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Akbarian F, Rossi C, Costers L, D'hooghe MB, D'haeseleer M, Nagels G, Van Schependom J. The spectral slope as a marker of excitation/inhibition ratio and cognitive functioning in multiple sclerosis. Hum Brain Mapp 2023; 44:5784-5794. [PMID: 37672569 PMCID: PMC10619404 DOI: 10.1002/hbm.26476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/09/2023] [Accepted: 08/20/2023] [Indexed: 09/08/2023] Open
Abstract
Multiple sclerosis (MS) is a neurodegenerative disease characterized by neuronal and synaptic loss, resulting in an imbalance of excitatory and inhibitory synaptic transmission and potentially cognitive impairment. Current methods for measuring the excitation/inhibition (E/I) ratio are mostly invasive, but recent research combining neurocomputational modeling with measurements of local field potentials has indicated that the slope with which the power spectrum of neuronal activity captured by electro- and/or magnetoencephalography rolls off, is a non-invasive biomarker of the E/I ratio. A steeper roll-off is associated with a stronger inhibition. This novel method can be applied to assess the E/I ratio in people with multiple sclerosis (pwMS), detect the effect of medication such as benzodiazepines, and explore its utility as a biomarker for cognition. We recruited 44 healthy control subjects and 95 pwMS who underwent resting-state magnetoencephalographic recordings. The 1/f spectral slope of the neural power spectra was calculated for each subject and for each brain region. As expected, the spectral slope was significantly steeper in pwMS treated with benzodiazepines (BZDs) compared to pwMS not receiving BZDs (p = .01). In the sub-cohort of pwMS not treated with BZDs, we observed a steeper slope in cognitively impaired pwMS compared to cognitively preserved pwMS (p = .01) and healthy subjects (p = .02). Furthermore, we observed a significant correlation between 1/f spectral slope and verbal and spatial working memory functioning in the brain regions located in the prefrontal and parietal cortex. In this study, we highlighted the value of the spectral slope in MS by quantifying the effect of benzodiazepines and by putting it forward as a potential biomarker of cognitive deficits in pwMS.
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Affiliation(s)
- Fahimeh Akbarian
- Department of Electronics and Informatics (ETRO)Vrije Universiteit BrusselBrusselsBelgium
- AIMS LabCenter for Neurosciences, Vrije Universiteit BrusselBrusselsBelgium
| | - Chiara Rossi
- Department of Electronics and Informatics (ETRO)Vrije Universiteit BrusselBrusselsBelgium
- AIMS LabCenter for Neurosciences, Vrije Universiteit BrusselBrusselsBelgium
| | - Lars Costers
- AIMS LabCenter for Neurosciences, Vrije Universiteit BrusselBrusselsBelgium
- icometrixLeuvenBelgium
| | | | - Miguel D'haeseleer
- National MS Center MelsbroekMelsbroekBelgium
- Department of NeurologyUZ BrusselBrusselsBelgium
| | - Guy Nagels
- AIMS LabCenter for Neurosciences, Vrije Universiteit BrusselBrusselsBelgium
- Department of NeurologyUZ BrusselBrusselsBelgium
- St Edmund HallUniversity of OxfordOxfordUK
| | - Jeroen Van Schependom
- Department of Electronics and Informatics (ETRO)Vrije Universiteit BrusselBrusselsBelgium
- AIMS LabCenter for Neurosciences, Vrije Universiteit BrusselBrusselsBelgium
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Lee SH, Lee GM, Lee DR, Lee JU. Factors related to paradoxical reactions during propofol-induced sedated endoscopy. Scand J Gastroenterol 2019; 54:371-376. [PMID: 30931652 DOI: 10.1080/00365521.2019.1585938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Objective: The factors related to paradoxical excitement during propofol-induced sedation remain unclear. We aimed to investigate this issue during sedated upper endoscopy. Material and methods: Among the health examinees scheduled for sedated upper endoscopy from June 2017 to December 2017, 421 participated in the study. Endoscopists were blinded to the information about the examinees and evaluated the development of paradoxical reactions. Propofol was exclusively used as the sedative agent via intermittent bolus injection. A multiple logistic regression analysis was performed to investigate the factors associated with paradoxical reactions. Results: The incidence of paradoxical reactions was 16.1%. Anxiety (adjusted odds ratio: 2.76; 95% confidence interval: 1.46 - 5.27; p = .002) and age (odds ratio: 0.92; 95% confidence interval: 0.89 - 0.96; p < .001) were significantly associated with paradoxical reactions. Of the nine items of the anxiety questionnaire, four had independent and significant associations with paradoxical reactions (i.e., excess worry, sleeping problems, somatic symptoms, and health concerns; odds ratios: 2.38, 2.71, 2.27 and 2.39, respectively). Conclusion: Propofol-induced paradoxical reactions tend to occur when an individual has anxiety and is of a young age. Further large population-based studies should be performed to confirm this phenomenon.
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Affiliation(s)
- Seung Hwa Lee
- a Center for Health Promotion and Endoscopy, Seohae Hospital , Seocheon , South Korea
| | - Gyu Min Lee
- b Center for Health Promotion and Endoscopy, Wonkwang University School of Medicine , Gunpo , South Korea
| | - Dong Ryul Lee
- b Center for Health Promotion and Endoscopy, Wonkwang University School of Medicine , Gunpo , South Korea
| | - Jung Un Lee
- b Center for Health Promotion and Endoscopy, Wonkwang University School of Medicine , Gunpo , South Korea
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Alterations of Gabaergic Activity by Amino-Oxyacetic Acid Influence Barbiturate- and Ethanol-Induced Sleep Time in Long-Sleep and Short-Sleep Mice. PSYCHOLOGICAL RECORD 2017. [DOI: 10.1007/bf03395892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
Anxiety is common among patients receiving intensive care. We discuss the signs and symptoms of anxiety in the intensive care unit. Appropriate treatment of anxiety should be initiated in a timely fashion so that patient compliance with treatment will be enhanced and the morbidity associated with critical illness can be reduced. Pharmacological and nonpharmacological strategies for management of anxiety are also presented.
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Affiliation(s)
- Mark H. Pollack
- From the Anxiety Disorders Program, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Theodore A. Stern
- From the Resident Psychiatric Consultation Service, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
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Ahn KH, Sewell A, Elander J, Pittman B, Ranganathan M, Gunduz-Bruce H, Krystal J, D'Souza DC. Role of GABA Deficit in Sensitivity to the Psychotomimetic Effects of Amphetamine. Neuropsychopharmacology 2015; 40:2822-31. [PMID: 25953357 PMCID: PMC4864658 DOI: 10.1038/npp.2015.132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/26/2015] [Accepted: 04/20/2015] [Indexed: 11/10/2022]
Abstract
Some schizophrenia patients are more sensitive to amphetamine (AMPH)-induced exacerbations in psychosis-an effect that correlates with higher striatal dopamine release. This enhanced vulnerability may be related to gamma-aminobutyric acid (GABA) deficits observed in schizophrenia. We hypothesized that a pharmacologically induced GABA deficit would create vulnerability to the psychotomimetic effects to the 'subthreshold' dose of AMPH in healthy subjects, which by itself would not induce clinically significant increase in positive symptoms. To test this hypothesis, a GABA deficit was induced by intravenous infusion of iomazenil (IOM; 3.7 μg/kg), an antagonist and partial inverse agonist of benzodiazepine receptor. A subthreshold dose of AMPH (0.1 mg/kg) was administered by intravenous infusion. Healthy subjects received placebo IOM followed by placebo AMPH, active IOM followed by placebo AMPH, placebo IOM followed by active AMPH, and active IOM followed by active AMPH in a randomized, double-blind crossover design over 4 test days. Twelve healthy subjects who had a subclinical response to active AMPH alone were included in the analysis. Psychotomimetic effects (Positive and Negative Syndrome Scale (PANSS)), perceptual alterations (Clinician Administered Dissociative Symptoms Scale (CADSS)), and subjective effects (visual analog scale) were captured before and after the administration of drugs. IOM significantly augmented AMPH-induced peak changes in PANSS positive symptom subscale and both subjective and objective CADSS scores. There were no pharmacokinetic interactions. In conclusion, GABA deficits increased vulnerability to amphetamine-induced psychosis-relevant effects in healthy subjects, suggesting that pre-existing GABA deficits may explain why a subgroup of schizophrenia patients are vulnerable to AMPH.
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Affiliation(s)
- Kyung-Heup Ahn
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Andrew Sewell
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Jacqueline Elander
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Brian Pittman
- Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Mohini Ranganathan
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Handan Gunduz-Bruce
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - John Krystal
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Deepak Cyril D'Souza
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, West Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA,Psychiatry Service, VA Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA, Tel: +1 860 203 932 5711, Fax: +1 860 203 937 4860, E-mail:
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Malone SM, Burwell SJ, Vaidyanathan U, Miller MB, McGue M, Iacono WG. Heritability and molecular-genetic basis of resting EEG activity: a genome-wide association study. Psychophysiology 2015; 51:1225-45. [PMID: 25387704 DOI: 10.1111/psyp.12344] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Several EEG parameters are potential endophenotypes for different psychiatric disorders. The present study consists of a comprehensive behavioral- and molecular-genetic analysis of such parameters in a large community sample (N = 4,026) of adolescent twins and their parents, genotyped for 527,829 single nucleotide polymorphisms (SNPs). Biometric heritability estimates ranged from .49 to .85, with a median of .78. The additive effect of all SNPs (SNP heritability) varied across electrodes. Although individual SNPs were not significantly associated with EEG parameters, several genes were associated with delta power. We also obtained an association between the GABRA2 gene and beta power (p < .014), consistent with findings reported by others, although this did not survive Bonferroni correction. If EEG parameters conform to a largely polygenic model of inheritance, larger sample sizes will be required to detect individual variants reliably.
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Affiliation(s)
- Stephen M Malone
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota, USA
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GABA Deficits Enhance the Psychotomimetic Effects of Δ9-THC. Neuropsychopharmacology 2015; 40:2047-56. [PMID: 25728472 PMCID: PMC4839528 DOI: 10.1038/npp.2015.58] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 02/09/2015] [Accepted: 02/18/2015] [Indexed: 11/08/2022]
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Schoenfeld TJ, Cameron HA. Adult neurogenesis and mental illness. Neuropsychopharmacology 2015; 40:113-28. [PMID: 25178407 PMCID: PMC4262910 DOI: 10.1038/npp.2014.230] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 02/07/2023]
Abstract
Several lines of evidence suggest that adult neurogenesis, the production of new neurons in adulthood, may play a role in psychiatric disorders, including depression, anxiety, and schizophrenia. Medications and other treatments for mental disorders often promote the proliferation of new neurons; the time course for maturation and integration of new neurons in circuitry parallels the delayed efficacy of psychiatric therapies; adverse and beneficial experiences similarly affect development of mental illness and neurogenesis; and ablation of new neurons in adulthood alters the behavioral impact of drugs in animal models. At present, the links between adult neurogenesis and depression seem stronger than those suggesting a relationship between new neurons and anxiety or schizophrenia. Yet, even in the case of depression there is currently no direct evidence for a causative role. This article reviews the data relating adult neurogenesis to mental illness and discusses where research needs to head in the future.
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Affiliation(s)
- Timothy J Schoenfeld
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Heather A Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA,Section on Neuroplasticity, NIMH, 35 Convent Drive, Building 35/3C915, Bethesda, MD 20892-3718, USA, Tel: +1 301 496 3814, Fax: +1 301 480 4564, E-mail:
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Tolerance to the rate-increasing and not rate-decreasing effects of pregnanolone in rats. Behav Pharmacol 2014; 21:736-44. [PMID: 20859199 DOI: 10.1097/fbp.0b013e32833fa79d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Chronic treatment with benzodiazepines, which positively modulate γ-aminobutyric acidA (GABAA) receptors, can lead to the development of tolerance. Similar effects might also occur during chronic treatment with positive modulators acting at other sites on GABAA receptors (e.g. neuroactive steroids). In this study, tolerance and cross tolerance were examined in seven rats treated daily with the neuroactive steroid pregnanolone (25.6 mg/kg/day) and responding under a fixed ratio 10 schedule of food presentation. Dose-effect curves were determined for positive GABAA modulators (pregnanolone, flunitrazepam, midazolam, and pentobarbital), and other drugs (ketamine and morphine) before, during, and after chronic treatment. Initially, daily pregnanolone administration increased responding; although tolerance developed to the rate-increasing effects after 14 weeks, tolerance did not develop to the rate-decreasing effects. The potencies of pregnanolone, midazolam, and morphine to decrease responding did not change during treatment, whereas flunitrazepam was more potent and pentobarbital and ketamine were less potent during treatment as compared to before treatment. Pregnanolone and midazolam were more potent after treatment than before treatment. The development of tolerance to the rate-increasing effects of pregnanolone indicates that neuroadaptations occur during chronic treatment; the fact that tolerance develops to only some effects suggests that the behavioral consequences of these neuroadaptations are limited.
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Talarek S, Orzelska J, Listos J, Mazur A, Fidecka S. Effects of chronic flunitrazepam treatment schedule on therapy-induced sedation and motor impairment in mice. Pharmacol Rep 2013; 65:50-8. [PMID: 23563023 DOI: 10.1016/s1734-1140(13)70963-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 10/08/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of the present study was to examine whether different treatment schedules could be associated with tolerance development to the ataxic and sedative effects of flunitrazepam in mice. METHODS Effects of repeated flunitrazepam administration were studied in the rotarod and the chimney test for motor coordination and in a photocell apparatus for locomotor activity in mice. Flunitrazepam doses varied in particular types of injections or in different experiment duration periods. RESULTS Repeated flunitrazepam administration (1 mg/kg, sc and 2 mg/kg, ip) for 8 consecutive days induced tolerance to the motor impairing effects of flunitrazepam in mice, both in the rotarod and the chimney test. In turn, no tolerance developed to sedative flunitrazepam effects, regarding either dose level, injection type or treatment duration. CONCLUSIONS Those findings confirmed the previous observations that tolerance to benzodiazepines was not simultaneous for each pharmacological property of the drugs. Interestingly enough, an acute dose of flunitrazepam (1 mg/kg, sc) in our study enhanced locomotor activity of mice.
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Affiliation(s)
- Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki 4A, PL 20-093, Lublin, Poland.
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Anxiolytic-like effects of somatostatin isoforms SST 14 and SST 28 in two animal models (Rattus norvegicus) after intra-amygdalar and intra-septal microinfusions. Psychopharmacology (Berl) 2011; 216:557-67. [PMID: 21424237 DOI: 10.1007/s00213-011-2248-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 02/25/2011] [Indexed: 12/19/2022]
Abstract
RATIONALE AND OBJECTIVES Somatostatin (SST) isoforms, SST 14 and SST 28, inhibit regulatory hormones in the periphery (e.g., growth hormone) and are widely distributed in the brain. In recent experiments, intracerebroventricular (ICV) SST produced anxiolytic-like effects in both behavioral and electrophysiological models. The sites of action of these anxiolytic effects in the brain, however, and the relative contributions of SST 14 and SST 28 to these effects are unknown. MATERIALS AND METHODS Anxiolytic effects were assessed in the plus-maze and shock-probe tests after (1) intra-amygdalar microinfusion of SST 14 (0.5 or 3 μg per hemisphere) or SST 28 (3 μg per hemisphere), (2) intra-septal microinfusion of SST 14 (0.5 or 1.5 μg per hemisphere) or SST 28 (1.5 μg per hemisphere), or (3) intra-striatal microinfusion of SST 14 (3 μg per hemisphere). RESULTS Intra-amygdalar and intra-septal microinfusions of SST 14 and SST 28 produced robust anxiolytic-like effects in the behavioral tests, unlike intra-striatal microinfusions. The magnitude of the anxiolytic effects in the amygdala and septum were comparable to those found previously with ICV SST 14, ICV L-779976, an SST (sst2) receptor agonist, and ICV diazepam, a classical benzodiazepine anxiolytic. CONCLUSIONS SST receptors in the septum and amygdala are responsive to both SST 14 and SST 28, but not those in the striatum. Although no obvious differences in the anxiolytic-like effects of the isoforms were detected, quantitative or even qualitative differences in their specific anxiolytic effects may occur in different sub-regions of the septum and amygdala, as has been found for benzodiazepine anxiolytics.
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Braidy HF, Singh P, Ziccardi VB. Safety of Deep Sedation in an Urban Oral and Maxillofacial Surgery Training Program. J Oral Maxillofac Surg 2011; 69:2112-9. [DOI: 10.1016/j.joms.2011.04.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/12/2011] [Accepted: 04/18/2011] [Indexed: 11/30/2022]
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Ahn K, Gil R, Seibyl J, Sewell RA, D'Souza DC. Probing GABA receptor function in schizophrenia with iomazenil. Neuropsychopharmacology 2011; 36:677-83. [PMID: 21068719 PMCID: PMC3055690 DOI: 10.1038/npp.2010.198] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several lines of evidence from post-mortem, brain imaging, and genetic studies in schizophrenia patients suggest that Gamma-amino butyric acid (GABA) deficits may contribute to the pathophysiology of schizophrenia. Pharmacological induction of a transient GABA-deficit state has been shown to enhance vulnerability of healthy subjects to the psychotomimetic effects of various drugs. Exacerbating or creating a GABA deficit was hypothesized to induce or unmask psychosis in schizophrenia patients, but not in healthy controls. To test this hypothesis, a transient GABA deficit was pharmacologically induced in schizophrenia patients and healthy controls using iomazenil, an antagonist and partial inverse agonist of the benzodiazepine receptor. In a double-blind, randomized, placebo-controlled study, clinically stable chronic schizophrenia patients (n=13) received iomazenil (3.7 μg administered intravenously over 10 min). Psychosis was measured using the Brief Psychiatric Rating Scale and perceptual alterations were measured using the Clinician Administered Dissociative Symptoms Scale before and after iomazenil administration. These data were compared with the effects of iomazenil in healthy subjects (n=20). Iomazenil produced increases in psychotic symptoms and perceptual alterations in schizophrenia patients, but not in healthy controls. The greater vulnerability of schizophrenia patients to the effects of iomazenil relative to controls provides further support for the GABA-deficit hypothesis of schizophrenia.
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Affiliation(s)
- Kyungheup Ahn
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Roberto Gil
- Department of Psychiatry, Columbia University School of Medicine, New York, NY, USA
| | - John Seibyl
- Institute for Neurodegenerative Disorders, New Haven, CT, USA
| | - Richard Andrew Sewell
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Deepak Cyril D'Souza
- Psychiatry Service, VA Connecticut Healthcare System, West Haven, CT, USA,Abraham Ribicoff Research Facilities, Connecticut Mental Health Center, New Haven, CT, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Psychiatry Service, 116A, VA Connecticut Healthcare System, 950 Campbell Avenue, West Haven, CT 06516, USA, Tel: +1 03 932 5711x 2594, Fax: +1 03 937 4860, E-mail:
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Talarek S, Orzelska J, Listos J, Fidecka S. Effects of sildenafil treatment on the development of tolerance to diazepam-induced motor impairment and sedation in mice. Pharmacol Rep 2011; 62:627-34. [PMID: 20885003 DOI: 10.1016/s1734-1140(10)70320-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 11/19/2009] [Indexed: 12/17/2022]
Abstract
We studied the effects of sildenafil, a selective inhibitor of PDE5, on the development and the expression of tolerance to diazepam (DZ)-induced motor impairment and sedation in mice. DZ-induced motor incoordination was assessed by the rotarod and chimney tests, and DZ-induced sedation was examined using a photocell apparatus. Sildenafil treatment enhanced the development of tolerance to the motor impairing effects, but not to the sedative effects, of DZ. Sildenafil treatment did not affect the expression of tolerance to DZ-induced motor impairment and sedation in mice. Our results suggest that sildenafil treatment, at least in part, affects the development of DZ tolerance.
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Affiliation(s)
- Sylwia Talarek
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Staszica 4, PL 20-081 Lublin, Poland
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Abstract
AbstractAnimal research suggests that central serotonergic neurons are involved in behavioral suppression, particularly anxiety-related inhibition. The hypothesis linking decreased serotonin transmission to reduced anxiety as the mechanism in the anxiolytic activity of benzodiazepines conflicts with most clinical observations. Serotonin antagonists show no marked capacity to alleviate anxiety. On the other hand, clinical signs of reduced serotonergic transmission (low 5-HIAA levels in the cerebrospinal fluid) are frequently associated with aggressiveness, suicide attempts, and increased anxiety. The target article attempts to reconcile such human and animal findings by investigating whether anxiety reduction or increased impulsivity is more Likely to account for animal behavioral changes associated with decreased serotonergic transmission. The effects of manipulating central serotonin in experimental anxiety paradigms in animals (punishment, extinction, novelty) are reviewed and compared with the effects of antianxiety drugs. Anxiety seems neither necessary nor sufficient to induce control by serotonergic neurons on behavior. Further evidence suggests that behavioral effects of anxiolytics thought to be mediated by decreases in anxiety are not caused by the ability of these drugs to reduce serotonin transmission. Blockade of serotonin transmission, especially at the level of the substantia nigra, results in a shift of behavior toward facilitation of responding. This behavioral shift is particularly marked when there is competition between acting and restraining response tendencies and when obstacles prevent the immediate attainment of an anticipated reward. It is proposed that serotonergic neurons are involved not only in behavioral arousal but also in enabling the organism to arrange or tolerate delay before acting. Decreases in serotonin transmission seem to be associated with the increased performance of behaviors that are usually suppressed, though not necessarily because of the alleviation of anxiety, which might contribute to the suppression.
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Kim I, Shu CW, Xu W, Shiau CW, Grant D, Vasile S, Cosford NDP, Reed JC. Chemical biology investigation of cell death pathways activated by endoplasmic reticulum stress reveals cytoprotective modulators of ASK1. J Biol Chem 2008; 284:1593-603. [PMID: 19004820 DOI: 10.1074/jbc.m807308200] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The accumulation of unfolded proteins in the endoplasmic reticulum (ER) is caused by many disease-relevant conditions, inducing conserved signaling events collectively known as the unfolded protein response. When ER stress is excessive or prolonged, cell death (usually occurring by apoptosis) is triggered. We undertook a chemical biology approach for investigating mechanisms of ER stress-induced cell death. Using a cell-based high throughput screening assay to identify compounds that rescued a neuronal cell line from thapsigargin-induced cell death, we identified benzodiazepinones that selectively inhibit cell death caused by inducers of ER stress (thapsigargin and tunicamycin) but not by inducers of extrinsic (tumor necrosis factor) or intrinsic (mitochondrial) cell death pathways. The compounds displayed activity in several cell lines and primary cultured neurons. Mechanism of action studies revealed that these compounds inhibit ER stress-induced activation of p38 MAPK and kinases responsible for c-Jun phosphorylation. Active benzodiazepinones suppressed cell death at the level of apoptotic signal kinase-1 (ASK1) within the IRE1 pathway but without directly inhibiting the kinase activity of ASK1 or >400 other kinases tested. Rather, active compounds enhanced phosphorylation of serine 967 of ASK1, promoting ASK1 binding to 14-3-3, an event associated with suppression of ASK1 function. Reducing ASK1 protein expression using small interfering RNA also protected cells from ER stress-induced apoptosis, confirming the importance of this protein kinase. Taken together, these findings demonstrate an essential role for ASK1 in cell death induced by ER stress. The compounds identified may prove useful for revealing endogenous mechanisms that regulate inhibitory phosphorylation of ASK1.
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Affiliation(s)
- InKi Kim
- Burnham Center for Chemical Genomics, Burnham Institute for Medical Research, La Jolla, California 92037, USA
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Tien LT, Ma T, Fan LW, Loh HH, Ho IK. Autoradiographic analysis of GABAA receptors in mu-opioid receptor knockout mice. Neurochem Res 2007; 32:1891-7. [PMID: 17562169 DOI: 10.1007/s11064-007-9373-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
Anatomical evidence indicates that gamma-aminobutyric acid (GABA)-ergic and opioidergic systems are closely linked and act on the same neurons. However, the regulatory mechanisms between GABAergic and opioidergic system have not been well characterized. In the present study, we investigated whether there are changes in GABA(A) receptors in mice lacking mu-opioid receptor gene. The GABA(A) receptor binding was carried out by autoradiography using [(3)H]-muscimol (GABA(A)), [(3)H]-flunitrazepam (FNZ, native type 1 benzodiazepine) and [(35)S]-t-butylbicyclophosphorothionate (TBPS, binding to GABA(A)-gated chloride channels) in brain slices of wild type and mu-opioid receptor knockout mice. The binding of [(3)H]-FNZ in mu-opioid receptor knockout mice was significantly higher than that of the wild type controls in most of the cortex and hippocampal CA1 and CA2 formations. mu-Opioid receptor knockout mice show significantly lower binding of [(35)S]-TBPS than that of the wild type mice in few of the cortical areas including ectorhinal cortex layers I, III, and V, but not in the hippocampus. There was no significant difference in binding of [(3)H]-muscimol between mu-opioid receptor knockout and wild type mice in the cortex and hippocampus. These data indicate that there are specific regional changes in GABA(A) receptor binding sites in mu-opioid receptor knockout mice. These data also suggest that there are compensatory up-regulation of benzodiazepine binding site of GABA(A) receptors in the cortex and hippocampus and down-regulation of GABA-gated chloride channel binding site of GABA(A) receptors in the cortex of the mu-opioid receptor knockout mice.
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Affiliation(s)
- Lu-Tai Tien
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA.
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Atack JR. The benzodiazepine binding site of GABA(A) receptors as a target for the development of novel anxiolytics. Expert Opin Investig Drugs 2006; 14:601-18. [PMID: 15926867 DOI: 10.1517/13543784.14.5.601] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Non-selective benzodiazepine (BZ) binding-site full agonists, exemplified by diazepam, act by enhancing the inhibitory effects of GABA at GABA(A) receptors containing either an alpha1, -2, -3 or -5 subunit. However, despite their proven clinical anxiolytic efficacy, such compounds possess a relatively narrow window between doses that produce anxiolysis and those that cause sedation, and are also associated with physical dependence and a potential for abuse. In the late 1980s and early 1990s a number of non-selective partial agonists, exemplified by bretazenil, pazinaclone and abecarnil, were described. Their reduced intrinsic efficacy relative to full agonists such as diazepam resulted in an improved preclinical pharmacological profile in that there was a large window between anxiolytic and sedative doses and their dependence and abuse liabilities were much lower. Unfortunately, these compounds failed, for a variety of reasons, to translate into clinical benefit, and as the public perception of BZs deteriorated interest in the area waned. However, the advent of molecular genetic and pharmacological approaches has begun to delineate which GABA(A) receptor subtypes are associated with the various pharmacological effects of the non-selective BZs. More specifically, the alpha2- and/or alpha3-containing GABA(A) receptors play a role in anxiety whereas the alpha1 subtype is involved in sedation, raising the possibility of a compound that selectively modulates alpha2- and/or alpha3-containing receptors but does not affect alpha1-containing receptors would be a non-sedating anxiolytic. In order to achieve selectivity for the alpha2/alpha3 subtypes relative to alpha1, two approaches may be used; selective affinity or selective efficacy. Selective affinity relies on a compound binding with higher affinity to the alpha2/alpha3 compared with alpha1 subtypes, but to date no such compounds have been described. On the other hand, subtype-selective efficacy relies on a compound binding to all subtypes but having different efficacies at various subtypes (relative selective efficacy, for example SL654198 or pagoclone) or having efficacy at some subtypes but none at others (absolute selective efficacy; for example, L-838417). The status of these and other BZ site compounds with claimed, but often not explicitly stated, GABA(A) subtype selectivity (such as ELB-139 and ocinaplon) will be reviewed in relation to their development as non-sedating anxiolytics for the treatment of generalised anxiety disorder.
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Affiliation(s)
- John R Atack
- Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Terlings Park, Eastwick Road, Harlow, Essex CM20 2QR, UK.
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D'Souza DC, Gil RB, Zuzarte E, MacDougall LM, Donahue L, Ebersole JS, Boutros NN, Cooper T, Seibyl J, Krystal JH. gamma-Aminobutyric acid-serotonin interactions in healthy men: implications for network models of psychosis and dissociation. Biol Psychiatry 2006; 59:128-37. [PMID: 16140281 DOI: 10.1016/j.biopsych.2005.06.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/29/2005] [Accepted: 06/17/2005] [Indexed: 11/16/2022]
Abstract
BACKGROUND This study tested the hypothesis that deficits in gamma-aminobutyric acid type A (GABA(A)) receptor function might create a vulnerability to the psychotogenic and perceptual altering effects of serotonergic (5-HT(2A/2C)) receptor stimulation. The interactive effects of iomazenil, an antagonist and partial inverse agonist of the benzodiazepine site of the GABA(A) receptor complex, and m-chlorophenylpiperazine (m-CPP), a partial agonist of 5-HT(2A/2C) receptors, were studied in 23 healthy male subjects. METHODS Subjects underwent 4 days of testing, during which they received intravenous infusions of iomazenil/placebo followed by m-CPP/placebo in a double-blind, randomized crossover design. Behavioral, cognitive, and hormonal data were collected before drug infusions and periodically for 200 min after. RESULTS Iomazenil and m-CPP interacted in a synergistic manner to produce mild psychotic symptoms and perceptual disturbances without impairing cognition. Iomazenil and m-CPP increased anxiety in an additive fashion. Iomazenil and m-CPP interacted in a synergistic manner to increase serum cortisol. CONCLUSIONS Gamma-aminobutyric acid-ergic deficits might increase the vulnerability to the psychotomimetic and perceptual altering effects of serotonergic agents. These data suggest that interactions between GABA(A) and 5-HT systems might contribute to the pathophysiology of psychosis and dissociative-like perceptual states.
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Affiliation(s)
- Deepak Cyril D'Souza
- Schizophrenia Biological Research Center, West Haven Veterans Affairs Medical Center, West Haven, Connecticut, USA.
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Jeong JH, Choi KB, Choi HJ, Song HJ, Min YS, Ko SK, Im BO, Sohn UD. Extremely Low Frequency Magnetic Fields Modulate Bicuculline-lnduced-Convulsion in Rats. Arch Pharm Res 2005; 28:587-91. [PMID: 15974447 DOI: 10.1007/bf02977763] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The effect of extremely low frequency (ELF, 60 Hz) magnetic fields (MFs) on convulsions was investigated in rats. We determined the onset and duration of convulsions induced by bicuculline alone or by co-exposure to MFs and bicuculline. In addition, we measured the GABA concentrations in the rat brains using HPLC-ECD. MFs strengthened the convulsion induced by bicuculline (0.3, 1, and 3 microg, i.c.v.), with a shortening of the onset time, but lengthening of the duration time. Co-exposure to MFs and bicuculline decreased the GABA levels in the cortex, hippocampus and hypothalamus, whereas MFs alone reduced the level of GABA only in the hippocampus. These results suggest that the exposure to MFs may modulate bicuculline-induced convulsions due to GABA neurotransmissions in rat brains.
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Affiliation(s)
- Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung Ang University, Seoul 156-756, Korea
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31
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Jeong JH, Choi KB, Moon NJ, Park ES, Sohn UD. Benzodiazepine system is involved in hyperalgesia in rats induced by the exposure to extremely low frequency magnetic fields. Arch Pharm Res 2005; 28:238-42. [PMID: 15789758 DOI: 10.1007/bf02977722] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Many reports demonstrate that extremely low frequency magnetic fields (ELF MFs, 60 Hz) may be involved in hyperalgesia. In a previous investigation, we suggested that MFs may produce hyperalgesia and such a response may be regulated by the benzodiazepine system. In order to further confirm this effect of MFs, we used diazepam and/or flumazenil with MFs exposure. When testing the pain threshold of rats using hot plate tests, MFs or diazepam (0.5 microg, i.c.v.; a benzodiazepine receptor agonist) induced hyperalgesic effects with the reduction of latency. These effects were blocked by a pretreatment of flumazenil (1.5 mg/kg, i.p.; a benzodiazepine receptor antagonist). When the rats were exposed simultaneously to MFs and diazepam, the latency tended to decrease without statistical significance. The induction of hyperalgesia by co-exposure to MFs and diazepam was also blocked by flumazenil. However, the pretreatment of GABA receptor antagonists such as bicuculline (0.1 microg, i.c.v.; a GABA(A) antagonist) or phaclofen (10 microg, i.c.v.; a GABA(B) antagonist) did not antagonize the hyperalgesic effect of MFs. These results suggest that the benzodiazepine system may be involved in MFs-induced hyperalgesia.
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Affiliation(s)
- Ji Hoon Jeong
- Department of Pharmacology, College of Pharmacy, Chung Ang University, Seoul 156-756, Korea
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Judge SJ, Ingram CD, Gartside SE. GABA receptor modulation of 5-HT neuronal firing: characterization and effect of moderate in vivo variations in glucocorticoid levels. Neurochem Int 2004; 45:1057-65. [PMID: 15337305 DOI: 10.1016/j.neuint.2004.05.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Accepted: 05/11/2004] [Indexed: 10/26/2022]
Abstract
Evidence from electrophysiological studies suggests that 5-HT neuronal firing in the dorsal raphe nucleus (DRN) may be regulated by both GABA(A) and GABA(B) receptors. Here, we addressed the question of whether the activity of individual 5-HT neurons is regulated by both GABA(A) and GABA(B) receptors. In addition, we examined the concentration-response relationships of GABA(A) and GABA(B) receptor activation and determined if GABA receptor regulation of 5-HT neuronal firing is altered by moderate alterations in circulating corticosterone. The activity of 5-HT neurons in the DRN of the rat was examined using in vitro extracellular electrophysiology. The firing of all individual neurons tested was inhibited by both the GABA(A) receptor agonist 4,5,6,7-tetrahydroisoxazolo-[5,4-c]-pyridin-3-ol hydrochloride (THIP) (25 microM) and the GABA(B) receptor agonist baclofen (1 microM). Responses to THIP (5, 10, 25 microM) and baclofen (1, 3, 10 microM) were concentration dependent and attenuated by the GABA(A) and GABA(B) receptor antagonists, bicuculline (50 microM) and phaclofen (200 microM), respectively. To examine the effects of corticosterone on the sensitivity of 5-HT neurons to GABA receptor activation, experiments were conducted on adrenalectomized animals with corticosterone maintained for two weeks at either a low or moderate level within the normal diurnal range. These changes in corticosterone levels had no significant effects on the 5-HT neuronal response to either GABA(A) or GABA(B) receptor activation. The data indicate that the control of 5-HT neuronal activity by GABA is mediated by both GABA(A) and GABA(B) receptors and that this control is insensitive to moderate changes in circulating glucocorticoid levels.
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Affiliation(s)
- Sarah J Judge
- Psychobiology Research Group, School of Neurology, Neurobiology and Psychiatry, The Medical School, University of Newcastle upon Tyne, NE2 4HH, UK.
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Abstract
The pharmacology of most addictive substances is being studied extensively, not just for their acute effects but also the mechanisms that lead to drug seeking and addiction. The understanding of how these drugs alter their effects at the molecular level with continuing use gives promise toward investigation of novel substances that may be used for treatment. Genetic predisposition and gender differences are also some of the areas where more research is needed. Women who are addicted are likely to continue drug use during pregnancy, which can have an impact on the next generation. Prevention measures at the population level are as important. Programs need to address risks, social issues, and environmental factors that promote drug use and addiction.
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Affiliation(s)
- Eric W Reynolds
- Department of Pediatrics, Division of Neonatology, University of Kentucky College of Medicine, Chandler Medical Center, 800 Rose Street, MS 477, Lexington, KY 40536, USA
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Kugaya A, Sanacora G, Verhoeff NPLG, Fujita M, Mason GF, Seneca NM, Bozkurt A, Khan SA, Anand A, Degen K, Charney DS, Zoghbi SS, Baldwin RM, Seibyl JP, Innis RB. Cerebral benzodiazepine receptors in depressed patients measured with [123I]iomazenil SPECT. Biol Psychiatry 2003; 54:792-9. [PMID: 14550678 DOI: 10.1016/s0006-3223(02)01788-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND A recent magnetic resonance spectroscopy (MRS) study revealed low gamma-aminobutyric acid (GABA) levels in the occipital cortex of depressed patients. No in vivo study has been reported to measure postsynaptic GABA receptors in the patients. METHODS Cortical benzodiazepine (BZ) binding to GABA(A) receptors was measured with [(123)I]iomazenil and single photon emission computed tomography in unmedicated patients with unipolar major depression (n = 13) and healthy subjects (n = 19). Group differences were evaluated by means of statistical parametric mapping (SPM) with partial volume correction for gray matter. Occipital GABA levels were determined by proton MRS in a subgroup (n = 6) of the patients. RESULTS No evidence of altered BZ binding was found in patients with depression compared with healthy control subjects in the SPM analysis. Although reduction in gray matter volume was observed in the frontal cortex and amygdala of the patients, partial volume correction of the atrophy did not change the result of unaltered BZ binding. GABA levels were found lower in the occipital cortex; however, BZ binding did not show significant relationship to GABA levels. CONCLUSIONS GABA(A) receptor binding measured in vivo with BZ radioligand binding are not altered in patients with depression.
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Affiliation(s)
- Akira Kugaya
- Department of Psychiatry, Yale University, New Haven, CT, USA
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Takamatsu H, Noda A, Kurumaji A, Murakami Y, Tatsumi M, Ichise R, Nishimura S. A PET study following treatment with a pharmacological stressor, FG7142, in conscious rhesus monkeys. Brain Res 2003; 980:275-80. [PMID: 12867268 DOI: 10.1016/s0006-8993(03)02987-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
FG7142 is a benzodiazepine partial inverse agonist, which is known as a pharmacological stressor. Several reports demonstrated that FG7142 produced anxiety in humans, non-human primates, and rodents, and impaired working memory in non-human primates and rodents. In this study, we examined the effect of FG7142 on cerebral blood flow and glucose metabolism using positron emission tomography (PET) in conscious rhesus monkeys. Male rhesus monkeys were intramuscularly treated with FG7142 (0.2 or 1.0 mg/kg, n=5, respectively), and regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of glucose (rCMRglc) were measured by PET 20 min and 40 min after treatment, respectively. During PET measurement, physiological parameters and plasma cortisol levels were monitored. FG7142 significantly decreased rCBF in the thalamus and rCMRglc in all brain regions examined in a dose-dependent manner without changes in physiological parameters. FG7142 also significantly increased plasma cortisol levels. The present study may provide an important insight into the understanding of the pathophysiology of anxiety and stress-related disorders in humans, and strongly suggesting that prevention of anxiety or stress is important when measuring conscious brain function.
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Affiliation(s)
- Hiroyuki Takamatsu
- The Medical and Pharmacological Research Center Foundation, Wo32, Inoyama-Town, Hakui-City, Ishikawa 925-0613, Japan.
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Allison C, Pratt JA. Neuroadaptive processes in GABAergic and glutamatergic systems in benzodiazepine dependence. Pharmacol Ther 2003; 98:171-95. [PMID: 12725868 DOI: 10.1016/s0163-7258(03)00029-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Knowledge of the neural mechanisms underlying the development of benzodiazepine (BZ) dependence remains incomplete. The gamma-aminobutyric acid (GABA(A)) receptor, being the main locus of BZ action, has been the main focus to date in studies performed to elucidate the neuroadaptive processes underlying BZ tolerance and withdrawal in preclinical studies. Despite this intensive effort, however, no clear consensus has been reached on the exact contribution of neuroadaptive processes at the level of the GABA(A) receptor to the development of BZ tolerance and withdrawal. It is likely that changes at the level of this receptor are inadequate in themselves as an explanation of these neuroadaptive processes and that neuroadaptations in other receptor systems are important in the development of BZ dependence. In particular, it has been hypothesised that as part of compensatory mechanisms to diazepam-induced chronic enhancement of GABAergic inhibition, excitatory mechanisms (including the glutamatergic system) become more sensitive [Behav. Pharmacol. 6 (1995) 425], conceivably contributing to BZ tolerance development and/or expression of withdrawal symptoms on cessation of treatment, including increased anxiety and seizure activity. Glutamate is a key candidate for changes in excitatory transmission mechanisms and BZ dependence, (1) since there are defined neuroanatomical relationships between glutamatergic and GABAergic neurons in the CNS and (2) because of the pivotal role of glutamatergic neurotransmission in mediating many forms of synaptic plasticity in the CNS, such as long-term potentiation and kindling events. Thus, it is highly possible that glutamatergic processes are also involved in the neuroadaptive processes in drug dependence, which can conceivably be considered as a form of synaptic plasticity. This review provides an overview of studies investigating changes in the GABAergic and glutamatergic systems in the brain associated with BZ dependence, with particular attention to the possible differential involvement of N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors in these processes.
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Affiliation(s)
- C Allison
- Department of Physiology and Pharmacology, Strathclyde Institute for Biomedical Sciences, University of Strathclyde, Taylor Street, G4 ONR, Glasgow, UK
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Andersen DL, Eckert AL, Tsai VWW, Burke CJ, Tannenberg AEG, Dodd PR. GABA(A) receptor sites in the developing human foetus. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 139:107-19. [PMID: 12480125 DOI: 10.1016/s0165-3806(02)00534-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
GABA(A) receptor sites were characterised in cerebral cortex tissue samples from deceased neurologically normal infants who had come to autopsy during the third trimester of pregnancy. Pharmacological parameters were obtained from homogenate binding studies which utilised the 'central-type' benzodiazepine ligands [3H]diazepam and [3H]flunitrazepam, and from the GABA activation of [3H]diazepam binding. It was found that the two radioligands behaved differently during development. The affinity of [3H]flunitrazepam for its binding site did not vary significantly between preparations, whereas the [3H]diazepam K(D) showed marked regional and developmental variations: infant tissues showed a distinctly lower affinity than adults for this ligand. The density of [3H]flunitrazepam binding sites increased approximately 35% during the third trimester to reach adult levels by term, whereas [3H]diazepam binding capacity declined slightly but steadily throughout development. The GABA activation of [3H]diazepam binding was less efficient early in the trimester, in that the affinity of the agonist was significantly lower, though it rose to adult levels by term. The strength of the enhancement response increased to adult levels over the same time-frame. The results strongly suggest that the subunit composition of cortical GABA(A) sites changes significantly during this important developmental stage.
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Affiliation(s)
- Danielle L Andersen
- Department of Biochemistry, University of Queensland, Brisbane 4072, Australia
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Romano-Torres M, Borja-Lascurain E, Chao-Rebolledo C, del-Río-Portilla Y, Corsi-Cabrera M. Effect of diazepam on EEG power and coherent activity: sex differences. Psychoneuroendocrinology 2002; 27:821-33. [PMID: 12183217 DOI: 10.1016/s0306-4530(01)00082-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benzodiazepine-steroid interactions and sex differences in brain and circulating levels of gonadal steroids, lead to hypothesized differential effects of DZ on EEG in women and men. Coherent activity has been shown to be relevant for binding information into global percepts therefore diazepam effects on EEG correlation and sex differences were assessed in a double-blind crossover study. Healthy males (9) and females (9) received a single-dose (5 mg) of diazepam or placebo. EEG was recorded with eyes open (FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2) before and 2 h after drug administration in two counterbalanced sessions. DZ selectively increased delta and theta EEG correlation among frontal regions and decreased it between right parieto-occipital (theta) and fronto-central regions (alpha2) in addition to an increase in beta2 interhemispheric correlation in men and women. Men showed increased beta1 interhemispheric correlation, decreased alpha1 and increased beta power; women showed in addition, decreased theta and alpha2 power. theta rhythm was more sensitive to DZ in women, whereas interhemispheric correlation was more affected in men. DZ had a sexually dimorphic effect on waking EEG and a disrupting effect on coherent activity, increasing balance among frontal regions and decreasing temporal coupling between anterior-posterior regions. These sex differences might be related to differences in brain organization and activational effects of female gonadal steroids which are higher in women than in men.
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Affiliation(s)
- M Romano-Torres
- Facultad de Psicología, Posgrado, Universidad Nacional Autónoma de México, Av Universidad 3004, México, DF 04510, Mexico
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Gifkins A, Greba Q, Kokkinidis L. Ventral tegmental area dopamine neurons mediate the shock sensitization of acoustic startle: A potential site of action for benzodiazepine anxiolytics. Behav Neurosci 2002. [DOI: 10.1037/0735-7044.116.5.785] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Delaney AJ, Sah P. Pathway-specific targeting of GABA(A) receptor subtypes to somatic and dendritic synapses in the central amygdala. J Neurophysiol 2001; 86:717-23. [PMID: 11495945 DOI: 10.1152/jn.2001.86.2.717] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurons in the central amygdala express two distinct types of ionotropic GABA receptor. One is the classical GABA(A) receptor that is blocked by low concentrations of bicuculline and positively modulated by benzodiazepines. The other is a novel type of ionotropic GABA receptor that is less sensitive to bicuculline but blocked by the GABA(C) receptor antagonist (1,2,5,6-tetrohydropyridine-4-yl) methylphosphinic acid (TPMPA) and by benzodiazepines. In this study, we examine the distribution of these two receptor types. Recordings of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) showed a wide variation in amplitude. Most events had amplitudes of < 50 pA, but a small minority had amplitudes >100 pA. Large-amplitude events also had rise times faster than small-amplitude events. Large-amplitude events were fully blocked by 10 microM bicuculline but unaffected by TPMPA. Small amplitude events were partially blocked by both bicuculline and TPMPA. Focal application of hypertonic sucrose to the soma evoked large-amplitude mIPSCs, whereas focal dendritic application of sucrose evoked small-amplitude mIPSCs. Thus inhibitory synapses on the dendrites of neurons in the central amygdala express both types of GABA receptor, but somatic synapses expressed purely GABA(A) receptors. Minimal stimulation revealed that inhibitory inputs arising from the laterally located intercalated cells innervate dendritic synapses, whereas inhibitory inputs of medial origin innervated somatic inhibitory synapses. These results show that different types of ionotropic GABA receptors are targeted to spatially and functionally distinct synapses. Thus benzodiazepines will have different modulatory effects on different inhibitory pathways in the central amygdala.
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Affiliation(s)
- A J Delaney
- Division of Neuroscience, John Curtin School of Medical Research, Australian National University, Canberra
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Kitabayashi Y, Ueda H, Narumoto J, Iizumi H, Tsuchida H, Murata N, Nakajima S, Fukui K. Chronic high-dose nitrazepam dependence 123I-IMP SPECT and EEG studies. Addict Biol 2001; 6:257-261. [PMID: 11900604 DOI: 10.1080/13556210120056507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A patient who took 50-100 mg nitrazepam per day for 25 years is presented. (123)I-IMP SPECT (autoradiography method) and EEG were performed sequentially on the subject during and after the withdrawal syndrome. Severe hypoperfusion of the whole brain on SPECT and diffuse slow activity on EEG were demonstrated during the withdrawal syndrome and subsequently remarkably improved. However, the hypofrontal pattern on both early and delayed images in SPECT was unchanged. The changes observed on SPECT and EEG reflect the pathophysiology of dependence and withdrawal. Additionally, the hypofrontal pattern remained unchanged suggesting that organic brain damage can develop as a result of chronic high-dose benzodiazepine abuse.
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Kellogg CK, Yao J, Pleger GL. Sex-specific effects of in utero manipulation of GABA(A) receptors on pre- and postnatal expression of BDNF in rats. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 121:157-67. [PMID: 10876028 DOI: 10.1016/s0165-3806(00)00039-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Exposure to diazepam (DZ) during the last week of in utero development in rats induces neurobehavioral effects that do not become apparent in exposed animals until young adult ages. Some of the effects are sex specific. This study evaluated the hypothesis that late gestational exposure to DZ, a positive modulator of GABA(A) receptors, affects the developmental appearance of brain-derived neurotrophic factor (BDNF), an effect that could be linked to the later consequences of the exposure. Pregnant Long-Evans rats were injected with DZ (2.5 mg/kg) over gestation days 14-20, and their male and female offspring were evaluated for levels of BDNF mRNA and protein in the cerebral cortex and hypothalamus at fetal day 20 and at postnatal ages spanning birth to young adulthood. The effects of the exposure were sex and region specific. At fetal day 20 the expression of BDNF was reduced by about 20% in the hypothalamus of males only. The early exposure affected postnatal expression of BDNF in the hypothalamus only modestly, influencing the age-related profile in both sexes. Postnatal development of BDNF in the cerebral cortex was significantly affected by the in utero exposure in males only with mRNA levels lower in the exposed group and protein levels higher during juvenile ages. At adulthood, both levels were lower in DZ-exposed males. GABA serves a role as a trophic factor during early development, and these results suggest that manipulation of GABA(A) receptors during early development could interact with the developmental action of other trophic factors thereby leading to altered neural organization and later neurobehavioral dysfunction.
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Affiliation(s)
- C K Kellogg
- Department of Brain and Cognitive Sciences, Room 186, Meliora Hall, University of Rochester, Rochester, NY 14627, USA.
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GABA receptors inhibited by benzodiazepines mediate fast inhibitory transmission in the central amygdala. J Neurosci 1999. [PMID: 10559379 DOI: 10.1523/jneurosci.19-22-09698.1999] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The amygdala is intimately involved in emotional behavior, and its role in the generation of anxiety and conditioned fear is well known. Benzodiazepines, which are commonly used for the relief of anxiety, are thought to act by enhancing the action of the inhibitory transmitter GABA. We have examined the properties of GABA-mediated inhibition in the amygdala. Whole-cell recordings were made from neurons in the lateral division of the central amygdala. Application of GABA evoked a current that reversed at the chloride equilibrium potential. Application of the GABA antagonists bicuculline or SR95531 inhibited the GABA-evoked current in a manner consistent with two binding sites. Stimulation of afferents to neurons in the central amygdala evoked an IPSC that was mediated by the release of GABA. The GABA(A) receptor antagonists bicuculline and picrotoxin failed to completely block the IPSC. The bicuculline-resistant IPSC was chloride-selective and was unaffected by GABA(B)-receptor antagonists. Furthermore, this current was insensitive to modulation by general anesthetics or barbiturates. In contrast to their actions at GABA(A) receptors, diazepam and flurazepam inhibited the bicuculline-resistant IPSC in a concentration-dependent manner. These effects were fully antagonized by the benzodiazepine site antagonist Ro15-1788. We conclude that a new type of ionotropic GABA receptor mediates fast inhibitory transmission in the central amygdala. This receptor may be a potential target for the development of new therapeutic strategies for anxiety disorders.
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Kellogg CK. Sex differences in long-term consequences of prenatal diazepam exposure: possible underlying mechanisms. Pharmacol Biochem Behav 1999; 64:673-80. [PMID: 10593189 DOI: 10.1016/s0091-3057(99)00137-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Prenatal exposure to diazepam, a benzodiazepine (BZD) compound, leads to pronounced effects on responses to stressors in exposed animals when they reach adulthood. Many of the responses are sex specific. The mechanisms mediating the effects of the exposure on the organism have not been elucidated; however, the time course for the appearance of altered function following in utero drug exposure indicates that the exposure interfered with neural organization of mechanisms mediating responses to stressors. The article discusses possible mechanisms that relate to sites of action of the drug in the developing brain: the GABA(A) receptor, and the mitochondrial BZD receptor. The mechanisms mediating the sex-specific impact of diazepam on the developing brain appear to be complex and interactive.
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Affiliation(s)
- C K Kellogg
- Department of Brain and Cognitive Sciences, University of Rochester, NY 14627, USA.
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Venturini I, Alho H, Podkletnova I, Corsi L, Rybnikova E, Pellicci R, Baraldi M, Pelto-Huikko M, Helén P, Zeneroli ML. Increased expression of peripheral benzodiazepine receptors and diazepam binding inhibitor in human tumors sited in the liver. Life Sci 1999; 65:2223-31. [PMID: 10576594 DOI: 10.1016/s0024-3205(99)00487-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The peripheral benzodiazepine receptor system triggers intracellular metabolic events and has been associated with cell proliferation. Its endogenous ligand, the diazepam binding inhibitor, contributes to steroidogenesis by promoting cholesterol delivery to the inner mitochondrial membrane. The present study was undertaken to verify whether this system is altered in tumors sited in the liver. Peripheral benzodiazepine receptors and diazepam binding inhibitor were studied using immunocytochemistry and in situ hybridization in 9 human tumors sited in the liver, in liver hyperplasia, cirrhotic nodular regeneration, intestinal adenocarcinoma and in surrounding non-tumoral tissue. Immunocytochemical staining and in situ hybridization demonstrated that peripheral benzodiazepine receptors and diazepam binding inhibitor were more prominently expressed in neoplastic cells than in non-tumoral tissue. They were present in the same cells, suggesting that diazepam binding inhibitor may act in an intracrine manner in these cells. Higher peripheral benzodiazepine receptors and diazepam binding inhibitor expression in tumor cells suggest an implication of this system in the metabolism of neoplastic cells. Furthermore the evaluation of peripheral benzodiazepine receptor and diazepam binding inhibitor expression might be useful in evaluating malignancy and in diagnostic approaches of tumors in liver tissue.
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Affiliation(s)
- I Venturini
- Cattedra di Semeiotica e Metodologia Medica, Università di Modena, Italy
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Tallman JF, Cassella JV, White G, Gallager DW. GABAA Receptors: Diversity and its Implications for CNS Disease. Neuroscientist 1999. [DOI: 10.1177/107385849900500610] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent advances in the molecular biology of GABAA receptors is described along with the impact of these advances on drug design for this family of receptors. The receptor molecular structure is described with particular emphasis on the sites to which the transmitter GABA and modulatory drugs, such as the benzodiazepines, bind. The relationship of subunit structure to the electrophysiological properties of GABAA receptors is detailed with emphasis on the functional subtyping of GABAA receptor responses. The behavioral pharmacological results of knockout and knockin models are described, along with the effects of specific drugs on sleep, anxiety, and learning in normal animals.
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Castro JL, Ricci D, Taira CA, Ramirez A. Central benzodiazepine involvement in clonidine cardiovascular actions. Can J Physiol Pharmacol 1999. [DOI: 10.1139/y99-086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is well known that the GABAergic and noradrenergic systems play an important role in blood pressure and heart rate regulation. Benzodiazepines and beta-carbolines, respectively, increase or decrease the probability of chloride-channel opening induced by GABA. The aim of this study was to determine, in conscious rats, the interaction existing between the central alpha2-adrenoceptor stimulation induced by clonidine and the facilitation or impairment of benzodiazepine receptor activity through the administration of either diazepam, a benzodiazepine receptor agonist, or methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM), an inverse benzodiazepine agonist. Clonidine (5-10 µg, intracerebroventricularly) reduced heart rate and increased mean blood pressure by activation of central alpha2-adrenoceptors. Diazepam (2 mg/kg, intravenously (i.v.)) induced an increase in heart rate, while DMCM (0.3 mg/kg, i.v.) elicited a bradycardic effect. The bradycardic effects induced by both clonidine and DMCM were antagonized by the prior administration of methylatropine (1.5 mg/kg, i.v.). DMCM (0.3 mg/kg, i.v.) prevented the clonidine effects on heart rate and mean blood pressure, while diazepam (2 mg/kg, i.v.) failed to modify these effects. Our results suggest that the bradycardic effects of clonidine are mediated by a vagal stimulation and are related to the activation of a GABAergic pathway.Key words: blood pressure, clonidine, diazepam, methyl 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM), heart rate.
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Tatsuo MA, Salgado JV, Yokoro CM, Duarte ID, Francischi JN. Midazolam-induced hyperalgesia in rats: modulation via GABA(A) receptors at supraspinal level. Eur J Pharmacol 1999; 370:9-15. [PMID: 10323274 DOI: 10.1016/s0014-2999(99)00096-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The effect of benzodiazepines on the nociceptive threshold was studied in rats using the tail-flick and the formalin tests. Systemic injection of midazolam (10 mg/kg, i.p.) induced a significant decrease of the tail-flick latency and produced a long-lasting nociceptive effect in the formalin test, thus characterising a hyperalgesic state. The hyperalgesia induced by midazolam in the tail-flick test was blocked by flumazenil, a specific antagonist for benzodiazepine sites associated with GABA(A) receptors. Picrotoxin, a Cl- channel blocker, inhibited midazolam-induced hyperalgesia in both tests. Midazolam caused hyperalgesia when administered intracerebroventricularly (i.c.v.; 25 microg) but not intrathecally (i.t.; 75 microg). I.c.v. but not i.t. (5 microg) injection of flumazenil suppressed the hyperalgesia induced by midazolam (10 mg/kg, i.p.). Combination of non-hyperalgesic doses of diazepam (10 mg/kg, i.p.) or ethanol (0.48 g/kg, oral) with midazolam (5 mg/kg, i.p.) also induced hyperalgesia. Our results demonstrate that midazolam and diazepam alone or in combination with ethanol can produce hyperalgesia by interacting with GABA(A) receptors at the supraspinal level in rats. The risk of hyperalgesia should be taken in account when these drugs are used in combination in humans.
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Affiliation(s)
- M A Tatsuo
- Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
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Grahn RE, Maswood S, McQueen MB, Watkins LR, Maier SF. Opioid-dependent effects of inescapable shock on escape behavior and conditioned fear responding are mediated by the dorsal raphe nucleus. Behav Brain Res 1999; 99:153-67. [PMID: 10512582 DOI: 10.1016/s0166-4328(98)00101-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Manipulations of the dorsal raphe nucleus (DRN) modulate the behavioral effects of exposure to inescapable shock (IS). Opiate agonists and antagonists also influence the impact of IS, but the role of the DRN in mediating these effects is unknown. The opiate antagonist naltrexone micro-injected into the region of the DRN immediately prior to IS prevented both the escape deficit and the enhancement of fear conditioning that occur 24 h later. Intra-DRN naltrexone administered at the time of later behavioral testing reduced, but did not eliminate, these effects of prior IS. Conversely, the opiate agonist morphine, in combination with a subthreshold number of 20 IS trials, induced an escape deficit and enhanced conditioned fear 24 h later. Microinjections of naltrexone into the dorsolateral periaqueductal gray area did not alter the effects of IS and electrolytic lesions of the DRN prevented the effect of the morphine-20 IS trial combination. The role of opioids in mediating the behavioral effects of IS is discussed.
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Affiliation(s)
- R E Grahn
- Department of Psychology, University of Colorado, Boulder 80309, USA.
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Hensch TK, Fagiolini M, Mataga N, Stryker MP, Baekkeskov S, Kash SF. Local GABA circuit control of experience-dependent plasticity in developing visual cortex. Science 1998; 282:1504-8. [PMID: 9822384 PMCID: PMC2851625 DOI: 10.1126/science.282.5393.1504] [Citation(s) in RCA: 694] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Sensory experience in early life shapes the mammalian brain. An impairment in the activity-dependent refinement of functional connections within developing visual cortex was identified here in a mouse model. Gene-targeted disruption of one isoform of glutamic acid decarboxylase prevented the competitive loss of responsiveness to an eye briefly deprived of vision, without affecting cooperative mechanisms of synapse modification in vitro. Selective, use-dependent enhancement of fast intracortical inhibitory transmission with benzodiazepines restored plasticity in vivo, rescuing the genetic defect. Specific networks of inhibitory interneurons intrinsic to visual cortex may detect perturbations in sensory input to drive experience-dependent plasticity during development.
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Affiliation(s)
- T K Hensch
- Laboratory for Neuronal Circuit Development, Brain Science Institute RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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