB agonist and antagonist on action potential-independent inhibitory postsynapfic currents (IPSCs), as well as holding current, were examined.Results: Superfusion of baclofen, a GABAB receptor agonist, significantly reduced the frequency of GABAA receptor-mediated miniature IPSCs (mIPSCs), in a Cd2+-sensitive manner, with no effect on the amplitude, indicating presynaptic inhibition on GABA release. In addition, baclofen induced a weak outward current only in a minority of subthalamic neurons. Both the pre- and post-synaptic effects of baclofen were prevented by the specific GABAB receptor antagonist,CGP55845. Furthermore, CGP55845 alone increased the frequency of mIPSCs,but had no effect on the holding current. Conclusion: These findings suggest the functional dominance of presynaptic GABAB receptors on the pallidosubthalamic terminals over the postsynaptic GABAB receptors on subthalamic neurons.Furthermore, the presynaptic, but not the postsynaptic, GABAB receptors are tonically active, suggesting that the presynaptic GABAB receptors in the subthalamic nucleus are potential therapeutic target for the treatment of Parkinson disease.

  7. Memory Effects of Benzodiazepines: Memory Stages and Types Versus Binding-Site Subtypes

    Directory of Open Access Journals (Sweden)

    Miroslav M. Savic

    2005-01-01

    Full Text Available Benzodiazepines are well established as inhibitory modulators of memory processing. This effect is especially prominent when applied before the acquisition phase of a memory task. This minireview concentrates on the putative subtype selectivity of the acquisition-impairing action of benzodiazepines. Namely, recent genetic studies and standard behavioral tests employing subtype-selective ligands pointed to the predominant involvement of two subtypes of benzodiazepine binding sites in memory modulation. Explicit memory learning seems to be affected through the GABAA receptors containing the α1 and α5 subunits, whereas the effects on procedural memory can be mainly mediated by the α1 subunit. The pervading involvement of the α1 subunit in memory modulation is not at all unexpected because this subunit is the major subtype, present in 60% of all GABAA receptors. On the other hand, the role of α5 subunits, mainly expressed in the hippocampus, in modulating distinct forms of memory gives promise of selective pharmacological coping with certain memory deficit states.

  8. Long-Term Use of Benzodiazepines: Implications and guidelines

    OpenAIRE

    Potts, Nicholas L.S.; K Ranga R Krishnan

    1992-01-01

    Problems associated with physical dependence and abuse of benzodiazepines by a small percentage of patients have reduced their popularity from the most commonly prescribed psychoactive drug in the 1970s to being prescribed for mainly short periods. Patients who benefit from long-term benzodiazepine use are nearly ignored by the medical community as a whole. This article details what patient population can improve from long-term benzodiazepine therapy, the risks and benefits of treatment, and ...

  9. Design, Synthesis and Biological Evaluation of Sulfamide and Triazole Benzodiazepines as Novel p53-MDM2 Inhibitors

    Directory of Open Access Journals (Sweden)

    Zhiliang Yu

    2014-09-01

    Full Text Available A series of sulfamide and triazole benzodiazepines were obtained with the principle of bioisosterism. The p53-murine double minute 2 (MDM2 inhibitory activity and in vitro antitumor activity were evaluated. Most of the novel benzodiazepines exhibited moderate protein binding inhibitory activity. Particularly, triazole benzodiazepines showed good inhibitory activity and antitumor potency. Compound 16 had promising antitumor activity against the U-2 OS human osteosarcoma cell line with an IC50 value of 4.17 μM, which was much better than that of nutlin-3. The molecular docking model also successfully predicted that this class of compounds mimicked the three critical residues of p53 binding to MDM2.

  10. Helix 11 Dynamics is Critical for Constitutive Androstane Receptor Activity

    OpenAIRE

    Wright, Edward; Busby, Scott A.; Wisecarver, Sarah; Vincent, Jeremy; Griffin, Patrick R.; Fernandez, Elias J.

    2011-01-01

    The constitutive androstane receptor (CAR) transactivation can occur in the absence of exogenous ligand and this activity is enhanced by agonists TCPOBOP and meclizine. We use biophysical and cell-based assays to show that increased activity of CAR(TCPOBOP) relative to CAR(meclizine) corresponds to a higher affinity of CAR(TCPOBOP) for the steroid receptor coactivator-1. Additionally, steady-state fluorescence spectra suggest conformational differences between CAR(TCPOBOP):RXR and CAR(meclizi...

  11. Differential interactions engendered by benzodiazepine and neuroactive steroid combinations on schedule-controlled responding in rats.

    Science.gov (United States)

    Gunter, Barak W; Platt, Donna M; Rowlett, James K

    2015-10-01

    Benzodiazepines are positive allosteric modulators of the GABAA receptor and are prescribed as anxiolytics, hypnotics, and anticonvulsants. While these drugs clearly have clinical value, their use is associated with unwanted side effects such as sedation and motor impairment. Neuroactive steroids are endogenous modulators of GABAA receptors and recent evidence has shown that combinations of the triazolo-benzodiazepine triazolam and the endogenous neuroactive steroid pregnanolone can produce both supra-additive anxiolytic effects and infra-additive reinforcing effects. In the present study, we investigated these same combinations as well as combinations of two clinically-relevant drugs from different chemical classes, the 1, 4 substituted (7-nitro) benzodiazepine clonazepam and the synthetic neuroactive steroid ganaxolone, in rats trained under a 10-response, fixed ratio (FR) schedule of food reinforcement. All four drugs induced a significant and dose-dependent suppression of food-maintained responding. From the dose-response functions, ED50s (i.e., the doses that engendered 50% of the maximum rate-decreasing effect) were generated for each drug. Dose-response functions for combinations of triazolam/pregnanolone, clonazepam/ganaxolone, triazolam/ganaxolone, and clonazepam/pregnanolone were then determined. Isobolographic analysis of the rate-decreasing effects of these combinations revealed that the potencies of the triazolam/pregnanolone combinations were supra-additive while the clonazepam/ganaxolone combinations were additive or infra-additive in relation to predicted values based on dose-additive effects. Furthermore, mixtures of clonazepam/pregnanolone were supra-additive while triazolam/ganaxolone combinations were additive, infra-additive and supra-additive. These results suggest that the ability of benzodiazepine and neuroactive steroid combinations to attenuate rates of food-maintained responding depends critically on both the constituent drugs and the

  12. Heterodimeric interaction between retinoid X receptor alpha and orphan nuclear receptor OR1 reveals dimerization-induced activation as a novel mechanism of nuclear receptor activation.

    OpenAIRE

    Wiebel, F F; Gustafsson, J.A.

    1997-01-01

    OR1 is a member of the steroid/thyroid hormone nuclear receptor superfamily which has been described to mediate transcriptional responses to retinoids and oxysterols. On a DR4 response element, an OR1 heterodimer with the nuclear receptor retinoid X receptor alpha (RXR alpha) has been described to convey transcriptional activation in both the absence and presence of the RXR ligand 9-cis retinoic acid, the mechanisms of which have remained unclear. Here, we dissect the effects of RXR alpha and...

  13. Retinoic Acid-mediated Nuclear Receptor Activation and Hepatocyte Proliferation

    Science.gov (United States)

    Bushue, Nathan; Wan, Yu-Jui Yvonne

    2016-01-01

    Due to their well-known differentiation and apoptosis-inducing abilities, retinoic acid (RA) and its analogs have strong anti-cancer efficacy in human cancers. However, in vivo RA is a liver mitogen. While speculation has persisted that RA-mediated signaling is likely involved in hepatocyte proliferation during liver regeneration, direct evidence is still required. Findings in support of this proposition include observations that a release of retinyl palmitate (the precursor of RA) occurs in liver stellate cells following liver injury. Nevertheless, the biological action of this released vitamin A is virtually unknown. More likely is that the released vitamin A is converted to RA, the biological form, and then bound to a specific receptor (retinoid x receptor; RXRα), which is most abundantly expressed in the liver. Considering the mitogenic effects of RA, the RA-activated RXRα would likely then influence hepatocyte proliferation and liver tissue repair. At present, the mechanism by which RA stimulates hepatocyte proliferation is largely unknown. This review summarizes the activation of nuclear receptors (peroxisome proliferator activated receptor-α, pregnane x receptor, constitutive androstane receptor, and farnesoid x receptor) in an RXRα dependent manner to induce hepatocyte proliferation, providing a link between RA and its proliferative role.

  14. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    of certain PAHs to activate the Ah receptor was assessed in H4IIE liver cancer cells, stably transfected with a luciferase reporter gene system. The positive control 2, 3,7, 8-tetrachlorodibenzodioxin (TCDD) caused a 13-14-fold induction of luciferase activity reaching maximum activity at 0.1 nM. DB...

  15. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    of certain PAHs to activate the Ah receptor was assessed in H4IIE liver cancer cells, stably transfected with a luciferase reporter gene system. The positive control 2, 3,7, 8-tetrachlorodibenzodioxin (TCDD) caused a 13-14-fold induction of luciferase activity reaching maximum activity at 0.1 nM. DB...

  16. Modulation of β-catenin signaling by glucagon receptor activation.

    Directory of Open Access Journals (Sweden)

    Jiyuan Ke

    Full Text Available The glucagon receptor (GCGR is a member of the class B G protein-coupled receptor family. Activation of GCGR by glucagon leads to increased glucose production by the liver. Thus, glucagon is a key component of glucose homeostasis by counteracting the effect of insulin. In this report, we found that in addition to activation of the classic cAMP/protein kinase A (PKA pathway, activation of GCGR also induced β-catenin stabilization and activated β-catenin-mediated transcription. Activation of β-catenin signaling was PKA-dependent, consistent with previous reports on the parathyroid hormone receptor type 1 (PTH1R and glucagon-like peptide 1 (GLP-1R receptors. Since low-density-lipoprotein receptor-related protein 5 (Lrp5 is an essential co-receptor required for Wnt protein mediated β-catenin signaling, we examined the role of Lrp5 in glucagon-induced β-catenin signaling. Cotransfection with Lrp5 enhanced the glucagon-induced β-catenin stabilization and TCF promoter-mediated transcription. Inhibiting Lrp5/6 function using Dickkopf-1(DKK1 or by expression of the Lrp5 extracellular domain blocked glucagon-induced β-catenin signaling. Furthermore, we showed that Lrp5 physically interacted with GCGR by immunoprecipitation and bioluminescence resonance energy transfer assays. Together, these results reveal an unexpected crosstalk between glucagon and β-catenin signaling, and may help to explain the metabolic phenotypes of Lrp5/6 mutations.

  17. Cloning, constitutive activity and expression profiling of two receptors related to relaxin receptors in Drosophila melanogaster.

    Science.gov (United States)

    Van Hiel, Matthias B; Vandersmissen, Hans Peter; Proost, Paul; Vanden Broeck, Jozef

    2015-06-01

    Leucine-rich repeat containing G protein-coupled receptors (LGRs) comprise a cluster of transmembrane proteins, characterized by the presence of a large N-terminal extracellular domain. This receptor group can be classified into three subtypes. Belonging to the subtype C LGRs are the mammalian relaxin receptors LGR7 (RXFP1) and LGR8 (RXFP2), which mediate important reproductive and other processes. We identified two related receptors in the genome of the fruit fly and cloned their open reading frames into an expression vector. Interestingly, dLGR3 demonstrated constitutive activity at very low doses of transfected plasmid, whereas dLGR4 did not show any basal activity. Both receptors exhibited a similar expression pattern during development, with relatively high transcript levels during the first larval stage. In addition, both receptors displayed higher expression in male adult flies as compared to female flies. Analysis of the tissue distribution of both receptor transcripts revealed a high expression of dLGR3 in the female fat body, while the expression of dLGR4 peaked in the midgut of both the wandering and adult stage. PMID:25064813

  18. DMPD: Receptor tyrosine kinases and the regulation of macrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 14726496 Receptor tyrosine kinases and the regulation of macrophage activation. Cor...(.csml) Show Receptor tyrosine kinases and the regulation of macrophage activation. PubmedID 14726496 Title Receptor tyrosine kinases

  19. Nuclear receptor corepressor-dependent repression of peroxisome-proliferator-activated receptor delta-mediated transactivation

    DEFF Research Database (Denmark)

    Krogsdam, Anne-M; Nielsen, Curt A F; Neve, Søren;

    2002-01-01

    delta-RXR alpha heterodimer bound to an acyl-CoA oxidase (ACO)-type peroxisome-proliferator response element recruited a glutathione S-transferase-NCoR fusion protein in a ligand-independent manner. Contrasting with most other nuclear receptors, PPAR delta was found to interact equally well......The nuclear receptor corepressor (NCoR) was isolated as a peroxisome-proliferator-activated receptor (PPAR) delta interacting protein using the yeast two-hybrid system. NCoR interacted strongly with the ligand-binding domain of PPAR delta, whereas interactions with the ligand-binding domains...

  20. Transcriptional activation of nuclear estrogen receptor and progesterone receptor and its regulation.

    Science.gov (United States)

    Xin, Qi-Liang; Qiu, Jing-Tao; Cui, Sheng; Xia, Guo-Liang; Wang, Hai-Bin

    2016-08-25

    Estrogen receptor (ER) and progesterone receptor (PR) are two important members of steroid receptors family, an evolutionarily conserved family of transcription factors. Upon binding to their ligands, ER and PR enter cell nucleus to interact with specific DNA element in the context of chromatin to initiate the transcription of diverse target genes, which largely depends on the timely recruitment of a wide range of cofactors. Moreover, the interactions between steroid hormones and their respective receptors also trigger post-translational modifications on these receptors to fine-tune their transcriptional activities. Besides the well-known phosphorylation modifications on tyrosine and serine/threonine residues, recent studies have identified several other covalent modifications, such as ubiquitylation and sumoylation. These post-translational modifications of steroid receptors affect its stability, subcellular localization, and/or cofactor recruitment; eventually influence the duration and extent of transcriptional activation. This review is to focus on the recent research progress on the transcriptional activation of nuclear ER and PR as well as their physiological functions in early pregnancy, which may help us to better understand related female reproductive diseases. PMID:27546504

  1. Scalability, reliability and validity of the benzodiazepine dependence self report questionnaire in outpatient benzodiazepine users

    NARCIS (Netherlands)

    Kan, C.C.; Breteler, M.H.M.; Timmermans, M.A.Y.; Ven, A.H.G.S. van der; Zitman, F.G.

    1999-01-01

    As there is no multidimensional instrument available which reflects the severity of BZD dependence comprehensively, the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) was developed and investigated. The Bendep-SRQ, Symptom Checlist-90, Schedules for Clinical Assessments in Neuropsy

  2. Monitoring leptin activity using the chicken leptin receptor.

    Science.gov (United States)

    Hen, Gideon; Yosefi, Sera; Ronin, Ana; Einat, Paz; Rosenblum, Charles I; Denver, Robert J; Friedman-Einat, Miriam

    2008-05-01

    We report on the construction of a leptin bioassay based on the activation of chicken leptin receptor in cultured cells. A human embryonic kidney (HEK)-293 cell line, stably transfected with the full-length cDNA of chicken leptin receptor together with a STAT3-responsive reporter gene specifically responded to recombinant human and Xenopus leptins. The observed higher sensitivity of chicken leptin receptor to the former is in agreement with the degree of sequence similarity among these species (about 60 and 38% identical amino acids between humans and chickens, and between humans and Xenopus respectively). The specific activation of signal transduction through the chicken leptin receptor, shown here for the first time, suggests that the transition of Gln269 (implicated in the Gln-to-Pro Zucker fatty mutation in rats) to Glu in chickens does not impair its activity. Analysis of leptin-like activity in human serum samples of obese and lean subjects coincided well with leptin levels determined by RIA. Serum samples of pre- and post partum cows showed a tight correlation with the degree of adiposity. However, specific activation of the chicken leptin receptor in this assay was not observed with serum samples from broiler or layer chickens (representing fat and lean phenotypes respectively) or with those from turkey. Similar leptin receptor activation profiles were observed with cells transfected with human leptin receptor. Further work is needed to determine whether the lack of leptin-like activity in the chicken serum samples is due to a lack of leptin in this species or simply to a serum level of leptin that is below the detection threshold. PMID:18434362

  3. Identification of COUP-TFII Orphan Nuclear Receptor as a Retinoic Acid-Activated Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, Schoen W; Suino-Powell, Kelly; Zhou, X Edward; Kretschman, Jennifer E; Reynolds, Ross; Vonrhein, Clemens; Xu, Yong; Wang, Liliang; Tsai, Sophia Y; Tsai, Ming-Jer; Xu, H Eric [Baylor; (Van Andel); (Globel Phasing); (Grand Valley)

    2010-01-12

    The chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and II) make up the most conserved subfamily of nuclear receptors that play key roles in angiogenesis, neuronal development, organogenesis, cell fate determination, and metabolic homeostasis. Although the biological functions of COUP-TFs have been studied extensively, little is known of their structural features or aspects of ligand regulation. Here we report the ligand-free 1.48 {angstrom} crystal structure of the human COUP-TFII ligand-binding domain. The structure reveals an autorepressed conformation of the receptor, where helix {alpha}10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. In contrast, in multiple cell lines, COUP-TFII exhibits constitutive transcriptional activity, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, and ligand binding, substantially reduce the COUP-TFII transcriptional activity. Importantly, retinoid acids are able to promote COUP-TFII to recruit coactivators and activate a COUP-TF reporter construct. Although the concentration needed is higher than the physiological levels of retinoic acids, these findings demonstrate that COUP-TFII is a ligand-regulated nuclear receptor, in which ligands activate the receptor by releasing it from the autorepressed conformation.

  4. Flavonoids with M1 Muscarinic Acetylcholine Receptor Binding Activity

    Directory of Open Access Journals (Sweden)

    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.

  5. Synthesis of 2-Substituted Benzimidazoles and 1,5-Disubstituted Benzodiazepines on Alumina and Zirconia Catalysts

    Institute of Scientific and Technical Information of China (English)

    M. REKH; A. HAMZA; B. R. VENUGOPAE; N. NAGARAJU

    2012-01-01

    In this study, alumina, zirconia, manganese oxide/alumina, and manganese oxide/zirconia have been investigated for their catalytic activity in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesise 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines respectively. Surface area, surface acidity, and morphology of the catalysts have been analysed and correlated with their catalytic activity. The isolated yields of 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines are in the range of 30% to 95%. A good correlation between the amount of surface acid sites as well as the surface morphology of the catalysts and the catalytic activity has been observed. This method has been found to be simple and economical. The solid supports could be regenerated and reused without much loss in their activity. Further, the solid supports have been also found to be effective as general catalysts in the condensation of o-phenylenediamine with other substituted aldehydes and ketones.

  6. Multiple autophosphorylation sites of the epidermal growth factor receptor are essential for receptor kinase activity and internalization. Contrasting significance of tyrosine 992 in the native and truncated receptors

    DEFF Research Database (Denmark)

    Sorkin, A; Helin, K; Waters, C M; Carpenter, G; Beguinot, L

    1992-01-01

    similar to a kinase-negative receptor. Mutation of tyrosine residue Y992 alone in the context of full length EGF receptor, however, did not affect receptor internalization or kinase activity toward phospholipase C-gamma 1. These data indicate that tyrosine 992 is critical for substrate phosphorylation and...... internalization only in the context of the truncated receptor, and that minor autophosphorylation sites, such as Y992, may act as compensatory regulatory sties in the absence of the major EGF receptor autophosphorylation sites....

  7. Peroxisome Proliferator-Activated Receptor and Vitamin D Receptor Signaling Pathways in Cancer Cells

    International Nuclear Information System (INIS)

    Peroxisome proliferator-activated receptors (PPARs) are members of the superfamily of nuclear hormone receptors, which respond to specific ligands such as polyunsaturated fatty acids by altering gene expression. Three subtypes of this receptor have been discovered, each evolving to achieve different biological functions. Like other nuclear receptors, the transcriptional activity of PPARs is affected not only by ligand-stimulation, but also by cross-talk with other molecules. For example, both PPARs and the RXRs are ligand-activated transcription factors that coordinately regulate gene expression. In addition, PPARs and vitamin D receptor (VDR) signaling pathways regulate a multitude of genes that are of importance for cellular functions including cell proliferation and cell differentiation. Interaction of the PPARs and VDR signaling pathways has been shown at the level of molecular cross-regulation of their transcription factor. A variety of ligands influencing the PPARs and VDR signaling pathways have been shown to reveal chemopreventive potential by mediating tumor suppressive activities in human cancers. Use of these compounds may represent a potential novel strategy to prevent cancers. This review summarizes the roles of the PPARs and the VDR in pathogenesis and progression of cancer

  8. Peroxisome Proliferator-Activated Receptor and Vitamin D Receptor Signaling Pathways in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Yasuko Kitagishi

    2013-10-01

    Full Text Available Peroxisome proliferator-activated receptors (PPARs are members of the superfamily of nuclear hormone receptors, which respond to specific ligands such as polyunsaturated fatty acids by altering gene expression. Three subtypes of this receptor have been discovered, each evolving to achieve different biological functions. Like other nuclear receptors, the transcriptional activity of PPARs is affected not only by ligand-stimulation, but also by cross-talk with other molecules. For example, both PPARs and the RXRs are ligand-activated transcription factors that coordinately regulate gene expression. In addition, PPARs and vitamin D receptor (VDR signaling pathways regulate a multitude of genes that are of importance for cellular functions including cell proliferation and cell differentiation. Interaction of the PPARs and VDR signaling pathways has been shown at the level of molecular cross-regulation of their transcription factor. A variety of ligands influencing the PPARs and VDR signaling pathways have been shown to reveal chemopreventive potential by mediating tumor suppressive activities in human cancers. Use of these compounds may represent a potential novel strategy to prevent cancers. This review summarizes the roles of the PPARs and the VDR in pathogenesis and progression of cancer.

  9. Peroxisome Proliferator-Activated Receptor and Vitamin D Receptor Signaling Pathways in Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Satoru, E-mail: smatsuda@cc.nara-wu.ac.jp; Kitagishi, Yasuko [Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506 (Japan)

    2013-10-21

    Peroxisome proliferator-activated receptors (PPARs) are members of the superfamily of nuclear hormone receptors, which respond to specific ligands such as polyunsaturated fatty acids by altering gene expression. Three subtypes of this receptor have been discovered, each evolving to achieve different biological functions. Like other nuclear receptors, the transcriptional activity of PPARs is affected not only by ligand-stimulation, but also by cross-talk with other molecules. For example, both PPARs and the RXRs are ligand-activated transcription factors that coordinately regulate gene expression. In addition, PPARs and vitamin D receptor (VDR) signaling pathways regulate a multitude of genes that are of importance for cellular functions including cell proliferation and cell differentiation. Interaction of the PPARs and VDR signaling pathways has been shown at the level of molecular cross-regulation of their transcription factor. A variety of ligands influencing the PPARs and VDR signaling pathways have been shown to reveal chemopreventive potential by mediating tumor suppressive activities in human cancers. Use of these compounds may represent a potential novel strategy to prevent cancers. This review summarizes the roles of the PPARs and the VDR in pathogenesis and progression of cancer.

  10. Neurotrophin receptors expression and JNK pathway activation in human astrocytomas

    International Nuclear Information System (INIS)

    Neurotrophins are growth factors that regulate cell growth, differentiation and apoptosis in the nervous system. Their diverse actions are mediated through two different transmembrane – receptor signaling systems: Trk receptor tyrosine kinases (TrkA, TrkB, TrkC) and p75NTR neurotrophin receptor. Trk receptors promote cell survival and differentiation while p75NTR induces, in most cases, the activity of JNK-p53-Bax apoptosis pathway or suppresses intracellular survival signaling cascades. Robust Trk activation blocks p75NTR -induced apoptosis by suppressing the JNK-p53-Bax pathway. The aim of this exploratory study was to investigate the expression levels of neurotrophin receptors, Trks and p75NTR, and the activation of JNK pathway in human astrocytomas and in adjacent non-neoplastic brain tissue. Formalin-fixed paraffin-embedded serial sections from 33 supratentorial astrocytomas (5 diffuse fibrillary astrocytomas, WHO grade II; 6 anaplastic astrocytomas, WHO grade III; 22 glioblastomas multiforme, WHO grade IV) were immunostained following microwave pretreatment. Polyclonal antibodies against TrkA, TrkB, TrkC and monoclonal antibodies against p75NTR and phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were used. The labeling index (LI), defined as the percentage of positive (labeled) cells out of the total number of tumor cells counted, was determined. Moderate to strong, granular cytoplasmic immunoreactivity for TrkA, TrkB and TrkC receptors was detected in greater than or equal to 10% of tumor cells in the majority of tumors independently of grade; on the contrary, p75NTR receptor expression was found in a small percentage of tumor cells (~1%) in some tumors. The endothelium of tumor capillaries showed conspicuous immunoreactivity for TrkB receptor. Trk immunoreactivity seemed to be localized in some neurons and astrocytes in non-neoplastic tissue. Phosphorylated forms of JNK (pJNK) and c-Jun (pc-Jun) were significantly co-expressed in a tumor grade

  11. Structural mechanism of glutamate receptor activation and desensitization.

    Science.gov (United States)

    Meyerson, Joel R; Kumar, Janesh; Chittori, Sagar; Rao, Prashant; Pierson, Jason; Bartesaghi, Alberto; Mayer, Mark L; Subramaniam, Sriram

    2014-10-16

    Ionotropic glutamate receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the vertebrate brain. To gain a better understanding of how structural changes gate ion flux across the membrane, we trapped rat AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) and kainate receptor subtypes in their major functional states and analysed the resulting structures using cryo-electron microscopy. We show that transition to the active state involves a 'corkscrew' motion of the receptor assembly, driven by closure of the ligand-binding domain. Desensitization is accompanied by disruption of the amino-terminal domain tetramer in AMPA, but not kainate, receptors with a two-fold to four-fold symmetry transition in the ligand-binding domains in both subtypes. The 7.6 Å structure of a desensitized kainate receptor shows how these changes accommodate channel closing. These findings integrate previous physiological, biochemical and structural analyses of glutamate receptors and provide a molecular explanation for key steps in receptor gating. PMID:25119039

  12. Abelson tyrosine kinase links PDGFbeta receptor activation to cytoskeletal regulation of NMDA receptors in CA1 hippocampal neurons

    Directory of Open Access Journals (Sweden)

    Beazely Michael A

    2008-12-01

    Full Text Available Abstract Background We have previously demonstrated that PDGF receptor activation indirectly inhibits N-methyl-D-aspartate (NMDA currents by modifying the cytoskeleton. PDGF receptor ligand is also neuroprotective in hippocampal slices and cultured neurons. PDGF receptors are tyrosine kinases that control a variety of signal transduction pathways including those mediated by PLCγ. In fibroblasts Src and another non-receptor tyrosine kinase, Abelson kinase (Abl, control PDGF receptor regulation of cytoskeletal dynamics. The mechanism whereby PDGF receptor regulates cytoskeletal dynamics in central neurons remains poorly understood. Results Intracellular applications of active Abl, but not heat-inactivated Abl, decreased NMDA-evoked currents in isolated hippocampal neurons. This mimics the effects of PDGF receptor activation in these neurons. The Abl kinase inhibitor, STI571, blocked the inhibition of NMDA currents by Abl. We demonstrate that PDGF receptors can activate Abl kinase in hippocampal neurons via mechanisms similar to those observed previously in fibroblasts. Furthermore, PDGFβ receptor activation alters the subcellular localization of Abl. Abl kinase is linked to actin cytoskeletal dynamics in many systems. We show that the inhibition of NMDA receptor currents by Abl kinase is blocked by the inclusion of the Rho kinase inhibitor, Y-27632, and that activation of Abl correlates with an increase in ROCK tyrosine phosphorylation. Conclusion This study demonstrates that PDGFβ receptors act via an interaction with Abl kinase and Rho kinase to regulated cytoskeletal regulation of NMDA receptor channels in CA1 pyramidal neurons.

  13. Epidermis-type lipoxygenase 3 regulates adipocyte differentiation and peroxisome proliferator-activated receptor gamma activity

    DEFF Research Database (Denmark)

    Hallenborg, Philip; Jørgensen, Claus; Petersen, Rasmus K;

    2010-01-01

    The nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) is essential for adipogenesis. Although several fatty acids and their derivatives are known to bind and activate PPAR gamma, the nature of the endogenous ligand(s) promoting the early stages of adipocyte differenti...

  14. New GABA amides activating GABA A-receptors

    OpenAIRE

    Peter Raster; Andreas Späth; Svetlana Bultakova; Pau Gorostiza; Burkhard König; Piotr Bregestovski

    2013-01-01

    We have prepared a series of new and some literature-reported GABA-amides and determined their effect on the activation of GABAA-receptors expressed in CHO cells. Special attention was paid to the purification of the target compounds to remove even traces of GABA contaminations, which may arise from deprotection steps in the synthesis. GABA-amides were previously reported to be partial, full or superagonists. In our hands these compounds were not able to activate GABAA-receptor channels in wh...

  15. Mechanisms of Activation of Receptor Tyrosine Kinases: Monomers or Dimers

    Directory of Open Access Journals (Sweden)

    Ichiro N. Maruyama

    2014-04-01

    Full Text Available Receptor tyrosine kinases (RTKs play essential roles in cellular processes, including metabolism, cell-cycle control, survival, proliferation, motility and differentiation. RTKs are all synthesized as single-pass transmembrane proteins and bind polypeptide ligands, mainly growth factors. It has long been thought that all RTKs, except for the insulin receptor (IR family, are activated by ligand-induced dimerization of the receptors. An increasing number of diverse studies, however, indicate that RTKs, previously thought to exist as monomers, are present as pre-formed, yet inactive, dimers prior to ligand binding. The non-covalently associated dimeric structures are reminiscent of those of the IR family, which has a disulfide-linked dimeric structure. Furthermore, recent progress in structural studies has provided insight into the underpinnings of conformational changes during the activation of RTKs. In this review, I discuss two mutually exclusive models for the mechanisms of activation of the epidermal growth factor receptor, the neurotrophin receptor and IR families, based on these new insights.

  16. Experimental study on the relationship between benzodiazepine receptor and the isoflurane-induced amnesia in mice%苯二氮(艹卓)受体与异氟烷遗忘作用关系的实验研究

    Institute of Scientific and Technical Information of China (English)

    廖艺聪; 刘强; 符香; 刘绪华; 李雨虹; 许历阳; 张珏; 孟晶

    2011-01-01

    Objective To investigate the effect of flumazenil on the isoflurane - induced amnesia and to reveal the relationship between benxodiazepine receptor and the mechanism oi isoflurane - induced amnesia.Methods 48 mice were randomized into six groups.The effects of intraperitoneal injection of different doses of flumazenil ( 0.5, 1.0 mg/kg) on the step - through latency and error times were observed in mice treated with isoflurane (0.2 ml/kg).Results Compared with the normal saline group , the step - through latency and error times had no statistical differences in the flumazenil groups ( P < 0.05 ); the isoflurance group and the isoflurance - flumazenil combination groups showed reduced step - through latency ( P< 0.05) and elevated error times ( P < 0.01 or P < 0.05 ).Compared with the isoflurance group, no statistical differences in step - through lateney and error times were observed between the isoflurance group and the isoflurance -flumazenil combination groups ( P > 0.05 ).Conclusion Flumazenil has no significant influence on the isoflurance - induced amnesia, suggesting that the isoflurance - induced amnesia is not related to henzodiazepine receptor.%目的 通过观察氟马西尼对异氟烷遗忘作用的影响,揭示异氟烷遗忘机制与苯二氮艹卓受体的关系.方法 将48只小鼠随机分成6组,采用避暗实验观察腹腔注射不同剂量氟马西尼(0.5、1.0 mg/kg)对异氟烷处理小鼠步入潜伏期和错误次数的影响.结果 与生理盐水组相比,氟马西尼单用组小鼠的步入潜伏期和错误次数均无明显差异(P>0.05);异氟烷单用或合用组步入潜伏期明显缩短(P0.05).结论 氟马西尼对异氟烷遗忘作用无明显影响,提示异氟烷遗忘作用与苯二氮艹卓受体关系不大.

  17. Calcium-sensing receptor activation depresses synaptic transmission

    OpenAIRE

    Phillips, Cecilia G.; Harnett, Mark T.; Chen, Wenyan; Smith, Stephen M.

    2008-01-01

    At excitatory synapses, decreases in cleft [Ca] arising from activity-dependent transmembrane Ca flux reduce the probability of subsequent transmitter release. Intense neural activity, induced by physiological and pathological stimuli, disturb the external microenvironment reducing extracellular [Ca] ([Ca]o) and thus may impair neurotransmission. Increases in [Ca]o activate the extracellular calcium sensing receptor (CaSR) which in turn inhibits non-selective cation channels (NSCC) at the maj...

  18. Kallikrein activates bradykinin B2 receptors in absence of kininogen.

    Science.gov (United States)

    Biyashev, Dauren; Tan, Fulong; Chen, Zhenlong; Zhang, Kai; Deddish, Peter A; Erdös, Ervin G; Hecquet, Claudie

    2006-03-01

    Kallikreins cleave plasma kininogens to release the bioactive peptides bradykinin (BK) or kallidin (Lys-BK). These peptides then activate widely disseminated B2 receptors with consequences that may be either noxious or beneficial. We used cultured cells to show that kallikrein can bypass kinin release to activate BK B2 receptors directly. To exclude intermediate kinin release or kininogen uptake from the cultured medium, we cultured and maintained cells in medium entirely free of animal proteins. We compared the responses of stably transfected Chinese hamster ovary (CHO) cells that express human B2 receptors (CHO B2) and cells that coexpress angiotensin I-converting enzyme (ACE) as well (CHO AB). We found that BK (1 nM or more) and tissue kallikrein (1-10 nM) both significantly increased release of arachidonic acid beyond unstimulated baseline level. An enzyme-linked immunoassay for kinin established that kallikrein did not release a kinin from CHO cells. We confirmed the absence of kininogen mRNA with RT-PCR to rule out kininogen synthesis by CHO cells. We next tested an ACE inhibitor for enhanced BK receptor activation in the absence of kinin release and synthesized an ACE-resistant BK analog as a control for these experiments. Enalaprilat (1 microM) potentiated kallikrein (100 nM) in CHO AB cells but was ineffective in CHO B2 cells that do not bear ACE. We concluded that kallikrein activated B2 receptors without releasing a kinin. Furthermore, inhibition of ACE enhanced the receptor activation by kallikrein, an action that may contribute to the manifold therapeutic effects of ACE inhibitors. PMID:16272198

  19. Allosteric activation mechanism of the cys-loop receptors

    Institute of Scientific and Technical Information of China (English)

    Yong-chang CHANG; Wen WU; Jian-liang ZHANG; Yao HUANG

    2009-01-01

    Binding of a neurotransmitter to its ionotropic receptor opens a distantly located ion channel, a process termed allosteric activation. Here we review recent advances in the molecular mechanism by which the cys-loop receptors are activated with emphasis on the best studied nicotinic acetylcholine receptors (nAChRs). With a combination of affinity labeling, mutagenesis, electrophysiology, kinetic modeling, electron microscopy (EM), and crystal structure analysis, the allosteric activation mechanism is emerging. Specifically, the binding domain and gating domain are interconnected by an allosteric activation network. Agonist binding induces conformational changes, resulting in the rotation of a β sheet of amino-terminal domain and outward movement of loop 2, loop F, and cys-loop, which are coupled to the M2-M3 linker to pull the channel to open. However, there are still some controversies about the movement of the channel-lining domain M2. Nine angstrom resolution EM structure of a nAChR imaged in the open state suggests that channel opening is the result of rotation of the M2 domain. In contrast, recent crystal structures of bacterial homologues of the cys-loop receptor family in apparently open state have implied an M2 tilting model with pore dilation and quaternary twist of the whole pentameric receptor. An elegant study of the nAChR using protonation scanning of M2 domain supports a similar pore dilation activation mechanism with minimal rotation of M2. This remains to be validated with other approaches including high resolution structure determination of the mammalian cys-loop receptors in the open state.

  20. The impact of benzodiazepine use on methadone maintenance treatment outcomes.

    Science.gov (United States)

    Brands, Bruna; Blake, Joan; Marsh, David C; Sproule, Beth; Jeyapalan, Renuka; Li, Selina

    2008-01-01

    The purposes of this study were to examine predictors of benzodiazepine use among methadone maintenance treatment patients, to determine whether baseline benzodiazepine use influenced ongoing use during methadone maintenance treatment, and to assess the effect of ongoing benzodiazepine use on treatment outcomes (i.e., opioid and cocaine use and treatment retention). A retrospective chart review of 172 methadone maintenance treatment patients (mean age = 34.6 years; standard deviation = 8.5 years; 64% male) from January 1997 to December 1999 was conducted. At baseline, 29% were "non-users" (past year) of benzodiazepine, 36% were "occasional users," and 35% were "regular/problem users." Regular/problem users were more likely to have started opioid use with prescription opioids, experienced more overdoses, and reported psychiatric comorbidity. Being female, more years of opioid use, and a history of psychiatric treatment were significant predictors of baseline benzodiazepine use. Ongoing benzodiazepine users were more likely to have opioid-positive and cocaine-positive urine screens during methadone maintenance treatment. Only ongoing cocaine use was negatively related to retention. Benzodiazepine use by methadone maintenance treatment patients is associated with a more complex clinical picture and may negatively influence treatment outcomes. PMID:18956528

  1. Valnoctamide enhances phasic inhibition: a potential target mechanism for the treatment of benzodiazepine-refractory status epilepticus

    OpenAIRE

    Spampanato, Jay; Dudek, F. Edward

    2014-01-01

    Valnoctamide (VCD), a derivative of valproate, suppresses electrographic seizures in animal models of status epilepticus (SE), even when the seizures are resistant to benzodiazepines (BZDs). We therefore tested the effect of VCD on miniature inhibitory post-synaptic currents (mIPSCs) in CA1 pyramidal cells to determine if VCD acts directly on GABAA receptors. Bath-applied VCD induced a specific, rapid, dose-dependent, and reversible slowing of the decay of mIPSCs (i.e., increased time constan...

  2. Disability pension as predictor of later use of benzodiazepines among benzodiazepine users

    OpenAIRE

    Hartz, Ingeborg; Tverdal, Aage; Skille, Eivind Å.; Skurtveit, Svetlana

    2010-01-01

    The proportion of Norwegians on disability pensions has doubled since the 1980s. The Norwegian Government wants action to stimulate the working capacity in those disability pensioners who have the potential to work. Information on factors that may impair rehabilitation efforts, including the unfavourable use of benzodiazepines, may be useful in this context. A longitudinal design, including data on 40–42 year old participants in Norwegian health surveys (year 1985–1989) linked to a prescripti...

  3. Benzodiazepines misuse: The study community level Thailand

    Directory of Open Access Journals (Sweden)

    Puangkot Sukdepat

    2010-01-01

    Full Text Available Context: Benzodiazepines (BZD misuse, abuse, and dependence are becoming a new problem in medicine, in Thailand, and the pharmacoepidemiology knowledge is insufficient. The aim of this study is to estimate the prevalence of benzodiazepine use, misuse, abuse, and dependence in the general population of the Ubon Rachathani province, in Thailand. Aims: To estimate the prevalence of benzodiazepine use, misuse, abuse, and dependence in the general population. Settings and Design: The cross-sectional household survey research was conducted from October 2008 to June 2009, with a target population age of 15 years and above. This took place in Ubon Ratchathani Province, in Thailand. Materials and Methods: A total sample size of 2280 were selected from three-stage stratified random sampling. BZD were identified with an accuracy of generic name, trade name, and drug characteristics. The DSM-IV questionnaire was used to define misuse, abuse, and dependence. The accuracy of dependence was interpreted with the help of the judgment of a psychiatric nurse. Statistical analysis: For the statistical analyses, prevalence was estimated with weight adjustment, variances estimated by the Teylor Series Linearization method, and interpreted with 95% confidence interval (CI. Results: There were 46,805 current users [3.9% (95% CI: 2.2-6.4], 26,404 misusers [2.2% (95% CI: 1.6-6.2], 7,203 abusers [0.6% (95% CI: 0.1 - 4.1], and 2,402 with dependence [0.2% (0.1-9.2]. When considering the group of current users in this study, 57.2% misusers, 16.6% abusers, and 5.9% with dependence were found, respectively. Conclusions: All prevalence of use was higher than previously reported, in Thailand, while more than half of the current users had a behavior of misuse. Surveillance of misuse should be undertaken in the current use. The medical professional should counsel the patient on the harm of misuse and limit the amount of medicine, with necessary dispensing.

  4. Interaction of the C-terminal acidic domain of the insulin receptor with histone modulates the receptor kinase activity.

    Science.gov (United States)

    Baron, V; Kaliman, P; Alengrin, F; Van Obberghen, E

    1995-04-01

    In this study, we investigated the role of the insulin receptor domain 1270-1280, an acid-rich sequence located in the receptor C-terminus. Antipeptide IgG raised against this sequence were obtained and used to analyze their effect on receptor function. Antipeptide IgG inhibited receptor autophosphorylation at Tyr1146, Tyr1150 and Tyr1151. These sites are known to be key modulators of the receptor activity. Autophosphorylation at other sites may also have been inhibited. The antipeptide antibody decreased the receptor kinase activity measured with poly(Glu80Tyr20) and a synthetic peptide corresponding to the proreceptor sequence 1142-1158. We provide evidence that the effect of the antibody on substrate phosphorylation may result from the control of the phosphorylation level of the receptor. Concerning the action of the antipeptide IgG on the receptor kinase activity, histone did not behave similarly to poly(Glu80Tyr20). The antibody recognizing sequence 1270-1280 competed with histone for an overlapping binding site. Histone also modulated insulin receptor autophosphorylation, supporting the idea that interference with domain 1270-1280 alters the receptor kinase. Our data suggest that the acidic region including residues 1270-1280 of the insulin receptor C-terminus is involved in the following events: (a) receptor binding with histone, an exogenous substrate of the receptor kinase, and (b) the regulation of receptor autophosphorylation and kinase activity. Based on these observations, we would like to propose that this insulin receptor domain could interact with cellular proteins modulating the receptor kinase. PMID:7744039

  5. Sphingosine-1-phosphate receptor 1 reporter mice reveal receptor activation sites in vivo

    OpenAIRE

    Kono, Mari; Tucker, Ana E.; Tran, Jennifer; Bergner, Jennifer B.; Turner, Ewa M; Proia, Richard L.

    2014-01-01

    Activation of the GPCR sphingosine-1-phosphate receptor 1 (S1P1) by sphingosine-1-phosphate (S1P) regulates key physiological processes. S1P1 activation also has been implicated in pathologic processes, including autoimmunity and inflammation; however, the in vivo sites of S1P1 activation under normal and disease conditions are unclear. Here, we describe the development of a mouse model that allows in vivo evaluation of S1P1 activation. These mice, known as S1P1 GFP signaling mice, produce a ...

  6. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    International Nuclear Information System (INIS)

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction

  7. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Shoko, E-mail: satosho@rs.tus.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp [Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Yonago 683-8503 (Japan); Tohkin, Masahiro, E-mail: tohkin@phar.nagoya-cu.ac.jp [Department of Medical Safety Science, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya 267-8603 (Japan); Gonzalez, Frank J., E-mail: gonzalef@mail.nih.gov [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Komai, Michio, E-mail: mkomai@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan)

    2013-11-15

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.

  8. Influence of phasic and tonic dopamine release on receptor activation

    DEFF Research Database (Denmark)

    Dreyer, Jakob Kristoffer Kisbye; Herrik, Kjartan F; Berg, Rune W; Hounsgaard, Jørn D

    2010-01-01

    Tonic and phasic dopamine release is implicated in learning, motivation, and motor functions. However, the relationship between spike patterns in dopaminergic neurons, the extracellular concentration of dopamine, and activation of dopamine receptors remains unresolved. In the present study, we...... develop a computational model of dopamine signaling that give insight into the relationship between the dynamics of release and occupancy of D(1) and D(2) receptors. The model is derived from first principles using experimental data. It has no free parameters and offers unbiased estimation of the...

  9. The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Olsen, Kristine Boisen; Erikstrup, Niels;

    2011-01-01

    The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately...... connected and some of the cardioprotective effects of Losartan are abolished by blocking the bradykinin B2 receptor (B2R) signaling. In this study, we investigated the ability of six clinically available ARBs to specifically bind and activate the B2R. First, we investigated their ability to activate...... phosphoinositide (PI) hydrolysis in COS-7 cells transiently expressing the B2R. We found that only Losartan activated the B2R, working as a partial agonist compared to the endogenous ligand bradykinin. This effect was blocked by the B2R antagonist HOE 140. A competitive binding analysis revealed that Losartan does...

  10. Peroxisome proliferator-activated receptors, metabolic syndrome and cardiovascular disease

    OpenAIRE

    Azhar, Salman

    2010-01-01

    Metabolic syndrome (MetS) is a constellation of risk factors including insulin resistance, central obesity, dyslipidemia and hypertension that markedly increase the risk of Type 2 diabetes (T2DM) and cardiovascular disease (CVD). The peroxisome proliferators-activated receptor (PPAR) isotypes, PPARα, PPARδ/β and PPARγ are ligand-activated nuclear transcription factors, which modulate the expression of an array of genes that play a central role in regulating glucose, lipid and cholesterol meta...

  11. Steroid signaling activation and intracellular localization of sex steroid receptors

    OpenAIRE

    Giraldi, Tiziana; Giovannelli, Pia; Di Donato, Marzia; Castoria, Gabriella; Migliaccio, Antimo; Auricchio, Ferdinando

    2010-01-01

    In addition to stimulating gene transcription, sex steroids trigger rapid, non-genomic responses in the extra-nuclear compartment of target cells. These events take place within seconds or minutes after hormone administration and do not require transcriptional activity of sex steroid receptors. Depending on cell systems, activation of extra-nuclear signaling pathways by sex steroids fosters cell cycle progression, prevents apoptosis, leads to epigenetic modifications and increases cell migrat...

  12. Activation of serotonin receptors promotes microglial injury-induced motility but attenuates phagocytic activity

    NARCIS (Netherlands)

    Krabbe, Grietje; Matyash, Vitali; Pannasch, Ulrike; Mamer, Lauren; Boddeke, Hendrikus W. G. M.; Kettenmann, Helmut

    2012-01-01

    Microglia, the brain immune cell, express several neurotransmitter receptors which modulate microglial functions. In this project we studied the impact of serotonin receptor activation on distinct microglial properties as serotonin deficiency not only has been linked to a number of psychiatric disea

  13. An improved ivermectin-activated chloride channel receptor for inhibiting electrical activity in defined neuronal populations

    DEFF Research Database (Denmark)

    Lynagh, Timothy Peter; Lynch, Joseph W

    2010-01-01

    for surgically implanted stimulus delivery methods and their use of nonhuman receptors. A third silencing method, an invertebrate glutamate-gated chloride channel receptor (GluClR) activated by ivermectin, solves the stimulus delivery problem as ivermectin is a safe, well tolerated drug that reaches...

  14. Screening of selected pesticides for oestrogen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Breinholt, Vibeke; Larsen, John Christian

    1999-01-01

    Twenty pesticides were tested for their ability to activate the oestrogen receptor in vitro using an,MCF7 cell proliferation assay and a Yeast Oestrogen Screen. The fungicides fenarimol, triadimefon, and triadimenol were identified as weak oestrogen receptor agonists, which at 10 mu M induces a 2.......0, 2.4, and 1.9-fold increase in proliferation of human MCF7 breast cancer cells (E3 clone). The relative proliferation efficiency (RPE) was 43-69%, indicating partial agonism at the oestrogen receptor. Several pesticides did not have any effect oil the proliferation response after 6 days of exposure......, including. chlorpyrifos, diuron, iprodion, linuron, pentachlorphenol, prochloraz, propioconazol, propyzamine, quintozen, tetrachorvinphos and tetradifon. Some pesticides resulted in a negligible proliferation response, which was nor statistically significant under the present experimental conditions. These...

  15. Screening of selected pesticides for oestrogen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne; Breinholt, Vibeke; Larsen, John Christian

    1999-01-01

    Twenty pesticides were tested for their ability to activate the oestrogen receptor in vitro using an,MCF7 cell proliferation assay and a Yeast Oestrogen Screen. The fungicides fenarimol, triadimefon, and triadimenol were identified as weak oestrogen receptor agonists, which at 10 mu M induces a 2.......0, 2.4, and 1.9-fold increase in proliferation of human MCF7 breast cancer cells (E3 clone). The relative proliferation efficiency (RPE) was 43-69%, indicating partial agonism at the oestrogen receptor. Several pesticides did not have any effect oil the proliferation response after 6 days of exposure......, including. chlorpyrifos, diuron, iprodion, linuron, pentachlorphenol, prochloraz, propioconazol, propyzamine, quintozen, tetrachorvinphos and tetradifon. Some pesticides resulted in a negligible proliferation response, which was nor statistically significant under the present experimental conditions...

  16. Glycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration

    Directory of Open Access Journals (Sweden)

    Ariel Avila

    2013-08-01

    Full Text Available Glycine receptors (GlyRs are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis.

  17. Improving benzodiazepine prescribing in family practice through review and education.

    OpenAIRE

    Rosser, W.W.; Simms, J. G.; Patten, D W; J. Forster

    1981-01-01

    Indications for and dosages of four commonly prescribed benzodiazepines were recorded at a family medicine centre with the aid of a computerized data collection system. Four guidelines were then developed for appropriate prescribing of these drugs: (a) benzodiazepines should be used less frequently with increasing age; (b) short-acting drugs are preferable to long-acting drugs; (c) patients 65 years of age and over should receive half the daily dose prescribed for younger patients; and (d) us...

  18. Alcohol and benzodiazepines generate anxiety, panic and phobias.

    Science.gov (United States)

    Cohen, S I

    1995-01-01

    In almost half the patients seeking advice for anxiety, panic and phobias the cause was alcohol or benzodiazepines. In the remainder it was psychological, usually a state of conflict or a traumatic event. When symptoms are persistent following a distressing event it is often the case that alcohol or benzodiazepines are keeping them going. There is a large variation in individual vulnerability and the mechanism responsible for these symptoms is rebound arousal. PMID:7769598

  19. Alcohol and benzodiazepines generate anxiety, panic and phobias.

    OpenAIRE

    Cohen, S I

    1995-01-01

    In almost half the patients seeking advice for anxiety, panic and phobias the cause was alcohol or benzodiazepines. In the remainder it was psychological, usually a state of conflict or a traumatic event. When symptoms are persistent following a distressing event it is often the case that alcohol or benzodiazepines are keeping them going. There is a large variation in individual vulnerability and the mechanism responsible for these symptoms is rebound arousal.

  20. Conserved phosphorylation sites in the activation loop of the Arabidopsis phytosulfokine receptor PSKR1 differentially affect kinase and receptor activity

    OpenAIRE

    Hartmann, Jens; Linke, Dennis; Bönniger, Christine; Tholey, Andreas; Sauter, Margret

    2015-01-01

    PSK (phytosulfokine) is a plant peptide hormone perceived by a leucine-rich repeat receptor kinase. Phosphosite mapping of epitope-tagged PSKR1 (phytosulfokine receptor 1) from Arabidopsis thaliana plants identified Ser696 and Ser698 in the JM (juxtamembrane) region and probably Ser886 and/or Ser893 in the AL (activation loop) as in planta phosphorylation sites. In vitro-expressed kinase was autophosphorylated at Ser717 in the JM, and at Ser733, Thr752, Ser783, Ser864, Ser911, Ser958 and Thr9...

  1. Conserved phosphorylation sites in the activation loop of the Arabidopsis phytosulfokine receptor PSKR1 differentially affect kinase and receptor activity.

    Science.gov (United States)

    Hartmann, Jens; Linke, Dennis; Bönniger, Christine; Tholey, Andreas; Sauter, Margret

    2015-12-15

    PSK (phytosulfokine) is a plant peptide hormone perceived by a leucine-rich repeat receptor kinase. Phosphosite mapping of epitope-tagged PSKR1 (phytosulfokine receptor 1) from Arabidopsis thaliana plants identified Ser(696) and Ser(698) in the JM (juxtamembrane) region and probably Ser(886) and/or Ser(893) in the AL (activation loop) as in planta phosphorylation sites. In vitro-expressed kinase was autophosphorylated at Ser(717) in the JM, and at Ser(733), Thr(752), Ser(783), Ser(864), Ser(911), Ser(958) and Thr(998) in the kinase domain. The LC-ESI-MS/MS spectra provided support that up to three sites (Thr(890), Ser(893) and Thr(894)) in the AL were likely to be phosphorylated in vitro. These sites are evolutionarily highly conserved in PSK receptors, indicative of a conserved function. Site-directed mutagenesis of the four conserved residues in the activation segment, Thr(890), Ser(893), Thr(894) and Thr(899), differentially altered kinase activity in vitro and growth-promoting activity in planta. The T899A and the quadruple-mutated TSTT-A (T890A/S893A/T894A/T899A) mutants were both kinase-inactive, but PSKR1(T899A) retained growth-promoting activity. The T890A and S893A/T894A substitutions diminished kinase activity and growth promotion. We hypothesize that phosphorylation within the AL activates kinase activity and receptor function in a gradual and distinctive manner that may be a means to modulate the PSK response. PMID:26472115

  2. Environmental phthalate monoesters activate pregnane X receptor-mediated transcription

    International Nuclear Information System (INIS)

    Phthalate esters, widely used as plasticizers in the manufacture of products made of polyvinyl chloride, induce reproductive and developmental toxicities in rodents. The mechanism that underlies these effects of phthalate exposure, including the potential role of members of the nuclear receptor superfamily, is not known. The present study investigates the effects of phthalates on the pregnane X receptor (PXR), which mediates the induction of enzymes involved in steroid metabolism and xenobiotic detoxification. The ability of phthalate monoesters to activate PXR-mediated transcription was assayed in a HepG2 cell reporter assay following transfection with mouse PXR (mPXR), human PXR (hPXR), or the hPXR allelic variants V140M, D163G, and A370T. Mono-2-ethylhexyl phthalate (MEHP) increased the transcriptional activity of both mPXR and hPXR (5- and 15-fold, respectively) with EC50 values of 7-8 μM. mPXR and hPXR were also activated by monobenzyl phthalate (MBzP, up to 5- to 6-fold) but were unresponsive to monomethyl phthalate and mono-n-butyl phthalate (M(n)BP) at the highest concentrations tested (300 μM). hPXR-V140M and hPXR-A370T exhibited patterns of phthalate responses similar to the wild-type receptor. By contrast, hPXR-D163G was unresponsive to all phthalate monoesters tested. Further studies revealed that hPXR-D163G did respond to rifampicin, but required approximately 40-fold higher concentrations than wild-type receptor, suggesting that the ligand-binding domain D163G variant has impaired ligand-binding activity. The responsiveness of PXR to activation by phthalate monoesters demonstrated here suggests that these ubiquitous environmental chemicals may, in part, exhibit their endocrine disruptor activities by altering PXR-regulated steroid hormone metabolism with potential adverse health effects in exposed individuals

  3. Hyaluronic acid induces activation of the κ-opioid receptor.

    Directory of Open Access Journals (Sweden)

    Barbara Zavan

    Full Text Available INTRODUCTION: Nociceptive pain is one of the most common types of pain that originates from an injury involving nociceptors. Approximately 60% of the knee joint innervations are classified as nociceptive. The specific biological mechanism underlying the regulation of nociceptors is relevant for the treatment of symptoms affecting the knee joint. Intra-articular administration of exogenous hyaluronic acid (HA in patients with osteoarthritis (OA appears to be particularly effective in reducing pain and improving patient function. METHODS: We performed an in vitro study conducted in CHO cells that expressed a panel of opioid receptors and in primary rat dorsal root ganglion (DRG neurons to determine if HA induces the activation of opioid peptide receptors (OPr using both aequorin and the fluorescent dye Fura-2/AM. RESULTS: Selective agonists and antagonists for each OPr expressed on CHO cells were used to test the efficacy of our in vitro model followed by stimulation with HA. The results showed that HA induces stimulatory effects on the κ receptor (KOP. These effects of HA were also confirmed in rat DRG neurons, which express endogenously the OPr. CONCLUSIONS: HA activates the KOP receptor in a concentration dependent manner, with a pEC(50 value of 7.57.

  4. Allosteric receptor activation by the plant peptide hormone phytosulfokine.

    Science.gov (United States)

    Wang, Jizong; Li, Hongju; Han, Zhifu; Zhang, Heqiao; Wang, Tong; Lin, Guangzhong; Chang, Junbiao; Yang, Weicai; Chai, Jijie

    2015-09-10

    Phytosulfokine (PSK) is a disulfated pentapeptide that has a ubiquitous role in plant growth and development. PSK is perceived by its receptor PSKR, a leucine-rich repeat receptor kinase (LRR-RK). The mechanisms underlying the recognition of PSK, the activation of PSKR and the identity of the components downstream of the initial binding remain elusive. Here we report the crystal structures of the extracellular LRR domain of PSKR in free, PSK- and co-receptor-bound forms. The structures reveal that PSK interacts mainly with a β-strand from the island domain of PSKR, forming an anti-β-sheet. The two sulfate moieties of PSK interact directly with PSKR, sensitizing PSKR recognition of PSK. Supported by biochemical, structural and genetic evidence, PSK binding enhances PSKR heterodimerization with the somatic embryogenesis receptor-like kinases (SERKs). However, PSK is not directly involved in PSKR-SERK interaction but stabilizes PSKR island domain for recruitment of a SERK. Our data reveal the structural basis for PSKR recognition of PSK and allosteric activation of PSKR by PSK, opening up new avenues for the design of PSKR-specific small molecules. PMID:26308901

  5. [Benzodiazepin addiction: a silent addiction among older people].

    Science.gov (United States)

    Oude Voshaar, R C

    2012-06-01

    Benzodiazepines are frequently prescribed for a longer period of time for anxiety disorders and insomnia in spite of the many guidelines to prescribe these drugs only short-term. These guidelines are based on the risk-benefit balance between long-term effectiveness and side effects like addiction, anterograde amnesia, and increased risk on falling (resulting in hip fractures), traffic accidents and even mortality. Also low-dose benzodiazepine use can lead to benzodiazepine dependence. Although initially most attention has been paid to the physical withdrawal syndrome, psychological aspects of benzodiazepine dependence have received more and more attention in the past decades. Recently, a relationship between the brain-reward system, involved in addiction, and benzodiazepine use, was demonstrated. When long-term benzodiazepine use is recognised as problematic by both physician and patient, different treatment modalities are available to support patients in achieving abstinence. One of every four patients is able to stop by themselves with the aid of a minimal intervention providing psychoeducation and encouragement. Two out of three long-term uses are able to stop their usage with the aid of systematic tapering protocols guided by a physician or psychologist. In case of an underlying insomnia or anxiety disorder, cognitive-behavioural therapy should be added to the tapering protocol. In contrast to the general opinion, advanced old age has no negative impact on the treatment response. PMID:22826915

  6. Evaluation of Anti-Hyperalgesic and Analgesic Effects of Two Benzodiazepines in Human Experimental Pain: A Randomized Placebo-Controlled Study

    OpenAIRE

    Vuilleumier, Pascal H.; Marie Besson; Jules Desmeules; Lars Arendt-Nielsen; Michele Curatolo

    2013-01-01

    BACKGROUND AND AIMS: Compounds that act on GABA-receptors produce anti-hyperalgesia in animal models, but little is known on their effects in humans. The aim of this study was to explore the potential usefulness of GABA-agonism for the control of pain in humans. Two agonists at the benzodiazepine-binding site of GABAA-receptors (clobazam and clonazepam) were studied using multiple experimental pain tests. Positive results would support further investigation of GABA agonism for the control of ...

  7. Neurohumoral activation in heart failure: the role of adrenergic receptors

    Directory of Open Access Journals (Sweden)

    Patricia C. Brum

    2006-09-01

    Full Text Available Heart failure (HF is a common endpoint for many forms of cardiovascular disease and a significant cause of morbidity and mortality. The development of end-stage HF often involves an initial insult to the myocardium that reduces cardiac output and leads to a compensatory increase in sympathetic nervous system activity. Acutely, the sympathetic hyperactivity through the activation of beta-adrenergic receptors increases heart rate and cardiac contractility, which compensate for decreased cardiac output. However, chronic exposure of the heart to elevated levels of catecholamines released from sympathetic nerve terminals and the adrenal gland may lead to further pathologic changes in the heart, resulting in continued elevation of sympathetic tone and a progressive deterioration in cardiac function. On a molecular level, altered beta-adrenergic receptor signaling plays a pivotal role in the genesis and progression of HF. beta-adrenergic receptor number and function are decreased, and downstream mechanisms are altered. In this review we will present an overview of the normal beta-adrenergic receptor pathway in the heart and the consequences of sustained adrenergic activation in HF. The myopathic potential of individual components of the adrenergic signaling will be discussed through the results of research performed in genetic modified animals. Finally, we will discuss the potential clinical impact of beta-adrenergic receptor gene polymorphisms for better understanding the progression of HF.A insuficiência cardíaca (IC é a via final comum da maioria das doenças cardiovasculares e uma das maiores causas de morbi-mortalidade. O desenvolvimento do estágio final da IC freqüentemente envolve um insulto inicial do miocárdio, reduzindo o débito cardíaco e levando ao aumento compensatório da atividade do sistema nervoso simpático (SNS. Existem evidências de que apesar da exposição aguda ser benéfica, exposições crônicas a elevadas concentra

  8. Implications of compound heterozygous insulin receptor mutations in congenital muscle fibre type disproportion myopathy for the receptor kinase activation

    DEFF Research Database (Denmark)

    Klein, H H; Müller, R; Vestergaard, H;

    1999-01-01

    We studied insulin receptor kinase activation in two brothers with congenital muscle fibre type disproportion myopathy and compound heterozygous mutations of the insulin receptor gene, their parents, and their unaffected brother. In the father who has a heterozygote Arg1174-->Gln mutation, in situ...... receptors to become insulin-dependently activated. The mother carries a point mutation at the last base pair in exon 17 which, due to abnormal alternative splicing, could lead to normally transcribed receptor or truncated receptor lacking the kinase region. Kinase activation was normal in the mother...... receptors in the mother's skeletal muscle are transcribed almost exclusively from the non-mutated allele. The mutation in exon 17 could lead to reduced transcription or rapid degradation of a predominantly transcribed truncated gene product or both....

  9. Activation of Penile Proadipogenic Peroxisome Proliferator-Activated Receptor with an Estrogen: Interaction with Estrogen Receptor Alpha during Postnatal Development

    Directory of Open Access Journals (Sweden)

    Mahmoud M. Mansour

    2008-01-01

    Full Text Available Exposure to the estrogen receptor alpha (ER ligand diethylstilbesterol (DES between neonatal days 2 to 12 induces penile adipogenesis and adult infertility in rats. The objective of this study was to investigate the in vivo interaction between DES-activated ER and the proadipogenic transcription factor peroxisome proliferator-activated receptor gamma (PPAR. Transcripts for PPARs , , and and 1a splice variant were detected in Sprague-Dawley normal rat penis with PPAR predominating. In addition, PPAR1b and PPAR2 were newly induced by DES. The PPAR transcripts were significantly upregulated with DES and reduced by antiestrogen ICI 182, 780. At the cellular level, PPAR protein was detected in urethral transitional epithelium and stromal, endothelial, neuronal, and smooth muscular cells. Treatment with DES activated ER and induced adipocyte differentiation in corpus cavernosum penis. Those adipocytes exhibited strong nuclear PPAR expression. These results suggest a biological overlap between PPAR and ER and highlight a mechanism for endocrine disruption.

  10. Mechanism of A2 adenosine receptor activation. I. Blockade of A2 adenosine receptors by photoaffinity labeling

    Energy Technology Data Exchange (ETDEWEB)

    Lohse, M.J.; Klotz, K.N.; Schwabe, U.

    1991-04-01

    It has previously been shown that covalent incorporation of the photoreactive adenosine derivative (R)-2-azido-N6-p-hydroxy-phenylisopropyladenosine ((R)-AHPIA) into the A1 adenosine receptor of intact fat cells leads to a persistent activation of this receptor, resulting in a reduction of cellular cAMP levels. In contrast, covalent incorporation of (R)-AHPIA into human platelet membranes, which contain only stimulatory A2 adenosine receptors, reduces adenylate cyclase stimulation via these receptors. This effect of (R)-AHPIA is specific for the A2 receptor and can be prevented by the adenosine receptor antagonist theophylline. Binding studies indicate that up to 90% of A2 receptors can be blocked by photoincorporation of (R)-AHPIA. However, the remaining 10-20% of A2 receptors are sufficient to mediate an adenylate cyclase stimulation of up to 50% of the control value. Similarly, the activation via these 10-20% of receptors occurs with a half-life that is only 2 times longer than that in control membranes. This indicates the presence of a receptor reserve, with respect to both the extent and the rate of adenylate cyclase stimulation. These observations require a modification of the models of receptor-adenylate cyclase coupling.

  11. Allosterism and Structure in Thermally Activated Transient Receptor Potential Channels.

    Science.gov (United States)

    Diaz-Franulic, Ignacio; Poblete, Horacio; Miño-Galaz, Germán; González, Carlos; Latorre, Ramón

    2016-07-01

    The molecular sensors that mediate temperature changes in living organisms are a large family of proteins known as thermosensitive transient receptor potential (TRP) ion channels. These membrane proteins are polymodal receptors that can be activated by cold or hot temperatures, depending on the channel subtype, voltage, and ligands. The stimuli sensors are allosterically coupled to a pore domain, increasing the probability of finding the channel in its ion conductive conformation. In this review we first discuss the allosteric coupling between the temperature and voltage sensor modules and the pore domain, and then discuss the thermodynamic foundations of thermo-TRP channel activation. We provide a structural overview of the molecular determinants of temperature sensing. We also posit an anisotropic thermal diffusion model that may explain the large temperature sensitivity of TRP channels. Additionally, we examine the effect of several ligands on TRP channel function and the evidence regarding their mechanisms of action. PMID:27297398

  12. Monocyte Signal Transduction Receptors in Active and Latent Tuberculosis

    Directory of Open Access Journals (Sweden)

    Magdalena Druszczynska

    2013-01-01

    Full Text Available The mechanisms that promote either resistance or susceptibility to TB disease remain insufficiently understood. Our aim was to compare the expression of cell signaling transduction receptors, CD14, TLR2, CD206, and β2 integrin LFA-1 on monocytes from patients with active TB or nonmycobacterial lung disease and healthy individuals with M.tb latency and uninfected controls to explain the background of the differences between clinical and subclinical forms of M.tb infection. A simultaneous increase in the expression of the membrane bound mCD14 receptor and LFA-1 integrin in patients with active TB may be considered a prodrome of breaking immune control by M.tb bacilli in subjects with the latent TB and absence of clinical symptoms.

  13. Activation of the chicken gonadotropin-inhibitory hormone receptor reduces gonadotropin releasing hormone receptor signaling.

    Science.gov (United States)

    Shimizu, Mamiko; Bédécarrats, Grégoy Y

    2010-06-01

    Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic peptide from the RFamide peptide family that has been identified in multiple avian species. Although GnIH has clearly been shown to reduce LH release from the anterior pituitary gland, its mechanism of action remains to be determined. The overall objectives of this study were (1) to characterize the GnIH receptor (GnIH-R) signaling pathway, (2) to evaluate potential interactions with gonadotropin releasing hormone type III receptor (GnRH-R-III) signaling, and (3) to determine the molecular mechanisms by which GnIH and GnRH regulate pituitary gonadotrope function during a reproductive cycle in the chicken. Using real-time PCR, we showed that in the chicken pituitary gland, GnIH-R mRNA levels fluctuate in an opposite manner to GnRH-R-III, with higher and lower levels observed during inactive and active reproductive stages, respectively. We demonstrated that the chicken GnIH-R signals by inhibiting adenylyl cyclase cAMP production, most likely by coupling to G(alphai). We also showed that this inhibition is sufficient to significantly reduce GnRH-induced cAMP responsive element (CRE) activation in a dose-dependent manner, and that the ratio of GnRH/GnIH receptors is a significant factor. We propose that in avian species, sexual maturation is characterized by a change in GnIH/GnRH receptor ratio, resulting in a switch in pituitary sensitivity from inhibitory (involving GnIH) to stimulatory (involving GnRH). In turn, decreasing GnIH-R signaling, combined with increasing GnRH-R-III signaling, results in significant increases in CRE activation, possibly initiating gonadotropin synthesis. PMID:20350548

  14. Receptor mapping in psychiatric patients with SPECT

    International Nuclear Information System (INIS)

    This paper summarizes some data of our studies with the single-photon-emission-computerized tomography (SPECT), focussing on the dopamine-D2- and the benzodiazepine receptor mapping. Benzodiazepine receptors: Central benzodiazepine receptors (BZr) can be visualized with iomazenil which is an analogue of the benzodiazepine antagonist flumazenil, labeled with 123-iodine. Since the involvement of the BZr system is discussed in the pathogenesis of anxiety and depression, patients with these disorders were investigated. A third study investigated the BZr-occupancy during benzodiazepine treatment (lorazepam). Results: (a) Patients with panic disorders had lower iomazenil uptake values compared to epileptic patients. (b) Depressed patients showed a positive correlation between severity of illness and frontal uptake. (c) BZr occupancy during lorazepam treatment was measurable, but not associated with lorazepam plasma levels. Dopamine-D2-receptors: With 123-I-iodobenzamide (IBZM), and iodine-labeled dopamine receptor ligand, the D2 receptor density can be measured by a semiquantitative approach (striatum/frontal cortex=ST/FC). Therefore, we investigated the D2-receptor occupancy during treatment with typical and atypical neuroleptics in relationship to dosages (normalized with different formulas of chlorpromazine equivalents), side effects, and prolactin plasma levels. Results: Dependent on the selected formula for chlorpromazine equivalents, the ST/FC ratio was correlated with dosages. Side effects and prolactin plasma levels showed a negative association with lower ST/FC ratios. (orig.)

  15. Thyrotropin Receptor Activation Increases Hyaluronan Production in Preadipocyte Fibroblasts

    OpenAIRE

    Zhang, Lei; Bowen, Timothy; Grennan-Jones, Fiona; Paddon, Carol; Giles, Peter; Webber, Jason; Steadman, Robert; Ludgate, Marian

    2009-01-01

    The thyrotropin receptor (TSHR) is expressed during lineage-specific differentiation (e.g. adipogenesis) and is activated by TSH, thyroid-stimulating antibodies, and gain-of-function mutations (TSHR*). Comparison of gene expression profiles of nonmodified human preadipocytes (n = 4) with the parallel TSHR* population revealed significant up-regulation of 27 genes including hyaluronan (HA) synthases (HAS) 1 and 2. The array data were confirmed by quantitative PCR of HAS1 and HAS2 and enzyme-li...

  16. Insect Repellents: Modulators of Mosquito Odorant Receptor Activity

    OpenAIRE

    Bohbot, Jonathan D.; Joseph C. Dickens

    2010-01-01

    Background DEET, 2-undecanone (2-U), IR3535 and Picaridin are widely used as insect repellents to prevent interactions between humans and many arthropods including mosquitoes. Their molecular action has only recently been studied, yielding seemingly contradictory theories including odorant-dependent inhibitory and odorant-independent excitatory activities on insect olfactory sensory neurons (OSNs) and odorant receptor proteins (ORs). Methodology/Principal Findings Here we characterize the act...

  17. A novel hydroxyfuroic acid compound as an insulin receptor activator – structure and activity relationship of a prenylindole moiety to insulin receptor activation

    Directory of Open Access Journals (Sweden)

    Tsai Henry J

    2009-07-01

    Full Text Available Abstract Background Diabetes Mellitus is a chronic disease and many patients of which require frequent subcutaneous insulin injection to maintain proper blood glucose levels. Due to the inconvenience of insulin administration, an orally active insulin replacement has long been a prime target for many pharmaceutical companies. Demethylasterriquinone (DMAQ B1, extracted from tropical fungus, Pseudomassaria sp., has been reported to be an orally effective agent at lowering circulating glucose levels in diabetic (db/db mice; however, the cytotoxicity associated with the quinone moiety has not been addressed thus far. Methods A series of hydroxyfuroic acid compounds were synthesized and tested for their efficacies at activating human insulin receptor. Cytotoxicity to Chinese hamster ovary cells, selectivities over insulin-like growth factor-1 (IGF-1, epidermal growth factor (EGF, and fibroblast growth factor (FGF receptors were examined in this study. Result and Conclusion This study reports a new non-quinone DMAQ B1 derivative, a hydroxyfuroic acid compound (D-410639, which is 128 fold less cytotoxic as DMAQ B1 and as potent as compound 2, a DMAQ B1 synthetic derivative from Merck, at activating human insulin receptor. D-410639 has little activation potential on IGF-1 receptor but is a moderate inhibitor to EGF receptor. Structure and activity relationship of the prenylindole moiety to insulin receptor activation is discussed.

  18. Positron emission tomography assessment of effects of benzodiazepines on regional glucose metabolic rate in patients with anxiety disorder

    International Nuclear Information System (INIS)

    Patients with generalized anxiety disorder (n = 18) entered a 21-day, double-blind, placebo-controlled random assignment trial of clorazepate. Positron emission tomography with 18F-deoxyglucose was carried out before and after treatment. Decreases in glucose metabolic rate in visual cortex and relative increases in the basal ganglia and thalamus were found. A correlation between regional changes in metabolic rate and regional benzodiazepine receptor binding density from other human autopsy studies was observed; brain regions highest in receptor density showed the greatest decrease in rate

  19. Positron emission tomography assessment of effects of benzodiazepines on regional glucose metabolic rate in patients with anxiety disorder

    Energy Technology Data Exchange (ETDEWEB)

    Buchsbaum, M.S.; Wu, J.; Haier, R.; Hazlett, E.; Ball, R.; Katz, M.; Sokolski, K.; Lagunas-Solar, M.; Langer, D.

    1987-06-22

    Patients with generalized anxiety disorder (n = 18) entered a 21-day, double-blind, placebo-controlled random assignment trial of clorazepate. Positron emission tomography with YF-deoxyglucose was carried out before and after treatment. Decreases in glucose metabolic rate in visual cortex and relative increases in the basal ganglia and thalamus were found. A correlation between regional changes in metabolic rate and regional benzodiazepine receptor binding density from other human autopsy studies was observed; brain regions highest in receptor density showed the greatest decrease in rate.

  20. Ultrastructural and biochemical analysis of fibrinogen receptors on activated thrombocytes

    International Nuclear Information System (INIS)

    The present studies have been concerned with the role of fibrinogen and its receptor, GP IIb/IIIa, during the activation and early aggregation of pigeon thrombocytes. Thrombocytes were surface labeled with 125I then separated on SDS-PAGE. Analysis by gel autoradiography revealed major bands at MW 145 kd and 98 kd, which corresponded to human GPIIb and GPIIIa. Immunologic similarity of the pigeon and human receptor components was established by dot blot analysis using polyclonal antibodies directed against human GPIIb and GPIIIa. Pigeon fibrinogen, isolated by plasma precipitation with PEG-1000 and purified over Sepharose 4B, was used to study receptor-ligand interaction. Separation of pigeon fibrinogen on SDS-PAGE resulted in three peptides having apparent MW of 62kd, 55kd, and 47kd which are comparable to human fibrinogen. Further similarity of human and pigeon fibrinogen was verified by immonodiffusion against an antibody specific for the human protein. The role of fibrinogen and its receptor in thrombocyte function was established by turbidimetric aggregation using thrombin as an agonist under conditions requiring Ca++ and fibrinogen

  1. Neutron activation analysis in receptor modeling in environmental chemistry

    International Nuclear Information System (INIS)

    The release of air pollutants in high enough concentrations can have adverse health effects on the general public, particularly in urban areas. To develop strategies to manage the quality of air pollution, it is necessary to understand the flow of materials through the system, the sources and sinks, transformation, and transport pathways of the species of interest. An approach that is extensively being used in our laboratories, as well as in many others, is the use of receptor modeling. These models are based on the concepts of conservation of mass and a mass balance analysis, which in turn is based on the characterization of airborne particles into their constituents. From these methods, sources contributing to air quality are identified from the perspective of the receptor or ambient sampler. Separation of the ambient particles containing trace elements into distinct size classes allows the study of various sources to be identified. Another reason for the rapid development of receptor models has been the concurrent development of a variety of analytical techniques that permit greatly improved analyses to provide the needed input data. Two of the most powerful methods are instrumental neutron activation analysis (INAA) and X-ray fluorescence (XRF), including particle-induced X-ray emission. By using these methods along with sophisticated receptor modeling and size fractionation, the authors have been able to identify specific sources of local and regional air pollution

  2. Dynamic correlation networks in human peroxisome proliferator-activated receptor-γ nuclear receptor protein.

    Science.gov (United States)

    Fidelak, Jeremy; Ferrer, Silvia; Oberlin, Michael; Moras, Dino; Dejaegere, Annick; Stote, Roland H

    2010-10-01

    Peroxisome proliferator-activated receptor-γ nuclear receptor (PPAR-γ) belongs to the superfamily of nuclear receptor proteins that function as ligand-dependent transcription factors and plays a specific physiological role as a regulator of lipid metabolism. A number of experimental studies have suggested that allostery plays an important role in the functioning of PPAR-γ. Here we use normal-mode analysis of PPAR-γ to characterize a network of dynamically coupled amino acids that link physiologically relevant binding surfaces such as the ligand-dependent activation domain AF-2 with the ligand binding site and the heterodimer interface. Multiple calculations were done in both the presence and absence of the agonist rosiglitazone, and the differences in dynamics were characterized. The global dynamics of the ligand binding domain were affected by the ligand, and in particular, changes to the network of dynamically correlated amino acids were observed with only small changes in conformation. These results suggest that changes in dynamic couplings can be functionally significant with respect to the transmission of allosteric signals. PMID:20496064

  3. Detecting constitutive activity and protean agonism at cannabinoid-2 receptor.

    Science.gov (United States)

    Beltramo, Massimiliano; Brusa, Rossella; Mancini, Isabella; Scandroglio, Paola

    2010-01-01

    Since the cannabinoid system is involved in regulating several physiological functions such as locomotor activity, cognition, nociception, food intake, and inflammatory reaction, it has been the subject of intense study. Research on the pharmacology of this system has enormously progressed in the last 20years. One intriguing aspect that emerged from this research is that cannabinoid receptors (CBs) express a high level of constitutive activity. Investigation on this particular aspect of receptor pharmacology has largely focused on CB1, the CB subtype highly expressed in several brain regions. More recently, research on constitutive activity on the other CB subtype, CB2, was stimulated by the increasing interest on its potential as target for the treatment of various pathologies (e.g., pain and inflammation). There are several possible implications of constitutive activity on the therapeutic action of both agonists and antagonists, and consequently, it is important to have valuable methods to study this aspect of CB2 pharmacology. In the present chapter, we describe three methods to study constitutive activity at CB2: two classical methods relying on the detection of changes in cAMP level and GTPγS binding and a new one based on cell impedance measurement. In addition, we also included a section on detection of protean agonism, which is an interesting pharmacological phenomenon strictly linked to constitutive activity. PMID:21036225

  4. Bioluminescence imaging of estrogen receptor activity during breast cancer progression.

    Science.gov (United States)

    Vantaggiato, Cristina; Dell'Omo, Giulia; Ramachandran, Balaji; Manni, Isabella; Radaelli, Enrico; Scanziani, Eugenio; Piaggio, Giulia; Maggi, Adriana; Ciana, Paolo

    2016-01-01

    Estrogen receptors (ER) are known to play an important regulatory role in mammary gland development as well as in its neoplastic transformation. Although several studies highlighted the contribution of ER signaling in the breast transformation, little is known about the dynamics of ER state of activity during carcinogenesis due to the lack of appropriate models for measuring the extent of receptor signaling in time, in the same animal. To this aim, we have developed a reporter mouse model for the non-invasive in vivo imaging of ER activity: the ERE-Luc reporter mouse. ERE-Luc is a transgenic mouse generated with a firefly luciferase (Luc) reporter gene driven by a minimal promoter containing an estrogen responsive element (ERE). This model allows to measure receptor signaling in longitudinal studies by bioluminescence imaging (BLI). Here, we have induced sporadic mammary cancers by treating systemically ERE-Luc reporter mice with DMBA (9,10-dimethyl 1,2-benzanthracene) and measured receptor signaling by in vivo imaging in individual animals from early stage until a clinically palpable tumor appeared in the mouse breast. We showed that DMBA administration induces an increase of bioluminescence in the whole abdominal area 6 h after treatment, the signal rapidly disappears. Several weeks later, strong bioluminescence is observed in the area corresponding to the mammary glands. In vivo and ex vivo imaging analysis demonstrated that this bioluminescent signal is localized in the breast area undergoing neoplastic transformation. We conclude that this non-invasive assay is a novel relevant tool to identify the activation of the ER signaling prior the morphological detection of the neoplastic transformation. PMID:27069764

  5. Benzodiazepine use in Denmark 1997-2008

    DEFF Research Database (Denmark)

    Holm, E.; Pedersen, H.; Fosbol, E.;

    2012-01-01

    Purpose: Analysis of the pattern of benzodiazepine (BZD) use over time in the period 1997-2008 in relation to age and comorbidity. Methods: All Danish citizens more than or equal to 10 years on January 1, 1997 were included in the study based on data from national databases. Main outcome measures...... were changes in BZD prevalence of use and intensity of use with respect to age, gender and comorbidity. Results: Prevalence of at least one prescription per individual within a year declined from 12.0% in 1997 to 10.7% in 2008 (P <0.0001). Among people aged 75-84 years use of BZDs dropped from 35.8% to.......27 (CI 3.25-3.30), OR for using more than 180 ddd/year 6.7 (CI 6.7-6.8). Conclusion: BZD-use has been markedly reduced in the Danish population from 1997-2008; however, one in four people aged 75-85 years and almost one in three of patients over 85 years still use BZDs. © 2012 Elsevier Masson SAS and...

  6. Alcohol Withdrawal Syndrome: Benzodiazepines and Beyond.

    Science.gov (United States)

    Sachdeva, Ankur; Choudhary, Mona; Chandra, Mina

    2015-09-01

    Alcohol dependence is an increasing and pervasive problem. Alcohol withdrawal symptoms are a part of alcohol dependence syndrome and are commonly encountered in general hospital settings, in most of the departments. Alcohol withdrawal syndrome ranges from mild to severe. The severe complicated alcohol withdrawal may present with hallucinations, seizures or delirium tremens. Benzodiazepines have the largest and the best evidence base in the treatment of alcohol withdrawal, and are considered the gold standard. Others, such as anticonvulsants, barbiturates, adrenergic drugs, and GABA agonists have been tried and have evidence. Supportive care and use of vitamins is essential in the management. Symptom triggered regime is favoured over fixed tapering dose regime, although monitoring through scales is cumbersome. This article aims to review the evidence base for appropriate clinical management of the alcohol withdrawal syndrome. We searched Pubmed for articles published in English on 'Alcohol withdrawal syndrome' in humans during the last 10 years. A total of 1182 articles came up. Articles not relevant to clinical utility and management were excluded based on the titles and abstract available. Full text articles, meta-analyses, systematic reviews and randomized controlled trials were obtained from this list and were considered for review. PMID:26500991

  7. Activation of glycine receptors modulates spontaneous epileptiform activity in the immature rat hippocampus

    Science.gov (United States)

    Chen, Rongqing; Okabe, Akihito; Sun, Haiyan; Sharopov, Salim; Hanganu-Opatz, Ileana L; Kolbaev, Sergei N; Fukuda, Atsuo; Luhmann, Heiko J; Kilb, Werner

    2014-01-01

    While the expression of glycine receptors in the immature hippocampus has been shown, no information about the role of glycine receptors in controlling the excitability in the immature CNS is available. Therefore, we examined the effect of glycinergic agonists and antagonists in the CA3 region of an intact corticohippocampal preparation of the immature (postnatal days 4–7) rat using field potential recordings. Bath application of 100 μm taurine or 10 μm glycine enhanced the occurrence of recurrent epileptiform activity induced by 20 μm 4-aminopyridine in low Mg2+ solution. This proconvulsive effect was prevented by 3 μm strychnine or after incubation with the loop diuretic bumetanide (10 μm), suggesting that it required glycine receptors and an active NKCC1-dependent Cl− accumulation. Application of higher doses of taurine (≥1 mm) or glycine (100 μm) attenuated recurrent epileptiform discharges. The anticonvulsive effect of taurine was also observed in the presence of the GABAA receptor antagonist gabazine and was attenuated by strychnine, suggesting that it was partially mediated by glycine receptors. Bath application of the glycinergic antagonist strychnine (0.3 μm) induced epileptiform discharges. We conclude from these results that in the immature hippocampus, activation of glycine receptors can mediate both pro- and anticonvulsive effects, but that a persistent activation of glycine receptors is required to suppress epileptiform activity. In summary, our study elucidated the important role of glycine receptors in the control of neuronal excitability in the immature hippocampus. PMID:24665103

  8. Peroxisome Proliferator–Activated Receptors and The Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2009-04-01

    Full Text Available BACKGROUND: Obesity is a growing threat to global health by virtue of its association with insulin resistance, inflammation, hypertension, and dyslipidemia, collectively known as the metabolic syndrome (MetS. The nuclear receptors PPARα and PPARγ are therapeutic targets for hypertriglyceridemia and insulin resistance, respectively, and drugs that modulate these receptors are currently in clinical use. More recent work on the PPARδ has uncovered a dual benefit for both hypertriglyceridemia and insulin resistance, highlighting the broad potential of PPARs in the treatment of metabolic disease. CONTENT: We have learned much about PPARs, the metabolic fat sensors, and the molecular pathways they regulate. Through their distinct tissue distribution and specific target gene activation, the three PPARs together control diverse aspects of fatty acid metabolism, energy balance, insulin sensitivity glucose homeostasis, inflammation, hypertension and atherosclerosis. These studies have advanced our understanding of the etiology for the MetS. Mechanisms revealed by these studies highlight the importance of emerging concepts, such as the endocrine function of adipose tissue, tissue-tissue cross-talk and lipotoxicity, in the pathogenesis of type 2 diabetes mellitus and CVD. SUMMARY: The elucidation of key regulators of energy balance and insulin signaling have revolutionized our understanding of fat and sugar metabolism and their intimate link. The three ‘lipidsensing’ (PPARα, PPARγ and PPARδ exemplify this connection, regulating diverse aspects of lipid and glucose homeostasis, and serving as bonafide therapeutic targets. KEYWORDS: peroxisome proliferator, activated receptor, metabolic syndrome.

  9. Identification of Modulators of the Nuclear Receptor Peroxisome Proliferator-Activated Receptor α (PPARα) in a Mouse Liver Gene Expression Compendium

    Science.gov (United States)

    The nuclear receptor family member peroxisome proliferator-activated receptor α (PPARα) is activated by therapeutic hypolipidemic drugs and environmentally-relevant chemicals to regulate genes involved in lipid transport and catabolism. Chronic activation of PPARα in rodents inc...

  10. Bronchoconstrictor effect of thrombin and thrombin receptor activating peptide in guinea-pigs in vivo

    OpenAIRE

    Cicala, Carla; Bucci, Mariarosaria; De Dominicis, Gianfranco; Harriot, Pat; Sorrentino, Ludovico; Cirino, Giuseppe

    1999-01-01

    Several thrombin cellular effects are dependent upon stimulation of proteinase activated receptor-1 (PAR-1) localized over the cellular surface. Following activation by thrombin, a new N-terminus peptide is unmasked on PAR-1 receptor, which functions as a tethered ligand for the receptor itself. Synthetic peptides called thrombin receptor activating peptides (TRAPs), corresponding to the N-terminus residue unmasked, reproduce several thrombin cellular effects, but are devoid of catalytic acti...

  11. D1 dopamine receptor activity of anti-parkinsonian drugs.

    Science.gov (United States)

    Fici, G J; Wu, H; VonVoigtlander, P F; Sethy, V H

    1997-01-01

    Clinical and preclinical investigations suggest that stimulation of D1 dopamine receptors may be responsible for dyskinesias induced by dopamine agonist treatment of Parkinson's Disease (PD), and that these dyskinesias may be decreased by treatment with a D1 antagonist (clozapine). Therefore, the effects of dopamine agonists and antagonists have been investigated in a primary cerebellar granule cell model of cAMP formation that seems to be highly responsive to the D1 receptors. SKF 38393, lisuride, apomorphine, pergolide, dopamine, bromocriptine and 7-OH-DPAT showed concentration-dependent increases in cAMP formation, with EC50s (in microM) of 0.013, 0.053, 0.25, 1.04, 2.18, 50.9 and 54.4, respectively. SKF 38393, apomorphine, dopamine and pergolide had similar intrinsic activity (100%), while the intrinsic activities of 7-OH-DPAT, bromocriptine and lisuride were 28.0%, 20.7% and 17.2%, respectively. SCH 23390, a selective D1 dopamine receptor antagonist, blocked an increase in cAMP formation produced by EC50 concentrations of all of the dopamine agonists investigated in this study. Clozapine concentration-dependently blocked pergolide-induced increases in cAMP and was approximately 1700-fold less potent than SCH 23390 (IC50: 0.97 microM and 0.56 nM, respectively). U-95666A (1-1000 microM), selective for the D2 receptors, showed no significant effect on cAMP, while pramipexole (0.1-100 microM), a D3 preferring agonist, did not elevate cAMP. These data suggest that primary cerebellar granule cell cultures are an excellent model for measuring D1 dopamine receptor-mediated changes in cellular cAMP. The results are discussed with reference to the relationship between the D1 receptor-stimulated increase in cAMP formation and the induction of dyskinesia in humans by these anti-parkinsonian drugs. PMID:9126882

  12. Methamphetamine Increases Locomotion and Dopamine Transporter Activity in Dopamine D5 Receptor-Deficient Mice

    OpenAIRE

    Hayashizaki, Seiji; Hirai, Shinobu; Ito, Yumi; Honda, Yoshiko; Arime, Yosefu; Sora, Ichiro; Okado, Haruo; Kodama, Tohru; Takada, Masahiko

    2013-01-01

    Dopamine regulates the psychomotor stimulant activities of amphetamine-like substances in the brain. The effects of dopamine are mediated through five known dopamine receptor subtypes in mammals. The functional relevance of D5 dopamine receptors in the central nervous system is not well understood. To determine the functional relevance of D5 dopamine receptors, we created D5 dopamine receptor-deficient mice and then used these mice to assess the roles of D5 dopamine receptors in the behaviora...

  13. Stimulation of cannabinoid receptor 2 (CB2 suppresses microglial activation

    Directory of Open Access Journals (Sweden)

    Fernandez Francisco

    2005-12-01

    Full Text Available Abstract Background Activated microglial cells have been implicated in a number of neurodegenerative disorders, including Alzheimer's disease (AD, multiple sclerosis (MS, and HIV dementia. It is well known that inflammatory mediators such as nitric oxide (NO, cytokines, and chemokines play an important role in microglial cell-associated neuron cell damage. Our previous studies have shown that CD40 signaling is involved in pathological activation of microglial cells. Many data reveal that cannabinoids mediate suppression of inflammation in vitro and in vivo through stimulation of cannabinoid receptor 2 (CB2. Methods In this study, we investigated the effects of a cannabinoid agonist on CD40 expression and function by cultured microglial cells activated by IFN-γ using RT-PCR, Western immunoblotting, flow cytometry, and anti-CB2 small interfering RNA (siRNA analyses. Furthermore, we examined if the stimulation of CB2 could modulate the capacity of microglial cells to phagocytise Aβ1–42 peptide using a phagocytosis assay. Results We found that the selective stimulation of cannabinoid receptor CB2 by JWH-015 suppressed IFN-γ-induced CD40 expression. In addition, this CB2 agonist markedly inhibited IFN-γ-induced phosphorylation of JAK/STAT1. Further, this stimulation was also able to suppress microglial TNF-α and nitric oxide production induced either by IFN-γ or Aβ peptide challenge in the presence of CD40 ligation. Finally, we showed that CB2 activation by JWH-015 markedly attenuated CD40-mediated inhibition of microglial phagocytosis of Aβ1–42 peptide. Taken together, these results provide mechanistic insight into beneficial effects provided by cannabinoid receptor CB2 modulation in neurodegenerative diseases, particularly AD.

  14. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    Directory of Open Access Journals (Sweden)

    E. Teodorov

    2012-10-01

    Full Text Available The periaqueductal gray (PAG has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc or 0.9% saline (up to 1 mL/kg and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05 because a lower percentage of kappa group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR. A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05 and lactating female rats (P < 0.01, with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in

  15. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    International Nuclear Information System (INIS)

    The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

  16. Behavioral meaningful opioidergic stimulation activates kappa receptor gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Teodorov, E. [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, São Paulo, SP (Brazil); Ferrari, M.F.R. [Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Fior-Chadi, D.R. [Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP (Brazil); Camarini, R. [Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Felício, L.F. [Departamento de Patologia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-06-01

    The periaqueductal gray (PAG) has been reported to be a location for opioid regulation of pain and a potential site for behavioral selection in females. Opioid-mediated behavioral and physiological responses differ according to the activity of opioid receptor subtypes. The present study investigated the effects of the peripheral injection of the kappa-opioid receptor agonist U69593 into the dorsal subcutaneous region of animals on maternal behavior and on Oprk1 gene activity in the PAG of female rats. Female Wistar rats weighing 200-250 g at the beginning of the study were randomly divided into 2 groups for maternal behavior and gene expression experiments. On day 5, pups were removed at 7:00 am and placed in another home cage that was distant from their mother. Thirty minutes after removing the pups, the dams were treated with U69593 (0.15 mg/kg, sc) or 0.9% saline (up to 1 mL/kg) and after 30 min were evaluated in the maternal behavior test. Latencies in seconds for pup retrieval, grouping, crouching, and full maternal behavior were scored. The results showed that U69593 administration inhibited maternal behavior (P < 0.05) because a lower percentage of U69593 group dams showed retrieval of first pup, retrieving all pups, grouping, crouching and displaying full maternal behavior compared to the saline group. Opioid gene expression was evaluated using real-time reverse-transcription polymerase chain reaction (RT-PCR). A single injection of U69593 increased Oprk1 PAG expression in both virgin (P < 0.05) and lactating female rats (P < 0.01), with no significant effect on Oprm1 or Oprd1 gene activity. Thus, the expression of kappa-opioid receptors in the PAG may be modulated by single opioid receptor stimulation and behavioral meaningful opioidergic transmission in the adult female might occur simultaneously to specific changes in gene expression of kappa-opioid receptor subtype. This is yet another alert for the complex role of the opioid system in female

  17. Genetic markers of a Munc13 protein family member, BAIAP3, are gender specifically associated with anxiety and benzodiazepine abuse in mice and humans.

    Science.gov (United States)

    Wojcik, Sonja M; Tantra, Martesa; Stepniak, Beata; Man, Kwun-Nok M; Müller-Ribbe, Katja; Begemann, Martin; Ju, Anes; Papiol, Sergi; Ronnenberg, Anja; Gurvich, Artem; Shin, Yong; Augustin, Iris; Brose, Nils; Ehrenreich, Hannelore

    2013-01-01

    Anxiety disorders and substance abuse, including benzodiazepine use disorder, frequently occur together. Unfortunately, treatment of anxiety disorders still includes benzodiazepines, and patients with an existing comorbid benzodiazepine use disorder or a genetic susceptibility for benzodiazepine use disorder may be at risk of adverse treatment outcomes. The identification of genetic predictors for anxiety disorders, and especially for benzodiazepine use disorder, could aid the selection of the best treatment option and improve clinical outcomes. The brain-specific angiogenesis inhibitor I-associated protein 3 (Baiap3) is a member of the mammalian uncoordinated 13 (Munc13) protein family of synaptic regulators of neurotransmitter exocytosis, with a striking expression pattern in amygdalae, hypothalamus and periaqueductal gray. Deletion of Baiap3 in mice leads to enhanced seizure propensity and increased anxiety, with the latter being more pronounced in female than in male animals. We hypothesized that genetic variation in human BAIAP3 may also be associated with anxiety. By using a phenotype-based genetic association study, we identified two human BAIAP3 single-nucleotide polymorphism risk genotypes (AA for rs2235632, TT for rs1132358) that show a significant association with anxiety in women and, surprisingly, with benzodiazepine abuse in men. Returning to mice, we found that male, but not female, Baiap3 knockout (KO) mice develop tolerance to diazepam more quickly than control animals. Analysis of cultured Baiap3 KO hypothalamus slices revealed an increase in basal network activity and an altered response to diazepam withdrawal. Thus, Baiap3/BAIAP3 is gender specifically associated with anxiety and benzodiazepine use disorder, and the analysis of Baiap3/BAIAP3-related functions may help elucidate mechanisms underlying the development of both disorders. PMID:23698091

  18. Characterization of human endothelial cell urokinase-type plasminogen activator receptor protein and messenger RNA

    DEFF Research Database (Denmark)

    Barnathan, E S; Kuo, A; Karikó, K;

    1990-01-01

    Human umbilical vein endothelial cells in culture (HUVEC) express receptors for urokinase-type plasminogen activators (u-PA). The immunochemical nature of this receptor and its relationship to u-PA receptors expressed by other cell types is unknown. Cross-linking active site-blocked u-PA to HUVEC...

  19. Dopamine receptor activation increases HIV entry into primary human macrophages.

    Directory of Open Access Journals (Sweden)

    Peter J Gaskill

    Full Text Available Macrophages are the primary cell type infected with HIV in the central nervous system, and infection of these cells is a major component in the development of neuropathogenesis and HIV-associated neurocognitive disorders. Within the brains of drug abusers, macrophages are exposed to increased levels of dopamine, a neurotransmitter that mediates the addictive and reinforcing effects of drugs of abuse such as cocaine and methamphetamine. In this study we examined the effects of dopamine on HIV entry into primary human macrophages. Exposure to dopamine during infection increased the entry of R5 tropic HIV into macrophages, irrespective of the concentration of the viral inoculum. The entry pathway affected was CCR5 dependent, as antagonizing CCR5 with the small molecule inhibitor TAK779 completely blocked entry. The effect was dose-dependent and had a steep threshold, only occurring above 108 M dopamine. The dopamine-mediated increase in entry required dopamine receptor activation, as it was abrogated by the pan-dopamine receptor antagonist flupenthixol, and could be mediated through both subtypes of dopamine receptors. These findings indicate that the effects of dopamine on macrophages may have a significant impact on HIV pathogenesis. They also suggest that drug-induced increases in CNS dopamine may be a common mechanism by which drugs of abuse with distinct modes of action exacerbate neuroinflammation and contribute to HIV-associated neurocognitive disorders in infected drug abusers.

  20. Drugged drivers in Norway with benzodiazepine detections.

    Science.gov (United States)

    Skurtveit, Svetlana; Abotnes, Bjørg; Christophersen, Asbjørg S

    2002-01-24

    Norwegian drugged drivers with benzodiazepine (BZD) detections have been studied with regard to drug use pattern and rearrest rate. During 1995, 3343 drivers were apprehended by the police in Norway due to the suspicion of influence by drugs. Blood samples from all drivers were sent to the National Institute of Forensic Toxicology (NIFT). The samples were analysed using a standard program covering the most commonly abused drugs on the marked in Norway. BZDs, representing some of the most frequently detected drugs, were found in approximately 30% (n = 1051) of the cases, represented by 14% (n = 150) female and 86% (n = 901) male drivers. In 8% of the cases, one BZD only was detected, half of these cases with one BZD could reflect therapeutic use. One or more BZDs were combined with illegal drug(s) (73%), other prescribed drugs (10%), and/or alcohol (24%). 62% of the drivers with BZD detections, had earlier been arrested for the same offence, or six cases per rearrested driver. The frequency of earlier arrests were lower for female (34%) than for male (67%) drivers. Alcohol was most frequently found for those arrested for the first time before 1992, while BZD or illegal drugs were most frequently found for those with their first arrest during 1992-1995. Our study shows that apprehended drivers using BZD are mainly represented by drug abusers due to frequent multi-drug use, blood concentrations representing doses above therapeutic levels and high rearrest rate for the same offence. A treatment program or other reactions, are thus necessary in addition to fines, prison penalty and suspension of driving licence. PMID:11852205

  1. NMDA receptor subunit expression and PAR2 receptor activation in colospinal afferent neurons (CANs during inflammation induced visceral hypersensitivity

    Directory of Open Access Journals (Sweden)

    Caudle Robert M

    2009-09-01

    Full Text Available Abstract Background Visceral hypersensitivity is a clinical observation made when diagnosing patients with functional bowel disorders. The cause of visceral hypersensitivity is unknown but is thought to be attributed to inflammation. Previously we demonstrated that a unique set of enteric neurons, colospinal afferent neurons (CANs, co-localize with the NR1 and NR2D subunits of the NMDA receptor as well as with the PAR2 receptor. The aim of this study was to determine if NMDA and PAR2 receptors expressed on CANs contribute to visceral hypersensitivity following inflammation. Recently, work has suggested that dorsal root ganglion (DRG neurons expressing the transient receptor potential vanilloid-1 (TRPV1 receptor mediate inflammation induced visceral hypersensitivity. Therefore, in order to study CAN involvement in visceral hypersensitivity, DRG neurons expressing the TRPV1 receptor were lesioned with resiniferatoxin (RTX prior to inflammation and behavioural testing. Results CANs do not express the TRPV1 receptor; therefore, they survive following RTX injection. RTX treatment resulted in a significant decrease in TRPV1 expressing neurons in the colon and immunohistochemical analysis revealed no change in peptide or receptor expression in CANs following RTX lesioning as compared to control data. Behavioral studies determined that both inflamed non-RTX and RTX animals showed a decrease in balloon pressure threshold as compared to controls. Immunohistochemical analysis demonstrated that the NR1 cassettes, N1 and C1, of the NMDA receptor on CANs were up-regulated following inflammation. Furthermore, inflammation resulted in the activation of the PAR2 receptors expressed on CANs. Conclusion Our data show that inflammation causes an up-regulation of the NMDA receptor and the activation of the PAR2 receptor expressed on CANs. These changes are associated with a decrease in balloon pressure in response to colorectal distension in non-RTX and RTX lesioned

  2. Baicalin Activates Glycine and [Formula: see text]-Aminobutyric Acid Receptors on Substantia Gelatinosa Neurons of the Trigeminal Subsnucleus Caudalis in Juvenile Mice.

    Science.gov (United States)

    Yin, Hua; Bhattarai, Janardhan Prasad; Oh, Sun Mi; Park, Soo Joung; Ahn, Dong Kuk; Han, Seong Kyu

    2016-04-01

    The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) receives nociceptive afferent inputs from thin-myelinated A[Formula: see text] fibers and unmyelinated C fibers and has been shown to be involved in the processing of orofacial nociceptive information. Scutellaria baicalensis Georgi (Huang-Qin, SbG), one of the 50 fundamental herbs of Chinese herbology, has been used historically as anti-inflammatory and antineoplastic medicine. Baicalin, one of the major compounds of SbG, has been reported to have neuroprotective, anti-inflammatory and analgesic effects. However, the receptor type activated by baicalin and its precise action mechanism on the SG neurons of Vc have not yet been studied. The whole-cell patch clamp technique was performed to examine the ion channels activated by baicalin on the SG neurons of Vc. In high Cl[Formula: see text] pipette solution, the baicalin (300[Formula: see text][Formula: see text]M) induced repeatable inward currents ([Formula: see text][Formula: see text]pA, [Formula: see text]) without desensitization on all the SG neurons tested. Further, the inward currents showed a concentration (0.1-3[Formula: see text]mM) dependent pattern. The inward current was sustained in the presence of tetrodotoxin (0.5[Formula: see text][Formula: see text]M), a voltage sensitive Na[Formula: see text] channel blocker. In addition, baicalin-induced inward currents were reduced in the presence of picrotoxin (50[Formula: see text][Formula: see text]M), a GABAA receptor antagonist, flumazenil (100[Formula: see text][Formula: see text]M), a benzodiazepine-sensitive GABAA receptor antagonist, and strychnine (2[Formula: see text][Formula: see text]M), a glycine receptor antagonist, respectively. These results indicate that baicalin has inhibitory effects on the SG neurons of the Vc, which are due to the activation of GABAA and/or the glycine receptor. Our results suggest that baicalin may be a potential target for orofacial pain modulation

  3. Takotsubo Cardiomyopathy and Catatonia in the Setting of Benzodiazepine Withdrawal

    Science.gov (United States)

    Peng, Teng J.

    2016-01-01

    We report two serious and unusual complications of benzodiazepine withdrawal in a single patient: takotsubo cardiomyopathy and catatonia. This 61-year-old female patient was brought to the emergency department with lethargy and within hours had declined into a state of catatonia. Although there was never a complaint of chest pain, ECG showed deep anterior T-wave inversions and cardiac enzymes were elevated. An echocardiogram was consistent with takotsubo cardiomyopathy. She later received 1 mg of midazolam and within minutes had resolution of catatonic symptoms. Careful history revealed that she had omitted her daily dose of lorazepam for 3 days prior to admission. To our knowledge, the case presented herein is the first report of simultaneous catatonia and takotsubo cardiomyopathy in the setting of benzodiazepine withdrawal. The pathogenesis of both conditions is poorly understood but may be indirectly related to the sudden decrease in γ-aminobutyric acid (GABA) signaling during benzodiazepine withdrawal. PMID:27547472

  4. Phenobarbital compared to benzodiazepines in alcohol withdrawal treatment

    DEFF Research Database (Denmark)

    Askgaard, Gro; Hallas, Jesper; Fink-Jensen, Anders; Molander, Anna Camilla; Madsen, Kenneth Grønkjær; Pottegård, Anton

    2016-01-01

    BACKGROUND: Long-acting benzodiazepines such as chlordiazepoxide are recommended as first-line treatment for alcohol withdrawal. These drugs are known for their abuse liability and might increase alcohol consumption among problem drinkers. Phenobarbital could be an alternative treatment option......, possibly with the drawback of a more pronounced acute toxicity. We evaluated if phenobarbital compared to chlordiazepoxide decreased the risk of subsequent use of benzodiazepines, alcohol recidivism and mortality. METHODS: The study was a register-based cohort study of patients admitted for alcohol...... withdrawal 1998-2013 and treated with either phenobarbital or chlordiazepoxide. Patients were followed for one year. We calculated hazard ratios (HR) for benzodiazepine use, alcohol recidivism and mortality associated with alcohol withdrawal treatment, while adjusting for confounders. RESULTS: A total of...

  5. Initial benzodiazepine use and improved health-related quality of life.

    NARCIS (Netherlands)

    van Hulten, Rolf; Teeuw, Bart; Bakker, Albert; Leufkens, Hubert G

    2005-01-01

    OBJECTIVE: The health-related quality of life (HRQOL) of initial benzodiazepine users was measured over time. Furthermore, benzodiazepine usage characteristics as determinants of change in mental and physical health status of the benzodiazepine users were examined. METHODS: In the only pharmacy of a

  6. Evidence that adiponectin receptor 1 activation exacerbates ischemic neuronal death

    Directory of Open Access Journals (Sweden)

    Thundyil John

    2010-08-01

    Full Text Available Abstract Background- Adiponectin is a hormone produced in and released from adipose cells, which has been shown to have anti-diabetic and anti-inflammatory actions in peripheral cells. Two cell surface adiponectin receptors (ADRs mediate the majority of the known biological actions of adiponectin. Thus far, ADR expression in the brain has been demonstrated in the arcuate and the paraventricular nucleus of hypothalamus, where its activation affects food intake. Recent findings suggest that levels of circulating adiponectin increase after an ischemic stroke, but the role of adiponectin receptor activation in stroke pathogenesis and its functional outcome is unclear. Methods- Ischemic stroke was induced in C57BL/6 mice by middle cerebral artery occlusion (MCAO for 1 h, followed by reperfusion. Primary cortical neuronal cultures were established from individual embryonic neocortex. For glucose deprivation (GD, cultured neurons were incubated in glucose-free Locke's medium for 6, 12 or 24 h. For combined oxygen and glucose deprivation (OGD, neurons were incubated in glucose-free Locke's medium in an oxygen-free chamber with 95% N2/5% CO2 atmosphere for either 3, 6, 9, 12 or 24 h. Primary neurons and brain tissues were analysed for Adiponectin and ADRs using reverse transcriptase polymerase chain reaction (RT-PCR, immunoblot and immunochemistry methods. Results- Cortical neurons express ADR1 and ADR2, and that the levels of ADR1 are increased in neurons in response to in vitro or in vivo ischemic conditions. Neurons treated with either globular or trimeric adiponectin exhibited increased vulnerability to oxygen and glucose deprivation which was associated with increased activation of a pro-apoptotic signaling cascade involving p38 mitogen-activated protein kinase (p38MAPK and AMP-activated protein kinase (AMPK. Conclusions- This study reveals a novel pathogenic role for adiponectin and adiponectin receptor activation in ischemic stroke. We show that

  7. UV-guided screening of benzodiazepine producing species in Penicillium

    DEFF Research Database (Denmark)

    Ostenfeld Larsen T; Frydenvang, Karla Andrea; Christian Frisvad J

    2000-01-01

    The benzodiazepine sclerotigenin (auranthine B) recently described as a metabolite of Penicillium sclerotigenum, has been isolated as the major metabolite from an isolate of P. commune. The structure of sclerotigenin was established by a single-crystal X-ray diffraction study and by NMR spectrosc......The benzodiazepine sclerotigenin (auranthine B) recently described as a metabolite of Penicillium sclerotigenum, has been isolated as the major metabolite from an isolate of P. commune. The structure of sclerotigenin was established by a single-crystal X-ray diffraction study and by NMR...

  8. Protein kinase C phosphorylation sensitizes but does not activate the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1)

    OpenAIRE

    Bhave, Gautam; HU, HUI-JUAN; Glauner, Kathi S.; Zhu, Weiguo; Wang, Haibin; Brasier, D. J.; Oxford, Gerry S; Gereau, Robert W.

    2003-01-01

    Protein kinase C (PKC) modulates the function of the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1). This modulation manifests as increased current when the channel is activated by capsaicin. In addition, studies have suggested that phosphorylation by PKC might directly gate the channel, because PKC-activating phorbol esters induce TRPV1 currents in the absence of applied ligands. To test whether PKC both modulates and gates the TRPV1 function by direct phosphorylation, w...

  9. Influence of metabotropic glutamate receptor agonists on the inhibitory effects of adenosine A1 receptor activation in the rat hippocampus

    OpenAIRE

    de Mendonça, Alexandre; Ribeiro, J. A.

    1997-01-01

    Glutamate and other amino acids are the main excitatory neurotransmitters in many brain regions, including the hippocampus, by activating ion channel-coupled glutamate receptors, as well as metabotropic receptors linked to G proteins and second messenger systems. Several conditions which promote the release of glutamate, like frequency stimulation and hypoxia, also lead to an increase in the extracellular levels of the important neuromodulator, adenosine. We studied whether the activation of ...

  10. The glucagon-like peptide 1 receptor agonist enhances intrinsic peroxisome proliferator-activated receptor γ activity in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Onuma, Hirohisa; Inukai, Kouichi, E-mail: kinukai@ks.kyorin-u.ac.jp; Kitahara, Atsuko; Moriya, Rie; Nishida, Susumu; Tanaka, Toshiaki; Katsuta, Hidenori; Takahashi, Kazuto; Sumitani, Yoshikazu; Hosaka, Toshio; Ishida, Hitoshi

    2014-08-22

    Highlights: • PPARγ activation was involved in the GLP-1-mediated anti-inflammatory action. • Exendin-4 enhanced endogenous PPARγ transcriptional activity in HUVECs. • H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement. • The anti-inflammatory effects of GLP-1 may be explained by PPARγ activation. - Abstract: Recent studies have suggested glucagon-like peptide-1 (GLP-1) signaling to exert anti-inflammatory effects on endothelial cells, although the precise underlying mechanism remains to be elucidated. In the present study, we investigated whether PPARγ activation is involved in the GLP-1-mediated anti-inflammatory action on endothelial cells. When we treated HUVEC cells with 0.2 ng/ml exendin-4, a GLP-1 receptor agonist, endogenous PPARγ transcriptional activity was significantly elevated, by approximately 20%, as compared with control cells. The maximum PPARγ activity enhancing effect of exendin-4 was observed 12 h after the initiation of incubation with exendin-4. As H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement, the signaling downstream from GLP-1 cross-talk must have been involved in PPARγ activation. In conclusion, our results suggest that GLP-1 has the potential to induce PPARγ activity, partially explaining the anti-inflammatory effects of GLP-1 on endothelial cells. Cross-talk between GLP-1 signaling and PPARγ activation would have major impacts on treatments for patients at high risk for cardiovascular disease.

  11. Synthesis of spiro[indolo-1,5-benzodiazepines] from 3-acetyl coumarins for use as possible antianxiety agents

    Indian Academy of Sciences (India)

    Raviraj A Kusanur; Manjunath Ghate; Manohar V Kulkarni

    2004-08-01

    3-Acetyl coumarins (1) when allowed react with isatin (2) gave corresponding 3-(3'-hydroxy-2'-oxo indolo) acetyl coumarins (3), which on dehydration afforded the corresponding ,-unsaturated ketones (4). Cyclocondensation of (4) with substituted -phenylene diamines resulted in novel 3-coumarinyl spiro[indolo-1,5-benzodiazepines] (5). Structures of all the compounds have been established on the basis of their IR, NMR and mass spectral data and have been screened for their antimicrobial activity and antianxiety activity in mice.

  12. Muscarinic receptor activation elicits sustained, recurring depolarizations in reticulospinal neurons.

    Science.gov (United States)

    Smetana, R W; Alford, S; Dubuc, R

    2007-05-01

    In lampreys, brain stem reticulospinal (RS) neurons constitute the main descending input to the spinal cord and activate the spinal locomotor central pattern generators. Cholinergic nicotinic inputs activate RS neurons, and consequently, induce locomotion. Cholinergic muscarinic agonists also induce locomotion when applied to the brain stem of birds. This study examined whether bath applications of muscarinic agonists could activate RS neurons and initiate motor output in lampreys. Bath applications of 25 microM muscarine elicited sustained, recurring depolarizations (mean duration of 5.0 +/- 0.5 s recurring with a mean period of 55.5 +/- 10.3 s) in intracellularly recorded rhombencephalic RS neurons. Calcium imaging experiments revealed that muscarine induced oscillations in calcium levels that occurred synchronously within the RS neuron population. Bath application of TTX abolished the muscarine effect, suggesting the sustained depolarizations in RS neurons are driven by other neurons. A series of lesion experiments suggested the caudal half of the rhombencephalon was necessary. Microinjections of muscarine (75 microM) or the muscarinic receptor (mAchR) antagonist atropine (1 mM) lateral to the rostral pole of the posterior rhombencephalic reticular nucleus induced or prevented, respectively, the muscarinic RS neuron response. Cells immunoreactive for muscarinic receptors were found in this region and could mediate this response. Bath application of glutamatergic antagonists (6-cyano-7-nitroquinoxaline-2,3-dione/D-2-amino-5-phosphonovaleric acid) abolished the muscarine effect, suggesting that glutamatergic transmission is needed for the effect. Ventral root recordings showed spinal motor output coincides with RS neuron sustained depolarizations. We propose that unilateral mAchR activation on specific cells in the caudal rhombencephalon activates a circuit that generates synchronous sustained, recurring depolarizations in bilateral populations of RS neurons. PMID

  13. Involvement of Activating NK Cell Receptors and Their Modulation in Pathogen Immunity

    Directory of Open Access Journals (Sweden)

    Francesco Marras

    2011-01-01

    Full Text Available Natural Killer (NK cells are endowed with cell-structure-sensing receptors providing inhibitory protection from self-destruction (inhibitory NK receptors, iNKRs, including killer inhibitory receptors and other molecules and rapid triggering potential leading to functional cell activation by Toll-like receptors (TLRs, cytokine receptors, and activating NK cell receptors including natural cytotoxicity receptors (NCRs, i.e., NKp46, NKp46, and NKp44. NCR and NKG2D recognize ligands on infected cells which may be endogenous or may directly bind to some structures derived from invading pathogens. In this paper, we address the known direct or indirect interactions between activating receptors and pathogens and their expression during chronic HIV and HCV infections.

  14. Cannabinoid activation of peroxisome proliferator-activated receptors: potential for modulation of inflammatory disease.

    Science.gov (United States)

    O'Sullivan, S E; Kendall, D A

    2010-08-01

    Cannabinoids act via cell surface G protein-coupled receptors (CB(1) and CB(2)) and the ion channel receptor TRPV1. Evidence has now emerged suggesting that an additional target is the peroxisome proliferator-activated receptor (PPAR) family of nuclear receptors. There are three PPAR subtypes alpha, delta (also known as beta) and gamma, which regulate cell differentiation, metabolism and immune function. The major endocannabinoids, anandamide and 2-arachidonoylglycerol, and ajulemic acid, a structural analogue of the phytocannabinoid Delta(9)-tetrahydrocannabinol (THC), have anti-inflammatory properties mediated by PPARgamma. Other cannabinoids which activate PPARgamma include N-arachidonoyl-dopamine, THC, cannabidiol, HU210, WIN55212-2 and CP55940. The endogenous acylethanolamines, oleoylethanolamide and palmitoylethanolamide regulate feeding and body weight, stimulate fat utilization and have neuroprotective effects mediated through PPARalpha. Other endocannabinoids that activate PPARalpha include anandamide, virodhamine and noladin ether. There is, as yet, little direct evidence for interactions of cannabinoids with PPARdelta. There is a convergence of effects of cannabinoids, acting via cell surface and nuclear receptors, on immune cell function which provides promise for the targeted therapy of a variety of immune, particularly neuroinflammatory, diseases. PMID:19833407

  15. In vitro neuronal network activity in NMDA receptor encephalitis

    Directory of Open Access Journals (Sweden)

    Jantzen Sabine U

    2013-02-01

    Full Text Available Abstract Background Anti-NMDA-encephalitis is caused by antibodies against the N-methyl-D-aspartate receptor (NMDAR and characterized by a severe encephalopathy with psychosis, epileptic seizures and autonomic disturbances. It predominantly occurs in young women and is associated in 59% with an ovarian teratoma. Results We describe effects of cerebrospinal fluid (CSF from an anti-N-methyl-D-aspartate receptor (NMDAR encephalitis patient on in vitro neuronal network activity (ivNNA. In vitro NNA of dissociated primary rat cortical populations was recorded by the microelectrode array (MEA system. The 23-year old patient was severely affected but showed an excellent recovery following multimodal immunomodulatory therapy and removal of an ovarian teratoma. Patient CSF (pCSF taken during the initial weeks after disease onset suppressed global spike- and burst rates of ivNNA in contrast to pCSF sampled after clinical recovery and decrease of NMDAR antibody titers. The synchrony of pCSF-affected ivNNA remained unaltered during the course of the disease. Conclusion Patient CSF directly suppresses global activity of neuronal networks recorded by the MEA system. In contrast, pCSF did not regulate the synchrony of ivNNA suggesting that NMDAR antibodies selectively regulate distinct parameters of ivNNA while sparing their functional connectivity. Thus, assessing ivNNA could represent a new technique to evaluate functional consequences of autoimmune encephalitis-related CSF changes.

  16. Regulation of platelet activating factor receptor coupled phosphoinositide-specific phospholipase C activity

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, W.J.

    1988-01-01

    The major objectives of this study were two-fold. The first was to establish whether binding of platelet activating factor (PAF) to its receptor was integral to the stimulation of polyphosphoinositide-specific phospholipase C (PLC) in rabbit platelets. The second was to determine regulatory features of this receptor-coupled mechanism. ({sup 3}H)PAF binding demonstrated two binding sites, a high affinity site with a inhibitory constant (Ki) of 2.65 nM and a low affinity site with a Ki of 0.80 {mu}M. PAF receptor coupled activation of phosphoinositide-specific PLC was studied in platelets which were made refractory, by short term pretreatments, to either PAF or thrombin. Saponin-permeabilized rabbit platelets continue to regulate the mechanism(s) coupling PAF receptors to PLC stimulation. However, TRP{gamma}S and GDP{beta}S, which affect guanine nucleotide regulatory protein functions, were unable to modulate the PLC activity to any appreciable extent as compared to PAF. The possible involvement of protein kinase C (PKC) activation in regulating PAF-stimulated PLC activity was studied in rabbit platelets pretreated with staurosporine followed by pretreatments with PAF or phorbol 12-myristate 13-acetate (PMA).

  17. Liganden des Benzodiazepin-Rezeptors: Studien über Benzodiazepine in pflanzlichen Geweben sowie über Hispidulin

    OpenAIRE

    Kavvadias, Dominique

    2003-01-01

    Im Rahmen dieser Arbeit wurden Liganden des zentralen Benzodiazepin-Rezeptors (BZD-R) aus pflanzlichen Geweben untersucht. Der erste Teil war dem Studium „natürlicher“ Benzodiazepine (BZD) gewidmet. Deren Vorkommen ist vielfach belegt; an ihrer Biogenese sind möglicherweise Mikroorganismen beteiligt. Es war nun zu prüfen, ob BZD auch unter Sterilbedingungen, d.h. nach Ausschluss mikrobieller Aktivität auftreten können. Hierzu wurden steril kultivierte pflanzliche Kalli und Regenerate, unter a...

  18. Plasminogen activation by receptor-bound urokinase. A kinetic study with both cell-associated and isolated receptor

    DEFF Research Database (Denmark)

    Ellis, V; Behrendt, N; Danø, K

    1991-01-01

    The specific cellular receptor for urokinase-type plasminogen activator (uPA) is found on a variety of cell types and has been postulated to play a central role in the mediation of pericellular proteolytic activity. We have studied the kinetics of plasminogen (Plg) activation catalyzed by uPA spe...

  19. Identification of key residues involved in the activation and signaling properties of dopamine D3 receptor.

    Science.gov (United States)

    Kota, Kokila; Kuzhikandathil, Eldo V; Afrasiabi, Milad; Lacy, Brett; Kontoyianni, Maria; Crider, A Michael; Song, Daniel

    2015-09-01

    The dopamine D3 receptor exhibits agonist-dependent tolerance and slow response termination (SRT) signaling properties that distinguish it from the closely-related D2 receptors. While amino acid residues important for D3 receptor ligand binding have been identified, the residues involved in activation of D3 receptor signaling and induction of signaling properties have not been determined. In this paper, we used cis and trans isomers of a novel D3 receptor agonist, 8-OH-PBZI, and site-directed mutagenesis to identify key residues involved in D3 receptor signaling function. Our results show that trans-8-OH-PBZI, but not cis-8-OH-PBZI, elicit the D3 receptor tolerance and SRT properties. We show that while both agonists require a subset of residues in the orthosteric binding site of D3 receptors for activation of the receptor, the ability of the two isomers to differentially induce tolerance and SRT is mediated by interactions with specific residues in the sixth transmembrane helix and third extracellular loop of the D3 receptor. We also show that unlike cis-8-OH-PBZI, which is a partial agonist at the dopamine D2S receptor and full agonist at dopamine D2L receptor, trans-8-OH-PBZI is a full agonist at both D2S and D2L receptors. The different effect of the two isomers on D3 receptor signaling properties and D2S receptor activation correlated with differential effects of the isomers on agonist-induced mouse locomotor activity. The two isomers of 8-OH-PBZI represent novel pharmacological tools for in silico D3 and D2 receptor homology modeling and for determining the role of D3 receptor tolerance and SRT properties in signaling and behavior. PMID:26116441

  20. Convergence on a Distinctive Assembly Mechanism by Unrelated Families of Activating Immune Receptors

    OpenAIRE

    Feng, Jianwen; Garrity, David; Call, Matthew E.; Moffett, Howell; Wucherpfennig, Kai W.

    2005-01-01

    Activating receptors in cells of hematopoetic origin include members of two unrelated protein families, the immunoglobulin (Ig) and C type lectins, which differ even in the orientation of the transmembrane (TM) domains. We examined assembly of four receptors with diverse function: the NK receptors KIR2DS and NKG2C/CD94, the Fc receptor for IgA, and the GPVI collagen receptor. For each of the four different receptors studied here, assembly results in the formation of a three-helix interface in...

  1. Monoclonal antibodies to the human insulin receptor that activate glucose transport but not insulin receptor kinase activity.

    OpenAIRE

    Forsayeth, J R; Caro, J F; Sinha, M K; Maddux, B A; Goldfine, I D

    1987-01-01

    Three mouse monoclonal antibodies were produced that reacted with the alpha subunit of the human insulin receptor. All three both immunoprecipitated 125I-labeled insulin receptors from IM-9 lymphocytes and competitively inhibited 125I-labeled insulin binding to its receptor. Unlike insulin, the antibodies failed to stimulate receptor autophosphorylation in both intact IM-9 lymphocytes and purified human placental insulin receptors. Moreover, unlike insulin, the antibodies failed to stimulate ...

  2. Topical Rosiglitazone Treatment Improves Ulcerative Colitis by Restoring Peroxisome Proliferator-Activated Receptor-gamma Activity

    DEFF Research Database (Denmark)

    Pedersen, G.; Brynskov, Jørn

    2010-01-01

    OBJECTIVES: Impaired epithelial expression of peroxisome proliferator-activated receptor-gamma (PPAR gamma) has been described in animal colitis models and briefly in patients with ulcerative colitis, but the functional significance in humans is not well defined. We examined PPAR gamma expression...

  3. Diabetes or peroxisome proliferator-activated receptor alpha agonist increases mitochondrial thioesterase I activity in heart

    Science.gov (United States)

    Peroxisome proliferator-activated receptor alpha (PPAR alpha) is a transcriptional regulator of the expression of mitochondrial thioesterase I (MTE-I) and uncoupling protein 3 (UCP3), which are induced in the heart at the mRNA level in response to diabetes. Little is known about the regulation of pr...

  4. Activation of Protease-Activated Receptor 2 Induces VEGF Independently of HIF-1

    Science.gov (United States)

    Rasmussen, Jeppe Grøndahl; Riis, Simone Elkjær; Frøbert, Ole; Yang, Sufang; Kastrup, Jens; Zachar, Vladimir; Simonsen, Ulf; Fink, Trine

    2012-01-01

    Background Human adipose stem cells (hASCs) can promote angiogenesis through secretion of proangiogenic factors such as vascular endothelial growth factor (VEGF). In other cell types, it has been shown that induction of VEGF is mediated by both protease activated receptor 2 (PAR2) and hypoxia inducible factor 1(HIF-1). The present study hypothesized that PAR2 stimulation through activation of kinase signaling cascades lead to induction of HIF-1 and secretion of VEGF. Methodology/Principal Findings Immunohistochemistry revealed the expression of PAR2 receptors on the surface of hASCs. Blocking the PAR2 receptors with a specific antibody prior to trypsin treatment showed these receptors are involved in trypsin-evoked increase in VEGF secretion from hASCs. Blocking with specific kinase inhibitors suggested that that activation of MEK/ERK and PI3-kinase/Akt pathways are involved in trypsin-eveoked induction of VEGF. The effect of the trypsin treatment on the transcription of VEGF peaked at 6 hours after the treatment and was comparable to the activation observed after keeping hASCs for 24 hours at 1% oxygen. In contrast to hypoxia, trypsin alone failed to induce HIF-1 measured with ELISA, while the combination of trypsin and hypoxia had an additive effect on both VEGF transcription and secretion, results which were confirmed by Western blot. Conclusion In hASCs trypsin and hypoxia induce VEGF expression through separate pathways. PMID:23049945

  5. New Target Genes for the Peroxisome Proliferator-Activated Receptor-γ (PPARγ Antitumour Activity: Perspectives from the Insulin Receptor

    Directory of Open Access Journals (Sweden)

    Daniela P. Foti

    2009-01-01

    Full Text Available The insulin receptor (IR plays a crucial role in mediating the metabolic and proliferative functions triggered by the peptide hormone insulin. There is considerable evidence that abnormalities in both IR expression and function may account for malignant transformation and tumour progression in some human neoplasias, including breast cancer. PPARγ is a ligand-activated, nuclear hormone receptor implicated in many pleiotropic biological functions related to cell survival and proliferation. In the last decade, PPARγ agonists—besides their known action and clinical use as insulin sensitizers—have proved to display a wide range of antineoplastic effects in cells and tissues expressing PPARγ, leading to intensive preclinical research in oncology. PPARγ and activators affect tumours by different mechanisms, involving cell proliferation and differentiation, apoptosis, antiinflammatory, and antiangiogenic effects. We recently provided evidence that PPARγ and agonists inhibit IR by non canonical, DNA-independent mechanisms affecting IR gene transcription. We conclude that IR may be considered a new PPARγ “target” gene, supporting a potential use of PPARγ agonists as antiproliferative agents in selected neoplastic tissues that overexpress the IR.

  6. Synthesis and conformational analysis of new derivatives of 7-chloro-1,3-dihydro-5-phenyl-2h-1,4-benzodiazepine-2-one

    CERN Document Server

    Imanzadeh, G H; Sadra, Y

    2011-01-01

    1,4-benzodiazepine-2-ones and their derivatives are prominent structures in medicinal chemistry. These biomolecules have wide biological activities and posses therapeutic applications. In this works, we introduce new derivatives of 1,4-benzodiazepine-2-ones which are synthesized using michael addition reaction of 7-chloro- 1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-ones with fumaric esters that matches with green chemistry protocols. The structures of all products are confirmed by FT-IR, 1H-NMR, 13C-NMR and MASS spectroscopy. Since the stereochemistry of 1,4-benzo diazepine-2-ones is important, we study the most stable conformer of one of the products as a model for conformational analysis by hyper chem soft ware and semi empirical AM1 program. Also, using the 1H-NMR spectrum, we investigate the produced diastereomers of one of products as a model.

  7. Psychological determinants of the intention to educate patients about benzodiazepines

    NARCIS (Netherlands)

    Ten Wolde, Geeske Brecht; Dijkstra, A.; Van Empelen, P.; Neven, A. Knuistingh; Zitman, F. G.

    2008-01-01

    Objective General practitioners and pharmacists do not properly educate their patients about the disadvantages of benzodiazepines. In order to increase and improve education, this study will investigate which psychological factors (i.e., beliefs, outcome expectation, social norm and self-efficacy) p

  8. Prolonged-release melatonin versus placebo for benzodiazepine discontinuation in patients with schizophrenia or bipolar disorder

    DEFF Research Database (Denmark)

    Baandrup, Lone; Lindschou, Jane; Winkel, Per;

    2016-01-01

    OBJECTIVES: We assessed if prolonged-release melatonin can facilitate withdrawal of long-term benzodiazepine usage in patients with schizophrenia or bipolar disorder. METHODS: Randomised, placebo-controlled, blinded, parallel superiority trial of 24 weeks duration. Participants were randomised to...... prolonged-release melatonin 2 mg daily versus matching placebo and were continuously guided to gradually reduce their usual benzodiazepine dosage. The primary outcome was mean benzodiazepine daily dosage at 24 weeks. Secondary outcomes included pattern of benzodiazepine dosage over time, benzodiazepine...... cessation proportion, and benzodiazepine withdrawal symptoms. RESULTS: In total, 86 patients (21-74 years) were enrolled: 42 were randomised to melatonin versus 44 to placebo. We found no significant effect of melatonin on mean benzodiazepine dosage at 24 weeks (melatonin group 8.01 mg versus placebo group...

  9. Peroxisome Proliferator-Activated Receptor-γ in Thyroid Autoimmunity

    Directory of Open Access Journals (Sweden)

    Silvia Martina Ferrari

    2015-01-01

    Full Text Available Peroxisome proliferator-activated receptor- (PPAR- γ expression has been shown in thyroid tissue from patients with thyroiditis or Graves’ disease and furthermore in the orbital tissue of patients with Graves’ ophthalmopathy (GO, such as in extraocular muscle cells. An increasing body of evidence shows the importance of the (C-X-C motif receptor 3 (CXCR3 and cognate chemokines (C-X-C motif ligand (CXCL9, CXCL10, and CXCL11, in the T helper 1 immune response and in inflammatory diseases such as thyroid autoimmune disorders. PPAR-γ agonists show a strong inhibitory effect on the expression and release of CXCR3 chemokines, in vitro, in various kinds of cells, such as thyrocytes, and in orbital fibroblasts, preadipocytes, and myoblasts from patients with GO. Recently, it has been demonstrated that rosiglitazone is involved in a higher risk of heart failure, stroke, and all-cause mortality in old patients. On the contrary, pioglitazone has not shown these effects until now; this favors pioglitazone for a possible use in patients with thyroid autoimmunity. However, further studies are ongoing to explore the use of new PPAR-γ agonists in the treatment of thyroid autoimmune disorders.

  10. Full and partial agonists of thromboxane prostanoid receptor unveil fine tuning of receptor superactive conformation and G protein activation.

    Directory of Open Access Journals (Sweden)

    Valérie Capra

    Full Text Available The intrahelical salt bridge between E/D(3.49 and R(3.50 within the E/DRY motif on helix 3 (H3 and the interhelical hydrogen bonding between the E/DRY and residues on H6 are thought to be critical in stabilizing the class A G protein-coupled receptors in their inactive state. Removal of these interactions is expected to generate constitutively active receptors. This study examines how neutralization of E(3.49/6.30 in the thromboxane prostanoid (TP receptor alters ligand binding, basal, and agonist-induced activity and investigates the molecular mechanisms of G protein activation. We demonstrate here that a panel of full and partial agonists showed an increase in affinity and potency for E129V and E240V mutants. Yet, even augmenting the sensitivity to detect constitutive activity (CA with overexpression of the receptor or the G protein revealed resistance to an increase in basal activity, while retaining fully the ability to cause agonist-induced signaling. However, direct G protein activation measured through bioluminescence resonance energy transfer (BRET indicates that these mutants more efficiently communicate and/or activate their cognate G proteins. These results suggest the existence of additional constrains governing the shift of TP receptor to its active state, together with an increase propensity of these mutants to agonist-induced signaling, corroborating their definition as superactive mutants. The particular nature of the TP receptor as somehow "resistant" to CA should be examined in the context of its pathophysiological role in the cardiovascular system. Evolutionary forces may have favored regulation mechanisms leading to low basal activity and selected against more highly active phenotypes.

  11. The Structure of the GM-CSF Receptor Complex Reveals a Distinct Mode of Cytokine Receptor Activation

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Guido; Hercus, Timothy R.; McClure, Barbara J.; Stomski, Frank C.; Dottore, Mara; Powell, Jason; Ramshaw, Hayley; Woodcock, Joanna M.; Xu, Yibin; Guthridge, Mark; McKinstry, William J.; Lopez, Angel F.; Parker, Michael W. (SVIMR-A); (Hanson)

    2008-08-11

    Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic cytokine that controls the production and function of blood cells, is deregulated in clinical conditions such as rheumatoid arthritis and leukemia, yet offers therapeutic value for other diseases. Its receptors are heterodimers consisting of a ligand-specific {alpha} subunit and a {beta}c subunit that is shared with the interleukin (IL)-3 and IL-5 receptors. How signaling is initiated remains an enigma. We report here the crystal structure of the human GM-CSF/GM-CSF receptor ternary complex and its assembly into an unexpected dodecamer or higher-order complex. Importantly, mutagenesis of the GM-CSF receptor at the dodecamer interface and functional studies reveal that dodecamer formation is required for receptor activation and signaling. This unusual form of receptor assembly likely applies also to IL-3 and IL-5 receptors, providing a structural basis for understanding their mechanism of activation and for the development of therapeutics.

  12. Complement Component C3 Binds to Activated Normal Platelets without Preceding Proteolytic Activation and Promotes Binding to Complement Receptor 1

    OpenAIRE

    Osama A Hamad; Nilsson, Per H.; Wouters, Diana; Lambris, John D.; Ekdahl, Kristina N.; Nilsson, Bo

    2010-01-01

    It has been reported that complement is activated on the surface of activated platelets, despite the presence of multiple regulators of complement activation. To reinvestigate the mechanisms by which activated platelets bind to complement components, the presence of complement proteins on the surfaces of nonactivated and thrombin receptor-activating peptide-activated platelets was analyzed by flow cytometry and Western blot analyses. C1q, C4, C3, and C9 were found to bind to thrombin receptor...

  13. TAM receptors affect adult brain neurogenesis by negative regulation of microglial cell activation1

    OpenAIRE

    Ji, Rui; Tian, Shifu; Lu, Helen J.; LU, QINGJUN; Yan ZHENG; Wang, Xiaomin; Ding, Jixiang; Li, Qiutang; Lu, Qingxian

    2013-01-01

    TAM tyrosine kinases play multiple functional roles including regulation of the target genes important in homeostatic regulation of cytokine receptors or Toll-like receptor-mediated signal transduction pathways. Here, we show that TAM receptors affect adult hippocampal neurogenesis and loss of TAM receptors impair hippocampal neurogenesis, largely attributed to exaggerated inflammatory responses by microglia characterized by increased MAP kinase and NF-κB activation and elevated production of...

  14. An amphipathic motif at the transmembrane-cytoplasmic junction prevents autonomous activation of the thrombopoietin receptor.

    OpenAIRE

    Staerk, Judith; Lacout, Catherine; Sato, Takeshi; Smith, Steven O.; Vainchenker, William; Constantinescu, Stefan

    2006-01-01

    Ligand binding to the thrombopoietin receptor (TpoR) is thought to impose a dimeric receptor conformation(s) leading to hematopoietic stem cell renewal, megakaryocyte differentiation, and platelet formation. Unlike other cytokine receptors, such as the erythropoietin receptor, TpoR contains an amphipathic KWQFP motif at the junction between the transmembrane (TM) and cytoplasmic domains. We show here that a mutant TpoR (delta5TpoR), where this sequence was deleted, is constitutively active. I...

  15. Structural motifs of importance for the constitutive activity of the orphan 7TM receptor EBI2: analysis of receptor activation in the absence of an agonist

    DEFF Research Database (Denmark)

    Benned-Jensen, Tau; Rosenkilde, Mette M

    2008-01-01

    The Epstein-Barr induced receptor 2 (EBI2) is a lymphocyte-expressed orphan seven transmembrane-spanning (7TM) receptor that signals constitutively through Galphai, as shown, for instance by guanosine 5'-O-(3-thio)triphosphate incorporation. Two regions of importance for the constitutive activity...

  16. Signaling Mechanism of Cannabinoid Receptor-2 Activation-Induced β-Endorphin Release.

    Science.gov (United States)

    Gao, Fang; Zhang, Ling-Hong; Su, Tang-Feng; Li, Lin; Zhou, Rui; Peng, Miao; Wu, Cai-Hua; Yuan, Xiao-Cui; Sun, Ning; Meng, Xian-Fang; Tian, Bo; Shi, Jing; Pan, Hui-Lin; Li, Man

    2016-08-01

    Activation of cannabinoid receptor-2 (CB2) results in β-endorphin release from keratinocytes, which then acts on primary afferent neurons to inhibit nociception. However, the underlying mechanism is still unknown. The CB2 receptor is generally thought to couple to Gi/o to inhibit cAMP production, which cannot explain the peripheral stimulatory effects of CB2 receptor activation. In this study, we found that in a keratinocyte cell line, the Gβγ subunits from Gi/o, but not Gαs, were involved in CB2 receptor activation-induced β-endorphin release. Inhibition of MAPK kinase, but not PLC, abolished CB2 receptor activation-induced β-endorphin release. Also, CB2 receptor activation significantly increased intracellular Ca(2+). Treatment with BAPTA-AM or thapsigargin blocked CB2 receptor activation-induced β-endorphin release. Using a rat model of inflammatory pain, we showed that the MAPK kinase inhibitor PD98059 abolished the peripheral effect of the CB2 receptor agonist on nociception. We thus present a novel mechanism of CB2 receptor activation-induced β-endorphin release through Gi/o-Gβγ-MAPK-Ca(2+) signaling pathway. Our data also suggest that stimulation of MAPK contributes to the peripheral analgesic effect of CB2 receptor agonists. PMID:26108183

  17. Human bradykinin B(2) receptor is activated by kallikrein and other serine proteases.

    Science.gov (United States)

    Hecquet, C; Tan, F; Marcic, B M; Erdös, E G

    2000-10-01

    Bradykinin (BK) and kallidin (Lys-BK), liberated from kininogens by kallikreins, are ligands of the BK B(2) receptor. We investigated whether kallikreins, besides releasing peptide agonist, could also activate the receptor directly. We studied the effect of porcine and human recombinant tissue kallikrein and plasma kallikrein on [Ca(2+)](i) mobilization and [(3)H]arachidonic acid release from cultured cells stably transfected to express human BK B(2) receptor (CHO/B(2), MDCK/B(2), HEK/B(2)), and endothelial cells were used as control cells. As with BK, the actions of kallikrein were blocked by the B(2) antagonist, HOE 140. Kallikrein was inactive on cells lacking B(2) receptor. Kallikrein and BK desensitized the receptor homologously but there was no cross-desensitization. Furthermore, 50 nM human cathepsin G and 50 nM trypsin also activated the receptor; this also was blocked by HOE 140. Experiments excluded a putative kinin release by proteases. [(3)H]AA release by BK was reduced by 40% by added kininase I (carboxypeptidase M); however, receptor activation by tissue kallikrein, trypsin, or cathepsin G was not affected. Prokallikrein and inhibited kallikrein were inactive, suggesting cleavage of a peptide bond in the receptor. Kallikreins were active on mutated B(2) receptor missing the 19 N-terminal amino acids, suggesting a type of activation different from that of thrombin receptor. Paradoxically, tissue kallikreins decreased the [(3)H]BK binding to the receptor with a low K(D) (3 nM) and inhibited it 78%. Thus, kallikreins and some other proteases activate human BK B(2) receptor directly, independent of BK release. The BK B(2) receptor may belong to a new group of serine protease-activated receptors. PMID:10999954

  18. Peroxisome Proliferator-Activated Receptors in Female Reproduction and Fertility

    Science.gov (United States)

    Carta, Gaspare; Artini, Paolo Giovanni

    2016-01-01

    Reproductive functions may be altered by the exposure to a multitude of endogenous and exogenous agents, drug or environmental pollutants, which are known to affect gene transcription through the peroxisome proliferator-activated receptors (PPARs) activation. PPARs act as ligand activated transcription factors and regulate metabolic processes such as lipid and glucose metabolism, energy homeostasis, inflammation, and cell proliferation and differentiation. All PPARs isotypes are expressed along the hypothalamic-pituitary-gonadal axis and are strictly involved in reproductive functions. Since female fertility and energy metabolism are tightly interconnected, the research on female infertility points towards the exploration of potential PPARs activating/antagonizing compounds, mainly belonging to the class of thiazolidinediones (TZDs) and fibrates, as useful agents for the maintenance of metabolic homeostasis in women with ovarian dysfunctions. In the present review, we discuss the recent evidence about PPARs expression in the hypothalamic-pituitary-gonadal axis and their involvement in female reproduction. Finally, the therapeutic potential of their manipulation through several drugs is also discussed.

  19. Behavioral and Neurophysiological Signatures of Benzodiazepine-Related Driving Impairments.

    Science.gov (United States)

    Stone, Bradly T; Correa, Kelly A; Brown, Timothy L; Spurgin, Andrew L; Stikic, Maja; Johnson, Robin R; Berka, Chris

    2015-01-01

    Impaired driving due to drug use is a growing problem worldwide; estimates show that 18-23.5% of fatal accidents, and up to 34% of injury accidents may be caused by drivers under the influence of drugs (Drummer et al., 2003; Walsh et al., 2004; NHTSA, 2010). Furthermore, at any given time, up to 16% of drivers may be using drugs that can impair one's driving abilities (NHTSA, 2009). Currently, drug recognition experts (DREs; law enforcement officers with specialized training to identify drugged driving), have the most difficult time with identifying drivers potentially impaired on central nervous system (CNS) depressants (Smith et al., 2002). The fact that the use of benzodiazepines, a type of CNS depressant, is also associated with the greatest likelihood of causing accidents (Dassanayake et al., 2011), further emphasizes the need to improve research tools in this area which can facilitate the refinement of, or additions to, current assessments of impaired driving. Our laboratories collaborated to evaluate both the behavioral and neurophysiological effects of a benzodiazepine, alprazolam, in a driving simulation (miniSim(TM)). This drive was combined with a neurocognitive assessment utilizing time synched neurophysiology (electroencephalography, ECG). While the behavioral effects of benzodiazepines are well characterized (Rapoport et al., 2009), we hypothesized that, with the addition of real-time neurophysiology and the utilization of simulation and neurocognitive assessment, we could find objective assessments of drug impairment that could improve the detection capabilities of DREs. Our analyses revealed that (1) specific driving conditions were significantly more difficult for benzodiazepine impaired drivers and (2) the neurocognitive tasks' metrics were able to classify "impaired" vs. "unimpaired" with up to 80% accuracy based on lane position deviation and lane departures. While this work requires replication in larger studies, our results not only identified

  20. Family C 7TM receptor dimerization and activation

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Sheikh, Søren P; Hansen, Jakob Lerche

    2006-01-01

    The family C seven transmembrane (7TM) receptors constitutes a small and especially well characterized subfamily of the large 7TM receptor superfamily. Approximately 50% of current prescription drugs target 7TM receptors, this biologically important family represents the largest class of drug-tar...

  1. Exercise reduces adipose tissue via cannabinoid receptor type 1 which is regulated by peroxisome proliferator-activated receptor-delta

    DEFF Research Database (Denmark)

    Yan, Zhen Cheng; Liu, Dao Yan; Zhang, Li Li;

    2007-01-01

    Obesity is one major cardiovascular risk factor. We tested effects of endurance exercise on cannabinoid receptor type 1 (CB1) and peroxisome proliferator-activated receptor-delta (PPAR-delta)-dependent pathways in adipose tissue. Male Wistar rats were randomly assigned to standard laboratory chow...... or a high-fat diet without and with regular endurance exercise. Exercise in rats on high-fat diet significantly reduced visceral fat mass, blood pressure, and adipocyte size (each p...

  2. Distinct RNA motifs are important for coactivation of steroid hormone receptors by steroid receptor RNA activator (SRA)

    OpenAIRE

    Lanz, Rainer B.; Razani, Bahram; Goldberg, Aaron D.; O'Malley, Bert W.

    2002-01-01

    Steroid receptor RNA activator (SRA) is an RNA transcript that functions as a eukaryotic transcriptional coactivator for steroid hormone receptors. We report here the isolation and functional characterization of distinct RNA substructures within the SRA molecule that constitute its coactivation function. We used comparative sequence analysis and free energy calculations to systematically study SRA RNA subdomains for identification of structured regions and base pairings, and we used site-dire...

  3. Calcium is the switch in the moonlighting dual function of the ligand-activated receptor kinase phytosulfokine receptor 1

    KAUST Repository

    Muleya, Victor

    2014-09-23

    Background: A number of receptor kinases contain guanylate cyclase (GC) catalytic centres encapsulated in the cytosolic kinase domain. A prototypical example is the phytosulfokine receptor 1 (PSKR1) that is involved in regulating growth responses in plants. PSKR1 contains both kinase and GC activities however the underlying mechanisms regulating the dual functions have remained elusive. Findings: Here, we confirm the dual activity of the cytoplasmic domain of the PSKR1 receptor. We show that mutations within the guanylate cyclase centre modulate the GC activity while not affecting the kinase catalytic activity. Using physiologically relevant Ca2+ levels, we demonstrate that its GC activity is enhanced over two-fold by Ca2+ in a concentration-dependent manner. Conversely, increasing Ca2+ levels inhibits kinase activity up to 500-fold at 100 nM Ca2+. Conclusions: Changes in calcium at physiological levels can regulate the kinase and GC activities of PSKR1. We therefore propose a functional model of how calcium acts as a bimodal switch between kinase and GC activity in PSKR1 that could be relevant to other members of this novel class of ligand-activated receptor kinases.

  4. Receptor activity modifying proteins (RAMPs) interact with the VPAC1 receptor: evidence for differential RAMP modulation of multiple signalling pathways

    International Nuclear Information System (INIS)

    Full text: Receptor activity modifying proteins (RAMP) constitute a family of three accessory proteins that affect the expression and/or phenotype of the calcitonin receptor (CTR) or CTR-like receptor (CRLR). In this study we screened a range of class II G protein-coupled receptors (PTH1, PTH2, GHRH, VPAC1, VPAC2 receptors) for possible RAMP interactions by measurement of receptor-induced translocation of c-myc tagged RAMP1 or HA tagged RAMP3. Of these, only the VPAC1 receptor caused significant translocation of c-myc-RAMP1 or HA-RAMP3 to the cell surface. Co-transfection of VPAC1 and RAMPs did not alter 125I-VIP binding and specificity. VPAC1 receptor function was subsequently analyzed through parallel determinations of cAMP accumulation and phosphoinositide (PI) hydrolysis in the presence and absence of each of the three RAMPs. In contrast to CTR-RAMP interaction, where there was an increase in cAMP Pharmacologisand a decrease in PI hydrolysis, VPAC1-RAMP interaction was characterized by a specific increase in agonist-mediated PI hydrolysis when co-transfected with RAMP2. This change was due to an enhancement of Emax with no change in EC50 value for VIP. No significant change in cAMP accumulation was observed. This is the first demonstration of an interaction of RAMPs with a G protein-coupled receptor outside the CTR family and may suggest a more generalized role for RAMPs in modulating G protein-coupled receptor signaling. Copyright (2001) Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists

  5. Significance of AT1 receptor independent activation of mineralocorticoid receptor in murine diabetic cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Yuji Nagatomo

    Full Text Available BACKGROUND: Diabetes mellitus (DM has deleterious influence on cardiac performance independent of coronary artery disease and hypertension. The objective of the present study was to investigate the role of the renin-angiotensin-aldosterone system, especially angiotensin II type 1a receptor (AT1aR and mineralocorticoid receptor (MR signaling, in left ventricular (LV dysfunction induced by diabetes mellitus (DM. METHODS AND RESULTS: DM was induced by intraperitoneal injection of streptozotocin (200 mg/kg BW in wild-type (WT or AT1aR knockout (KO male mice, and they were bred during 6 or 12 weeks. Some KO mice were administered the MR antagonist eplerenone (100 mg/kg body weight. At 6 weeks, LV diastolic function was impaired in WT-DM, but preserved in KO-DM. At that time point MR mRNA expression was upregulated, NADPH oxidase subunit (p47phox and glutathione peroxidase (GPx1 mRNA expression were upregulated, the staining intensities of LV tissue for 4-hydroxy-2-nonenal was stronger in immunohistochemistry, the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL positive cells was increased, Bcl-2 protein expression was significantly downregulated, and the expression of SERCA2a and phosphorylated phospholamban was depressed in WT-DM, while these changes were not seen in KO-DM. At 12 weeks, however, these changes were also noted in KO-DM. Eplerenone arrested those changes. The plasma aldosterone concentration was elevated in WT-DM but not in KO-DM at 6 weeks. It showed 3.7-fold elevation at 12 weeks even in KO-DM, which suggests "aldosterone breakthrough" phenomenon. However, the aldosterone content in LV tissue was unchanged in KO-DM. CONCLUSIONS: DM induced diastolic dysfunction was observed even in KO at 12 weeks, which was ameliorated by minelarocorticoid receptor antagonist, eplerenone. AT1-independent MR activation in the LV might be responsible for the pathogenesis of diabetic cardiomyopathy.

  6. Repressive effects of resveratrol on androgen receptor transcriptional activity.

    Directory of Open Access Journals (Sweden)

    Wen-feng Shi

    Full Text Available BACKGROUND: The chemopreventive effects of resveratrol (RSV on prostate cancer have been well established; the androgen receptor (AR plays pivotal roles in prostatic tumorigenesis. However, the exact underlying molecular mechanisms about the effects of RSV on AR have not been fully elucidated. A model system is needed to determine whether and how RSV represses AR transcriptional activity. METHODOLOGY: The AR cDNA was first cloned into the retroviral vector pOZ-N and then integrated into the genome of AR-negative HeLa cells to generate the AR(+ cells. The constitutively expressed AR was characterized by monitoring hormone-stimulated nuclear translocation, DNA binding, and transcriptional activation, with the AR(- cells serving as controls. AR(+ cells were treated with RSV, and both AR protein levels and AR transcriptional activity were measured simultaneously. Chromatin immunoprecipitation (ChIP assays were used to detect the effects of RSV on the recruitment of AR to its cognate element (ARE. RESULTS: AR in the AR (+ stable cell line functions in a manner similar to that of endogenously expressed AR. Using this model system we clearly demonstrated that RSV represses AR transcriptional activity independently of any effects on AR protein levels. However, neither the hormone-mediated nucleus translocation nor the AR/ARE interaction was affected by RSV treatment. CONCLUSION: We demonstrated unambiguously that RSV regulates AR target gene expression, at least in part, by repressing AR transcriptional activity. Repressive effects of RSV on AR activity result from mechanisms other than the affects of AR nuclear translocation or DNA binding.

  7. Effects of Sulfonylureas on Peroxisome Proliferator-Activated Receptor γ Activity and on Glucose Uptake by Thiazolidinediones

    OpenAIRE

    Kyeong Won Lee; Yun Hyi Ku; Min Kim; Byung Yong Ahn; Sung Soo Chung; Kyong Soo Park

    2011-01-01

    Background Sulfonylurea primarily stimulates insulin secretion by binding to its receptor on the pancreatic β-cells. Recent studies have suggested that sulfonylureas induce insulin sensitivity through peroxisome proliferator-activated receptor γ (PPARγ), one of the nuclear receptors. In this study, we investigated the effects of sulfonylurea on PPARγ transcriptional activity and on the glucose uptake via PPARγ. Methods Transcription reporter assays using Cos7 cells were performed to determine...

  8. Trans-activation by thyroid hormone receptors: functional parallels with steroid hormone receptors.

    OpenAIRE

    Thompson, C C; Evans, R M

    1989-01-01

    The effects of thyroid hormones are mediated through nuclear receptor proteins that modulate the transcription of specific genes in target cells. We previously isolated cDNAs encoding two different mammalian thyroid hormone receptors, one from human placenta (hTR beta) and the other from rat brain (rTR alpha), and showed that their in vitro translation products bind thyroid hormones with the characteritistic affinities of the native thyroid hormone receptor. We now demonstrate that both of th...

  9. Modulation of Opioid Receptor Ligand Affinity and Efficacy Using Active and Inactive State Receptor Models

    OpenAIRE

    Anand, Jessica P.; Purington, Lauren C.; Pogozheva, Irina D.; Traynor, John R.; Mosberg, Henry I.

    2012-01-01

    Mu opioid receptor (MOR) agonists are widely used for the treatment of pain; however chronic use results in the development of tolerance and dependence. It has been demonstrated that co-administration of a MOR agonist with a delta opioid receptor (DOR) antagonist maintains the analgesia associated with MOR agonists, but with reduced negative side effects. Using our newly refined opioid receptor models for structure-based ligand design, we have synthesized several pentapeptides with tailored a...

  10. Can Specific Protein-Lipid Interactions Stabilize an Active State of the Beta 2 Adrenergic Receptor?

    Science.gov (United States)

    Neale, Chris; Herce, Henry D; Pomès, Régis; García, Angel E

    2015-10-20

    G-protein-coupled receptors are eukaryotic membrane proteins with broad biological and pharmacological relevance. Like all membrane-embedded proteins, their location and orientation are influenced by lipids, which can also impact protein function via specific interactions. Extensive simulations totaling 0.25 ms reveal a process in which phospholipids from the membrane's cytosolic leaflet enter the empty G-protein binding site of an activated β2 adrenergic receptor and form salt-bridge interactions that inhibit ionic lock formation and prolong active-state residency. Simulations of the receptor embedded in an anionic membrane show increased lipid binding, providing a molecular mechanism for the experimental observation that anionic lipids can enhance receptor activity. Conservation of the arginine component of the ionic lock among Rhodopsin-like G-protein-coupled receptors suggests that intracellular lipid ingression between receptor helices H6 and H7 may be a general mechanism for active-state stabilization. PMID:26488656

  11. Activation of 5-hyrdoxytryptamine 7 receptors within the rat nucleus tractus solitarii modulates synaptic properties.

    Science.gov (United States)

    Matott, Michael P; Kline, David D

    2016-03-15

    Serotonin (5-HT) is a potent neuromodulator with multiple receptor types within the cardiorespiratory system, including the nucleus tractus solitarii (nTS) - the central termination site of visceral afferent fibers. The 5-HT7 receptor facilitates cardiorespiratory reflexes through its action in the brainstem and likely in the nTS. However, the mechanism and site of action for these effects is not clear. In this study, we examined the expression and function of 5-HT7 receptors in the nTS of Sprague-Dawley rats. 5-HT7 receptor mRNA and protein were identified across the rostrocaudal extent of the nTS. To determine 5-HT7 receptor function, we examined nTS synaptic properties following 5-HT7 receptor activation in monosynaptic nTS neurons in the in vitro brainstem slice preparation. Application of 5-HT7 receptor agonists altered tractus solitarii evoked and spontaneous excitatory postsynaptic currents which were attenuated with a selective 5-HT7 receptor antagonist. 5-HT7 receptor-mediated changes in excitatory postsynaptic currents were also altered by block of 5-HT1A and GABAA receptors. Interestingly, 5-HT7 receptor activation also reduced the amplitude but not frequency of GABAA-mediated inhibitory currents. Together these results indicate a complex role for 5-HT7 receptors in the nTS that mediate its diverse effects on cardiorespiratory parameters. PMID:26779891

  12. Triclocarban mediates induction of xenobiotic metabolism through activation of the constitutive androstane receptor and the estrogen receptor alpha.

    Directory of Open Access Journals (Sweden)

    Mei-Fei Yueh

    Full Text Available Triclocarban (3,4,4'-trichlorocarbanilide, TCC is used as a broad-based antimicrobial agent that is commonly added to personal hygiene products. Because of its extensive use in the health care industry and resistance to degradation in sewage treatment processes, TCC has become a significant waste product that is found in numerous environmental compartments where humans and wildlife can be exposed. While TCC has been linked to a range of health and environmental effects, few studies have been conducted linking exposure to TCC and induction of xenobiotic metabolism through regulation by environmental sensors such as the nuclear xenobiotic receptors (XenoRs. To identify the ability of TCC to activate xenobiotic sensors, we monitored XenoR activities in response to TCC treatment using luciferase-based reporter assays. Among the XenoRs in the reporter screening assay, TCC promotes both constitutive androstane receptor (CAR and estrogen receptor alpha (ERα activities. TCC treatment to hUGT1 mice resulted in induction of the UGT1A genes in liver. This induction was dependent upon the constitutive active/androstane receptor (CAR because no induction occurred in hUGT1Car(-/- mice. Induction of the UGT1A genes by TCC corresponded with induction of Cyp2b10, another CAR target gene. TCC was demonstrated to be a phenobarbital-like activator of CAR in receptor-based assays. While it has been suggested that TCC be classified as an endocrine disruptor, it activates ERα leading to induction of Cyp1b1 in female ovaries as well as in promoter activity. Activation of ERα by TCC in receptor-based assays also promotes induction of human CYP2B6. These observations demonstrate that TCC activates nuclear xenobiotic receptors CAR and ERα both in vivo and in vitro and might have the potential to alter normal physiological homeostasis. Activation of these xenobiotic-sensing receptors amplifies gene expression profiles that might represent a mechanistic base for

  13. Sulpiride and the role of dopaminergic receptor blockade in the antipsychotic activity of neuroleptics

    International Nuclear Information System (INIS)

    It is now generally recognized that dopamine receptors excist in the CNS as different subtypes: D1 receptors, associated with adenylyl cyclase activity, and D2 receptor, uncoupled to a cyclic APM generating system. In order to understand the role of D1 and D2 receptors in the antipsychotic action of neuroleptics, we have performed subchronic treatment with haloperidol, a drug which acts on D1 receptors, and sulpiride, a selective antagonist to D2 receptors. Long-term treatment with haloperidol does not induce significant supersensitivity of the D2 receptors. In fact under these conditions 3H-(-)-sulpiride binding, which is a marker of D2 receptor function, does not increase in rat striatum, while the long-term administration of sulpiride, itself produces supersensitivity of D2 receptors. Moreover, sulpiride does not induce supersensitivity of the D1 receptors, characterized by 3H-spiroperidol binding. These data suggest that both types of dopamine receptors may be involved in the clinical antipsychotic effects of neuroleptics. Unilateral leison of the nigrostriatal dopaminergic pathway produces an increase of striatal dopaminergic receptors, measured either by 3H-spiroperidol and 3H-(-)-sulpiride binding. These findings suggest that D1 and D2 receptors are present in postsynaptic membranes while it is still not known whether they exist in the same cellular elements. (author)

  14. The role of ECL2 in CGRP receptor activation: a combined modelling and experimental approach

    Science.gov (United States)

    Woolley, Michael. J.; Watkins, Harriet A.; Taddese, Bruck; Karakullukcu, Z. Gamze; Barwell, James; Smith, Kevin J.; Hay, Debbie L.; Poyner, David R.; Reynolds, Christopher A.; Conner, Alex C.

    2013-01-01

    The calcitonin gene-related peptide (CGRP) receptor is a complex of a calcitonin receptor-like receptor (CLR), which is a family B G-protein-coupled receptor (GPCR) and receptor activity modifying protein 1. The role of the second extracellular loop (ECL2) of CLR in binding CGRP and coupling to Gs was investigated using a combination of mutagenesis and modelling. An alanine scan of residues 271–294 of CLR showed that the ability of CGRP to produce cAMP was impaired by point mutations at 13 residues; most of these also impaired the response to adrenomedullin (AM). These data were used to select probable ECL2-modelled conformations that are involved in agonist binding, allowing the identification of the likely contacts between the peptide and receptor. The implications of the most likely structures for receptor activation are discussed. PMID:24047872

  15. Investigating real-time activation of adenosine receptors by bioluminescence resonance energy transfer technique

    Science.gov (United States)

    Huang, Yimei; Yang, Hongqin; Zheng, Liqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

    2013-02-01

    Adenosine receptors play important roles in many physiological and pathological processes, for example regulating myocardial oxygen consumption and the release of neurotransmitters. The activations of adenosine receptors have been studied by some kinds of techniques, such as western blot, immunohistochemistry, etc. However, these techniques cannot reveal the dynamical response of adenosine receptors under stimulation. In this paper, bioluminescence resonance energy transfer technique was introduced to study the real-time activation of adenosine receptors by monitoring the dynamics of cyclic adenosine monophosphate (cAMP) level. The results showed that there were significant differences between adenosine receptors on real-time responses under stimulation. Moreover, the dynamics of cAMP level demonstrated that competition between adenosine receptors existed. Taken together, our study indicates that monitoring the dynamics of cAMP level using bioluminescence resonance energy transfer technique could be one potential approach to investigate the mechanism of competitions between adenosine receptors.

  16. Role of receptors in Bacillus thuringiensis crystal toxin activity.

    Science.gov (United States)

    Pigott, Craig R; Ellar, David J

    2007-06-01

    Bacillus thuringiensis produces crystalline protein inclusions with insecticidal or nematocidal properties. These crystal (Cry) proteins determine a particular strain's toxicity profile. Transgenic crops expressing one or more recombinant Cry toxins have become agriculturally important. Individual Cry toxins are usually toxic to only a few species within an order, and receptors on midgut epithelial cells have been shown to be critical determinants of Cry specificity. The best characterized of these receptors have been identified for lepidopterans, and two major receptor classes have emerged: the aminopeptidase N (APN) receptors and the cadherin-like receptors. Currently, 38 different APNs have been reported for 12 different lepidopterans. Each APN belongs to one of five groups that have unique structural features and Cry-binding properties. While 17 different APNs have been reported to bind to Cry toxins, only 2 have been shown to mediate toxin susceptibly in vivo. In contrast, several cadherin-like proteins bind to Cry toxins and confer toxin susceptibility in vitro, and disruption of the cadherin gene has been associated with toxin resistance. Nonetheless, only a small subset of the lepidopteran-specific Cry toxins has been shown to interact with cadherin-like proteins. This review analyzes the interactions between Cry toxins and their receptors, focusing on the identification and validation of receptors, the molecular basis for receptor recognition, the role of the receptor in resistant insects, and proposed models to explain the sequence of events at the cell surface by which receptor binding leads to cell death. PMID:17554045

  17. Mechanisms Governing the Activation and Trafficking of Yeast G Protein-coupled Receptors

    OpenAIRE

    Stefan, Christopher J.; Overton, Mark C.; Blumer, Kendall J.

    1998-01-01

    We have addressed the mechanisms governing the activation and trafficking of G protein-coupled receptors (GPCRs) by analyzing constitutively active mating pheromone receptors (Ste2p and Ste3p) of the yeast Saccharomyces cerevisiae. Substitution of the highly conserved proline residue in transmembrane segment VI of these receptors causes constitutive signaling. This proline residue may facilitate folding of GPCRs into native, inactive conformations, and/or mediate a...

  18. Endocytosis of activated receptors and clathrin-coated pit formation: deciphering the chicken or egg relationship

    OpenAIRE

    1996-01-01

    The fundamental mechanisms by which receptors once targeted for endocytosis are found in coated pits is an important yet unresolved question. Specifically, are activated receptors simply trapped on encountering preexisting coated pits, subsequently being rapidly internalized? Or do the receptors themselves, by active recruitment, gather soluble coat and cytosolic components and initiate the rapid assembly of new coated pits that then mediate their internalization? To explore this question, we...

  19. Nuclear factor RIP140 modulates transcriptional activation by the estrogen receptor.

    OpenAIRE

    Cavaillès, V; Dauvois, S; L'Horset, F; Lopez, G; Hoare, S.; Kushner, P J; Parker, M G

    1995-01-01

    A conserved region in the hormone-dependent activation domain AF2 of nuclear receptors plays an important role in transcriptional activation. We have characterized a novel nuclear protein, RIP140, that specifically interacts in vitro with this domain of the estrogen receptor. This interaction was increased by estrogen, but not by anti-estrogens and the in vitro binding capacity of mutant receptors correlates with their ability to stimulate transcription. RIP140 also interacts with estrogen re...

  20. Tryptophan at the transmembrane–cytosolic junction modulates thrombopoietin receptor dimerization and activation

    OpenAIRE

    Defour, Jean-Philippe; Itaya, Miki; Gryshkova, Vitalina; Brett, Ian C.; Pecquet, Christian; Sato, Takeshi; Smith, Steven O.; Stefan N. Constantinescu

    2013-01-01

    Dimerization of single-pass membrane receptors is essential for activation. In the human thrombopoietin receptor (TpoR), a unique amphipathic RWQFP motif separates the transmembrane (TM) and intracellular domains. Using a combination of mutagenesis, spectroscopy, and biochemical assays, we show that W515 of this motif impairs dimerization of the upstream TpoR TM helix. TpoR is unusual in that a specific residue is required for this inhibitory function, which prevents receptor self-activation....

  1. Recent trends in benzodiazepine use by injecting drug users in Victoria and Tasmania.

    Science.gov (United States)

    Fry, Craig L; Bruno, Raimondo B

    2002-12-01

    To address the lack of data on patterns of benzodiazepine use among injecting drug users (IDU) in Victoria and Tasmania, convenience samples of 152 Melbourne and 100 Hobart IDU were recruited from needle and syringe programme outlets and administered a structured survey on patterns of benzodiazepine use, injection-related health problems and drug use history. Most respondents had used benzodiazepines during the preceding 6 months, and more than one-third (Melbourne 36%, 95% CI, 28-44; Hobart 37%, 95% CI, 27-47) had injected benzodiazepines during this period. Diazepam was the preferred benzodiazepine for those using orally, while intravenous benzodiazepine users preferred to inject temazepam. Benzodiazepine injection for Melbourne IDU was related to greater levels of injection-related health problems. Patterns of benzodiazepine use amongst Melbourne and Hobart IDU are different to that in other Australian jurisdictions, with available data suggesting that prevalence of injection may be increasing. Ongoing monitoring of benzodiazepine injection, together with in-depth studies of supply characteristics and health impacts in jurisdictions where significant trends are detected is needed. Consideration of regulatory, supply, education and training options for the prevention of benzodiazepine injection is also indicated. PMID:12537706

  2. Adipocyte insulin receptor activity maintains adipose tissue mass and lifespan.

    Science.gov (United States)

    Friesen, Max; Hudak, Carolyn S; Warren, Curtis R; Xia, Fang; Cowan, Chad A

    2016-08-01

    Type 2 diabetes follows a well-defined progressive pathogenesis, beginning with insulin resistance in metabolic tissues such as the adipose. Intracellular signaling downstream of insulin receptor activation regulates critical metabolic functions of adipose tissue, including glucose uptake, lipogenesis, lipolysis and adipokine secretion. Previous studies have used the aP2 promoter to drive Cre recombinase expression in adipose tissue. Insulin receptor (IR) knockout mice created using this aP2-Cre strategy (FIRKO mice) were protected from obesity and glucose intolerance. Later studies demonstrated the promiscuity of the aP2 promoter, casting doubts upon the tissue specificity of aP2-Cre models. It is our goal to use the increased precision of the Adipoq promoter to investigate adipocyte-specific IR function. Towards this end we generated an adipocyte-specific IR knockout (AIRKO) mouse using an Adipoq-driven Cre recombinase. Here we report AIRKO mice are less insulin sensitive throughout life, and less glucose tolerant than wild-type (WT) littermates at the age of 16 weeks. In contrast to WT littermates, the insulin sensitivity of AIRKO mice is unaffected by age or dietary regimen. At any age, AIRKO mice are comparably insulin resistant to old or obese WT mice and have a significantly reduced lifespan. Similar results were obtained when these phenotypes were re-examined in FIRKO mice. We also found that the AIRKO mouse is protected from high-fat diet-induced weight gain, corresponding with a 90% reduction in tissue weight of major adipose depots compared to WT littermates. Adipose tissue mass reduction is accompanied by hepatomegaly and increased hepatic steatosis. These data indicate that adipocyte IR function is crucial to systemic energy metabolism and has profound effects on adiposity, hepatic homeostasis and lifespan. PMID:27246738

  3. Kallikrein Promotes Inflammation in Human Dental Pulp Cells Via Protease-Activated Receptor-1.

    Science.gov (United States)

    Hayama, Tomomi; Kamio, Naoto; Okabe, Tatsu; Muromachi, Koichiro; Matsushima, Kiyoshi

    2016-07-01

    Plasma kallikrein (KLKB1), a serine protease, cleaves high-molecular weight kininogen to produce bradykinin, a potent vasodilator and pro-inflammatory peptide. In addition, KLKB1 activates plasminogen and other leukocyte and blood coagulation factors and processes pro-enkephalin, prorenin, and C3. KLKB1 has also been shown to cleave protease-activated receptors in vascular smooth muscle cells to regulate the expression of epidermal growth factor receptor. In this study, we investigated KLKB1-dependent inflammation and activation of protease-activated receptor-1 in human dental pulp cells. These cells responded to KLKB1 stimulation by increasing intracellular Ca(2+) , upregulating cyclooxygenase-2, and secreting prostaglandin E2 . Remarkably, SCH79797, an antagonist of protease-activated receptor-1, blocked these effects. Thus, these data indicate that KLKB1 induces inflammatory reactions in human dental tissues via protease-activated receptor 1. J. Cell. Biochem. 117: 1522-1528, 2016. © 2015 Wiley Periodicals, Inc. PMID:26566265

  4. Symptom-triggered benzodiazepine therapy for alcohol withdrawal syndrome in the emergency department: a comparison with the standard fixed dose benzodiazepine regimen.

    LENUS (Irish Health Repository)

    Cassidy, Eugene M

    2012-10-01

    The aim of the study was to compare symptom-triggered and standard benzodiazepine regimens for the treatment of alcohol withdrawal syndrome in an emergency department clinical decision unit. The authors found that the symptom-triggered approach reduced cumulative benzodiazepine dose and length of stay.

  5. Endothelial Cells Promote Pigmentation through Endothelin Receptor B Activation.

    Science.gov (United States)

    Regazzetti, Claire; De Donatis, Gian Marco; Ghorbel, Houda Hammami; Cardot-Leccia, Nathalie; Ambrosetti, Damien; Bahadoran, Philippe; Chignon-Sicard, Bérengère; Lacour, Jean-Philippe; Ballotti, Robert; Mahns, Andre; Passeron, Thierry

    2015-12-01

    Findings of increased vascularization in melasma lesions and hyperpigmentation in acquired bilateral telangiectatic macules suggested a link between pigmentation and vascularization. Using high-magnification digital epiluminescence dermatoscopy, laser confocal microscopy, and histological examination, we showed that benign vascular lesions of the skin have restricted but significant hyperpigmentation compared with the surrounding skin. We then studied the role of microvascular endothelial cells in regulating skin pigmentation using an in vitro co-culture model using endothelial cells and melanocytes. These experiments showed that endothelin 1 released by microvascular endothelial cells induces increased melanogenesis signaling, characterized by microphthalmia-associated transcription factor phosphorylation, and increased tyrosinase and dopachrome tautomerase levels. Immunostaining for endothelin 1 in vascular lesions confirmed the increased expression on the basal layer of the epidermis above small vessels compared with perilesional skin. Endothelin acts through the activation of endothelin receptor B and the mitogen-activated protein kinase, extracellular signal-regulated kinase (ERK)1/2, and p38, to induce melanogenesis. Finally, culturing of reconstructed skin with microvascular endothelial cells led to increased skin pigmentation that could be prevented by inhibiting EDNRB. Taken together these results demonstrated the role of underlying microvascularization in skin pigmentation, a finding that could open new fields of research for regulating physiological pigmentation and for treating pigmentation disorders such as melasma. PMID:26308584

  6. Tyrosine kinase JAK1 is associated with the granulocyte-colony-stimulating factor receptor and both become tyrosine-phosphorylated after receptor activation.

    OpenAIRE

    Nicholson, S. E.; Oates, A. C.; Harpur, A G; Ziemiecki, A; Wilks, A F; Layton, J E

    1994-01-01

    Granulocyte-colony-stimulating factor (G-CSF) stimulates the proliferation and differentiation of cells of the neutrophil lineage by interaction with a specific receptor. Early signal transduction events following G-CSF receptor activation were studied. We detected tyrosine phosphorylation of both the G-CSF receptor and the protein tyrosine kinase JAK1 following G-CSF binding to the human G-CSF receptor. In vitro, the kinase activity of JAK1 was increased by G-CSF stimulation. Coimmunoprecipi...

  7. Selenoprotein W controls epidermal growth factor receptor surface expression, activation and degradation via receptor ubiquitination

    Science.gov (United States)

    Epidermal growth factor (EGF) receptor (EGFR) is the founding member of the ErbB family of growth factor receptors that modulate a complex network of intracellular signaling pathways controlling growth, proliferation and differentiation. Selenoprotein W (SEPW1) is a diet-regulated, highly conserved...

  8. Plasma soluble urokinase plasminogen activator receptor in children with urinary tract infection

    DEFF Research Database (Denmark)

    Wittenhagen, Per; Andersen, Jesper Brandt; Hansen, Anita; Lindholm, Lone; Rønne, Frederik Malmborg; Theil, Jørn; Tvede, Michael; Eugen-Olsen, Jesper

    2011-01-01

    In this prospective study we investigated the role of plasma levels of soluble urokinase plasminogen activator receptor (suPAR) in children with urinary tract infection.......In this prospective study we investigated the role of plasma levels of soluble urokinase plasminogen activator receptor (suPAR) in children with urinary tract infection....

  9. The adipogenic acetyltransferase Tip60 targets activation function 1 of peroxisome proliferator-activated receptor gamma

    DEFF Research Database (Denmark)

    van Beekum, Olivier; Brenkman, Arjan B; Grøntved, Lars;

    2008-01-01

    proteins with which this nuclear receptor interacts under specific conditions. Here we identify the HIV-1 Tat-interacting protein 60 (Tip60) as a novel positive regulator of PPARgamma transcriptional activity. Using tandem mass spectrometry, we found that PPARgamma and the acetyltransferase Tip60 interact......-mediated reduction of Tip60 protein impairs differentiation of 3T3-L1 preadipocytes. Taken together, these findings qualify the acetyltransferase Tip60 as a novel adipogenic factor....

  10. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

    International Nuclear Information System (INIS)

    Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the β-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the β-adrenergic pathway, adenylate cyclase activity and β-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. β-Adrenergic receptors were identified in BAT using [125I]iodocyanopindolol. Binding sites had the characteristics of mixed β1- and β2-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in β-adrenergic receptor density due to a loss of the β1-adrenergic subtype. This BAT β-adrenergic receptor downregulation was tissue specific, since myocardial β-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of β-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability

  11. Modulation of receptors and adenylate cyclase activity during sucrose feeding, food deprivation, and cold exposure

    Energy Technology Data Exchange (ETDEWEB)

    Scarpace, P.J.; Baresi, L.A.; Morley, J.E. (Veterans Administration Medical Center, Los Angeles, CA (USA) Univ. of California, Los Angeles (USA))

    1987-12-01

    Thermogenesis in brown adipose tissue (BAT) serves as a regulator of body temperature and weight maintenance. Thermogenesis can be stimulated by catecholamine activation of adenylate cyclase through the {beta}-adrenergic receptor. To investigate the effects of sucrose feeding, food deprivation, and cold exposure on the {beta}-adrenergic pathway, adenylate cyclase activity and {beta}-adrenergic receptors were assessed in rat BAT after 2 wk of sucrose feeding, 2 days of food deprivation, or 2 days of cold exposure. {beta}-Adrenergic receptors were identified in BAT using ({sup 125}I)iodocyanopindolol. Binding sites had the characteristics of mixed {beta}{sub 1}- and {beta}{sub 2}-type adrenergic receptors at a ratio of 60/40. After sucrose feeding or cold exposure, there was the expected increase in BAT mitochondrial mass as measured by total cytochrome-c oxidase activity but a decrease in {beta}-adrenergic receptor density due to a loss of the {beta}{sub 1}-adrenergic subtype. This BAT {beta}-adrenergic receptor downregulation was tissue specific, since myocardial {beta}-adrenergic receptors were unchanged with either sucrose feeding or cold exposure. Forskolin-stimulated adenylate cyclase activity increased in BAT after sucrose feeding or cold exposure but not after food deprivation. These data suggest that in BAT, sucrose feeding or cold exposure result in downregulation of {beta}-adrenergic receptors and that isoproterenol-stimulated adenylate cyclase activity was limited by receptor availability.

  12. Antileishmanial activity of the estrogen receptor modulator raloxifene.

    Directory of Open Access Journals (Sweden)

    Juliana Q Reimão

    2014-05-01

    Full Text Available BACKGROUND: The treatment of leishmaniasis relies mostly on parenteral drugs with potentially serious adverse effects. Additionally, parasite resistance in the treatment of leishmaniasis has been demonstrated for the majority of drugs available, making the search for more effective and less toxic drugs and treatment regimens a priority for the control of leishmaniasis. The aims of this study were to evaluate the antileishmanial activity of raloxifene in vitro and in vivo and to investigate its mechanism of action against Leishmania amazonensis. METHODOLOGY/PRINCIPAL FINDINGS: Raloxifene was shown to possess antileishmanial activity in vitro against several species with EC50 values ranging from 30.2 to 38.0 µM against promastigotes and from 8.8 to 16.2 µM against intracellular amastigotes. Raloxifene's mechanism of action was investigated through transmission electron microscopy and labeling with propidium iodide, DiSBAC2(3, rhodamine 123 and monodansylcadaverine. Microscopic examinations showed that raloxifene treated parasites displayed autophagosomes and mitochondrial damage while the plasma membrane remained continuous. Nonetheless, plasma membrane potential was rapidly altered upon raloxifene treatment with initial hyperpolarization followed by depolarization. Loss of mitochondrial membrane potential was also verified. Treatment of L. amazonensis-infected BALB/c mice with raloxifene led to significant decrease in lesion size and parasite burden. CONCLUSIONS/SIGNIFICANCE: The results of this work extend the investigation of selective estrogen receptor modulators as potential candidates for leishmaniasis treatment. The antileishmanial activity of raloxifene was demonstrated in vitro and in vivo. Raloxifene produces functional disorder on the plasma membrane of L. amazonensis promastigotes and leads to functional and morphological disruption of mitochondria, which culminate in cell death.

  13. A bacterial tyrosine phosphatase inhibits plant pattern recognition receptor activation

    Science.gov (United States)

    Perception of pathogen-associated molecular patterns (PAMPs) by surface-localised pattern-recognition receptors (PRRs) is a key component of plant innate immunity. Most known plant PRRs are receptor kinases and initiation of PAMP-triggered immunity (PTI) signalling requires phosphorylation of the PR...

  14. Estrogen Receptor β Activation Rapidly Modulates Male Sexual Motivation through the Transactivation of Metabotropic Glutamate Receptor 1a.

    Science.gov (United States)

    Seredynski, Aurore L; Balthazart, Jacques; Ball, Gregory F; Cornil, Charlotte A

    2015-09-23

    In addition to the transcriptional activity of their liganded nuclear receptors, estrogens, such as estradiol (E2), modulate cell functions, and consequently physiology and behavior, within minutes through membrane-initiated events. The membrane-associated receptors (mERs) underlying the acute effects of estrogens on behavior have mostly been documented in females where active estrogens are thought to be of ovarian origin. We determined here, by acute intracerebroventricular injections of specific agonists and antagonists, the type(s) of mERs that modulate rapid effects of brain-derived estrogens on sexual motivation in male Japanese quail. Brain aromatase blockade acutely inhibited sexual motivation. Diarylpropionitrile (DPN), an estrogen receptor β (ERβ)-specific agonist, and to a lesser extent 17α-estradiol, possibly acting through ER-X, prevented this effect. In contrast, drugs targeting ERα (PPT and MPP), GPR30 (G1 and G15), and the Gq-mER (STX) did not affect sexual motivation. The mGluR1a antagonist LY367385 significantly inhibited sexual motivation but mGluR2/3 and mGluR5 antagonists were ineffective. LY367385 also blocked the behavioral restoration induced by E2 or DPN, providing functional evidence that ERβ interacts with metabotropic glutamate receptor 1a (mGluR1a) signaling to acutely regulate male sexual motivation. Together these results show that ERβ plays a key role in sexual behavior regulation and the recently uncovered cooperation between mERs and mGluRs is functional in males where it mediates the acute effects of estrogens produced centrally in response to social stimuli. The presence of an ER-mGluR interaction in birds suggests that this mechanism emerged relatively early in vertebrate history and is well conserved. Significance statement: The membrane-associated receptors underlying the acute effects of estrogens on behavior have mostly been documented in females, where active estrogens are thought to be of ovarian origin. Using acute

  15. Characterization of human endothelial cell urokinase-type plasminogen activator receptor protein and messenger RNA

    DEFF Research Database (Denmark)

    Barnathan, E S; Kuo, A; Karikó, K; Rosenfeld, L; Murray, S C; Behrendt, N; Rønne, E; Weiner, D; Henkin, J; Cines, D B

    1990-01-01

    Human umbilical vein endothelial cells in culture (HUVEC) express receptors for urokinase-type plasminogen activators (u-PA). The immunochemical nature of this receptor and its relationship to u-PA receptors expressed by other cell types is unknown. Cross-linking active site-blocked u-PA to HUVEC...... endothelial cell cDNA library using the polymerase chain reaction (PCR) and oligonucleotide primers corresponding to the DNA sequence of the receptor cloned from transformed human fibroblasts (Roldan et al, EMBO J 9:467, 1990). The size of the cDNA (approximately 1,054 base pairs, bp) and the presence of a...

  16. Estimation of Cessation Rates among Danish Users of Benzodiazepines

    DEFF Research Database (Denmark)

    Støvring, Henrik; Gasse, Christiane

    cessation hazards among incident users of benzodiazepines, in particular with respect to potential changes after three months use. Methods: Follow-up on a 25% randomly selected cohort of all Danes (n = 1,612,171) in the period Jan 1, 1995, to Jul 1, 2007, identified through the Danish civil registration...... of cessation rates should be preferred over duration, as they can explicitly account for censoring and provide cause specific hazard estimates of cessation rates....

  17. The G Protein-Coupled Estrogen Receptor Agonist G-1 Inhibits Nuclear Estrogen Receptor Activity and Stimulates Novel Phosphoproteomic Signatures.

    Science.gov (United States)

    Smith, L Cody; Ralston-Hooper, Kimberly J; Ferguson, P Lee; Sabo-Attwood, Tara

    2016-06-01

    Estrogen exerts cellular effects through both nuclear (ESR1 and ESR2) and membrane-bound estrogen receptors (G-protein coupled estrogen receptor, GPER); however, it is unclear if they act independently or engage in crosstalk to influence hormonal responses. To investigate each receptor's role in proliferation, transcriptional activation, and protein phosphorylation in breast cancer cells (MCF-7), we employed selective agonists for ESR1 propyl-pyrazole-triol (PPT), ESR2 diarylpropionitrile (DPN), and GPER (G-1) and also determined the impact of xenoestrogens bisphenol-A (BPA) and genistein on these effects. As anticipated, 17β-estradiol (E2), PPT, DPN, BPA, and genistein each enhanced proliferation and activation of an ERE-driven reporter gene whereas G-1 had no significant impact. However, G-1 significantly reduced E2-, PPT-, DPN-, BPA-, and genistein-induced proliferation and ERE activation at doses greater than 500 nM indicating that G-1 mediated inhibition is not ESR isotype specific. As membrane receptors initiate cascades of phosphorylation events, we performed a global phosphoproteomic analysis on cells exposed to E2 or G-1 to identify potential targets of receptor crosstalk via downstream protein phosphorylation targets. Of the 211 phosphorylated proteins identified, 40 and 13 phosphoproteins were specifically modified by E2 and G-1, respectively. Subnetwork enrichment analysis revealed several processes related to cell cycle were specifically enriched by G-1 compared with E2. Further there existed a number of newly identified proteins that were specifically phosphorylated by G-1. These phosphorylation networks highlight specific proteins that may modulate the inhibitory effects of G-1 and suggest a novel role for interference with nuclear receptor activity driven by E2 and xenoestrogens. PMID:27026707

  18. Group III metabotropic glutamate receptors and D1-like and D2-like dopamine receptors interact in the rat nucleus accumbens to influence locomotor activity.

    Science.gov (United States)

    David, Hélène N; Abraini, Jacques H

    2002-03-01

    Evidence for functional interactions between metabotropic glutamate (mGlu) receptors and dopamine (DA) neurotransmission is now clearly established. In the present study, we investigated interactions between group III mGlu receptors and D1- and D2-like receptors in the nucleus accumbens (NAcc). Administration, into the NAcc, of the selective group III mGlu receptor agonist, AP4, resulted in an increase in locomotor activity, which was blocked by pretreatment with the group III mGlu receptor antagonist, MPPG. In addition, pretreatment with AP4 further blocked the increase in motor activity induced by the D1-like receptor agonist, SKF 38393, but potentiated the locomotor responses induced by either the D2-like receptor agonist, quinpirole, or coinfusion of SKF 38393 and quinpirole. MPPG reversed the effects of AP4 on the motor responses induced by D1-like and/or D2-like receptor activation. These results confirm that glutamate transmission may control DA-dependent locomotor function through mGlu receptors and further indicate that group III mGlu receptors oppose the behavioural response produced by D1-like receptor activation and favour those produced by D2-like receptor activation. PMID:11906529

  19. Oligomerization of opioid receptors with β2-adrenergic receptors: A role in trafficking and mitogen-activated protein kinase activation

    OpenAIRE

    Jordan, B. A.; Trapaidze, N.; Gomes, I; Nivarthi, R.; Devi, L.A.

    2000-01-01

    G-protein-coupled receptors (GPCRs) have recently joined the list of cell surface receptors that dimerize. Dimerization has been shown to alter the ligand-binding, signaling, and trafficking properties of these receptors. Recent studies have shown that GPCRs heterodimerize with closely related members, resulting in the modulation of their function. In this study, we have attempted to determine whether members of GPCR superfamilies that couple to different families of G...

  20. Regulatory network of inflammation downstream of proteinase-activated receptors

    Directory of Open Access Journals (Sweden)

    Hurst Robert E

    2007-03-01

    Full Text Available Abstract Background Protease-activated receptors (PAR are present in the urinary bladder, and their expression is altered in response to inflammation. PARs are a unique class of G protein-coupled that carry their own ligands, which remain cryptic until unmasked by proteolytic cleavage. Although the canonical signal transduction pathway downstream of PAR activation and coupling with various G proteins is known and leads to the rapid transcription of genes involved in inflammation, the effect of PAR activation on the downstream transcriptome is unknown. We have shown that intravesical administration of PAR-activating peptides leads to an inflammatory reaction characterized by edema and granulocyte infiltration. Moreover, the inflammatory response to intravesical instillation of known pro-inflammatory stimuli such as E. coli lipopolysaccharide (LPS, substance P (SP, and antigen was strongly attenuated by PAR1- and to a lesser extent by PAR2-deficiency. Results Here, cDNA array experiments determined inflammatory genes whose expression is dependent on PAR1 activation. For this purpose, we compared the alteration in gene expression in wild type and PAR1-/- mice induced by classical pro-inflammatory stimuli (LPS, SP, and antigen. 75 transcripts were considered to be dependent on PAR-1 activation and further annotated in silico by Ingenuity Pathways Analysis (IPA and gene ontology (GO. Selected transcripts were target validated by quantitative PCR (Q-PCR. Among PAR1-dependent transcripts, the following have been implicated in the inflammatory process: b2m, ccl7, cd200, cd63, cdbpd, cfl1, dusp1, fkbp1a, fth1, hspb1, marcksl1, mmp2, myo5a, nfkbia, pax1, plaur, ppia, ptpn1, ptprcap, s100a10, sim2, and tnfaip2. However, a balanced response to signals of injury requires a transient cellular activation of a panel of genes together with inhibitory systems that temper the overwhelming inflammation. In this context, the activation of genes such as dusp1 and

  1. Determinants of benzodiazepine brain uptake: lipophilicity versus binding affinity.

    Science.gov (United States)

    Arendt, R M; Greenblatt, D J; Liebisch, D C; Luu, M D; Paul, S M

    1987-01-01

    Factors influencing brain uptake of benzodiazepine derivatives were evaluated in adult Sprague Dawley rats (n = 8-10 per drug). Animals received single intraperitoneal doses of alprazolam, triazolam, lorazepam, flunitrazepam, diazepam, midazolam, desmethyldiazepam, or clobazam. Concentrations of each drug (and metabolites) in whole brain and serum 1 h after dosage were determined by gas chromatography. Serum free fraction was measured by equilibrium dialysis. In vitro binding affinity (apparent Ki) of each compound was estimated based on displacement of tritiated flunitrazepam in washed membrane preparations from rat cerebral cortex. Lipid solubility of each benzodiazepine was estimated using the reverse-phase liquid chromatographic (HPLC) retention index at physiologic pH. There was no significant relation between brain:total serum concentration ratio and either HPLC retention (r = 0.18) or binding Ki (r = -0.34). Correction of uptake ratios for free as opposed to total serum concentration yielded a highly significant correlation with HPLC retention (r = 0.78, P less than 0.005). However, even the corrected ratio was not correlated with binding Ki (r = -0.22). Thus a benzodiazepine's capacity to diffuse from systemic blood into brain tissue is much more closely associated with the physicochemical property of lipid solubility than with specific affinity. Unbound rather than total serum or plasma concentration most accurately reflects the quantity of drug available for diffusion. PMID:2888155

  2. Activation of transforming potential of the human insulin receptor gene

    International Nuclear Information System (INIS)

    A retrovirus containing part of the human insulin receptor (hIR) gene was constructed by replacing ros sequences in the avian sarcoma virus UR2 with hIR cDNA sequences coding for 46 amino acids of the extracellular domain and the entire transmembrane and cytoplasmic domains of the β subunit of hIR. The resulting virus, named UIR, contains the hIR sequence fused to the 5' portion of the UR2 gag gene coding for p19. UIR is capable of transforming chicken embryo fibroblasts and promoting formation of colonies in soft agar; however, it does not form tumors in vivo. A variant that arose from the parental UIR is capable of efficiently inducing sarcomas in vivo. UIR-transformed cells exhibit higher rates of glucose uptake and growth than normal cells. The 4-kilobase UIR genome codes for a membrane-associated, glycosylated gag-hIR fusion protein of 75 kDa designated P75/sup gag-hir/. P75/sup gag-hir/ contains a protein tyrosine kinase activity that is capable of undergoing autophosphorylation and of phosphorylating foreign substrates in vitro; it is phosphorylated at both serine and tyrosine residues in vivo

  3. Activation of transforming potential of the human insulin receptor gene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, L.H.; Lin, B.; Jong, S.M.J.; Dixon, D.; Ellis, L.; Roth, R.A.; Rutter, W.J.

    1987-08-01

    A retrovirus containing part of the human insulin receptor (hIR) gene was constructed by replacing ros sequences in the avian sarcoma virus UR2 with hIR cDNA sequences coding for 46 amino acids of the extracellular domain and the entire transmembrane and cytoplasmic domains of the ..beta.. subunit of hIR. The resulting virus, named UIR, contains the hIR sequence fused to the 5' portion of the UR2 gag gene coding for p19. UIR is capable of transforming chicken embryo fibroblasts and promoting formation of colonies in soft agar; however, it does not form tumors in vivo. A variant that arose from the parental UIR is capable of efficiently inducing sarcomas in vivo. UIR-transformed cells exhibit higher rates of glucose uptake and growth than normal cells. The 4-kilobase UIR genome codes for a membrane-associated, glycosylated gag-hIR fusion protein of 75 kDa designated P75/sup gag-hir/. P75/sup gag-hir/ contains a protein tyrosine kinase activity that is capable of undergoing autophosphorylation and of phosphorylating foreign substrates in vitro; it is phosphorylated at both serine and tyrosine residues in vivo

  4. DCC constrains tumour progression via its dependence receptor activity.

    Science.gov (United States)

    Castets, Marie; Broutier, Laura; Molin, Yann; Brevet, Marie; Chazot, Guillaume; Gadot, Nicolas; Paquet, Armelle; Mazelin, Laetitia; Jarrosson-Wuilleme, Loraine; Scoazec, Jean-Yves; Bernet, Agnès; Mehlen, Patrick

    2012-02-23

    The role of deleted in colorectal carcinoma (DCC) as a tumour suppressor has been a matter of debate for the past 15 years. DCC gene expression is lost or markedly reduced in the majority of advanced colorectal cancers and, by functioning as a dependence receptor, DCC has been shown to induce apoptosis unless engaged by its ligand, netrin-1 (ref. 2). However, so far no animal model has supported the view that the DCC loss-of-function is causally implicated as predisposing to aggressive cancer development. To investigate the role of DCC-induced apoptosis in the control of tumour progression, here we created a mouse model in which the pro-apoptotic activity of DCC is genetically silenced. Although the loss of DCC-induced apoptosis in this mouse model is not associated with a major disorganization of the intestines, it leads to spontaneous intestinal neoplasia at a relatively low frequency. Loss of DCC-induced apoptosis is also associated with an increase in the number and aggressiveness of intestinal tumours in a predisposing APC mutant context, resulting in the development of highly invasive adenocarcinomas. These results demonstrate that DCC functions as a tumour suppressor via its ability to trigger tumour cell apoptosis. PMID:22158121

  5. Antipeptide antibody that specifically inhibits insulin receptor autophosphorylation and protein kinase activity

    International Nuclear Information System (INIS)

    Two site-specific antibodies that immunoprecipitate the human insulin receptor have been prepared by immunizing rabbits with chemically synthesized peptides derived from the cDNA-predicted amino acid sequence of the β subunit of the proreceptor. Antibodies to the carboxyl terminus (AbP5) and to a domain around tyrosine-960 (AbP4) specifically recognize the β subunit of the receptor on immunoblots. Both antibodies immunoprecipitated 125I-labeled insulin-receptor complexes and the autophosphorylated receptor. Although neither antibody inhibited insulin binding to the receptor, both insulin-dependent autophosphorylation and exogenous substrate phosphorylation were inhibited by AbP4. Inhibition by AbP4 was dependent upon the phosphorylation state of the receptor; it was not detected when the receptor was autophosphorylated prior to addition of AbP4. AbP4 did not inhibit activity of the related epidermal growth factor (EGF)-receptor tyrosine protein kinase nor did it inhibit the activity of cAMP-dependent kinase or protein kinase C. The observation that an antibody directed to residues 952-967 of the proreceptor neutralizes the protein kinase activity of the β subunit suggest that this region may play a critical role in the function of the hormone-dependent, protein tyrosine-specific kinase activity of the insulin receptor

  6. Benzodiazepine prescribing behaviour and attitudes: a survey among general practitioners practicing in northern Thailand

    OpenAIRE

    Critchley Julia; Garner Paul; Srisurapanont Manit; Wongpakaran Nahathai

    2005-01-01

    Abstract Background Over-prescribing of benzodiazepines appears common in many countries, a better understanding of prescribing practices and attitudes may help develop strategies to reduce prescribing. This study aimed to evaluate benzodiazepine prescribing behaviour and attitudes in general practitioners practising in Chiang Mai and Lampoon, Thailand. Methods Questionnaire survey of general practitioners in community hospitals, to estimate: i) use of benzodiazepines for anxiety/insomnia, pa...

  7. A Molecular Mechanism for Sequential Activation of a G Protein-Coupled Receptor

    DEFF Research Database (Denmark)

    Grundmann, Manuel; Tikhonova, Irina G; Hudson, Brian D; Smith, Nicola J; Mohr, Klaus; Ulven, Trond; Milligan, Graeme; Kenakin, Terry; Kostenis, Evi

    2016-01-01

    Ligands targeting G protein-coupled receptors (GPCRs) are currently classified as either orthosteric, allosteric, or dualsteric/bitopic. Here, we introduce a new pharmacological concept for GPCR functional modulation: sequential receptor activation. A hallmark feature of this is a stepwise ligand...... binding mode with transient activation of a first receptor site followed by sustained activation of a second topographically distinct site. We identify 4-CMTB (2-(4-chlorophenyl)-3-methyl-N-(thiazol-2-yl)butanamide), previously classified as a pure allosteric agonist of the free fatty acid receptor 2, as...... mutational and pharmacological perturbations along with computational methods, and propose a kinetic model applicable to the analysis of sequential receptor activation. We envision this form of dynamic agonism as a common principle of nature to spatiotemporally encode cellular information....

  8. Quantitative structure-activity relationships of selective antagonists of glucagon receptor using QuaSAR descriptors.

    Science.gov (United States)

    Manoj Kumar, Palanivelu; Karthikeyan, Chandrabose; Hari Narayana Moorthy, Narayana Subbiah; Trivedi, Piyush

    2006-11-01

    In the present paper, quantitative structure activity relationship (QSAR) approach was applied to understand the affinity and selectivity of a novel series of triaryl imidazole derivatives towards glucagon receptor. Statistically significant and highly predictive QSARs were derived for glucagon receptor inhibition by triaryl imidazoles using QuaSAR descriptors of molecular operating environment (MOE) employing computer-assisted multiple regression procedure. The generated QSAR models revealed that factors related to hydrophobicity, molecular shape and geometry predominantly influences glucagon receptor binding affinity of the triaryl imidazoles indicating the relevance of shape specific steric interactions between the molecule and the receptor. Further, QSAR models formulated for selective inhibition of glucagon receptor over p38 mitogen activated protein (MAP) kinase of the compounds in the series highlights that the same structural features, which influence the glucagon receptor affinity, also contribute to their selective inhibition. PMID:17077558

  9. Function of the cytoplasmic tail of human calcitonin receptor-like receptor in complex with receptor activity-modifying protein 2

    International Nuclear Information System (INIS)

    Receptor activity-modifying protein 2 (RAMP2) enables calcitonin receptor-like receptor (CRLR) to form an adrenomedullin (AM)-specific receptor. Here we investigated the function of the cytoplasmic C-terminal tail (C-tail) of human (h)CRLR by co-transfecting its C-terminal mutants into HEK-293 cells stably expressing hRAMP2. Deleting the C-tail from CRLR disrupted AM-evoked cAMP production or receptor internalization, but did not affect [125I]AM binding. We found that CRLR residues 428-439 are required for AM-evoked cAMP production, though deleting this region had little effect on receptor internalization. Moreover, pretreatment with pertussis toxin (100 ng/mL) led to significant increases in AM-induced cAMP production via wild-type CRLR/RAMP2 complexes. This effect was canceled by deleting CRLR residues 454-457, suggesting Gi couples to this region. Flow cytometric analysis revealed that CRLR truncation mutants lacking residues in the Ser/Thr-rich region extending from Ser449 to Ser467 were unable to undergo AM-induced receptor internalization and, in contrast to the effect on wild-type CRLR, overexpression of GPCR kinases-2, -3 and -4 failed to promote internalization of CRLR mutants lacking residues 449-467. Thus, the hCRLR C-tail is crucial for AM-evoked cAMP production and internalization of the CRLR/RAMP2, while the receptor internalization is dependent on the aforementioned GPCR kinases, but not Gs coupling.

  10. Use of benzodiazepines or benzodiazepine related drugs and the risk of cancer: a population-based case-control study

    DEFF Research Database (Denmark)

    Pottegård, Anton; Friis, Søren; Andersen, Morten;

    2013-01-01

    AIM: Studies of the carcinogenic potential of benzodiazepines and related drugs (BZRD) have been equivocal. A recent study reported a 35% excess cancer risk among users of hypnotics, including benzodiazepines. METHOD: Using Danish nationwide registers, we conducted a matched case-control study of...... 1.01, 2.02), liver 1.81 (95% CI 1.18, 2.80), lung 1.38 (95% CI 1.23, 1.54), pancreas 1.35 (95% CI 1.02, 1.79) and kidney 1.39 (95% CI 1.01, 1.91). For tobacco-related cancers, the OR was 1.15 (95% CI 1.09, 1.22) and for the remaining cancer sites 1.01 (95% CI 0.94, 1.08). Sub-group analyses revealed...

  11. Dopamine receptor activation modulates GABA neuron migration from the basal forebrain to the cerebral cortex.

    Science.gov (United States)

    Crandall, James E; McCarthy, Deirdre M; Araki, Kiyomi Y; Sims, John R; Ren, Jia-Qian; Bhide, Pradeep G

    2007-04-01

    GABA neurons of the cerebral cortex and other telencephalic structures are produced in the basal forebrain and migrate to their final destinations during the embryonic period. The embryonic basal forebrain is enriched in dopamine and its receptors, creating a favorable environment for dopamine to influence GABA neuron migration. However, whether dopamine receptor activation can influence GABA neuron migration is not known. We show that dopamine D1 receptor activation promotes and D2 receptor activation decreases GABA neuron migration from the medial and caudal ganglionic eminences to the cerebral cortex in slice preparations of embryonic mouse forebrain. Slice preparations from D1 or D2 receptor knock-out mouse embryos confirm the findings. In addition, D1 receptor electroporation into cells of the basal forebrain and pharmacological activation of the receptor promote migration of the electroporated cells to the cerebral cortex. Analysis of GABA neuron numbers in the cerebral wall of the dopamine receptor knock-out mouse embryos further confirmed the effects of dopamine receptor activation on GABA neuron migration. Finally, dopamine receptor activation mobilizes striatal neuronal cytoskeleton in a manner consistent with the effects on neuronal migration. These data show that impairing the physiological balance between D1 and D2 receptors can alter GABA neuron migration from the basal forebrain to the cerebral cortex. The intimate relationship between dopamine and GABA neuron development revealed here may offer novel insights into developmental disorders such as schizophrenia, attention deficit or autism, and fetal cocaine exposure, all of which are associated with dopamine and GABA imbalance. PMID:17409246

  12. The orphan nuclear receptor Rev-Erbalpha is a peroxisome proliferator-activated receptor (PPAR) gamma target gene and promotes PPARgamma-induced adipocyte differentiation

    DEFF Research Database (Denmark)

    Fontaine, Coralie; Dubois, Guillaume; Duguay, Yannick;

    2003-01-01

    Rev-Erbalpha (NR1D1) is an orphan nuclear receptor encoded on the opposite strand of the thyroid receptor alpha gene. Rev-Erbalpha mRNA is induced during adipocyte differentiation of 3T3-L1 cells, and its expression is abundant in rat adipose tissue. Peroxisome proliferator-activated receptor gamma...

  13. Gemfibrozil, a lipid lowering drug, inhibits the activation of primary human microglia via peroxisome proliferator-activated receptor β

    OpenAIRE

    Jana, Malabendu; Pahan, Kalipada

    2012-01-01

    Microglial activation participates in the pathogenesis of various neuroinflammatory and neurodegenerative diseases. However, mechanisms by which microglial activation could be controlled are poorly understood. Peroxisome proliferator-activated receptors (PPAR) are transcription factors belonging to the nuclear receptor super family with diverse effect. This study underlines the importance of PPARβ/δ in mediating the anti-inflammatory effect of gemfibrozil, an FDA-approved lipid-lowering drug,...

  14. Activation of the A2A adenosine G-protein-coupled receptor by conformational selection.

    Science.gov (United States)

    Ye, Libin; Van Eps, Ned; Zimmer, Marco; Ernst, Oliver P; Prosser, R Scott

    2016-05-12

    Conformational selection and induced fit are two prevailing mechanisms to explain the molecular basis for ligand-based activation of receptors. G-protein-coupled receptors are the largest class of cell surface receptors and are important drug targets. A molecular understanding of their activation mechanism is critical for drug discovery and design. However, direct evidence that addresses how agonist binding leads to the formation of an active receptor state is scarce. Here we use (19)F nuclear magnetic resonance to quantify the conformational landscape occupied by the adenosine A2A receptor (A2AR), a prototypical class A G-protein-coupled receptor. We find an ensemble of four states in equilibrium: (1) two inactive states in millisecond exchange, consistent with a formed (state S1) and a broken (state S2) salt bridge (known as 'ionic lock') between transmembrane helices 3 and 6; and (2) two active states, S3 and S3', as identified by binding of a G-protein-derived peptide. In contrast to a recent study of the β2-adrenergic receptor, the present approach allowed identification of a second active state for A2AR. Addition of inverse agonist (ZM241385) increases the population of the inactive states, while full agonists (UK432097 or NECA) stabilize the active state, S3', in a manner consistent with conformational selection. In contrast, partial agonist (LUF5834) and an allosteric modulator (HMA) exclusively increase the population of the S3 state. Thus, partial agonism is achieved here by conformational selection of a distinct active state which we predict will have compromised coupling to the G protein. Direct observation of the conformational equilibria of ligand-dependent G-protein-coupled receptor and deduction of the underlying mechanisms of receptor activation will have wide-reaching implications for our understanding of the function of G-protein-coupled receptor in health and disease. PMID:27144352

  15. Oral administration of protease inhibits enterotoxigenic Escherichia coli receptor activity in piglet small intestine.

    OpenAIRE

    Mynott, T L; Luke, R K; Chandler, D S

    1996-01-01

    The virulence of enterotoxigenic Escherichia coli (ETEC) is attributed to their ability to adhere via fimbrial adhesins to specific receptors located on the intestinal mucosa. A novel approach to preventing ETEC induced diarrhoea would be to prevent attachment of ETEC to intestine by proteolytically modifying the receptor attachment sites. This study aimed to examine the effect of bromelain, a proteolytic extract obtained from pineapple stems, on ETEC receptor activity in porcine small intest...

  16. Identification of Essential Cannabinoid-binding Domains: STRUCTURAL INSIGHTS INTO EARLY DYNAMIC EVENTS IN RECEPTOR ACTIVATION*

    OpenAIRE

    Shim, Joong-Youn; Bertalovitz, Alexander C.; Kendall, Debra A.

    2011-01-01

    The classical cannabinoid agonist HU210, a structural analog of (−)-Δ9-tetrahydrocannabinol, binds to brain cannabinoid (CB1) receptors and activates signal transduction pathways. To date, an exact molecular description of the CB1 receptor is not yet available. Utilizing the minor binding pocket of the CB1 receptor as the primary ligand interaction site, we explored HU210 binding using lipid bilayer molecular dynamics (MD) simulations. Among the potential ligand contact residues, we identifie...

  17. Functional Characterization of Nuclear Receptor and Co-activator Binding Loci in the Human Genome

    OpenAIRE

    Maguire, Kim, (Thesis)

    2010-01-01

    Steroid hormones, such as oestrogen, mediate their effects via activation of oestrogen regulated genes using nuclear receptors. Selective oestrogen receptor modulators (SERMs), such as Tamoxifen, are used to treat oestrogen responsive breast cancers, hctioning to act as oestrogen antagonists, preventing the oestrogen receptor biding DNA and blocking gene expression. However, Tamoxifen has been identified as an oestrogen agonist in other tissues which can often lead to secondary tumors in the ...

  18. Behavioral and neurophysiological signatures of benzodiazepine-related driving impairments

    Directory of Open Access Journals (Sweden)

    Bradly T Stone

    2015-11-01

    Full Text Available Impaired driving due to drug use is a growing problem, worldwide; estimates show that 18-23.5% of fatal accidents, and up to 34% of injury accidents may be caused by drivers under the influence of drugs (Drummer et al., 2003; NHTSA, 2010; Walsh et al., 2004. Furthermore, at any given time, up to 16% of drivers may be using drugs that can impair one’s driving abilities (NHTSA, 2009. Currently, drug recognition experts (law enforcement officers with specialized training to identify drugged driving, have the most difficult time with identifying drivers potentially impaired on central nervous system (CNS depressants (Smith, Hayes, Yolton, Rutledge, & Citek, 2002. The fact that the use of benzodiazepines, a type of CNS depressant, is also associated with the greatest likelihood of causing accidents (Dassanayake, Michie, Carter, & Jones, 2011, further emphasizes the need to improve research tools in this area which can facilitate the refinement of, or additions to, current assessments of impaired driving. Our laboratories collaborated to evaluate both the behavioral and neurophysiological effects of a benzodiazepine, alprazolam, in a driving simulation (miniSim™. This drive was combined with a neurocognitive assessment utilizing time synched neurophysiology (EEG, ECG. While the behavioral effects of benzodiazepines are well characterized (Rapoport et al., 2009, we hypothesized that, with the addition of real-time neurophysiology and the utilization of simulation and neurocognitive assessment, we could find objective assessments of drug impairment that could improve the detection capabilities of drug recognition experts. Our analyses revealed that 1 specific driving conditions were significantly more difficult for benzodiazepine impaired drivers and; 2 the neurocognitive tasks’ metrics were able to classify impaired vs. unimpaired with up to 80% accuracy based on lane position deviation and lane departures. While this work requires replication in

  19. Pharmacology and toxicology of fibrates as hypolipidemic drugs mediated by nuclear receptor peroxisome proliferator—activated receptor

    Institute of Scientific and Technical Information of China (English)

    SugaT

    2002-01-01

    PPAR(peroxisome proliferator-activated receptor) is a family of nuclear receptor.In recent years,it has been focused for the discovery and development of new drugs which are mediated by PPARs.Fibrate hypolipidemic drugs are the specific and potent ligands to PPAR alpha and have been widely used for the treatment of hyperlipidemia.But these drugs induce hepatocarcinogenesis in rodent animals after the long-term administration.However,there are species differences on these phenomena which are not seen in mammals ioncluding human.To clarify the mechanism of carcinogenesis by these drugs in important for the evaluation of safety of these drugs in human.

  20. Prenatal Allospecific NK Cell Tolerance Hinges on Instructive Allorecognition through the Activating Receptor during Development.

    Science.gov (United States)

    Alhajjat, Amir M; Strong, Beverly S; Lee, Amanda E; Turner, Lucas E; Wadhwani, Ram K; Ortaldo, John R; Heusel, Jonathan W; Shaaban, Aimen F

    2015-08-15

    Little is known about how the prenatal interaction between NK cells and alloantigens shapes the developing NK cell repertoire toward tolerance or immunity. Specifically, the effect on NK cell education arising from developmental corecognition of alloantigens by activating and inhibitory receptors with shared specificity is uncharacterized. Using a murine prenatal transplantation model, we examined the manner in which this seemingly conflicting input affects NK cell licensing and repertoire formation in mixed hematopoietic chimeras. We found that prenatal NK cell tolerance arose from the elimination of phenotypically hostile NK cells that express an allospecific activating receptor without coexpressing any allospecific inhibitory receptors. Importantly, the checkpoint for the system appeared to occur centrally within the bone marrow during the final stage of NK cell maturation and hinged on the instructive recognition of allogeneic ligand by the activating receptor rather than through the inhibitory receptor as classically proposed. Residual nondeleted hostile NK cells expressing only the activating receptor exhibited an immature, anergic phenotype, but retained the capacity to upregulate inhibitory receptor expression in peripheral sites. However, the potential for this adaptive change to occur was lost in developmentally mature chimeras. Collectively, these findings illuminate the intrinsic process in which developmental allorecognition through the activating receptor regulates the emergence of durable NK cell tolerance and establishes a new paradigm to fundamentally guide future investigations of prenatal NK cell-allospecific education. PMID:26136432

  1. Activity of recombinant trypsin isoforms on human proteinase-activated receptors (PAR): mesotrypsin cannot activate epithelial PAR-1, -2, but weakly activates brain PAR-1

    OpenAIRE

    Grishina, Zoryana; Ostrowska, Ewa; Halangk, Walter; Sahin-Tóth, Miklós; Reiser, Georg

    2005-01-01

    Trypsin-like serine proteinases trigger signal transduction pathways through proteolytic cleavage of proteinase-activated receptors (PARs) in many tissues. Three members, PAR-1, PAR-2 and PAR-4, are trypsin substrates, as trypsinolytic cleavage of the extracellular N terminus produces receptor activation. Here, the ability of the three human pancreatic trypsin isoforms (cationic trypsin, anionic trypsin and mesotrypsin (trypsin IV)) as recombinant proteins was tested on PARs.Using fura 2 [Ca2...

  2. UVB increases urokinase-type plasminogen activator receptor (uPAR) expression.

    Science.gov (United States)

    Marschall, C; Lengyel, E; Nobutoh, T; Braungart, E; Douwes, K; Simon, A; Magdolen, V; Reuning, U; Degitz, K

    1999-07-01

    Keratinocytes synthesize and secrete urokinase-type plasminogen activator, which binds to its specific receptor on keratinocytes. When bound to urokinase-type plasminogen activator receptor, urokinase-type plasminogen activator proteolytically converts surface bound plasminogen to plasmin, which in turn cleaves many extracellular components leading to pericellular proteolysis. The activation of the urokinase system has been observed during re-epithelialization of skin wounds and in lesions of the autoimmune blistering skin disease pemphigus. As pemphigus is photoinducible, we investigated the effect of ultraviolet B on urokinase-type plasminogen activator and urokinase-type plasminogen activator receptor expression in the epidermal keratinocyte cell line A431. Ultraviolet B increased cellular and secreted urokinase-type plasminogen activator protein (enzyme-linked immunosorbent assay) and urokinase-type plasminogen activator receptor cell surface expression (flow cytometry) 24 h postirradiation. Northern blot analysis indicated that ultraviolet B increased urokinase-type plasminogen activator receptor mRNA. Compared with a more rapid mRNA induction by epidermal growth factor (maximal after 4 h) the ultraviolet B response was maximal after 24 h and prolonged up to 36 h. The mRNA induction was not dependent on protein synthesis as judged by cycloheximide incubation. Ultraviolet B did not influence urokinase-type plasminogen activator receptor mRNA stability (actinomycin D incubation). A transiently transfected chloramphenicol acetyltransferase-reporter construct containing a -398/+51 urokinase-type plasminogen activator receptor promoter fragment was activated when cells were exposed to ultraviolet B. This induction was almost completely abolished by mutating a -182/-176 AP-1 binding sequence. Ultraviolet B increased the binding capacity at this AP-1 motif in electrophoretic mobility shift assays. These data identify a distinct transcriptional mechanism by which

  3. Identification of essential cannabinoid-binding domains: structural insights into early dynamic events in receptor activation.

    Science.gov (United States)

    Shim, Joong-Youn; Bertalovitz, Alexander C; Kendall, Debra A

    2011-09-23

    The classical cannabinoid agonist HU210, a structural analog of (-)-Δ(9)-tetrahydrocannabinol, binds to brain cannabinoid (CB1) receptors and activates signal transduction pathways. To date, an exact molecular description of the CB1 receptor is not yet available. Utilizing the minor binding pocket of the CB1 receptor as the primary ligand interaction site, we explored HU210 binding using lipid bilayer molecular dynamics (MD) simulations. Among the potential ligand contact residues, we identified residues Phe-174(2.61), Phe-177(2.64), Leu-193(3.29), and Met-363(6.55) as being critical for HU210 binding by mutational analysis. Using these residues to guide the simulations, we determined essential cannabinoid-binding domains in the CB1 receptor, including the highly sought after hydrophobic pocket important for the binding of the C3 alkyl chain of classical and nonclassical cannabinoids. Analyzing the simulations of the HU210-CB1 receptor complex, the CP55940-CB1 receptor complex, and the (-)-Δ(9)-tetrahydrocannabinol-CB1 receptor complex, we found that the positioning of the C3 alkyl chain and the aromatic stacking between Trp-356(6.48) and Trp-279(5.43) is crucial for the Trp-356(6.48) rotamer change toward receptor activation through the rigid-body movement of H6. The functional data for the mutant receptors demonstrated reductions in potency for G protein activation similar to the reductions seen in ligand binding affinity for HU210. PMID:21795705

  4. Receptor interconversion model of hormone action. 3. Estrogen receptor mediated repression of reporter gene activity in A431 cells.

    Science.gov (United States)

    Nag, A; Park, I; Krust, A; Smith, R G

    1990-03-20

    The chicken estrogen receptor exists in three interconvertible forms, two of which bind estradiol with high affinity and one which lacks the capacity to bind estradiol. Interconversion is regulated by reactions involving ATP/Mg2+. By cotransfecting into A431 cells estrogen receptor cDNA in an expression vector together with the pA2 (-821/-87) tk-CAT vitellogenin construct, we demonstrate that constitutive expression of chloramphenicol acetyltransferase (CAT) activity can be regulated either by selection of ligand or by modifying phosphorylation reactions in the recipient cells. In the presence of estrogen receptors, constitutive expression of CAT activity is inhibited in three situations: (i) in the absence of an estrogenic ligand; (ii) in the presence of an anti-estrogen; and (iii) in the presence of an estrogenic ligand together with 12-O-tetradecanoylphorbol 13-acetate (TPA). Estrogen receptor mediated repression of constitutive CAT activity is not observed with the pA2 (-331/-87) tk-CAT construct, indicating that DNA sequences required for repression are located between -821 and -331 base pairs upstream of the transcription initiation site. PMID:2346742

  5. Functional residues essential for the activation of the CB1 cannabinoid receptor.

    Science.gov (United States)

    Shim, Joong-Youn; Padgett, Lea

    2013-01-01

    Recently developed X-ray crystal structures of active state G-protein-coupled receptors have opened the way for detailed examination of the movement of the transmembrane (TM) helices and the specific residues involved in the receptor activation upon ligand binding. Previous modeling studies have indicated that the brain cannabinoid (CB1) receptor binds with a ligand at least in part through a hydrophobic tail on the ligand. This interaction is believed to be similar to the rotameric toggle switch proposed for the β2 adrenergic receptor (β2AR). In the present study, an active state model for the CB1 receptor, guided by the X-ray structure of the active state for β2AR, was constructed with HU210 bound as a ligand. Molecular dynamics (MD) simulations were employed to provide a smooth progression between inactive and active states of the receptor. This model was compared with our previously published CB1 receptor model to identify the functional residues that play key roles in triggering receptor conformational changes upon agonist binding. Movements in TM helices and functional residues are discussed. W279(5.43), contributing to an inward movement of the fifth TM helix (TM5) to the helical core, could serve as another rotameric switch for receptor activation. V282(5.46), interacting with the ligand's hydrophobic C3 alkyl chain, appears to play a key role in TM5 inward movement centered at L286(5.50) and subsequent coupling to V204(3.40). V204(3.40), closely interacting with the TM5 and TM6 hydrophobic patch residues in the middle of the receptor, particularly I290(5.54) and L352(6.44), appears to facilitate helical rearrangements, leading to the breakage of the ionic lock and the rotameric change of Y397(7.53), which are key features of the active state. PMID:23332708

  6. β-Arrestin biosensors reveal a rapid, receptor-dependent activation/deactivation cycle.

    Science.gov (United States)

    Nuber, Susanne; Zabel, Ulrike; Lorenz, Kristina; Nuber, Andreas; Milligan, Graeme; Tobin, Andrew B; Lohse, Martin J; Hoffmann, Carsten

    2016-03-31

    (β-)Arrestins are important regulators of G-protein-coupled receptors (GPCRs). They bind to active, phosphorylated GPCRs and thereby shut off 'classical' signalling to G proteins, trigger internalization of GPCRs via interaction with the clathrin machinery and mediate signalling via 'non-classical' pathways. In addition to two visual arrestins that bind to rod and cone photoreceptors (termed arrestin1 and arrestin4), there are only two (non-visual) β-arrestin proteins (β-arrestin1 and β-arrestin2, also termed arrestin2 and arrestin3), which regulate hundreds of different (non-visual) GPCRs. Binding of these proteins to GPCRs usually requires the active form of the receptors plus their phosphorylation by G-protein-coupled receptor kinases (GRKs). The binding of receptors or their carboxy terminus as well as certain truncations induce active conformations of (β-)arrestins that have recently been solved by X-ray crystallography. Here we investigate both the interaction of β-arrestin with GPCRs, and the β-arrestin conformational changes in real time and in living human cells, using a series of fluorescence resonance energy transfer (FRET)-based β-arrestin2 biosensors. We observe receptor-specific patterns of conformational changes in β-arrestin2 that occur rapidly after the receptor-β-arrestin2 interaction. After agonist removal, these changes persist for longer than the direct receptor interaction. Our data indicate a rapid, receptor-type-specific, two-step binding and activation process between GPCRs and β-arrestins. They further indicate that β-arrestins remain active after dissociation from receptors, allowing them to remain at the cell surface and presumably signal independently. Thus, GPCRs trigger a rapid, receptor-specific activation/deactivation cycle of β-arrestins, which permits their active signalling. PMID:27007855

  7. GABA-A receptor-mediated signaling alters the structure of spontaneous activity in the developing retina

    OpenAIRE

    Wang, Chih-Tien; Blankenship, Aaron G.; Anishchenko, Anastasia; Elstrott, Justin; Fikhman, Michael; Nakanishi, Shigetada; Feller, Marla B

    2007-01-01

    Ambient GABA modulates firing patterns in adult neural circuits by tonically activating extrasynaptic GABA-A receptors. Here, we demonstrate that during a developmental period when activation of GABA-A receptors causes membrane depolarization, tonic activation of GABA-A receptors blocks all spontaneous activity recorded in retinal ganglion cells (RGCs) and starburst amacrine cells (SACs). Bath application of the GABA-A receptor agonist muscimol blocked spontaneous correlated increases in intr...

  8. Direct activation of Transient Receptor Potential Vanilloid 1(TRPV1) by Diacylglycerol (DAG)

    OpenAIRE

    Oh Seog; Kim Yong; Park Chul-Kyu; Zhu Mei; Jung Sung; Woo Dong; Lee C Justin

    2008-01-01

    Abstract The capsaicin receptor, known as transient receptor potential channel vanilloid subtype 1 (TRPV1), is activated by a wide range of noxious stimulants and putative ligands such as capsaicin, heat, pH, anandamide, and phosphorylation by protein kinase C (PKC). However, the identity of endogenous activators for TRPV1 under physiological condition is still debated. Here, we report that diacylglycerol (DAG) directly activates TRPV1 channel in a membrane-delimited manner in rat dorsal root...

  9. Modulation of visceral pain and inflammation by protease-activated receptors

    OpenAIRE

    Vergnolle, Nathalie

    2004-01-01

    The gastrointestinal (GI) tract is exposed to a large array of proteases, under both physiological and pathophysiological conditions. The discovery of G protein-coupled receptors activated by proteases, the protease-activated receptors (PARs), has highlighted new signaling functions for proteases in the GI tract, particularly in the domains of inflammation and pain mechanisms. Activation of PARs by selective peptidic agonists in the intestine or the pancreas leads to inflammatory events and c...

  10. Interactions between Human Liver Fatty Acid Binding Protein and Peroxisome Proliferator Activated Receptor Selective Drugs

    OpenAIRE

    Tony Velkov

    2013-01-01

    Fatty acid binding proteins (FABPs) act as intracellular shuttles for fatty acids as well as lipophilic xenobiotics to the nucleus, where these ligands are released to a group of nuclear receptors called the peroxisome proliferator activated receptors (PPARs). PPAR mediated gene activation is ultimately involved in maintenance of cellular homeostasis through the transcriptional regulation of metabolic enzymes and transporters that target the activating ligand. Here we show that liver- (L-) FA...

  11. Quercetin Directly Interacts with Vitamin D Receptor (VDR): Structural Implication of VDR Activation by Quercetin

    OpenAIRE

    Lee, Ki-Young; Choi, Hye-Seung; Choi, Ho-Sung; Chung, Ka Young; Lee, Bong-Jin; Maeng, Han-Joo; Seo, Min-Duk

    2016-01-01

    The vitamin D receptor (VDR) is a member of the nuclear receptor (NR) superfamily. The VDR binds to active vitamin D3 metabolites, which stimulates downstream transduction signaling involved in various physiological activities such as calcium homeostasis, bone mineralization, and cell differentiation. Quercetin is a widely distributed flavonoid in nature that is known to enhance transactivation of VDR target genes. However, the detailed molecular mechanism underlying VDR activation by quercet...

  12. Enzymatic Regulation of Steroidogenesis and Nuclear Receptor Activation : Special Focus on Vitamin D and Sex Hormones

    OpenAIRE

    LUNDQVIST, JOHAN

    2011-01-01

    Enzyme-catalyzed reactions are important to regulate steroidogenesis and nuclear receptor activation. The present investigation examines the role of steroid metabolism catalyzed by CYP7B1 for regulation of hormone receptor activation and the effects of vitamin D on enzymatic regulation of steroidogenesis. The study reports data indicating that CYP7B1 can regulate estrogenic signaling by converting estrogens into inactive or less active metabolites. Similar results were obtained for CYP7B1-med...

  13. A2A adenosine receptor antagonism enhances synaptic and motor effects of cocaine via CB1 cannabinoid receptor activation.

    Directory of Open Access Journals (Sweden)

    Alessandro Tozzi

    Full Text Available BACKGROUND: Cocaine increases the level of endogenous dopamine (DA in the striatum by blocking the DA transporter. Endogenous DA modulates glutamatergic inputs to striatal neurons and this modulation influences motor activity. Since D2 DA and A2A-adenosine receptors (A2A-Rs have antagonistic effects on striatal neurons, drugs targeting adenosine receptors such as caffeine-like compounds, could enhance psychomotor stimulant effects of cocaine. In this study, we analyzed the electrophysiological effects of cocaine and A2A-Rs antagonists in striatal slices and the motor effects produced by this pharmacological modulation in rodents. PRINCIPAL FINDINGS: Concomitant administration of cocaine and A2A-Rs antagonists reduced glutamatergic synaptic transmission in striatal spiny neurons while these drugs failed to produce this effect when given in isolation. This inhibitory effect was dependent on the activation of D2-like receptors and the release of endocannabinoids since it was prevented by L-sulpiride and reduced by a CB1 receptor antagonist. Combined application of cocaine and A2A-R antagonists also reduced the firing frequency of striatal cholinergic interneurons suggesting that changes in cholinergic tone might contribute to this synaptic modulation. Finally, A2A-Rs antagonists, in the presence of a sub-threshold dose of cocaine, enhanced locomotion and, in line with the electrophysiological experiments, this enhanced activity required activation of D2-like and CB1 receptors. CONCLUSIONS: The present study provides a possible synaptic mechanism explaining how caffeine-like compounds could enhance psychomotor stimulant effects of cocaine.

  14. Glucose-Sensing Receptor T1R3: A New Signaling Receptor Activated by Glucose in Pancreatic β-Cells.

    Science.gov (United States)

    Kojima, Itaru; Nakagawa, Yuko; Hamano, Kunihisa; Medina, Johan; Li, Longfei; Nagasawa, Masahiro

    2015-01-01

    Subunits of the sweet taste receptors T1R2 and T1R3 are expressed in pancreatic β-cells. Compared with T1R3, mRNA expression of T1R2 is considerably lower. At the protein level, expression of T1R2 is undetectable in β-cells. Accordingly, a major component of the sweet taste-sensing receptor in β-cells may be a homodimer of T1R3 rather than a heterodimer of T1R2/T1R3. Inhibition of this receptor by gurmarin or deletion of the T1R3 gene attenuates glucose-induced insulin secretion from β-cells. Hence the T1R3 homodimer functions as a glucose-sensing receptor (GSR) in pancreatic β-cells. When GSR is activated by the T1R3 agonist sucralose, elevation of intracellular ATP concentration ([ATP]i) is observed. Sucralose increases [ATP]i even in the absence of ambient glucose, indicating that sucralose increases [ATP]i not simply by activating glucokinase, a rate-limiting enzyme in the glycolytic pathway. In addition, sucralose augments elevation of [ATP]i induced by methylsuccinate, suggesting that sucralose activates mitochondrial metabolism. Nonmetabolizable 3-O-methylglucose also increases [ATP]i and knockdown of T1R3 attenuates elevation of [ATP]i induced by high concentration of glucose. Collectively, these results indicate that the T1R3 homodimer functions as a GSR; this receptor is involved in glucose-induced insulin secretion by activating glucose metabolism probably in mitochondria. PMID:25947913

  15. Positron-emissionstomografisk kortlaegning af den levende menneskehjernes receptorer

    DEFF Research Database (Denmark)

    Gjedde, A

    2001-01-01

    tracers are used in diseases of the basal ganglia, whereas serotonin, benzodiazepine, and opiate tracers are used in lesions of the cerebral cortex. PET has revealed loss of dopaminergic terminals and dopamine synthetic capacity in Parkinson's disease, MPTP intoxication, and Lesch-Nyhan's syndrome......PET can map neurotransmitter synthesis, storage, release, binding to receptors, and re-uptake in the brain with tracer concentrations in the picomolar or nanomolar range. Tracers are analogues of naturally occurring precursors or ligands, or are drugs, which bind with varying degrees of specificity......; release of dopamine after administration of cocaine and amphetamine, and in motor activity and cognition; increased synaptic dopamine and release of dopamine, and the 70-90% neuroleptic occupancy of dopamine receptors in the striatum, in patients with schizophrenia; loss of muscarinic and nicotinergic...

  16. Expression of protease-activated receptor 1 and 2 and anti-tubulogenic activity of protease-activated receptor 1 in human endothelial colony-forming cells.

    Directory of Open Access Journals (Sweden)

    Tiago M Fortunato

    Full Text Available Endothelial colony-forming cells (ECFCs are obtained from the culture of human peripheral blood mononuclear cell (hPBMNC fractions and are characterised by high proliferative and pro-vasculogenic potential, which makes them of great interest for cell therapy. Here, we describe the detection of protease-activated receptor (PAR 1 and 2 amongst the surface proteins expressed in ECFCs. Both receptors are functionally coupled to extracellular signal-regulated kinase (ERK 1 and 2, which become activated and phosphorylated in response to selective PAR1- or PAR2-activating peptides. Specific stimulation of PAR1, but not PAR2, significantly inhibits capillary-like tube formation by ECFCs in vitro, suggesting that tubulogenesis is negatively regulated by proteases able to stimulate PAR1 (e.g. thrombin. The activation of ERKs is not involved in the regulation of tubulogenesis in vitro, as suggested by use of the MEK inhibitor PD98059 and by the fact that PAR2 stimulation activates ERKs without affecting capillary tube formation. Both qPCR and immunoblotting showed a significant downregulation of vascular endothelial growth factor 2 (VEGFR2 in response to PAR1 stimulation. Moreover, the addition of VEGF (50-100 ng/ml but not basic Fibroblast Growth Factor (FGF (25-100 ng/ml rescued tube formation by ECFCs treated with PAR1-activating peptide. Therefore, we propose that reduction of VEGF responsiveness resulting from down-regulation of VEGFR2 is underlying the anti-tubulogenic effect of PAR1 activation. Although the role of PAR2 remains elusive, this study sheds new light on the regulation of the vasculogenic activity of ECFCs and suggests a potential link between adult vasculogenesis and the coagulation cascade.

  17. The role of transmembrane segment II in 7TM receptor activation

    DEFF Research Database (Denmark)

    Benned-Jensen, Tau; Rosenkilde, M M

    2009-01-01

    , accumulating evidence emphasize that this is not the case. In this review, we focus on TM-II with an emphasis on position II:20/2.60, and present data from structure-activity studies on a range of Family A 7TM receptors including chemokine, ghrelin and melanocortin receptors in addition to the orphan EBI2...

  18. Tumor-Suppressive Activity of Lunatic Fringe in Prostate through Differential Modulation of Notch Receptor Activation

    Directory of Open Access Journals (Sweden)

    Shubing Zhang

    2014-02-01

    Full Text Available Elevated Notch ligand and receptor expression has been associated with aggressive forms of prostate cancer, suggesting a role for Notch signaling in regulation of prostate tumor initiation and progression. Here, we report a critical role for Lunatic Fringe (Lfng, which encodes an O-fucosylpeptide 3-ß-N-acetylglucosaminyltransferase known to modify epidermal growth factor repeats of Notch receptor proteins, in regulation of prostate epithelial differentiation and proliferation, as well as in prostate tumor suppression. Deletion of Lfng in mice caused altered Notch activation in the prostate, associated with elevated accumulation of Notch1, Notch2, and Notch4 intracellular domains, decreased levels of the putative Notch3 intracellular fragment, as well as increased expression of Hes1, Hes5, and Hey2. Loss of Lfng resulted in expansion of the basal layer, increased proliferation of both luminal and basal cells, and ultimately, prostatic intraepithelial neoplasia. The Lfng-null prostate showed down-regulation of prostatic tumor suppressor gene NKX3.1 and increased androgen receptor expression. Interestingly, expression of LFNG and NKX3.1 were positively correlated in publically available human prostate cancer data sets. Knockdown of LFNG in DU-145 prostate cancer cells led to expansion of CD44+CD24− and CD49f+CD24− stem/progenitor-like cell population associated with enhanced prostatosphere-forming capacity. Taken together, these data revealed a tumor-suppressive role for Lfng in the prostate through differential regulation of Notch signaling.

  19. DMPD: Proximal effects of Toll-like receptor activation in dendritic cells. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17142025 Proximal effects of Toll-like receptor activation in dendritic cells. Watt...) (.svg) (.html) (.csml) Show Proximal effects of Toll-like receptor activation in dendritic cells. PubmedID... 17142025 Title Proximal effects of Toll-like receptor activation in dendritic ce

  20. P2Y2 receptor activation decreases blood pressure and increases renal Na+ excretion

    OpenAIRE

    Rieg, Timo; Gerasimova, Maria; Boyer, José L.; Insel, Paul A.; Vallon, Volker

    2011-01-01

    ATP and UTP are endogenous agonists of P2Y2/4 receptors. To define the in vivo effects of P2Y2 receptor activation on blood pressure and urinary excretion, we compared the response to INS45973, a P2Y2/4 receptor agonist and UTP analog, in wild-type (WT) and P2Y2 receptor knockout (P2Y2−/−) mice. INS45973 was administered intravenously as a bolus injection or continuous infusion to determine effects on blood pressure and renal function, respectively. Within seconds, bolus application of INS459...

  1. PROKR2 missense mutations associated with Kallmann syndrome impair receptor signalling activity.

    Science.gov (United States)

    Monnier, Carine; Dodé, Catherine; Fabre, Ludovic; Teixeira, Luis; Labesse, Gilles; Pin, Jean-Philippe; Hardelin, Jean-Pierre; Rondard, Philippe

    2009-01-01

    Kallmann syndrome (KS) combines hypogonadism due to gonadotropin-releasing hormone deficiency, and anosmia or hyposmia, related to defective olfactory bulb morphogenesis. In a large series of KS patients, ten different missense mutations (p.R85C, p.R85H, p.R164Q, p.L173R, p.W178S, p.Q210R, p.R268C, p.P290S, p.M323I, p.V331M) have been identified in the gene encoding the G protein-coupled receptor prokineticin receptor-2 (PROKR2), most often in the heterozygous state. Many of these mutations were, however, also found in clinically unaffected individuals, thus raising the question of their actual implication in the KS phenotype. We reproduced each of the ten mutations in a recombinant murine Prokr2, and tested their effects on the signalling activity in transfected HEK-293 cells, by measuring intracellular calcium release upon ligand-activation of the receptor. We found that all mutated receptors except one (M323I) had decreased signalling activities. These could be explained by different defective mechanisms. Three mutations (L173R, W178S, P290S) impaired cell surface-targeting of the receptor. One mutation (Q210R) abolished ligand-binding. Finally, five mutations (R85C, R85H, R164Q, R268C, V331M) presumably impaired G protein-coupling of the receptor. In addition, when wild-type and mutant receptors were coexpressed in HEK-293 cells, none of the mutant receptors that were retained within the cells did affect cell surface-targeting of the wild-type receptor, and none of the mutant receptors properly addressed at the plasma membrane did affect wild-type receptor signalling activity. This argues against a dominant negative effect of the mutations in vivo. PMID:18826963

  2. Activation of peroxisome proliferator-activated receptor-α enhances fatty acid oxidation in human adipocytes

    International Nuclear Information System (INIS)

    Highlights: → PPARα activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. → PPARα activation also increased insulin-dependent glucose uptake in human adipocytes. → PPARα activation did not affect lipid accumulation in human adipocytes. → PPARα activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-α (PPARα) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPARα in adipocytes have been unclarified. We examined the functions of PPARα using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPARα by GW7647, a potent PPARα agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPARγ, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPARα activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPARγ is activated. On the other hand, PPARα activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPARα-dependent manner. Moreover, PPARα activation increased the production of CO2 and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPARα stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPARα agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected effects of PPARα activation are very valuable for managing diabetic conditions accompanied by obesity, because PPAR

  3. Activating Effect of Benzbromarone, a Uricosuric Drug, on Peroxisome Proliferator-Activated Receptors

    Directory of Open Access Journals (Sweden)

    Chiyoko Kunishima

    2007-01-01

    Full Text Available Benzbromarone, a uricosuric drug, reportedly causes hepatic hypertrophy accompanied by proliferation of peroxisomes in rats. To elucidate the mechanisms underlying induction of peroxisome proliferation by benzbromarone, we examined binding affinity for peroxisome proliferator-activated receptor α (PPARα and γ (PPARγ, and effects on the binding activity of PPARs with peroxisome proliferation-responsive element (PPRE and expression of the PPARs target protein. Binding affinity of benzbromarone for PPARα and PPARγ was examined by reporter gene assay. Binding activity of PPARs with PPRE was determined by electric mobility shift assay, and expression of lipoprotein lipase (LPL and acyl-CoA synthetase (ACS by Western blot method. Benzbromarone displayed affinity for PPARα and PPARγ, and promoted binding of PPARs to PPRE. Furthermore, cultured cells with benzbromarone added showed upregulated expression of LPL and ACS. These results suggest that benzbromarone induces peroxisome proliferation in hepatocytes by binding to PPARs, and controls expression of proteins related to lipid metabolism.

  4. Activating effect of benzbromarone, a uricosuric drug, on peroxisome proliferator-activated receptors.

    Science.gov (United States)

    Kunishima, Chiyoko; Inoue, Ikuo; Oikawa, Toshihiro; Nakajima, Hiromu; Komoda, Tsugikazu; Katayama, Shigehiro

    2007-01-01

    Benzbromarone, a uricosuric drug, reportedly causes hepatic hypertrophy accompanied by proliferation of peroxisomes in rats. To elucidate the mechanisms underlying induction of peroxisome proliferation by benzbromarone, we examined binding affinity for peroxisome proliferator-activated receptor alpha (PPARalpha) and gamma (PPARgamma), and effects on the binding activity of PPARs with peroxisome proliferation-responsive element (PPRE) and expression of the PPARs target protein. Binding affinity of benzbromarone for PPARalpha and PPARgamma was examined by reporter gene assay. Binding activity of PPARs with PPRE was determined by electric mobility shift assay, and expression of lipoprotein lipase (LPL) and acyl-CoA synthetase (ACS) by Western blot method. Benzbromarone displayed affinity for PPARalpha and PPARgamma, and promoted binding of PPARs to PPRE. Furthermore, cultured cells with benzbromarone added showed upregulated expression of LPL and ACS. These results suggest that benzbromarone induces peroxisome proliferation in hepatocytes by binding to PPARs, and controls expression of proteins related to lipid metabolism. PMID:18274627

  5. The low density lipoprotein receptor-related protein/alpha2-macroglobulin receptor regulates cell surface plasminogen activator activity on human trophoblast cells.

    Science.gov (United States)

    Zhang, J C; Sakthivel, R; Kniss, D; Graham, C H; Strickland, D K; McCrae, K R

    1998-11-27

    The low density lipoprotein receptor-related protein/alpha2-macroglobulin receptor (LRP/alpha2MR) mediates the internalization of numerous ligands, including prourokinase (pro-UK) and complexes between two-chain urokinase (tc-u-PA) and plasminogen activator inhibitor type-1 (PAI-1). It has been suggested that through its ability to internalize these ligands, LRP/alpha2MR may regulate the expression of plasminogen activator activity on cell surfaces; this hypothesis, however, has not been experimentally confirmed. To address this issue, we assessed the ability of LRP/alpha2MR to regulate plasminogen activator activity on human trophoblast cells, which express both LRP/alpha2MR and the urokinase receptor (uPAR). Trophoblasts internalized and degraded exogenous 125I-pro-UK (primarily following its conversion to tc-u-PA and incorporation into tc-u-PA.PAI complexes) in an LRP/alpha2MR-dependent manner, which was inhibited by the LRP/alpha2MR receptor-associated protein. Receptor-associated protein also caused a approximately 50% reduction in cell surface plasminogen activator activity and delayed the regeneration of unoccupied uPAR by cells on which uPAR were initially saturated with pro-UK. Identical effects were caused by anti-LRP/alpha2MR antibodies. These results demonstrate that LRP/alpha2MR promotes the expression of cell surface plasminogen activator activity on trophoblasts by facilitating the clearance of tc-u-PA.PAI complexes and regeneration of unoccupied cell surface uPAR. PMID:9822706

  6. Orexin receptor antagonists as therapeutic agents for insomnia

    OpenAIRE

    Equihua, Ana C.; Alberto K De La Herrán-Arita; Drucker-Colin, Rene

    2013-01-01

    Insomnia is a common clinical condition characterized by difficulty initiating or maintaining sleep, or non-restorative sleep with impairment of daytime functioning. Currently, treatment for insomnia involves a combination of cognitive behavioral therapy (CBTi) and pharmacological therapy. Among pharmacological interventions, the most evidence exists for benzodiazepine (BZD) receptor agonist drugs (GABAA receptor), although concerns persist regarding their safety and their limited efficacy. T...

  7. Structural basis for AMPA receptor activation and ligand selectivity

    DEFF Research Database (Denmark)

    Hogner, A; Kastrup, Jette Sandholm Jensen; Jin, R;

    2002-01-01

    structures reveal that AMPA agonists with an isoxazole moiety adopt different binding modes in the receptor, dependent on the substituents of the isoxazole. Br-HIBO displays selectivity among different AMPA receptor subunits, and the design and structure determination of the S1S2J-Y702F mutant in complex...... with Br-HIBO and ACPA have allowed us to explain the molecular mechanism behind this selectivity and to identify key residues for ligand recognition. The agonists induce the same degree of domain closure as AMPA, except for Br-HIBO, which shows a slightly lower degree of domain closure. An excellent...... the functional studies on the full-length receptor, form a powerful platform for the design of new selective agonists....

  8. P2X7 receptor antagonist activity of the anti-allergic agent oxatomide.

    Science.gov (United States)

    Yoshida, Kazuki; Ito, Masaaki; Matsuoka, Isao

    2015-11-15

    Activation of the P2X7 receptor by extracellular ATP is associated with various immune responses including allergic inflammation. Anti-allergic agents, such as H1-antihistamines, are known to inhibit the effects of different chemical mediators such as acetylcholine and platelet-activating factor. Therefore, we hypothesized that some anti-allergic agents might affect P2X7 receptor function. Using N18TG2 and J774 cells, which express functional P2X7 receptors, the effects of several anti-allergic agents on P2X7 receptor function were investigated by monitoring the ATP-induced increase in intracellular Ca(2+) concentrations ([Ca(2+)]i). Among the various agents tested, oxatomide significantly inhibited P2X7 receptor-mediated [Ca(2+)]i elevation in a concentration-dependent manner without affecting the P2Y2 receptor-mediated response in both N18TG2 and J774 cells. Consistently, oxatomide inhibited P2X7 receptor-mediated membrane current and downstream responses such as mitogen-activated protein kinase activation, inflammation-related gene induction, and cell death. In addition, oxatomide inhibited P2X7 receptor-mediated degranulation in mouse bone marrow-derived mast cells. Whole cell patch clamp analyses in HEK293 cells expressing human, mouse, and rat P2X7 receptors revealed that the inhibitory effect of oxatomide on ATP-induced current was most prominent for the human P2X7 receptor and almost non-existent for the rat P2X7 receptor. The potent inhibitory effects of oxatomide on human P2X7 receptor-mediated function were confirmed in RPMI8226 human B cell-like myeloma cells, which endogenously express the P2X7 receptor. Our results demonstrated that the antihistamine oxatomide also acts as a P2X7 receptor antagonist. Future studies should thus evaluate whether P2X7 receptor antagonism contributes to the anti-allergic effects of oxatomide. PMID:26463039

  9. Peroxisome proliferator-activated receptoractivation and excess energy burning in hepatocarcinogenesis.

    Science.gov (United States)

    Misra, Parimal; Reddy, Janardan K

    2014-03-01

    Peroxisome proliferator-activated receptor-α (PPARα) modulates the activities of all three interlinked hepatic fatty acid oxidation systems, namely mitochondrial and peroxisomal β-oxidation and microsomal ω-oxidation pathways. Hyperactivation of PPARα, by both exogenous and endogenous activators up-regulates hepatic fatty acid oxidation resulting in excess energy burning in liver contributing to the development of liver cancer in rodents. Sustained PPARα signaling disproportionately increases H2O2-generating fatty acid metabolizing enzymes as compared to H2O2-degrading enzymes in liver leading to enhanced generation of DNA damaging reactive oxygen species, progressive endoplasmic reticulum stress and inflammation. These alterations also contribute to increased liver cell proliferation with changes in apoptosis. Thus, reactive oxygen species, oxidative stress and hepatocellular proliferation are likely the main contributing factors in the pathogenesis of hepatocarcinogenesis, mediated by sustained PPARα activation-related energy burning in liver. Furthermore, the transcriptional co-activator Med1, a key subunit of the Mediator complex, is essential for PPARα signaling in that both PPARα-null and Med1-null hepatocytes are unresponsive to PPARα activators and fail to give rise to liver tumors when chronically exposed to PPARα activators. PMID:24291192

  10. Utilizing the folate receptor for active targeting of cancer nanotherapeutics

    Directory of Open Access Journals (Sweden)

    Grant L. Zwicke

    2012-12-01

    Full Text Available The development of specialized nanoparticles for use in the detection and treatment of cancer is increasing. Methods are being proposed and tested that could target treatments more directly to cancer cells, which could lead to higher efficacy and reduced toxicity, possibly even eliminating the adverse effects of damage to the immune system and the loss of quick replicating cells. In this mini-review we focus on recent studies that employ folate nanoconjugates to target the folate receptor. Folate receptors are highly overexpressed on the surface of many tumor types. This expression can be exploited to target imaging molecules and therapeutic compounds directly to cancerous tissues.

  11. Noradrenergic modulation of basolateral amygdala neuronal activity: opposing influences of alpha-2 and beta receptor activation.

    Science.gov (United States)

    Buffalari, Deanne M; Grace, Anthony A

    2007-11-01

    Substantial data exists demonstrating the importance of the amygdala and the locus ceruleus (LC) in responding to stress, aversive memory formation, and the development of stress-related disorders; however, little is known about the effects of norepinephrine (NE) on amygdala neuronal activity in vivo. The basolateral nucleus of the amygdala (BLA) receives dense NE projections from the LC, NE increases in the BLA in response to stress, and the BLA can also modulate the LC via reciprocal projections. These experiments examined the effects of noradrenergic agents on spontaneous and evoked responses of BLA neurons. NE iontophoresis inhibited spontaneous firing and decreased the responsiveness of BLA neurons to electrical stimulation of entorhinal cortex and sensory association cortex (Te3). Confirmed BLA projection neurons exhibited exclusively inhibitory responses to NE. Systemic administration of propranolol, a beta-receptor antagonist, decreased the spontaneous firing rate and potentiated the NE-evoked inhibition of BLA neurons. In addition, iontophoresis of the alpha-2 agonist clonidine, footshock administration, and LC stimulation mimicked the effects of NE iontophoresis on spontaneous activity. Furthermore, the effects of LC stimulation were partially blocked by systemic administration of alpha 2 and beta receptor antagonists. This is the first study to demonstrate the actions of directly applied and stimulus-evoked NE in the BLA in vivo, and provides a mechanism by which beta receptors can mediate the important behavioral consequences of NE within the BLA. The interaction between these two structures is particularly relevant with regard to their known involvement in stress responses and stress-related disorders. PMID:17989300

  12. The Hinge Region of Human Thyroid-Stimulating Hormone (TSH) Receptor Operates as a Tunable Switch between Hormone Binding and Receptor Activation

    OpenAIRE

    Majumdar, Ritankar; Dighe, Rajan R.

    2012-01-01

    The mechanism by which the hinge regions of glycoprotein hormone receptors couple hormone binding to activation of downstream effecters is not clearly understood. In the present study, agonistic (311.62) and antagonistic (311.87) monoclonal antibodies (MAbs) directed against the TSH receptor extracellular domain were used to elucidate role of the hinge region in receptor activation. MAb 311.62 which identifies the LRR/Cb-2 junction (aa 265-275), increased the affinity of TSHR for the hormone ...

  13. Roles of activin receptor-like kinase 7 signaling and its target, peroxisome proliferator-activated receptor γ, in lean and obese adipocytes

    OpenAIRE

    Yogosawa, Satomi; Izumi, Tetsuro

    2013-01-01

    We recently discovered a novel signaling pathway involving activin receptor-like kinase 7 (ALK7), one of the type I transforming growth factor-β receptors. ALK7 and activated Smads 2, 3, and 4 inhibit the master regulators of adipogenesis, CCAAT/enhancer-binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) specifically in differentiated adipocytes, but surprisingly increase both the adipocyte size and lipid content by suppressing lipolysis. Here, we show that, a...

  14. Chronic regulation of colonic epithelial secretory function by activation of G protein-coupled receptors.

    LENUS (Irish Health Repository)

    Toumi, F

    2011-02-01

    Enteric neurotransmitters that act at G protein-coupled receptors (GPCRs) are well known to acutely promote epithelial Cl(-) and fluid secretion. Here we examined if acute GPCR activation might have more long-term consequences for epithelial secretory function.

  15. Direct activation of GABAA receptors by substances in the organic acid fraction of Japanese sake.

    Science.gov (United States)

    Izu, Hanae; Shigemori, Kensuke; Eguchi, Masaya; Kawane, Shuhei; Fujii, Shouko; Kitamura, Yuji; Aoshima, Hitoshi; Yamada, Yasue

    2017-01-01

    We investigated the effect of substances present in Japanese sake on the response of ionotropic γ-aminobutyric acid (GABA)A receptors expressed in Xenopus oocytes. Sake was fractionated by ion-exchange chromatography. The fraction containing organic acids (OA fraction) showed agonist activities on the GABAA receptor. OA fractions from sake were analyzed by capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). Of the 64 compounds identified, 13 compounds showed GABAA receptor agonist activities. Especially, l-lactic acid showed high agonist activity and its EC50 value was 37μM. Intraperitoneal injections of l-lactic acid, gluconic acid, and pyruvic acid (10, 10, and 5mg/kg BW, respectively), which showed agonistic activity on the GABAA receptor, led to significant anxiolytic effects during an elevated plus-maze test in mice. PMID:27507485

  16. Effects related to gene-gene interactions of peroxisome proliferator-activated receptor on essential hypertension

    Institute of Scientific and Technical Information of China (English)

    俞浩

    2013-01-01

    Objective To explore the impact of the gene-gene interaction among the single nucleotide polymorphisms(SNPs) of peroxisome proliferator-activated receptorα/δ/γ on essential hypertension(EH).Methods

  17. Differential Requirement of the Extracellular Domain in Activation of Class B G Protein-coupled Receptors.

    Science.gov (United States)

    Zhao, Li-Hua; Yin, Yanting; Yang, Dehua; Liu, Bo; Hou, Li; Wang, Xiaoxi; Pal, Kuntal; Jiang, Yi; Feng, Yang; Cai, Xiaoqing; Dai, Antao; Liu, Mingyao; Wang, Ming-Wei; Melcher, Karsten; Xu, H Eric

    2016-07-15

    G protein-coupled receptors (GPCRs) from the secretin-like (class B) family are key players in hormonal homeostasis and are important drug targets for the treatment of metabolic disorders and neuronal diseases. They consist of a large N-terminal extracellular domain (ECD) and a transmembrane domain (TMD) with the GPCR signature of seven transmembrane helices. Class B GPCRs are activated by peptide hormones with their C termini bound to the receptor ECD and their N termini bound to the TMD. It is thought that the ECD functions as an affinity trap to bind and localize the hormone to the receptor. This in turn would allow the hormone N terminus to insert into the TMD and induce conformational changes of the TMD to activate downstream signaling. In contrast to this prevailing model, we demonstrate that human class B GPCRs vary widely in their requirement of the ECD for activation. In one group, represented by corticotrophin-releasing factor receptor 1 (CRF1R), parathyroid hormone receptor (PTH1R), and pituitary adenylate cyclase activating polypeptide type 1 receptor (PAC1R), the ECD requirement for high affinity hormone binding can be bypassed by induced proximity and mass action effects, whereas in the other group, represented by glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R), the ECD is required for signaling even when the hormone is covalently linked to the TMD. Furthermore, the activation of GLP-1R by small molecules that interact with the intracellular side of the receptor is dependent on the presence of its ECD, suggesting a direct role of the ECD in GLP-1R activation. PMID:27226600

  18. Artificial sweeteners and salts producing a metallic taste sensation activate TRPV1 receptors.

    Science.gov (United States)

    Riera, Céline E; Vogel, Horst; Simon, Sidney A; le Coutre, Johannes

    2007-08-01

    Throughout the world many people use artificial sweeteners (AS) for the purpose of reducing caloric intake. The most prominently used of these molecules include saccharin, aspartame (Nutrasweet), acesulfame-K, and cyclamate. Despite the caloric advantage they provide, one key concern in their use is their aversive aftertaste that has been characterized on a sensory level as bitter and/or metallic. Recently, it has been shown that the activation of particular T2R bitter taste receptors is partially involved with the bitter aftertaste sensation of saccharin and acesulfame-K. To more fully understand the biology behind these phenomena we have addressed the question of whether AS could stimulate transient receptor potential vanilloid-1 (TRPV1) receptors, as these receptors are activated by a large range of structurally different chemicals. Moreover, TRPV1 receptors and/or their variants are found in taste receptor cells and in nerve terminals throughout the oral cavity. Hence, TRPV1 activation could be involved in the AS aftertaste or even contribute to the poorly understood metallic taste sensation. Using Ca(2+) imaging on TRPV1 receptors heterologously expressed in the human embryonic kidney (HEK) 293 cells and on dissociated primary sensory neurons, we find that in both systems, AS activate TRPV1 receptors, and, moreover, they sensitize these channels to acid and heat. We also found that TRPV1 receptors are activated by CuSO(4), ZnSO(4), and FeSO(4), three salts known to produce a metallic taste sensation. In summary, our results identify a novel group of compounds that activate TRPV1 and, consequently, provide a molecular mechanism that may account for off tastes of sweeteners and metallic tasting salts. PMID:17567713

  19. Some considerations on the role of benzodiazepines in the treatment of depression

    OpenAIRE

    Cassano, G B; Conti, L.

    1981-01-01

    1 Benzodiazepines are regarded as pure anxiolytics, and their value in the treatment of depression is controversial. Nevertheless, symptoms of anxiety and depression coexist in patients with endogenous or neurotic depression, and clinical trials indicate that depressed patients respond better to a benzodiazepine-tricyclic antidepressant combination than to either drug alone.

  20. A control study on treatment for benzodiazepine dependence with trazodone

    Directory of Open Access Journals (Sweden)

    ZHANG Hong-ju

    2013-05-01

    Full Text Available Objective To determine the efficacy and safety of trazodone in the treatment of benzodiazepine dependence. Methods Forty insomnia patients who met the Classification and Diagnostic Criteria of Mental Disorders in China Third Edition (CCMD-3 of dependence syndrome due to benzodiazepine were involved in the study. Patients were randomly assigned to trazodone group and placebo group for 3 months. The efficacy were assessed by Withdrawal Symptoms Checklist, Hamilton Anxiety Rating Scale (HAMA and polysomnography (PSG. Adverse events were assessed by Treatment Emergent Symptom Scale (TESS. Results The Withdrawal Symptoms Checklist of trazodone group was significantly lower after 7 d treatment than that of placebo group (P = 0.000, and HAMA score of the trazodone group was also significantly lower after 15 d treatment than that of placebo group (P = 0.000. There were no difference in Withdrawal Symptoms Checklist and HAMA of placebo group before and after treatment. Withdrawal Symptoms Checklist and HAMA of the trazodone group were decreased after treatment (P = 0.000. In comparison with placebo group, sleep parameters of the trazodone, including total sleep time (TST, sleep efficiency (SE, sleep latency (SL and slow wave sleep (SWS time presented improvement after 7 d treatment (P = 0.000, for all. After trazodone treatment, total sleep time, slow wave sleep time, sleep efficiency and sleep latency were improved (P = 0.000, for all. No obvious adverse reaction occurred. There were no significant differences in TESS scores between pre? and post?treatment in both groups (P > 0.05. Conclusion Trazodone is markedly effective and safe in the treatment for benzodiazepine dependence.

  1. Activation of mitogen activated protein kinases via complement receptor type 2

    Institute of Scientific and Technical Information of China (English)

    LUO Min-hua 罗敏华; CHEN Ming-liang 陈明亮; Heribert Stoiber; Manfred P Dierich

    2004-01-01

    Background Complement receptor type 2 (CR2) is the receptor for C3d and C3dg and for Epstein-Barr virus. The aim of our study was to explore whether CR2 can independently mediate the activation of mitogen-activated protein kinases (MAPKs, including ERK, JNK, and p38MAPK), and to highlight the molecular mechanism of CD4+ cell deletion in AIDS.Results FACS results showed that the positive rates of HOS-CR2 and HOS-CD4CR2 cells were greater than 96%, and Western blot showed that the CR2 expression levels on HOS-CR2 and HOS-CD4CR2 cells were high. Activation and blocking tests of MAPKs (ERK, JNK, and p38MAPK) were carried out in HOS-CR2, HOS-CD4, and HOS-CD4CR2 cells. The activation of MAPKs in HOS-CR2 cells stimulated with PMA (100 ng/ml) and NHS (10%) was identical. The activation of MAPKs increased at 5 minutes, reached a peak at 10 minutes, and decreased to baseline within 30 minutes, all in a time-dependent manner; the activation of MAPKs was blocked by anti-CR2 McAb, PD98059 (inhibitor of ERK), and Wortmanin (inhibitor of PI-3K), respectively. In HOS-CD4 cells, MAPKs were activated by HIV-gp160. In HOS-CD4CR2 cells, MAPK activation was induced by HIV-gp160, 10% NHS, and HIV-gp160+10%NHS; phosphorylation of p38MAPK was dramatically induced by HIV-gp160+NHS, and lasted for 1 hour. The cell proliferation results showed that HIV-gp160 inhibited the proliferation of HOS-CD4 and HOS-CD4CR2 cells (P<0.01) and that NHS enhanced the effect of HIV-gp160 (P<0.01).Conclusions The activation of MAPKs is independently mediated by CR2 and that anti-CR2 McAb, PD98059, and Wortmanin block the activation of MAPKs, respectively. The results of the signal transduction and cell proliferation assays of HOS-CD4CR2 cells show that CR2 plays a role in the pathogenesis of HIV infection, especially in the inhibition of CD4+ cell proliferation.

  2. Thrombin functions as an inflammatory mediator through activation of its receptor

    OpenAIRE

    1996-01-01

    A rat model of inflammation was used to investigate the biological effects of thrombin. The thrombin-specific inhibitor Hirulog markedly attentuated the carrageenin-induced edema of the paw of the rat. Injection of thrombin into the paw also produced edema. The effect of thrombin was due to activation of its receptor; a thrombin receptor activating peptide (TRAP) reproduced the effects of thrombin in causing edema. TRAP also increased vascular permeability as demonstrated by extravasation of ...

  3. Therapy for acute pancreatitis with platelet-activating factor receptor antagonists

    OpenAIRE

    Chen, Chong; Xia, Shi-hai; Chen, Hong; Li, Xiao-Hong

    2008-01-01

    Acute pancreatitis (AP) causes release of platelet-activating factor (PAF), which induces systemic effects that contribute to circulatory disturbances and multiple organ failure. PAF is a cell surface secretion of bioactive lipid, which could produce physiological and pathological effects by binding to its cell surface receptor called platelet-activating factor receptor (PAF-R). Studies showed that PAF participates in the occurrence and development of AP and administration of platelet-activat...

  4. Receptor activator of nuclear factor kappa B ligand and osteoprotegerin levels in gingival crevicular fluid

    OpenAIRE

    Fatemeh Sarlati; Mandana Sattari; Shilan Razzaghi; Malihe Nasiri

    2012-01-01

    Background: Osteoclastogenesis is coordinated by the interaction of three members of the tumor necrosis factor (TNF) superfamily: Osteoprotegerin (OPG)/receptor activator of nuclear factor kappa B ligand (RANKL)/receptor activator of nuclear factor kappa B (RANK). The aim of this study was to investigate RANKL and OPG levels, and their relative ratio in gingival crevicular fluid (GCF) of patients with chronic and aggressive periodontitis, as well as healthy controls. Materials and Methods:...

  5. Farnesoid X Receptor Inhibits the Transcriptional Activity of Carbohydrate Response Element Binding Protein in Human Hepatocytes

    OpenAIRE

    Caron, Sandrine; Huaman Samanez, Carolina; Dehondt, Hélène; Ploton, Maheul; Briand, Olivier; Lien, Fleur; Dorchies, Emilie; Dumont, Julie; Postic, Catherine; Cariou, Bertrand; Lefebvre, Philippe; Staels, Bart

    2013-01-01

    The glucose-activated transcription factor carbohydrate response element binding protein (ChREBP) induces the expression of hepatic glycolytic and lipogenic genes. The farnesoid X receptor (FXR) is a nuclear bile acid receptor controlling bile acid, lipid, and glucose homeostasis. FXR negatively regulates hepatic glycolysis and lipogenesis in mouse liver. The aim of this study was to determine whether FXR regulates the transcriptional activity of ChREBP in human hepatocytes and to unravel the...

  6. Evaluation on Potential Contributions of Protease Activated Receptors Related Mediators in Allergic Inflammation

    OpenAIRE

    Huiyun Zhang; Xiaoning Zeng; Shaoheng He

    2014-01-01

    Protease activated receptors (PARs) have been recognized as a distinctive four-member family of seven transmembrane G protein-coupled receptors (GPCRs) that can be cleaved by certain serine proteases. In recent years, there has been considerable interest in the role of PARs in allergic inflammation, the fundamental pathologic changes of allergy, but the potential roles of PARs in allergy remain obscure. Since many of these proteases are produced and actively involved in the pathologic process...

  7. Kallikrein activates bradykinin B2 receptors in the absence of kininogen

    OpenAIRE

    Biyashev, Dauren; Tan, Fulong; Chen, Zhenlong; Zhang, Kai; Deddish, Peter A.; Erdös, Ervin G.; Hecquet, Claudie

    2005-01-01

    Kallikreins cleave plasma kininogens to release the bioactive peptides bradykinin (BK) or kallidin (Lys-BK). These peptides then activate widely disseminated B2 receptors with consequences that may be either noxious or beneficial. We used cultured cells to show that kallikrein can bypass kinin release to activate BK B2 receptors directly. To exclude intermediate kinin release or kininogen uptake from the culture medium, we cultured and maintained cells in medium entirely free of animal protei...

  8. Constitutive Activity among Orphan Class-A G Protein Coupled Receptors

    OpenAIRE

    Martin, Adam L.; Michael A Steurer; Aronstam, Robert S.

    2015-01-01

    The purpose of this study was to evaluate the extent of constitutive activity among orphan class-A G protein coupled receptors within the cAMP signaling pathway. Constitutive signaling was revealed by changes in gene expression under control of the cAMP response element. Gene expression was measured in Chinese hamster ovary cells transiently co-transfected with plasmids containing a luciferase reporter and orphan receptor. Criteria adopted for defining constitutive activation were: 1) 200% el...

  9. Identification of Functionally Relevant Lysine Residues That Modulate Human Farnesoid X Receptor Activation

    OpenAIRE

    Sun, An-Qiang; Luo, Yuhuan; Backos, Donald S.; Xu, Shuhua; Balasubramaniyan, Natarajan; Reigan, Philip; Suchy, Frederick J.

    2013-01-01

    Base amino acid lysine residues play an important role in regulation of nuclear receptors [e.g., farnesyl X receptor (FXR)], leading to enhanced or suppressed biologic activity. To understand the molecular mechanisms and the subsequent effects in modulating FXR functions in diverse biologic processes, we individually replaced eight highly conserved lysine residues of human FXR (hFXR) with arginine. The effects of each mutated FXR on target gene activation, subcellular localization, protein-pr...

  10. Defective lysosomal targeting of activated fibroblast growth factor receptor 3 in achondroplasia

    OpenAIRE

    Cho, Jay Y.; Guo, Changsheng; Torello, Monica; Lunstrum, Gregory P.; Iwata, Tomoko; Deng, Chuxia; Horton, William A.

    2003-01-01

    Mutations of fibroblast growth factor receptor 3 (FGFR3) are responsible for achondroplasia (ACH) and related dwarfing conditions in humans. The pathogenesis involves constitutive activation of FGFR3, which inhibits proliferation and differentiation of growth plate chondrocytes. Here we report that activating mutations in FGFR3 increase the stability of the receptor. Our results suggest that the mutations disrupt c-Cbl-mediated ubiquitination that serves as a targeting signal for lysosomal de...

  11. Steroid receptor RNA activator (SRA1): unusual bifaceted gene products with suspected relevance to breast cancer

    OpenAIRE

    Leygue, Etienne

    2007-01-01

    The steroid receptor RNA activator (SRA) is a unique modulator of steroid receptor transcriptional activity, as it is able to mediate its coregulatory effects as a RNA molecule. Recent findings, however, have painted a more complex picture of the SRA gene (SRA1) products. Indeed, even though SRA was initially thought to be noncoding, several RNA isoforms have now been found to encode an endogenous protein (SRAP), which is well conserved among Chordata. Although the function of SRAP remains la...

  12. The role of κ-opioid receptor activation in mediating antinociception and addiction

    OpenAIRE

    Wang, Yu-hua; Sun, Jian-feng; Tao, Yi-min; Chi, Zhi-Qiang; Liu, Jing-gen

    2010-01-01

    The κ-opioid receptor (KOR), a member of the opioid receptor family, is widely expressed in the central nervous system and peripheral tissues. Substantial evidence has shown that activation of KOR by agonists and endogenous opioid peptides in vivo may produce a strong analgesic effect that is free from the abuse potential and the adverse side effects of μ-opioid receptor (MOR) agonists, such as morphine. In addition, activation of the KOR has also been shown to exert an inverse effect on morp...

  13. EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

    International Nuclear Information System (INIS)

    Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα+) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells

  14. EPO-independent functional EPO receptor in breast cancer enhances estrogen receptor activity and promotes cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Reinbothe, Susann; Larsson, Anna-Maria; Vaapil, Marica; Wigerup, Caroline [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Sun, Jianmin [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Jögi, Annika [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Neumann, Drorit [Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel); Rönnstrand, Lars [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); Påhlman, Sven, E-mail: sven.pahlman@med.lu.se [Department of Laboratory Medicine, Translational Cancer Research, Medicon Village, Lund University, SE-223 81 Lund (Sweden); CREATE Health, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv (Israel)

    2014-02-28

    Highlights: • New anti-human EPOR antibody confirms full-length EPOR expression in breast cancer cells. • Proliferation of breast cancer cells is not affected by rhEPO treatment in vitro. • EPOR knockdown impairs proliferation of ERa positive breast cancer cells. • EPOR knockdown reduces AKT phosphorylation and ERa activity. - Abstract: The main function of Erythropoietin (EPO) and its receptor (EPOR) is the stimulation of erythropoiesis. Recombinant human EPO (rhEPO) is therefore used to treat anemia in cancer patients. However, clinical trials have indicated that rhEPO treatment might promote tumor progression and has a negative effect on patient survival. In addition, EPOR expression has been detected in several cancer forms. Using a newly produced anti-EPOR antibody that reliably detects the full-length isoform of the EPOR we show that breast cancer tissue and cells express the EPOR protein. rhEPO stimulation of cultured EPOR expressing breast cancer cells did not result in increased proliferation, overt activation of EPOR (receptor phosphorylation) or a consistent activation of canonical EPOR signaling pathway mediators such as JAK2, STAT3, STAT5, or AKT. However, EPOR knockdown experiments suggested functional EPO receptors in estrogen receptor positive (ERα{sup +}) breast cancer cells, as reduced EPOR expression resulted in decreased proliferation. This effect on proliferation was not seen in ERα negative cells. EPOR knockdown decreased ERα activity further supports a mechanism by which EPOR affects proliferation via ERα-mediated mechanisms. We show that EPOR protein is expressed in breast cancer cells, where it appears to promote proliferation by an EPO-independent mechanism in ERα expressing breast cancer cells.

  15. Multiple activities of insect repellents on odorant receptors in mosquitoes

    Science.gov (United States)

    Several lines of evidence suggest that insect repellent molecules reduce mosquito-host contacts by interacting with odorants and odorant receptors (ORs) ultimately affecting olfactory-driven behaviors. We describe the molecular effects of ten insect repellents and a pyrethroid insecticide with known...

  16. Activation of the Retinoid X Receptor Modulates Angiotensin II-Induced Smooth Muscle Gene Expression and Inflammation in Vascular Smooth Muscle Cells

    OpenAIRE

    Lehman, Allison M.B.; Montford, John R.; Horita, Henrick; Ostriker, Allison C.; Weiser-Evans, Mary C. M.; Nemenoff, Raphael A.; Furgeson, Seth B.

    2014-01-01

    The retinoid X receptor (RXR) partners with numerous nuclear receptors, such as the peroxisome proliferator activated receptor (PPAR) family, liver X receptors (LXRs), and farnesoid X receptor (FXR). Although each heterodimer can be activated by specific ligands, a subset of these receptors, defined as permissive nuclear receptors, can also be activated by RXR agonists known as rexinoids. Many individual RXR heterodimers have beneficial effects in vascular smooth muscle cells (SMCs). Because ...

  17. Activation of Nuclear Receptors RAR, RXR, and LXR Does Not Reduce Cuprizone-Induced Demyelination in Mice

    OpenAIRE

    Davina Kruczek; Tim Clarner; Cordian Beyer; Markus Kipp; Jörg Mey

    2015-01-01

    Experiments with animal models of multiple sclerosis have shown that the expression of retinoid X receptors (RXR) increases during demyelination and that RXR is involved in the regulation of remyelination. After ligand binding RXRs form heterodimeric transcription factors with other nuclear receptor (NR) families including the retinoic acid receptors (RAR) and liver X receptors (LXR). We tested whether activation of these nuclear receptor complexes reduces pathological demyelination using the...

  18. Increased amphetamine-induced locomotor activity, sensitization and accumbal dopamine release in M5 muscarinic receptor knockout mice

    OpenAIRE

    Schmidt, Lene S.; Miller, Anthony D.; Lester, Deranda B.; Bay-Richter, Cecilie; Schülein, Christina; Schmidt, Henriette F.; Wess, Jürgen; Blaha, Charles D.; Woldbye, David P.D.; Fink-Jensen, Anders; Wortwein, Gitta

    2009-01-01

    Muscarinic M5 receptors are the only muscarinic receptor subtype expressed by dopamine-containing neurons of the ventral tegmental area. These cells play an important role for the reinforcing properties of psychostimulants and M5 receptors modulate their activity. Previous studies showed that M5 receptor knockout (M5−/−) mice are less sensitive to the reinforcing properties of addictive drugs. Here we investigate the role of M5 receptors in the effects of amphetamine and cocaine on locomotor ...

  19. The DEAD-Box Protein DP103 (Ddx20 or Gemin-3) Represses Orphan Nuclear Receptor Activity via SUMO Modification

    OpenAIRE

    Lee, Martin B.; Lebedeva, Lioudmila A.; Suzawa, Miyuki; Wadekar, Subhagya A.; Desclozeaux, Marion; Ingraham, Holly A.

    2005-01-01

    Structural analysis of nuclear receptor subfamily V orphan nuclear receptors suggests that ligand-independent mechanisms must regulate this subclass of receptors. Here, we report that steroidogenic factor 1 (SF-1) and liver receptor homolog 1 are repressed via posttranslational SUMO modification at conserved lysines within the hinge domain. Indeed, mutating these lysines or adding the SUMO isopeptidase SENP1 dramatically increased both native and Gal4-chimera receptor activities. The mechanis...

  20. Structure-activity relationships for the antifungal activity of selective estrogen receptor antagonists related to tamoxifen.

    Directory of Open Access Journals (Sweden)

    Arielle Butts

    Full Text Available Cryptococcosis is one of the most important invasive fungal infections and is a significant contributor to the mortality associated with HIV/AIDS. As part of our program to repurpose molecules related to the selective estrogen receptor modulator (SERM tamoxifen as anti-cryptococcal agents, we have explored the structure-activity relationships of a set of structurally diverse SERMs and tamoxifen derivatives. Our data provide the first insights into the structural requirements for the antifungal activity of this scaffold. Three key molecular characteristics affecting anti-cryptococcal activity emerged from our studies: 1 the presence of an alkylamino group tethered to one of the aromatic rings of the triphenylethylene core; 2 an appropriately sized aliphatic substituent at the 2 position of the ethylene moiety; and 3 electronegative substituents on the aromatic rings modestly improved activity. Using a cell-based assay of calmodulin antagonism, we found that the anti-cryptococcal activity of the scaffold correlates with calmodulin inhibition. Finally, we developed a homology model of C. neoformans calmodulin and used it to rationalize the structural basis for the activity of these molecules. Taken together, these data and models provide a basis for the further optimization of this promising anti-cryptococcal scaffold.

  1. An audit of prescribing practices for benzodiazepines and Z-drugs.

    LENUS (Irish Health Repository)

    Cadogan, C

    2015-03-01

    Concerns persist over the use of benzodiazepines and Z-drugs in Ireland. A prospective prescription audit was conducted in 81 community pharmacies across Ireland over a four week period. The study sought to assess the level of prescription compliance with key components of benzodiazepine and Z-drug prescribing guidelines. 28% of audit booklets issued were returned, yielding data on 4,418 prescriptions. The findings suggest that little progress has been made in improving the prescribing of benzodiazepines and Z-drugs in Ireland in the decade since publication of the Benzodiazepine Committee\\'s report. Fewer than one fifth of prescriptions (18.8%) were fully compliant with the assessment criteria and the majority (53.7%) had multiple discrepancies. This study highlights the importance of monitoring and auditing benzodiazepine and Z-drug prescribing practices. Interventions involving patients, prescribers and pharmacists are required to improve the prescribing and use of these medications in Ireland.

  2. Activated HER-receptors in predicting outcome of ER-positive breast cancer patients treated with adjuvant endocrine therapy

    DEFF Research Database (Denmark)

    Larsen, Mathilde Skaarup; Bjerre, Karsten; Lykkesfeldt, Anne Elisabeth; Giobbie-Hurder, Anita; Lænkholm, Anne Vibeke; Henriksen, Katrine L; Ejlertsen, Bent Laursen; Rasmussen, Birgitte

    2012-01-01

    The four human epidermal growth factor receptors (HER1-4) are involved in growth stimulation and may play a role in endocrine resistance. The receptors form dimers, leading to activation by mutual phosphorylation. Our purpose was to explore the role of the activated receptors (pHER1, pHER2, pHER3...

  3. Across-sectional survey on benzodiazepine use among older people in an Italian region

    Directory of Open Access Journals (Sweden)

    Francesco Donato

    2005-06-01

    Full Text Available

    Background. Benzodiazepines are among the most commonly prescribed drugs in Italy and they are often used inappropriately according to guidelines for their rational use.

    The aim of this study was to investigate the prevalence and pattern of use of benzodiazepine amongst the general population aged 65-84 years in the Friuli-Venezia Giulia Region, in North-East Italy.

    Methods. A total of 40 general practitioners participated in the study. Two data sources were used in the research. The first was the Health Search Database, the second was a short questionnaire administered by the general practitioners to the 65 to 84 year old patients attending their surgeries for any reason during the study period. Data on the use of benzodiazepines between 1st February and 31st July 2001 were extracted from both the Health Search Database using drug prescriptions and the questionnaires.

    Results. Of the 10,468 patients aged 65-84 years with complete demographical data in the general practitioners’ patient lists, 2,369 subjects used benzodiazepines, hypnotics and over the counter drugs. Overall prevalence of benzodiazepine use was 21.5% (95% confidence interval: 19.8-23.1%. Of the benzodiazepine users, 66.9% consumed a short-intermediate half-life and 33.1% a long half-life benzodiazepine. Most patients took benzodiazepines at night (68.2%, less frequently in the daytime and at night (23.7%, or in the daytime only (8.1%. Most users (89.2% said they had been taking benzodiazepine for years.

    Conclusions. Benzodiazepine use was associated with patient characteristics, such as being female, using analgesics or antidepressants and the presence of a chronic disease especially cancer or chronic heart failure.

  4. Benzodiazepine prescribing behaviour and attitudes: a survey among general practitioners practicing in northern Thailand

    Directory of Open Access Journals (Sweden)

    Critchley Julia

    2005-06-01

    Full Text Available Abstract Background Over-prescribing of benzodiazepines appears common in many countries, a better understanding of prescribing practices and attitudes may help develop strategies to reduce prescribing. This study aimed to evaluate benzodiazepine prescribing behaviour and attitudes in general practitioners practising in Chiang Mai and Lampoon, Thailand. Methods Questionnaire survey of general practitioners in community hospitals, to estimate: i use of benzodiazepines for anxiety/insomnia, panic disorder, depression, essential hypertension, and uncomplicated low back pain and ii views on the optimal duration of benzodiazepine use. Results Fifty-five of 100 general practitioners returned the completed questionnaires. They reported use of benzodiazepines for anxiety/insomnia (n = 51, 93%, panic disorder (n = 43, 78%, depression (n = 26, 43%, essential hypertension (n = 15, 27 % and uncomplicated low back pain (n = 10, 18%. Twenty-eight general practitioners would prescribe benzodiazepines for non-psychiatric conditions, 17 for use as muscle relaxants. Seventy-five per cent, 62% and 29% of the general practitioners agreed or totally agreed with the use of benzodiazepines for insomnia, anxiety and depression, respectively. Practitioners agreed that prescribing should be less than one week (80%; or from 1 week to 1 month (47%; or 1 to 4 months (16%; or 4 to 6 months (5% or more than 6 months (2%. Twenty-five general practitioners (45% accepted that they used benzodiazepines excessively in the past year. Conclusion A considerable proportion of general practitioners in Chiang Mai and Lampoon, Thailand inappropriately use benzodiazepines for physical illnesses, especially essential hypertension and uncomplicated low back pain. However, almost half of them thought that they overused benzodiazepines. General practitioner's lack of time, knowledge and skills should be taken into account in improving prescribing behaviour and attitudes.

  5. The Relaxin Receptor (RXFP1) Utilizes Hydrophobic Moieties on a Signaling Surface of Its N-terminal Low Density Lipoprotein Class A Module to Mediate Receptor Activation*

    Science.gov (United States)

    Kong, Roy C. K.; Petrie, Emma J.; Mohanty, Biswaranjan; Ling, Jason; Lee, Jeremy C. Y.; Gooley, Paul R.; Bathgate, Ross A. D.

    2013-01-01

    The peptide hormone relaxin is showing potential as a treatment for acute heart failure. Although it is known that relaxin mediates its actions through the G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), little is known about the molecular mechanisms by which relaxin binding results in receptor activation. Previous studies have highlighted that the unique N-terminal low density lipoprotein class A (LDLa) module of RXFP1 is essential for receptor activation, and it has been hypothesized that this module is the true “ligand” of the receptor that directs the conformational changes necessary for G protein coupling. In this study, we confirmed that an RXFP1 receptor lacking the LDLa module binds ligand normally but cannot signal through any characterized G protein-coupled receptor signaling pathway. Furthermore, we comprehensively examined the contributions of amino acids in the LDLa module to RXFP1 activity using both gain-of-function and loss-of-function mutational analysis together with NMR structural analysis of recombinant LDLa modules. Gain-of-function studies with an inactive RXFP1 chimera containing the LDLa module of the human LDL receptor (LB2) demonstrated two key N-terminal regions of the module that were able to rescue receptor signaling. Loss-of-function mutations of residues in these regions demonstrated that Leu-7, Tyr-9, and Lys-17 all contributed to the ability of the LDLa module to drive receptor activation, and judicious amino acid substitutions suggested this involves hydrophobic interactions. Our results demonstrate that these key residues contribute to interactions driving the active receptor conformation, providing further evidence of a unique mode of G protein-coupled receptor activation. PMID:23926099

  6. The relaxin receptor (RXFP1) utilizes hydrophobic moieties on a signaling surface of its N-terminal low density lipoprotein class A module to mediate receptor activation.

    Science.gov (United States)

    Kong, Roy C K; Petrie, Emma J; Mohanty, Biswaranjan; Ling, Jason; Lee, Jeremy C Y; Gooley, Paul R; Bathgate, Ross A D

    2013-09-27

    The peptide hormone relaxin is showing potential as a treatment for acute heart failure. Although it is known that relaxin mediates its actions through the G protein-coupled receptor relaxin family peptide receptor 1 (RXFP1), little is known about the molecular mechanisms by which relaxin binding results in receptor activation. Previous studies have highlighted that the unique N-terminal low density lipoprotein class A (LDLa) module of RXFP1 is essential for receptor activation, and it has been hypothesized that this module is the true "ligand" of the receptor that directs the conformational changes necessary for G protein coupling. In this study, we confirmed that an RXFP1 receptor lacking the LDLa module binds ligand normally but cannot signal through any characterized G protein-coupled receptor signaling pathway. Furthermore, we comprehensively examined the contributions of amino acids in the LDLa module to RXFP1 activity using both gain-of-function and loss-of-function mutational analysis together with NMR structural analysis of recombinant LDLa modules. Gain-of-function studies with an inactive RXFP1 chimera containing the LDLa module of the human LDL receptor (LB2) demonstrated two key N-terminal regions of the module that were able to rescue receptor signaling. Loss-of-function mutations of residues in these regions demonstrated that Leu-7, Tyr-9, and Lys-17 all contributed to the ability of the LDLa module to drive receptor activation, and judicious amino acid substitutions suggested this involves hydrophobic interactions. Our results demonstrate that these key residues contribute to interactions driving the active receptor conformation, providing further evidence of a unique mode of G protein-coupled receptor activation. PMID:23926099

  7. Cellular, Molecular Consequences of Peroxisome Proliferator- Activated ReceptorActivation in Ovarian Cancer Cells

    Directory of Open Access Journals (Sweden)

    Sara Vignati

    2006-10-01

    Full Text Available Peroxisome proliferator-activated receptor-δ (PPAR-δ is a ligand-activated transcription factor. In addition to its canonical role in lipid, glucose metabolism, PPAR-δ controls cell proliferation, death, differentiation in several tissues. Here we have examined the expression of PPAR-δ in ovarian tumors, the cellular, molecular consequences of its activation in ovarian cancer cells. PPAR-δ was expressed in a large number of epithelial ovarian tumors, cell lines. The PPAR-δ lig, ciglitazone inhibited the growth, clonogenic survival of ovarian cancer cells, inducing cell cycle arrest, cell death. Growth inhibition by ciglitazone was reversed by the PPAR-δ antagonist GW9662, indicating the involvement of PPAR-δ- dependent mechanisms. Microarray-based gene profiling revealed complex changes in the transcriptional program of ovarian cancer cells on treatment with ciglitazone, identified multiple pathways that may contribute to PPAR-δ ligands' antitumor activity. Genes upregulated by ciglitazone were predominantly associated with metabolic, differentiation, tumorsuppressor pathways, whereas downregulated genes were involved in cell proliferation, cell cycle, cell organization, steroid biosynthesis. Collectively, our data indicate that PPAR-δ activation by selective agonists is a valid strategy for ovarian cancer therapy, prevention, should be tested alone, in combination with other anticancer drugs.

  8. Soluble TL1A is sufficient for activation of death receptor 3.

    Science.gov (United States)

    Bittner, Sebastian; Knoll, Gertrud; Füllsack, Simone; Kurz, Maria; Wajant, Harald; Ehrenschwender, Martin

    2016-01-01

    Death receptor 3 (DR3) is a typical member of the tumor necrosis factor receptor family, and was initially identified as a T-cell co-stimulatory molecule. However, further studies revealed a more complex and partly dichotomous role for DR3 and its ligand TL1A under (patho)physiological conditions. TL1A and DR3 are not only a driving force in the development of autoimmune and inflammatory diseases, but also play an important role in counteracting these processes through an increase in the number of regulatory T cells. Ligands of the tumor necrosis factor family typically occur in two forms, membrane-bound and soluble, that can differ strikingly with respect to their efficacy in activating their corresponding receptor(s). Ligand-based approaches to activate the TL1A-DR3 pathway therefore require understanding of the molecular prerequisites of TL1A-based DR3 activation. To date, this has not been addressed. Here, we show that recombinant soluble trimeric TL1A is fully sufficient to strongly activate DR3-associated pro- and anti-apoptotic signaling pathways. In contrast to the TRAIL death receptors, which are much better activated by soluble TRAIL upon secondary ligand oligomerization, but similarly to the death receptor tumor necrosis factor receptor 1, DR3 is efficiently activated by soluble TL1A trimers. Additionally, we have measured the affinity of TL1A-DR3 interaction in a cell-based system, and demonstrated TL1A-induced DR3 internalization. Identification of DR3 as a tumor necrosis factor receptor that responds to soluble ligand trimers without further oligomerization provides a basis for therapeutic exploitation of the TL1A-DR3 pathway. PMID:26509650

  9. Modulation by group I mGLU receptor activation and group III mGLU receptor blockade of locomotor responses induced by D1-like and D2-like receptor agonists in the nucleus accumbens.

    Science.gov (United States)

    Rouillon, Christophe; Degoulet, Mickael; Chevallier, Karine; Abraini, Jacques H; David, Hélène N

    2008-03-10

    Evidence for functional motor interactions between group I and group III metabotropic glutamatergic (mGlu) receptors and dopamine neurotransmission is now clearly established [David, H.N., Abraini, J.H., 2001a. The group I metabotropic glutamate receptor antagonist S-4-CPG modulates the locomotor response produced by the activation of D1-like, but not D2-like, dopamine receptors in the rat nucleus accumbens. Eur. J. Neurosci. 15, 2157-2164, David, H.N., Abraini, J.H., 2002. Group III metabotropic glutamate receptors and D1-like and D2-like dopamine receptors interact in the rat nucleus accumbens to influence locomotor activity. Eur. J. Neurosci. 15, 869-875]. Nevertheless, whether or not and how, activation of group I and blockade of group III mGlu receptors modulate the motor responses induced by the activation of dopaminergic receptors in the NAcc still remains unknown. Answering this question needs to be assessed since functional interactions between neurotransmitters in the NAcc are well known to depend upon the level of activation of glutamatergic and/or dopaminergic receptors and because the effects of glutamatergic receptor agonists and antagonists on dopaminergic receptor-mediated locomotor responses are not always reciprocal as shown in previous studies. Our results show that activation of group I mGlu receptors by DHPG in the NAcc potentiated the locomotor response induced by intra-NAcc activation of D1-like receptors and blocked those induced by D2-like presynaptic or postsynaptic receptors. Alternatively, blockade of group III mGlu receptors by MPPG in the NAcc potentiated the locomotor responses mediated by D1-like receptors and by D2-like postsynaptic receptors and inhibited that induced by D2-like presynaptic receptors. These results compiled with previous data demonstrate that group I mGlu receptors and group III mGlu receptors can modulate the locomotor responses produced by D1-like and/or D2-like receptor agonists in a complex phasic and tonic

  10. Effect of Cannabinoid Receptor Activation on Spreading Depression

    OpenAIRE

    Kazemi, Hadi; Rahgozar, Mehdi; Speckmann, Erwin-Josef; Gorji, Ali

    2012-01-01

    Objective(s):The objective of this study was to evaluate the effect of cannabinoid on cortical spreading depression (CSD) in rat brain. Cannabis has been used for centuries for both symptomatic and prophylactic treatment of different types of headaches including migraine. CSD is believed to be a putative neuronal mechanism underlying migraine aura and subsequent pain. Materials and Methods:The effects of Delta9-tetrahydrocannabinol (THC), as well as, cannabinoid CB1 and CB2 receptor agonists ...

  11. Stress Exacerbates Neuropathic Pain via Glucocorticoid and NMDA Receptor Activation

    OpenAIRE

    Alexander, Jessica K.; DeVries, A. Courtney; KIGERL, KRISTINA A.; Dahlman, Jason M.; G.Popovich, Phillip

    2009-01-01

    There is growing recognition that psychological stress influences pain. Hormones that comprise the physiological response to stress (e.g. corticosterone; CORT) may interact with effectors of neuropathic pain. To test this hypothesis, mice received a spared nerve injury (SNI) after exposure to 60 min restraint stress. In stressed mice, allodynia was consistently increased. The mechanism(s) underlying the exacerbated pain response involves CORT acting via glucocorticoid receptors (GRs); RU486, ...

  12. Structural basis for activation of G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Gether, Ulrik; Asmar, Fazila; Meinild, Anne Kristine;

    2002-01-01

    Our understanding of how G-protein-coupled receptors (GPCRs) operate at the molecular level has been considerably improved over the last few years. The application of advanced biophysical techniques as well as the availability of high-resolution structural information has allowed insight both int......-expression with the cAMP sensitive Cl- channel CFTR (cystic fibrosis transmembrane conductance regulator) and electrophysiological measurements....

  13. Activation of peroxisome proliferator-activated receptor-{alpha} enhances fatty acid oxidation in human adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi; Sakamoto, Tomoya; Takahashi, Nobuyuki [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kawada, Teruo, E-mail: fat@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-04-22

    Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. {yields} PPAR{alpha} activation also increased insulin-dependent glucose uptake in human adipocytes. {yields} PPAR{alpha} activation did not affect lipid accumulation in human adipocytes. {yields} PPAR{alpha} activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPAR{alpha} in adipocytes have been unclarified. We examined the functions of PPAR{alpha} using human multipotent adipose tissue-derived stem cells as a human adipocyte model. Activation of PPAR{alpha} by GW7647, a potent PPAR{alpha} agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPAR{gamma}, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPAR{alpha} activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPAR{gamma} is activated. On the other hand, PPAR{alpha} activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPAR{alpha}-dependent manner. Moreover, PPAR{alpha} activation increased the production of CO{sub 2} and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPAR{alpha} stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPAR{alpha} agonists could improve insulin resistance without lipid accumulation in adipocytes. The expected

  14. Class A scavenger receptor promotes osteoclast differentiation via the enhanced expression of receptor activator of NF-κB (RANK)

    International Nuclear Information System (INIS)

    Osteoclasts originate from bone marrow monocyte/macrophage lineage cells, and their differentiation depends on macrophage colony-stimulating factor (M-CSF) and receptor activator nuclear factor kappa B (RANK) ligand. Class A scavenger receptor (SR-A) is one of the principal functional molecules of macrophages, and its level of expression declines during osteoclast differentiation. To investigate the role of SR-A in osteoclastogenesis, we examined pathological changes in femoral bone and the expression levels of osteoclastogenesis-related molecules in SR-A-/- mice. The femoral osseous density of SR-A-/- mice was higher than that of SR-A+/+ mice, and the number of multinucleated osteoclasts was significantly decreased. An in vitro differentiation assay revealed that the differentiation of multinucleated osteoclasts from bone marrow-derived progenitor cells is impaired in SR-A-/- mice. Elimination of SR-A did not alter the expression level of the M-CSF receptor, c-fms; however, the expression levels of RANK and RANK-related osteoclast-differentiation molecules such as nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) and microphthalmia-associated transcription factor (MITF) significantly decreased. Furthermore, acetylated low-density lipoprotein (AcLDL), an SR-A ligand, significantly increased the expression level of RANK and MITF during osteoclast differentiation. These data indicate that SR-A promotes osteoclastogenesis via augmentation of the expression level of RANK and its related molecules.

  15. Class A scavenger receptor promotes osteoclast differentiation via the enhanced expression of receptor activator of NF-{kappa}B (RANK)

    Energy Technology Data Exchange (ETDEWEB)

    Takemura, Kenichi [Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556 (Japan); Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto (Japan); Sakashita, Naomi; Fujiwara, Yukio; Komohara, Yoshihiro; Lei, XiaoFeng; Ohnishi, Koji [Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556 (Japan); Suzuki, Hiroshi [National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido (Japan); Kodama, Tatsuhiko [Department of Molecular Biology and Medicine, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo (Japan); Mizuta, Hiroshi [Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto (Japan); Takeya, Motohiro, E-mail: takeya@kumamoto-u.ac.jp [Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556 (Japan)

    2010-01-22

    Osteoclasts originate from bone marrow monocyte/macrophage lineage cells, and their differentiation depends on macrophage colony-stimulating factor (M-CSF) and receptor activator nuclear factor kappa B (RANK) ligand. Class A scavenger receptor (SR-A) is one of the principal functional molecules of macrophages, and its level of expression declines during osteoclast differentiation. To investigate the role of SR-A in osteoclastogenesis, we examined pathological changes in femoral bone and the expression levels of osteoclastogenesis-related molecules in SR-A{sup -/-} mice. The femoral osseous density of SR-A{sup -/-} mice was higher than that of SR-A{sup +/+} mice, and the number of multinucleated osteoclasts was significantly decreased. An in vitro differentiation assay revealed that the differentiation of multinucleated osteoclasts from bone marrow-derived progenitor cells is impaired in SR-A{sup -/-} mice. Elimination of SR-A did not alter the expression level of the M-CSF receptor, c-fms; however, the expression levels of RANK and RANK-related osteoclast-differentiation molecules such as nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) and microphthalmia-associated transcription factor (MITF) significantly decreased. Furthermore, acetylated low-density lipoprotein (AcLDL), an SR-A ligand, significantly increased the expression level of RANK and MITF during osteoclast differentiation. These data indicate that SR-A promotes osteoclastogenesis via augmentation of the expression level of RANK and its related molecules.

  16. Evidence for Activation of Toll-Like Receptor and Receptor for Advanced Glycation End Products in Preterm Birth

    Directory of Open Access Journals (Sweden)

    Taketoshi Noguchi

    2010-01-01

    Full Text Available Objective. Individuals with inflammation have a myriad of pregnancy aberrations including increasing their preterm birth risk. Toll-like receptors (TLRs and receptor for advanced glycation end products (RAGE and their ligands were all found to play a key role in inflammation. In the present study, we reviewed TLR and RAGE expression, their ligands, and signaling in preterm birth. Research Design and Methods. A systematic search was performed in the electronic databases PubMed and ScienceDirect up to July 2010, combining the keywords “preterm birth,” “TLR”, “RAGE”, “danger signal”, “alarmin”, “genomewide,” “microarray,” and “proteomics” with specific expression profiles of genes and proteins. Results. This paper provides data on TLR and RAGE levels and critical downstream signaling events including NF-kappaB-dependent proinflammatory cytokine expression in preterm birth. About half of the genes and proteins specifically present in preterm birth have the properties of endogenous ligands “alarmin” for receptor activation. The interactions between the TLR-mediated acute inflammation and RAGE-mediated chronic inflammation have clear implications for preterm birth via the TLR and RAGE system, which may be acting collectively. Conclusions. TLR and RAGE expression and their ligands, signaling, and functional activation are increased in preterm birth and may contribute to the proinflammatory state.

  17. Gastrin-Releasing Peptide Receptor Mediates Activation of the Epidermal Growth Factor Receptor in Lung Cancer Cells

    Directory of Open Access Journals (Sweden)

    Sufi Mary Thomas

    2005-04-01

    Full Text Available Gastrin-releasing peptide receptor (GRPR and the epidermal growth factor receptor (EGFR are expressed in several cancers including non-small cell lung carcinoma (NSCLC. Here we demonstrate the activation of EGFR by the GRPR ligand, gastrin-releasing peptide (GRP, in NSCLC cells. GRP induced rapid activation of p44/42 MAPK in lung cancer cells through EGFR. GRP-mediated activation of MAPK in NSCLC cells was abrogated by pretreatment with the anti-EGFR-neutralizing antibody, C225. Pretreatment of NSCLC cells with neutralizing antibodies to the EGFR ligands, TGF-α or HB-EGF, also decreased GRP-mediated MAPK activation. On matrix metalloproteinase (MMP inhibition, GRP failed to activate MAPK in NSCLC cells. EGF and GRP both stimulated NSCLC proliferation, and inhibition of either EGFR or GRPR resulted in cell death. Combining a GRPR antagonist with the EGFR tyrosine kinase inhibitor, gefitinib, resulted in additive cytotoxic effects. Additive effects were seen at gefitinib concentrations from 1 to 18μM, encompassing the ID50 values of both gefitinib-sensitive and gefitinib-resistant NSCLC cell lines. Because a major effect of GRPR appears to be promoting the release of EGFR ligand, this study suggests that a greater inhibition of cell proliferation may occur by abrogating EGFR ligand release in consort with inhibition of EGFR.

  18. Antisense epidermal growth factor receptor RNA transfection in human glioblastoma cells down-regulates telomerase activity and telomere length

    OpenAIRE

    Tian, X-X; Pang, JC-S; J. Zheng; Chen, J; To, S S T; Ng, H-K

    2002-01-01

    Epidermal growth factor receptor is overexpressed and/or amplified in up to 50% of glioblastomas, suggesting an important role of this gene in glial tumorigenesis and progression. In the present study we demonstrated that epidermal growth factor receptor is involved in regulation of telomerase activity in glioblastoma. Antisense-epidermal growth factor receptor approach was used to inhibit epidermal growth factor receptor expression of glioblastoma U87MG cells. Telomerase activity in antisens...

  19. Involvement of Ca2+-activated K+ Channels in Receptor-Regulated Sperm Motility in Rats

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Previous voltage-clamp studies have demonstrated the modulation of sperm Ca2+-activated K+ (KCa) channels expressed in Xenopus oocytes by angiotensin Ⅱ (Ang Ⅱ)and extracellular ATP via AT1 receptor and P2U receptor, respectively. In the presentstudy, we investigated the involvement of KCa channels in receptor-regulated spermmotility of the rat using a computer-aided sperm analysis system, HTM-IVOS, in con-junction with Ca2+-mobilizing agents, receptor agonists/antagonists and KCa channelsblockers.The percentage of motile sperm was increased by ionomycin (0. 5 μmol/L), whichcould be inhibited by K+ channel blockers, tetraethylammonium (TEA 1 μmol/L ) orcharybdotoxin (ChTX, 300 nmol/L) indicating the presence of KCa channels. AngⅡ, at low concentration, 10 nmol/L, was found to increase motility, however, athigher concentration, 1 μmol/L, percentage of motility was found to be suppressed.Both stimulatory and inhibitory effects of Ang Ⅱ could be reversed by losartan, aspecific antagonist of AT 1 receptors, but not AT 2 antagonist PD123177, indicating theinvolvement of AT1 but not AT2 receptor in mediating both effects. ChTX also abol-ished both stimulatory and inhibitory effects of Ang H, suggesting the involvement ofKCa channels. The percentage of motility was also enhanced by extracellular ATP, afactor known to be involved in sperm activation. The ATP-enhanced sperm motilitywas mimicked by UTP , and inhibited by ChTX and reactive blue, an antagonist of P2receptor, indicating the involvement of both P2U and KCa channels. RT-PCR studywas also conducted to confirm the expression of KCa channels, AT1 receptors and P2Ureceptor, but not AT2 receptor, in rat caudal epididymal sperm. The present findingssuggest an important role of KCa channels in the regulation of sperm motility by AT1and P 2U receptors.

  20. Sedative-Hypnotic and Receptor Binding Studies of Fermented Marine Organisms.

    Science.gov (United States)

    Joung, Hye-Young; Kang, Young Mi; Lee, Bae-Jin; Chung, Sun Yong; Kim, Kyung-Soo; Shim, Insop

    2015-09-01

    This study was performed to investigate the sedative-hypnotic activity of γ-aminobutyric acid (GABA)-enriched fermented marine organisms (FMO), including sea tangle (FST) and oyster (FO) by Lactobacillus brevis BJ20 (L. brevis BJ20). FST and FO were tested for their binding activity of the GABAA-benzodiazepine and 5-HT2C receptors, which are well-known molecular targets for sleep aids. We also measured the sleep latency and sleep duration during pentobarbital-induced sleep in mice after oral administration of FST and FO. In GABAA and 5-HT2C receptor binding assays, FST displayed an effective concentration-dependent binding affinity to GABAA receptor, similar to the binding affinity to 5-HT2C receptor. FO exhibited higher affinity to 5-HT2C receptor, compared with the GABAA receptor. The oral administration of FST and FO produced a dose-dependent decrease in sleep latency and increase in sleep duration in pentobarbital-induced hypnosis. The data demonstrate that FST and FO possess sedative-hypnotic activity possibly by modulating GABAA and 5-HT2C receptors. We propose that FST and FO might be effective agents for treatment of insomnia. PMID:26336589

  1. Proteolytic activity of the purified hormone-binding subunit in the estrogen receptor.

    Science.gov (United States)

    Molinari, A M; Abbondanza, C; Armetta, I; Medici, N; Minucci, S; Moncharmont, B; Nigro, V; Puca, G A

    1991-05-15

    The hormone-binding subunit of the calf uterus estradiol receptor was purified as a hormone-free molecule. Immunoaffinity chromatography with a specific monoclonal antibody was used as the final step. The purified subunit was specifically labeled by radioactive diisopropyl fluorophosphate. The diisopropyl fluorophosphate-labeled amino acid was serine. The purified receptor was able to release the fluorogenic or chromogenic group from synthetic peptides containing phenylalanine at the carboxyl terminus. This occurred only in the presence of estradiol and was hampered by aprotinin and diisopropyl fluorophosphate. Estradiol-dependent hydrolytic activity was also found in the eluate from gel slices after SDS/PAGE of purified receptor. This activity comigrated with the renaturable estradiol-binding activity. The estradiol antagonists 4-hydroxytamoxifen and ICI 164,384 as well as other steroid hormones were unable to activate this hydrolytic activity. PMID:1709742

  2. Structural plasticity of GABAergic axons is regulated by network activity and GABAA receptor activation

    Directory of Open Access Journals (Sweden)

    Anne eSchuemann

    2013-06-01

    Full Text Available Coordinated changes at excitatory and inhibitory synapses are essential for normal brain development and function. It is well established that excitatory neurons undergo structural changes, but our knowledge about inhibitory structural plasticity is rather scarce. Here we present a quantitative analysis of the dynamics of GABAergic boutons in the dendritic region of the hippocampal CA1 area using time-lapse two-photon imaging in organotypic hippocampal cultures from GAD65-GFP mice. We show that ~20% of inhibitory boutons are not stable. They are appearing, disappearing and reappearing at specific locations along the inhibitory axon and reflect immature or incomplete synapses. Furthermore, we observed that persistent boutons show large volume fluctuations over several hours, suggesting that presynaptic content of inhibitory synapses is not constant. Our data show that inhibitory boutons are highly dynamic structures and suggest that inhibitory axons are continuously probing potential locations for inhibitory synapse formation by redistributing presynaptic material along the axon.In addition, we found that neuronal activity affects the exploratory dynamics of inhibitory axons. Blocking network activity rapidly reduces the number of transient boutons, whereas enhancing activity reduces the number of persistent inhibitory boutons, possibly reflecting enhanced competition between boutons along the axon. The latter effect requires signaling through GABAA receptors. We propose that activity-dependent regulation of bouton dynamics contributes to inhibitory synaptic plasticity.

  3. Extracellular granzyme K mediates endothelial activation through the cleavage of protease-activated receptor-1.

    Science.gov (United States)

    Sharma, Mehul; Merkulova, Yulia; Raithatha, Sheetal; Parkinson, Leigh G; Shen, Yue; Cooper, Dawn; Granville, David J

    2016-05-01

    Granzymes are a family of serine proteases that were once thought to function exclusively as mediators of cytotoxic lymphocyte-induced target cell death. However, non-apoptotic roles for granzymes, including granzyme K (GzK), have been proposed. As recent studies have observed elevated levels of GzK in the plasma of patients diagnosed with clinical sepsis, we hypothesized that extracellular GzK induces a proinflammatory response in endothelial cells. In the present study, extracellular GzK proteolytically activated protease-activated receptor-1 leading to increased interleukin 6 and monocyte chemotactic protein 1 production in endothelial cells. Enhanced expression of intercellular adhesion molecule 1 along with an increased capacity for adherence of THP-1 cells was also observed. Characterization of downstream pathways implicated the mitogen-activated protein kinase p38 pathway for intercellular adhesion molecule 1 expression, and both the p38 and the extracellular signal-regulated protein kinases 1 and 2 pathways in cytokine production. GzK also increased tumour necrosis factor α-induced inflammatory adhesion molecule expression. Furthermore, the physiological inhibitor of GzK, inter-α-inhibitor protein, significantly inhibited GzK activity in vitro. In summary, extracellular GzK promotes a proinflammatory response in endothelial cells. PMID:26936634

  4. Acanthamoeba protease activity promotes allergic airway inflammation via protease-activated receptor 2.

    Directory of Open Access Journals (Sweden)

    Mi Kyung Park

    Full Text Available Acanthamoeba is a free-living amoeba commonly present in the environment and often found in human airway cavities. Acanthamoeba possesses strong proteases that can elicit allergic airway inflammation. To our knowledge, the aeroallergenicity of Acanthamoeba has not been reported. We repeatedly inoculated mice with Acanthamoeba trophozoites or excretory-secretory (ES proteins intra-nasally and evaluated symptoms and airway immune responses. Acanthamoeba trophozoites or ES proteins elicited immune responses in mice that resembled allergic airway inflammation. ES proteins had strong protease activity and activated the expression of several chemokine genes (CCL11, CCL17, CCL22, TSLP, and IL-25 in mouse lung epithelial cells. The serine protease inhibitor phenyl-methane-sulfonyl fluoride (PMSF inhibited ES protein activity. ES proteins also stimulated dendritic cells and enhanced the differentiation of naive T cells into IL-4-secreting T cells. After repeated inoculation of the protease-activated receptor 2 knockout mouse with ES proteins, airway inflammation and Th2 immune responses were markedly reduced, but not to basal levels. Furthermore, asthma patients had higher Acanthamoeba-specific IgE titers than healthy controls and we found Acanthamoeba specific antigen from house dust in typical living room. Our findings suggest that Acanthamoeba elicits allergic airway symptoms in mice via a protease allergen. In addition, it is possible that Acanthamoeba may be one of the triggers human airway allergic disease.

  5. Assessing the efficacy of melatonin to curtail benzodiazepine/Z drug abuse.

    Science.gov (United States)

    Cardinali, Daniel P; Golombek, Diego A; Rosenstein, Ruth E; Brusco, Luis I; Vigo, Daniel E

    2016-07-01

    The abuse of benzodiazepine (BZP) and Z drugs has become, due to the tolerance and dependence they produce, a serious public health problem. Thirty years ago, we demonstrated in experimental animals the interaction of melatonin with central BZD receptors, and in 1997 we published the first series of elderly patients who reduced BZP consumption after melatonin treatment. Almost every single neuron in the hypothalamic suprachiasmatic nuclei (SCN), the central pacemaker of the circadian system, contains γ-aminobutyric acid (GABA) and many results in animals point out to a melatonin interaction with GABA-containing neurons. In addition, central-type BZD antagonism, that obliterates GABAA receptor function, blunted most behavioral effects of melatonin including sleep. Melatonin is involved in the regulation of human sleep. This is supported by the temporal relationship between the rise of plasma melatonin levels and sleep propensity as well as by the sleep-promoting effects of exogenously administered melatonin. Both meta-analyses and consensus agreements give support to the therapeutic use of melatonin in sleep disorders. This action is attributed to MT1 and MT2 melatoninergic receptors localized in the SCN, as well as in other brain areas. This review discusses available data on the efficacy of melatonin to curtail chronic BZD/Z drug use in insomnia patients. A major advantage is that melatonin has a very safe profile, it is usually remarkably well tolerated and, in some studies, it has been administered to patients at very large doses and for long periods of time, without any potentiality of abuse. Further studies on this application of melatonin are warranted. PMID:26438969

  6. Ligand Perception, Activation, and Early Signaling of Plant Steroid Receptor Brassinosteroid Insensitive 1

    Institute of Scientific and Technical Information of China (English)

    Jianjun Jiang; Chi Zhang; Xuelu Wang

    2013-01-01

    Leucine-rich repeat receptor-like kinases (LRR-RLKs) belong to a large group of cell surface proteins involved in many aspects of plant development and environmental responses in both monocots and dicots. Brassinosteroid insensitive 1 (BRI1), a member of the LRR X subfamily, was first identified through several forward genetic screenings for mutants insensitive to brassinosteroids (BRs), which are a class of plant-specific steroid hormones. Since its identification, BRI1 and its homologs had been proved as receptors perceiving BRs and initiating BR signaling. The co-receptor BRI1-associated kinase 1 and its homologs, and other BRI1 interacting proteins such as its inhibitor BRI1 kinase inhibitor 1 (BKI1) were identified by genetic and biochemical approaches. The detailed mechanisms of BR perception by BRI1 and the activation of BRI1 receptor complex have also been elucidated. Moreover, several mechanisms for termination of the activated BRI1 signaling were also discovered. In this review, we will focus on the recent advances on the mechanism of BRI1 phosphorylation and activation, the regulation of its receptor complex, the structure basis of BRI1 ectodomain and BR recognition, its direct substrates, and the termination of the activated BRI1 receptor complex.

  7. Activation of the kinin B1 receptor attenuates melanoma tumor growth and metastasis.

    Directory of Open Access Journals (Sweden)

    Patricia Dillenburg-Pilla

    Full Text Available Melanoma is a very aggressive tumor that does not respond well to standard therapeutic approaches, such as radio- and chemotherapies. Furthermore, acquiring the ability to metastasize in melanoma and many other tumor types is directly related to incurable disease. The B1 kinin receptor participates in a variety of cancer-related pathophysiological events, such as inflammation and angiogenesis. Therefore, we investigated whether this G protein-coupled receptor plays a role in tumor progression. We used a murine melanoma cell line that expresses the kinin B1 receptor and does not express the kinin B2 receptor to investigate the precise contribution of activation of the B1 receptor in tumor progression and correlated events using various in vitro and in vivo approaches. Activation of the kinin B1 receptor in the absence of B2 receptor inhibits cell migration in vitro and decreases tumor formation in vivo. Moreover, tumors formed from cells stimulated with B1-specific agonist showed several features of decreased aggressiveness, such as smaller size and infiltration of inflammatory cells within the tumor area, higher levels of pro-inflammatory cytokines implicated in the host anti-tumor immune response, lower number of cells undergoing mitosis, a poorer vascular network, no signs of invasion of surrounding tissues or metastasis and increased animal survival. Our findings reveal that activation of the kinin B1 receptor has a host protective role during murine melanoma tumor progression, suggesting that the B1 receptor could be a new anti-tumor GPCR and provide new opportunities for therapeutic targeting.

  8. Analgesic tone conferred by constitutively active mu opioid receptors in mice lacking β-arrestin 2

    Directory of Open Access Journals (Sweden)

    Hales Tim G

    2011-04-01

    Full Text Available Abstract Hedonic reward, dependence and addiction are unwanted effects of opioid analgesics, linked to the phasic cycle of μ opioid receptor activation, tolerance and withdrawal. In vitro studies of recombinant G protein coupled receptors (GPCRs over expressed in cell lines reveal an alternative tonic signaling mechanism that is independent of agonist. Such studies demonstrate that constitutive GPCR signaling can be inhibited by inverse agonists but not by neutral antagonists. However, ligand-independent activity has been difficult to examine in vivo, at the systems level, due to relatively low levels of constitutive activity of most GPCRs including μ receptors, often necessitating mutagenesis or pharmacological manipulation to enhance basal signaling. We previously demonstrated that the absence of β-arrestin 2 (β-arr2 augments the constitutive coupling of μ receptors to voltage-activated Ca2+ channels in primary afferent dorsal root ganglion neurons from β-arr2-/- mice. We used this in vitro approach to characterize neutral competitive antagonists and inverse agonists of the constitutively active wild type μ receptors in neurons. We administered these agents to β-arr2-/- mice to explore the role of constitutive μ receptor activity in nociception and hedonic tone. This study demonstrates that the induction of constitutive μ receptor activity in vivo in β-arr2-/- mice prolongs tail withdrawal from noxious heat, a phenomenon that was reversed by inverse agonists, but not by antagonists that lack negative efficacy. By contrast, the aversive effects of inverse agonists were similar in β-arr2-/- and β-arr2+/+ mice, suggesting that hedonic tone was unaffected.

  9. Activation of GLP-1 Receptor Promotes Bone Marrow Stromal Cell Osteogenic Differentiation through β-Catenin

    Directory of Open Access Journals (Sweden)

    Jingru Meng

    2016-04-01

    Full Text Available Glucagon-like peptide 1 (GLP-1 plays an important role in regulating bone remodeling, and GLP-1 receptor agonist shows a positive relationship with osteoblast activity. However, GLP-1 receptor is not found in osteoblast, and the mechanism of GLP-1 receptor agonist on regulating bone remodeling is unclear. Here, we show that the GLP-1 receptor agonist exendin-4 (Ex-4 promoted bone formation and increased bone mass and quality in a rat unloading-induced bone loss model. These functions were accompanied by an increase in osteoblast number and serum bone formation markers, while the adipocyte number was decreased. Furthermore, GLP-1 receptor was detected in bone marrow stromal cells (BMSCs, but not in osteoblast. Activation of GLP-1 receptor by Ex-4 promoted the osteogenic differentiation and inhibited BMSC adipogenic differentiation through regulating PKA/β-catenin and PKA/PI3K/AKT/GSK3β signaling. These findings reveal that GLP-1 receptor regulates BMSC osteogenic differentiation and provide a molecular basis for therapeutic potential of GLP-1 against osteoporosis.

  10. Small-molecule nociceptin receptor agonist ameliorates mast cell activation and pain in sickle mice.

    Science.gov (United States)

    Vang, Derek; Paul, Jinny A; Nguyen, Julia; Tran, Huy; Vincent, Lucile; Yasuda, Dennis; Zaveri, Nurulain T; Gupta, Kalpna

    2015-12-01

    Treatment of pain with morphine and its congeners in sickle cell anemia is suboptimal, warranting the need for analgesics devoid of side effects, addiction and tolerance liability. Small-molecule nociceptin opioid receptor ligands show analgesic efficacy in acute and chronic pain models. We show that AT-200, a high affinity nociceptin opioid receptor agonist with low efficacy at the mu opioid receptor, ameliorated chronic and hypoxia/reoxygenation-induced mechanical, thermal and deep tissue/musculoskeletal hyperalgesia in HbSS-BERK sickle mice. The antinociceptive effect of AT-200 was antagonized by SB-612111, a nociceptin opioid receptor antagonist, but not naloxone, a non-selective mu opioid receptor antagonist. Daily 7-day treatment with AT-200 did not develop tolerance and showed a sustained anti-nociceptive effect, which improved over time and led to reduced plasma serum amyloid protein, neuropeptides, inflammatory cytokines and mast cell activation in the periphery. These data suggest that AT-200 ameliorates pain in sickle mice via the nociceptin opioid receptor by reducing inflammation and mast cell activation without causing tolerance. Thus, nociceptin opioid receptor agonists are promising drugs for treating pain in sickle cell anemia. PMID:26294734

  11. Salt Bridges Overlapping the Gonadotropin-Releasing Hormone Receptor Agonist Binding Site Reveal a Coincidence Detector for G Protein-Coupled Receptor Activation

    OpenAIRE

    Janovick, Jo Ann; Pogozheva, Irina D.; Mosberg, Henry I.; Conn, P. Michael

    2011-01-01

    G protein-coupled receptors (GPCRs) play central roles in most physiological functions, and mutations in them cause heritable diseases. Whereas crystal structures provide details about the structure of GPCRs, there is little information that identifies structural features that permit receptors to pass the cellular quality control system or are involved in transition from the ground state to the ligand-activated state. The gonadotropin-releasing hormone receptor (GnRHR), because of its small s...

  12. Spontaneous Synaptic Activation of Muscarinic Receptors by Striatal Cholinergic Neuron Firing.

    Science.gov (United States)

    Mamaligas, Aphroditi A; Ford, Christopher P

    2016-08-01

    Cholinergic interneurons (CHIs) play a major role in motor and learning functions of the striatum. As acetylcholine does not directly evoke postsynaptic events at most striatal synapses, it remains unclear how postsynaptic cholinergic receptors encode the firing patterns of CHIs in the striatum. To examine the dynamics of acetylcholine release, we used optogenetics and paired recordings from CHIs and medium spiny neurons (MSNs) virally overexpressing G-protein-activated inwardly rectifying potassium (GIRK) channels. Due to the efficient coupling between endogenous muscarinic receptors and GIRK channels, we found that firing of individual CHIs resulted in monosynaptic spontaneous inhibitory post-synaptic currents (IPSCs) in MSNs. Paired CHI-MSN recordings revealed that the high probability of acetylcholine release at these synapses allowed muscarinic receptors to faithfully encode physiological activity patterns from individual CHIs without failure. These results indicate that muscarinic receptors in striatal output neurons reliably decode CHI firing. PMID:27373830

  13. Evidence that leptin-induced weight loss requires activation of both forebrain and hindbrain receptors

    OpenAIRE

    Ruth B.S. Harris

    2013-01-01

    Previous studies with chronic decerebrate rats and rats infused with leptin into the 4th ventricle suggest that hindbrain leptin receptors attenuate the catabolic effect of forebrain leptin receptor activation. To test this further rats were fitted with both 3rd and 4th ventricle cannulae. They were infused for 12 days with different combinations of saline, low dose leptin or leptin receptor antagonist (leptin mutein protein). Infusion of 0.1 μg leptin/day into the 3rd ventricle or 0.6 μg lep...

  14. Ligand binding and activation mechanism og the glucagon-like peptide-1 receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye

    In recent years, G-protein coupled receptors (GPCRs) have become important drug targets, which makes elucidation of their molecular structure and functional domains increasingly important for designing new and better therapeutic agents. The Glucagon-Like Peptide-1 receptor (GLP-1R) is a GPCR. Its...... molecule-mediated activation of GLP-1R (Study II). A fully functional, cysteine-deprived and Cterminally truncated GLP-1R is developed and characterised in Study III. In Study IV, a cAMP biosensor is used to investigate the cAMP kinetics of GLP-1R upon stimulation with different receptor agonists...

  15. Molecular simulation of receptors of physiologically active compounds for purposes of medical chemistry

    Science.gov (United States)

    Baskin, Igor I.; Palyulin, Vladimir A.; Zefirov, Nikolai S.

    2009-06-01

    The general strategy of the molecular simulation of biological receptors and their interaction with ligands is considered. The procedures for construction of 3D protein models, molecular docking, evaluation of model quality, determination of the free energy of protein binding with ligands are discussed. The methods of molecular design of new medicaments based on molecular models of biological targets: virtual screening and de novo design, are presented. Examples of the above-listed approaches for the simulation of a number of pharmacologically significant receptors, analysis of receptor-ligand interactions and design of new biologically active organic compounds are given.

  16. Xanomeline binding to and activation of muscarinic receptors

    Czech Academy of Sciences Publication Activity Database

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

    Pianoro: Medimond, 2009 - (Fisher, A.; Hanin, I.), s. 145-148 ISBN 978-88-7587-528-2. [International Conference Alzheimer ´s diseases/Parkinson´s diseases /9./. Praha (CZ), 11.05.2009-15.05.2009] R&D Projects: GA AV ČR(CZ) IAA500110703; GA ČR GA305/09/0681; GA MŠk(CZ) LC554 Grant ostatní: EC(XE) LiPiDiDiet 211696 Institutional research plan: CEZ:AV0Z50110509 Keywords : xanomeline * muscarinic receptors * signal transduction Subject RIV: FH - Neurology

  17. Molecular architecture of mouse activating NKR-P1 receptors

    Czech Academy of Sciences Publication Activity Database

    Kolenko, Petr; Rozbeský, Daniel; Vaněk, Ondřej; Kopecký, V. Jr.; Hofbauerová, Kateřina; Novák, Petr; Pompach, Petr; Hašek, Jindřich; Skálová, Tereza; Bezouška, Karel; Dohnálek, Jan

    2011-01-01

    Roč. 175, č. 3 (2011), s. 434-441. ISSN 1047-8477 R&D Projects: GA MŠk 1M0505; GA ČR GA303/09/0477; GA ČR GD305/09/H008; GA ČR GA305/07/1073; GA ČR GAP207/10/1040; GA AV ČR KJB101120805 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50200510 Keywords : NK cell * C-type lectin-like receptor * X-ray structure Subject RIV: CE - Biochemistry Impact factor: 3.406, year: 2011

  18. Transcriptional activation by the thyroid hormone receptor through ligand-dependent receptor recruitment and chromatin remodelling

    DEFF Research Database (Denmark)

    Grøntved, Lars; Waterfall, Joshua J; Kim, Dong Wook;

    2015-01-01

    facilitates recruitment of co-activators to activate transcription. Here we show that in addition to hormone-independent TR occupancy, ChIP-seq against endogenous TR in mouse liver tissue demonstrates considerable hormone-induced TR recruitment to chromatin associated with chromatin remodelling and activated...

  19. Selective effects of ligands on vitamin D3 receptor- and retinoid X receptor-mediated gene activation in vivo.

    OpenAIRE

    Lemon, B D; Freedman, L P

    1996-01-01

    Steroid/nuclear hormone receptors are ligand-regulated transcription f factors that play key roles in cell regulation, differentiation, and oncogenesis. Many nuclear receptors, including the human 1,25-dihydroxyvitamin D3 receptor (VDR), bind cooperatively to DNA either as homodimers or as heterodimers with the 9-cis retinoic acid (RA) receptor (retinoid X-receptor [RXR]). We have previously reported that the ligands for VDR and RXR can differentially modulate the affinity of the receptors' i...

  20. Common and distinct mechanisms of activation of rhodopsin and other G protein-coupled receptors

    OpenAIRE

    Sumire Nakamura; Takeshi Itabashi; Daisuke Ogawa; Tetsuji Okada

    2013-01-01

    Detailed and systematic examination of high-resolution structural data is a rational strategy for understanding the function of biological macromolecules. G protein-coupled receptors (GPCRs) are an exceptionally valuable superfamily of proteins for such analysis. The most intriguing question is how a variety of extracellular stimuli evoke structural changes in the intracellular surface of the receptors. The recent active-like crystal structures of GPCRs provide information for uncovering comm...