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[A role of neurosteroids in the pathogenesis of psychiatric disorders]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:31-36. [PMID: 37084362 DOI: 10.17116/jnevro202312304131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
Abstract
Despite the proven importance of neurosteroids in many physiological processes, their role in the pathogenesis of the most of psychiatric disorders remains relatively understudied. This article reviews the current clinical evidence on the effects of neurosteroids on the formation and treatment of anxiety disorder, depression, bipolar disorder, and schizophrenia. In particular, the article points out the ambivalent nature of the effects of neurosteroids on GABAA- and other receptors. We are especially interested in the anxiolytic and anxiogenic effects of some neurosteroids, the antidepressant effect of allopregnanolone in treating postpartum and other forms of depression, and the nature of short- and long-term mechanisms of antidepressant effects of neurosteroids of different types. The currently unproven hypothesis about the effect of changes in the level of neurosteroids on the course of bipolar disorder is also discussed, with an analysis of the scientific evidence on the development of schizophrenic symptomatology in relation to changing neurosteroid levels in the context of positive and cognitive symptoms.
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Potential Role of the Antidepressants Fluoxetine and Fluvoxamine in the Treatment of COVID-19. Int J Mol Sci 2022; 23:ijms23073812. [PMID: 35409171 PMCID: PMC8998734 DOI: 10.3390/ijms23073812] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/24/2022] [Accepted: 03/24/2022] [Indexed: 02/04/2023] Open
Abstract
Mapping non-canonical cellular pathways affected by approved medications can accelerate drug repurposing efforts, which are crucial in situations with a global impact such as the COVID-19 pandemic. Fluoxetine and fluvoxamine are well-established and widely-used antidepressive agents that act as serotonin reuptake inhibitors (SSRI-s). Interestingly, these drugs have been reported earlier to act as lysosomotropic agents, inhibitors of acid sphingomyelinase in the lysosomes, and as ligands of sigma-1 receptors, mechanisms that might be used to fight severe outcomes of COVID-19. In certain cases, these drugs were administered for selected COVID-19 patients because of their antidepressive effects, while in other cases, clinical studies were performed to assess the effect of these drugs on treating COVID-19 patients. Clinical studies produced promising data that encourage the further investigation of fluoxetine and fluvoxamine regarding their use in COVID-19. In this review, we summarize experimental data and the results of the performed clinical studies. We also provide an overview of previous knowledge on the tissue distribution of these drugs and by integrating this information with the published experimental results, we highlight the real opportunity of using these drugs in our fight against COVID-19.
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Angiogenic Effects of Anxiolytic Fabomotizole. DOKL BIOCHEM BIOPHYS 2021; 497:63-65. [PMID: 33895918 DOI: 10.1134/s1607672921020101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 11/23/2022]
Abstract
In vitro experiments performed on an isolated human endothelial HUVEC cell culture showed that the anxiolytic fabomotizole, which, in addition to the anxiolytic effect, has neuroprotective and cardioprotective activities largely associated with its agonistic action on sigma-1 receptors and shows a pronounced angiogenic activity. Fabomotizole angiogenic activity is realized in the range concentration from 10-5 to 10-8 M and is doze-dependent. In the literature, data on the presence of angiogenic activity in sigma receptor agonists have not been previously reported.
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Dual-targeting Approach on Histamine H 3 and Sigma-1 Receptor Ligands as Promising Pharmacological Tools in the Treatment of CNS-linked Disorders. Curr Med Chem 2021; 28:2974-2995. [PMID: 32767910 DOI: 10.2174/0929867327666200806103144] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 11/22/2022]
Abstract
With the recent market approval of Pitolisant (Wakix®), the interest in clinical application for novel multifunctional histamine H3 receptor antagonists has clearly increased. Several combinations of different H3R pharmacophores with pharmacophoric elements of other G-protein coupled receptors, transporters, or enzymes have been synthesized by numerous pharmaceutical companies and academic institutions. Since central nervous system disorders are characterized by diverse physiological dysfunctions and deregulations of a complex network of signaling pathways, optimal multipotent drugs should simultaneously and peculiarly modulate selected groups of biological targets. Interestingly, very recent studies have shown that some clinically evaluated histamine H3 receptor antagonists possess a nanomolar affinity for sigma-1 receptor binding sites, suggesting that this property might play a role in their overall efficacy. The sigma-1 receptor, unusual and yet obscure protein, is supposed to be involved in numerous CNS pathologies through neuroprotection and neuroplasticity. These two different biological structures, histamine H3 and sigma-1 receptors, combined, can represent a potential fruitful target for therapeutic developments in tackling numerous human diseases.
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Neuroleptic Chlorpromazine Modulates Ca 2+ Responses in Macrophages. DOKL BIOCHEM BIOPHYS 2020; 490:25-28. [PMID: 32342308 DOI: 10.1134/s160767292001010x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 11/23/2022]
Abstract
Using Fura-2AM microfluorimetry, we have shown for the first time that sigma-1 receptor antagonist neuroleptic chlorpromazine significantly inhibits glutoxim- and molixan-induced Ca2+ responses and Ca2+ responses induced by endoplasmic reticulum Са2+-ATPase inhibitors thapsigargin and cyclopiazonic acid in rat peritoneal macrophages. The results suggest the involvement of sigma-1 receptors in the signaling cascade induced by glutoxim or molixan and leading to intracellular Ca2+ concentration increase and in the regulation of store-dependent Ca2+ entry in macrophages.
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Examination of Cardioprotective Effects of Fabomotizole Hydrochloride in Translational Rat Model of Chronic Heart Failure. Bull Exp Biol Med 2019; 168:33-37. [PMID: 31741244 DOI: 10.1007/s10517-019-04639-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Indexed: 11/26/2022]
Abstract
A translational rat model of chronic heart failure was employed to examine the cardioprotective effect of fabomotizole hydrochloride. Fabomotizole therapy for 28 days (15 mg/kg/day intraperitoneally) restored inotropic function of the left ventricle and increased ejection fraction from 54±3 to 65±3% (p=0.001). The inotropic function returned to normal against the background of significantly reduced myocardial expression of angiotensin (p=0.01) and glucocorticoid (p=0.03) receptors and significant increased expression of sigma-1 receptors (p=0.04). Inhibition of abnormal expression of angiotensin and glucocorticoid receptors responsible for activation of the pathological cascades underlying the postinfarction remodeling of the left ventricle as well as activation of the expression of cytoprotective sigma-1 receptors are viewed as the key features of the cardioprotective action of fabomotizole hydrochloride.
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In vitro and in vivo Human Metabolism of ( S)-[ 18F]Fluspidine - A Radioligand for Imaging σ 1 Receptors With Positron Emission Tomography (PET). Front Pharmacol 2019; 10:534. [PMID: 31263411 PMCID: PMC6585474 DOI: 10.3389/fphar.2019.00534] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 04/29/2019] [Indexed: 12/26/2022] Open
Abstract
(S)-[18F]fluspidine ((S)-[18F]1) has recently been explored for positron emission tomography (PET) imaging of sigma-1 receptors in humans. In the current report, we have used plasma samples of healthy volunteers to investigate the radiometabolites of (S)-[18F]1 and elucidate their structures with LC-MS/MS. For the latter purpose additional in vitro studies were conducted by incubation of (S)-[18F]1 and (S)-1 with human liver microsomes (HLM). In vitro metabolites were characterized by interpretation of MS/MS fragmentation patterns from collision-induced dissociation or by use of reference compounds. Thereby, structures of corresponding radio-HPLC-detected radiometabolites, both in vitro and in vivo (human), could be identified. By incubation with HLM, mainly debenzylation and hydroxylation occurred, beside further mono- and di-oxygenations. The product hydroxylated at the fluoroethyl side chain was glucuronidated. Plasma samples (10, 20, 30 min p.i., n = 5-6), obtained from human subjects receiving 250–300 MBq (S)-[18F]1 showed 97.2, 95.4, and 91.0% of unchanged radioligand, respectively. In urine samples (90 min p.i.) the fraction of unchanged radioligand was only 2.6% and three major radiometabolites were detected. The one with the highest percentage, also found in plasma, matched the glucuronide formed in vitro. Only a small amount of debenzylated metabolite was detected. In conclusion, our metabolic study, in particular the high fractions of unchanged radioligand in plasma, confirms the suitability of (S)-[18F]1 as PET radioligand for sigma-1 receptor imaging.
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Sigma-1 Receptor Inhibition Reduces Neuropathic Pain Induced by Partial Sciatic Nerve Transection in Mice by Opioid-Dependent and -Independent Mechanisms. Front Pharmacol 2019; 10:613. [PMID: 31263413 PMCID: PMC6584826 DOI: 10.3389/fphar.2019.00613] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/15/2019] [Indexed: 12/12/2022] Open
Abstract
Sigma-1 (σ1) receptor antagonists are promising tools for neuropathic pain treatment, but it is unknown whether σ1 receptor inhibition ameliorates the neuropathic signs induced by nerve transection, in which the pathophysiological mechanisms and response to drug treatment differ from other neuropathic pain models. In addition, σ1 antagonism ameliorates inflammatory pain through modulation of the endogenous opioid system, but it is unknown whether this occurs during neuropathic pain. We investigated the effect of σ1 inhibition on the painful hypersensitivity associated with the spared nerve injury (SNI) model in mice. Wild-type (WT) mice developed prominent cold (acetone test), mechanical (von Frey test), and heat hypersensitivity (Hargreaves test) after SNI. σ1 receptor knockout (ခσ1-KO) mice did not develop cold allodynia and showed significantly less mechanical allodynia, although they developed heat hyperalgesia after SNI. The systemic acute administration of the selective σ1 receptor antagonist S1RA attenuated all three types of SNI-induced hypersensitivity in WT mice. These ameliorative effects of S1RA were reversed by the administration of the σ1 agonist PRE-084, and were absent in σ1-KO mice, indicating the selectivity of S1RA-induced effects. The opioid antagonist naloxone and its peripherally restricted analog naloxone methiodide prevented S1RA-induced effects in mechanical and heat hypersensitivity, but not in cold allodynia, indicating that opioid-dependent and -independent mechanisms are involved in the effects of this σ1 antagonist. The repeated administration of S1RA twice a day during 10 days reduced SNI-induced cold, mechanical, and heat hypersensitivity without inducing analgesic tolerance during treatment. These effects were observed up to 12 h after the last administration, when S1RA was undetectable in plasma or brain, indicating long-lasting pharmacodynamic effects. These data suggest that σ1 antagonism may have therapeutic value for the treatment of neuropathic pain induced by the transection of peripheral nerves.
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Modulation by Sigma-1 Receptor of Morphine Analgesia and Tolerance: Nociceptive Pain, Tactile Allodynia and Grip Strength Deficits During Joint Inflammation. Front Pharmacol 2019; 10:136. [PMID: 30853912 PMCID: PMC6395397 DOI: 10.3389/fphar.2019.00136] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 02/06/2019] [Indexed: 12/31/2022] Open
Abstract
Sigma-1 receptor antagonism increases the effects of morphine on nociceptive pain, even in morphine-tolerant animals. However, it is unknown whether these receptors are able to modulate morphine antinociception and tolerance during inflammatory pain. Here we used a mouse model to test the modulation of morphine effects by the selective sigma-1 antagonist S1RA (MR309), by determining its effect on inflammatory tactile allodynia (von Frey filaments) and on grip strength deficits induced by joint inflammation (a measure of pain-induced functional disability), and compared the results with those for nociceptive heat pain recorded with the unilateral hot plate (55°C) test. The subcutaneous (s.c.) administration of morphine induced antinociceptive effects to heat stimuli, and restored mechanical threshold and grip strength in mice with periarticular inflammation induced by Complete Freund’s Adjuvant. S1RA (80 mg/kg, s.c.) administered alone did not induce any effect on nociceptive heat pain or inflammatory allodynia, but was able to partially reverse grip strength deficits. The association of S1RA with morphine, at doses inducing little or no analgesic-like effects when administered alone, resulted in a marked antinociceptive effect to heat stimuli and complete reversion of inflammatory tactile allodynia. However, S1RA administration did not increase the effect of morphine on grip strength deficits induced by joint inflammation. When S1RA (80 mg/kg, s.c.) was administered to morphine-tolerant animals, it rescued the analgesic-like effects of this opioid in all three pain measures. However, when S1RA was repeatedly given during the induction of morphine tolerance (and not on the day of behavioral evaluation) it failed to affect tolerance to the effects of morphine on nociceptive heat pain or inflammatory allodynia, but completely preserved the effects of this opioid on grip strength deficits. These effects of S1RA on morphine tolerance cannot be explained by pharmacokinetic interactions, given that the administration of S1RA did not modify concentrations of morphine or morphine-3-glucuronide (a major morphine metabolite) in morphine-tolerant animals in plasma or brain tissue. We conclude that sigma-1 receptors play a pivotal role in the control of morphine analgesia and tolerance in nociceptive and inflammatory pain, although in a manner dependent on the type of painful stimulus explored.
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Sigma-1 receptors control immune-driven peripheral opioid analgesia during inflammation in mice. Proc Natl Acad Sci U S A 2017; 114:8396-8401. [PMID: 28716934 PMCID: PMC5547590 DOI: 10.1073/pnas.1620068114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sigma-1 antagonism potentiates the antinociceptive effects of opioid drugs, so sigma-1 receptors constitute a biological brake to opioid drug-induced analgesia. The pathophysiological role of this process is unknown. We aimed to investigate whether sigma-1 antagonism reduces inflammatory pain through the disinhibition of the endogenous opioidergic system in mice. The selective sigma-1 antagonists BD-1063 and S1RA abolished mechanical and thermal hyperalgesia in mice with carrageenan-induced acute (3 h) inflammation. Sigma-1-mediated antihyperalgesia was reversed by the opioid antagonists naloxone and naloxone methiodide (a peripherally restricted naloxone analog) and by local administration at the inflamed site of monoclonal antibody 3-E7, which recognizes the pan-opioid sequence Tyr-Gly-Gly-Phe at the N terminus of most endogenous opioid peptides (EOPs). Neutrophils expressed pro-opiomelanocortin, the precursor of β-endorphin (a known EOP), and constituted the majority of the acute immune infiltrate. β-endorphin levels increased in the inflamed paw, and this increase and the antihyperalgesic effects of sigma-1 antagonism were abolished by reducing the neutrophil load with in vivo administration of an anti-Ly6G antibody. The opioid-dependent sigma-1 antihyperalgesic effects were preserved 5 d after carrageenan administration, where macrophages/monocytes were found to express pro-opiomelanocortin and to now constitute the majority of the immune infiltrate. These results suggest that immune cells harboring EOPs are needed for the antihyperalgesic effects of sigma-1 antagonism during inflammation. In conclusion, sigma-1 receptors curtail immune-driven peripheral opioid analgesia, and sigma-1 antagonism produces local opioid analgesia by enhancing the action of EOPs of immune origin, maximizing the analgesic potential of immune cells that naturally accumulate in painful inflamed areas.
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Genetic inactivation and pharmacological blockade of sigma-1 receptors prevent paclitaxel-induced sensory-nerve mitochondrial abnormalities and neuropathic pain in mice. Mol Pain 2014; 10:11. [PMID: 24517272 PMCID: PMC3924235 DOI: 10.1186/1744-8069-10-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 02/07/2014] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Paclitaxel, a widely-used antineoplastic drug, produces a painful peripheral neuropathy that in rodents is associated with peripheral-nerve mitochondrial alterations. The sigma-1 receptor (σ1R) is a ligand-regulated molecular chaperone involved in mitochondrial calcium homeostasis and pain hypersensitivity. This receptor plays a key role in paclitaxel-induced neuropathic pain, but it is not known whether it also modulates mitochondrial abnormalities.In this study, we used a mouse model of paclitaxel-induced neuropathic pain to test the involvement of the σ1R in the mitochondrial abnormalities associated with paclitaxel, by using genetic (σ1R knockout mice) and pharmacological (σ1R antagonist) approaches. RESULTS Paclitaxel administration to wild-type (WT) mice produced cold- and mechanical-allodynia, and an increase in the frequency of swollen and vacuolated mitochondria in myelinated A-fibers, but not in C-fibers, of the saphenous nerve. Behavioral and mitochondrial alterations were marked at 10 days after paclitaxel-administration and had resolved at day 28. In contrast, paclitaxel treatment did not induce allodynia or mitochondrial abnormalities in σ1R knockout mice. Moreover, the prophylactic treatment of WT mice with BD-1063 also prevented the neuropathic pain and mitochondrial abnormalities induced by paclitaxel. CONCLUSIONS These results suggest that activation of the σ1R is necessary for development of the sensory nerve mitochondrial damage and neuropathic pain produced by paclitaxel. Therefore, σ1R antagonists might have therapeutic value for the prevention of paclitaxel-induced neuropathy.
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(+)-Morphine attenuates the (-)-morphine-produced tail-flick inhibition via the sigma-1 receptor in the mouse spinal cord. Life Sci 2011; 89:875-7. [PMID: 21989208 PMCID: PMC3220751 DOI: 10.1016/j.lfs.2011.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/16/2011] [Accepted: 09/10/2011] [Indexed: 11/29/2022]
Abstract
AIMS We have previously demonstrated that pretreatment with (+)-morphine given intrathecally attenuates the intrathecal (-)-morphine-produced tail-flick inhibition. The phenomenon has been defined as antianalgesia against (-)-morphine-produced analgesia. Present experiments were then undertaken to determine if the antianalgesic effect induced by (+)-morphine given spinally is mediated by the stimulation of the sigma-1 receptor in the mouse spinal cord. MAIN METHODS Sigma-1 receptor ligands, N-[2-(3,4-Dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine dihydrobromide (BD1047) and (+)-pentazocine were used to determine if (+)-morphine-induced antianalgesia is mediated by the stimulation of sigma-1 receptors in the mouse spinal cord. Tail-flick test was employed to measure the nociceptive response. All compounds were given intrathecally. KEY FINDINGS Pretreatment with BD1047 (1-10 μg) or (+)-pentazocine (0.1-10 μg) dose-dependently reversed the attenuation of the (-)-morphine-produced tail-flick inhibition induced by (+)-morphine (10 pg). BD1047 and (+)-pentazocine injected alone did not affect (-)-morphine-produced tail-flick inhibition. SIGNIFICANCE The finding indicates that (+)-morphine attenuates the (-)-morphine-produced tail-flick inhibition via the activation of the sigma-1 receptors in the mouse spinal cord. Sigma-1 receptors may play an important role in opioid analgesia in the mouse spinal cord.
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Ethanol exposure in early adolescence inhibits intrinsic neuronal plasticity via sigma-1 receptor activation in hippocampal CA1 neurons. Alcohol Clin Exp Res 2011; 35:885-904. [PMID: 21314692 PMCID: PMC3083503 DOI: 10.1111/j.1530-0277.2010.01419.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND We demonstrated previously that rats exposed to chronic intermittent ethanol (CIE) vapors in early adolescence show increased magnitudes of long-term potentiation (LTP) of excitatory transmission when recorded at dendritic synapses in hippocampus. Large amplitude LTP following CIE exposure is mediated by sigma-1 receptors; however, not yet addressed is the role of sigma-1 receptors in modulating the intrinsic properties of neurons to alter their action potential firing during LTP. METHODS Activity-induced plasticity of spike firing was investigated using rat hippocampal slice recordings to measure changes in both field excitatory postsynaptic potentials (fEPSPs) and population spikes (pop. spikes) concomitantly at dendritic inputs and soma of CA1 pyramidal neurons, respectively. RESULTS We observed unique modifications in plasticity of action potential firing in hippocampal slices from CIE exposed adolescent rats, where the induction of large amplitude LTP by 100 Hz stimulations was accompanied by reduced CA1 neuronal excitability--reflected as decreased pop. spike efficacy and impaired activity-induced fEPSP-to-spike (E-S) potentiation. In contrast, LTP induction in ethanol-naïve control slices resulted in increased spike efficacy and robust E-S potentiation. E-S potentiation impairments emerged at 24 hours after CIE treatment cessation, but not before the alcohol withdrawal period, and were restored with bath-application of the sigma-1 receptor selective antagonist BD1047, but not the NMDA receptor antagonist d-AP5. Further evidence revealed a significantly shortened somatic fEPSP time course in adolescent CIE-withdrawn hippocampal slices during LTP; however, paired-pulse data show no apparent correspondence between E-S dissociation and altered recurrent feedback inhibition. CONCLUSIONS Results here suggest that acute withdrawal from adolescent CIE exposure triggers sigma-1 receptors that act to depress the efficacy of excitatory inputs in triggering action potentials during LTP. Such withdrawal-induced depression of E-S plasticity in hippocampus probably entails sigma-1 receptor modulation of 1 or several voltage-gated ion channels controlling the neuronal input-output dynamics.
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Antagonism by haloperidol and its metabolites of mechanical hypersensitivity induced by intraplantar capsaicin in mice: role of sigma-1 receptors. Psychopharmacology (Berl) 2009; 205:21-33. [PMID: 19326101 PMCID: PMC2695546 DOI: 10.1007/s00213-009-1513-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Accepted: 03/01/2009] [Indexed: 02/03/2023]
Abstract
RATIONALE We evaluated the effects of haloperidol and its metabolites on capsaicin-induced mechanical hypersensitivity (allodynia) and on nociceptive pain induced by punctate mechanical stimuli in mice. RESULTS Subcutaneous administration of haloperidol or its metabolites I or II (reduced haloperidol) dose-dependently reversed capsaicin-induced (1 microg, intraplantar) mechanical hypersensitivity of the hind paw (stimulated with a nonpainful, 0.5-g force, punctate stimulus). The order of potency of these drugs to induce antiallodynic effects was the order of their affinity for brain sigma-1 (sigma(1)) receptor ([(3)H](+)-pentazocine-labeled). Antiallodynic activity of haloperidol and its metabolites was dose-dependently prevented by the selective sigma(1) receptor agonist PRE-084, but not by naloxone. These results suggest the involvement of sigma(1) receptors, but discard any role of the endogenous opioid system, on the antiallodynic effects. Dopamine receptor antagonism also appears unlikely to be involved in these effects, since the D(2)/D(3) receptor antagonist (-)-sulpiride, which had no affinity for sigma(1) receptors, showed no antiallodynic effect. None of these drugs modified hind-paw withdrawal after a painful (4 g force) punctate mechanical stimulus in noncapsaicin-sensitized animals. As expected, the control drug gabapentin showed antiallodynic but not antinociceptive activity, whereas clonidine exhibited both activities and rofecoxib, used as negative control, showed neither. CONCLUSION These results show that haloperidol and its metabolites I and II produce antiallodynic but not antinociceptive effects against punctate mechanical stimuli and suggest that their antiallodynic effect may be due to blockade of sigma(1) receptors but not to dopamine receptor antagonism.
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Involvement of the sigma1 (sigma1) receptor in the anti-amnesic, but not antidepressant-like, effects of the aminotetrahydrofuran derivative ANAVEX1-41. Br J Pharmacol 2007; 152:267-79. [PMID: 17641675 PMCID: PMC1978257 DOI: 10.1038/sj.bjp.0707386] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 05/04/2007] [Accepted: 05/22/2007] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Tetrahydro-N, N-dimethyl-5, 5-diphenyl-3-furanmethanamine hydrochloride (ANAVEX1-41) is a potent muscarinic and sigma(1) (sigma (1)) receptor ligand. The sigma (1) receptor modulates glutamatergic and cholinergic responses in the forebrain and selective agonists are potent anti-amnesic and antidepressant DRUGS. WE HAVE HERE ANALYSED THE SIGMA (1) COMPONENT IN THE BEHAVIOURAL EFFECTS OF ANAVEX1-41. EXPERIMENTAL APPROACH Binding of ANAVEX1-41 to muscarinic and sigma (1) receptors were measured using cell membranes. Behavioural effects of ANAVEX1-41 were tested in mice using memory (spontaneous alternation, passive avoidance, water-maze) and antidepressant-like activity (forced swimming) procedures. KEY RESULTS In vitro, ANAVEX1-41 was a potent muscarinic (M(1)>M(3), M(4)>M(2) with K(i) ranging from 18 to 114 nM) and selective sigma (1) ligand (sigma (1), K(i)=44 nM; sigma (2), K(i)=4 microM). In mice, ANAVEX1-41 failed to affect learning when injected alone (0.03-1 mg kg(-1)), but attenuated scopolamine-induced amnesia with a bell-shaped dose response (maximum at 0.1 mg kg(-1)). The sigma (1) antagonist BD1047 blocked the anti-amnesic effect of ANAVEX1-41 on both short- and long-term memories. Pretreatment with a sigma (1) receptor-directed antisense oligodeoxynucleotide prevented effects of ANAVEX1-41 only in the passive avoidance procedure, measuring long-term memory. ANAVEX1-41 reduced behavioural despair at 30 and 60 mg kg(-1), without involving the sigma (1) receptor, as it was not blocked by BD1047 or the antisense oligodeoxynucleotide. CONCLUSIONS AND IMPLICATIONS ANAVEX1-41 is a potent anti-amnesic drug, acting through muscarinic and sigma (1) receptors. The latter component may be involved in the enhancing effects of the drug on long-term memory processes.
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