1
|
Dubovsky SL, Marshall D. Benzodiazepines Remain Important Therapeutic Options in Psychiatric Practice. PSYCHOTHERAPY AND PSYCHOSOMATICS 2022; 91:307-334. [PMID: 35504267 DOI: 10.1159/000524400] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 03/29/2022] [Indexed: 12/27/2022]
Abstract
Benzodiazepines and medications acting on benzodiazepine receptors that do not have a benzodiazepine structure (z-drugs) have been viewed by some experts and regulatory bodies as having limited benefit and significant risks. Data presented in this article support the use of these medications as treatments of choice for acute situational anxiety, chronic anxiety disorders, insomnia, alcohol withdrawal syndromes, and catatonia. They may also be useful adjuncts in the treatment of anxious depression and mania, and for medically ill patients. Tolerance develops to sedation and possibly psychomotor impairment, but not to the anxiolytic effect of benzodiazepines. Sedation can impair cognitive function in some patients, but assertions that benzodiazepines increase the risk of dementia are not supported by recent data. Contrary to popular opinion, benzodiazepines are not frequently misused or conduits to misuse of other substances in patients without substance use disorders who are prescribed these medications for appropriate indications; most benzodiazepine misuse involves medications that are obtained from other people. Benzodiazepines are usually not lethal in overdose except when ingested with other substances, especially alcohol and opioids. Benzodiazepines comprise one of the few classes of psychotropic medication the mechanisms of action of which are clearly delineated, allowing for greater precision in their clinical use. These medications, therefore, belong in the therapeutic armamentarium of the knowledgeable clinician.
Collapse
Affiliation(s)
- Steven L Dubovsky
- Department of Psychiatry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA.,Departments of Psychiatry and Medicine, University of Colorado School of Medicine, Denver, Colorado, USA
| | - Dori Marshall
- Department of Psychiatry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| |
Collapse
|
2
|
Doron R, Sever A, Handelsman A, Toledano R, Franko M, Hirshler Y, Shamir A, Burstein O, Rehavi M. GABA A Receptor Density Is Not Altered by a Novel Herbal Anxiolytic Treatment. J Mol Neurosci 2018; 65:110-117. [PMID: 29737465 DOI: 10.1007/s12031-018-1078-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/27/2018] [Indexed: 01/06/2023]
Abstract
Anxiety disorders are highly prevalent and considered a major public health concern worldwide. Current anxiolytics are of limited efficacy and associated with various side effects. Our novel herbal treatment (NHT), composed of four constituents, was shown to reduce anxiety-like behavior while precluding a common side effect caused by current anxiolytics, i.e., sexual dysfunction. Nevertheless, NHT's mechanism of action is yet to be determined. There is evidence that some medicinal herbs interact with the GABAergic system. Therefore, we aimed to examine whether NHT's anxiolytic-like effect is exerted by alterations in GABAA receptor density in the hippocampus, prefrontal cortex, and hypothalamus. The effects of 3-weeks treatment with NHT on anxiety-like behavior and locomotion were assessed using the elevated plus maze (EPM) and the open field test (OFT), respectively. Regional GABAA receptor levels were analyzed using [3H] RO15-1788 high-affinity binding assays. In stressed mice, NHT reduced anxiety-like behavior similarly to the benzodiazepine, clonazepam, while locomotion remained intact. Lack of changes or minor changes in regional GABAA receptor density in the brain were induced by NHT or clonazepam. In naive mice, performance in the EPM, locomotion and GABAA receptor densities were not altered by treatment with NHT or clonazepam. These findings support NHT as an efficacious and safe anxiolytic, although the GABAergic involvement remains to be further elucidated.
Collapse
Affiliation(s)
- Ravid Doron
- School of Behavioral Sciences, The Academic College Tel Aviv Yaffo, 6818211, Tel Aviv, Israel.
- Department of Education and Psychology, The Open University of Israel, 4353701, Ra'anana, Israel.
| | - Avital Sever
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Assaf Handelsman
- School of Behavioral Sciences, The Academic College Tel Aviv Yaffo, 6818211, Tel Aviv, Israel
| | - Roni Toledano
- Department of Education and Psychology, The Open University of Israel, 4353701, Ra'anana, Israel
| | - Motty Franko
- School of Behavioral Sciences, The Academic College Tel Aviv Yaffo, 6818211, Tel Aviv, Israel
| | - Yafit Hirshler
- Department of Education and Psychology, The Open University of Israel, 4353701, Ra'anana, Israel
| | - Alon Shamir
- Faculty of Medicine, Technion - Israel Institute of Technology, 3200003, Haifa, Israel
- Mazor Mental Health Center, 2423314, Akko, Israel
| | - Or Burstein
- School of Behavioral Sciences, The Academic College Tel Aviv Yaffo, 6818211, Tel Aviv, Israel
| | - Moshe Rehavi
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 6997801, Tel Aviv, Israel
- The Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel Aviv University, 6997801, Tel Aviv, Israel
| |
Collapse
|
3
|
Liang L, Zhou H, Zhang S, Yuan J, Wu H. Effects of gut microbiota disturbance induced in early life on the expression of extrasynaptic GABA-A receptor α5 and δ subunits in the hippocampus of adult rats. Brain Res Bull 2017; 135:113-119. [DOI: 10.1016/j.brainresbull.2017.09.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/21/2017] [Accepted: 09/26/2017] [Indexed: 12/26/2022]
|
4
|
Effects of Traumatic Stress Induced in the Juvenile Period on the Expression of Gamma-Aminobutyric Acid Receptor Type A Subunits in Adult Rat Brain. Neural Plast 2017; 2017:5715816. [PMID: 28352479 PMCID: PMC5352903 DOI: 10.1155/2017/5715816] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/18/2017] [Accepted: 02/15/2017] [Indexed: 12/04/2022] Open
Abstract
Studies have found that early traumatic experience significantly increases the risk of posttraumatic stress disorder (PTSD). Gamma-aminobutyric acid (GABA) deficits were proposed to be implicated in development of PTSD, but the alterations of GABA receptor A (GABAAR) subunits induced by early traumatic stress have not been fully elucidated. Furthermore, previous studies suggested that exercise could be more effective than medications in reducing severity of anxiety and depression but the mechanism is unclear. This study used inescapable foot-shock to induce PTSD in juvenile rats and examined their emotional changes using open-field test and elevated plus maze, memory changes using Morris water maze, and the expression of GABAAR subunits (γ2, α2, and α5) in subregions of the brain in the adulthood using western blotting and immunohistochemistry. We aimed to observe the role of GABAAR subunits changes induced by juvenile trauma in the pathogenesis of subsequent PTSD in adulthood. In addition, we investigated the protective effects of exercise for 6 weeks and benzodiazepine (clonazepam) for 2 weeks. This study found that juvenile traumatic stress induced chronic anxiety and spatial memory loss and reduced expression of GABAAR subunits in the adult rat brains. Furthermore, exercise led to significant improvement as compared to short-term BZ treatment.
Collapse
|
5
|
Brown GG, Ostrowitzki S, Stein MB, von Kienlin M, Liu TT, Simmons A, Wierenga C, Stein OY, Bruns A, Bischoff-Grethe A, Paulus M. Temporal profile of brain response to alprazolam in patients with generalized anxiety disorder. Psychiatry Res 2015. [PMID: 26211623 DOI: 10.1016/j.pscychresns.2015.06.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study investigated the temporal pattern of brain response to emotional stimuli during 28 days of alprazolam treatment among patients with generalized anxiety disorder (GAD) randomized 2:1 to drug or placebo in a double-blind design. Functional magnetic resonance imaging scans obtained during an emotion face matching task (EFMT) and an affective stimulus expectancy task (STIMEX) were performed at baseline, one hour after initial drug administration and 28 days later. Alprazolam significantly reduced scores on the Hamilton Anxiety Scale and the Penn State Worry Questionnaire after one week and 28 days of treatment. Brain activation in the amygdala during the EFMT and in the insula during the STIMEX was reduced one hour after alprazolam administration but returned to baseline levels at Day 28. Exploratory analyses revealed significant treatment differences in brain activity during the STIMEX on Day 28 in frontal lobe, caudate nucleus, middle temporal gyrus, secondary visual cortex, and supramarginal gyrus. These results are consistent with the notion that the neural mechanisms supporting sustained treatment effects of benzodiazepines in GAD differ from those underlying their acute effects.
Collapse
Affiliation(s)
- Gregory G Brown
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA.
| | - Susanne Ostrowitzki
- Neuroscience, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Murray B Stein
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Markus von Kienlin
- Neuroscience, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Thomas T Liu
- Department of Radiology, University of California San Diego, San Diego, CA, USA
| | - Alan Simmons
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Christina Wierenga
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Orah Y Stein
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA
| | - Andreas Bruns
- Neuroscience, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | | | - Martin Paulus
- Department of Psychiatry, University of California San Diego, San Diego, CA, USA; Laureate Institute for Brain Research, Tulsa, OK, USA
| |
Collapse
|
6
|
Wright BT, Gluszek CF, Heldt SA. The effects of repeated zolpidem treatment on tolerance, withdrawal-like symptoms, and GABAA receptor mRNAs profile expression in mice: comparison with diazepam. Psychopharmacology (Berl) 2014; 231:2967-79. [PMID: 24531568 DOI: 10.1007/s00213-014-3473-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a short-acting, non-benzodiazepine hypnotic that acts as a full agonist at α1-containing GABAA receptors. Overall, zolpidem purportedly has fewer instances of abuse and dependence than traditionally used benzodiazepines. However, several studies have shown that zolpidem may be more similar to benzodiazepines in terms of behavioral tolerance and withdrawal symptoms. OBJECTIVES In the current study, we examined whether subchronic zolpidem or diazepam administration produced deficits in zolpidem's locomotor-impairing effects, anxiety-like behaviors, and changes in GABAAR subunit messenger RNA (mRNA). METHODS Mice were given subchronic injections of either zolpidem (10 mg/kg), diazepam (20 mg/kg), or vehicle twice daily for 7 days. On day 8, mice were given a challenge dose of zolpidem (2 mg/kg) or vehicle before open field testing. Another set of mice underwent the same injection regimen but were sacrificed on day 8 for qRT-PCR analysis. RESULTS We found that subchronic zolpidem and diazepam administration produced deficits in the acute locomotor-impairing effects of zolpidem and increased anxiety-like behaviors 1 day after drug termination. In addition, we found that subchronic treatment of zolpidem and diazepam induced distinct but overlapping GABAAR subunit mRNA changes in the cortex but few changes in the hippocampus, amygdala, or prefrontal cortex. Levels of mRNA measured in separate mice after a single injection of either zolpidem or diazepam revealed no mRNA changes. CONCLUSIONS In mice, subchronic treatment of zolpidem and diazepam can produce deficits in the locomotor-impairing effects of zolpidem, anxiety-like withdrawal symptoms, and subunit-specific mRNA changes.
Collapse
Affiliation(s)
- Brittany T Wright
- The Department of Anatomy and Neurobiology, Neuroscience Institute, University of Tennessee Health Science Center, 855 Monroe Ave, Memphis, TN, 38163, USA
| | | | | |
Collapse
|
7
|
The behavioral pharmacology of zolpidem: evidence for the functional significance of α1-containing GABA(A) receptors. Psychopharmacology (Berl) 2014; 231:1865-96. [PMID: 24563183 DOI: 10.1007/s00213-014-3457-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/11/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Zolpidem is a positive allosteric modulator of γ-aminobutyric acid (GABA) with preferential binding affinity and efficacy for α1-subunit containing GABA(A) receptors (α1-GABA(A)Rs). Over the last three decades, a variety of animal models and experimental procedures have been used in an attempt to relate the behavioral profile of zolpidem and classic benzodiazepines (BZs) to their interaction with α1-GABA(A)Rs. OBJECTIVES This paper reviews the results of rodent and non-human primate studies that have evaluated the effects of zolpidem on motor behaviors, anxiety, memory, food and fluid intake, and electroencephalogram (EEG) sleep patterns. Also included are studies that examined zolpidem's discriminative, reinforcing, and anticonvulsant effects as well as behavioral signs of tolerance and withdrawal. RESULTS The literature reviewed indicates that α1-GABA(A)Rs play a principle role in mediating the hypothermic, ataxic-like, locomotor- and memory-impairing effects of zolpidem and BZs. Evidence also suggests that α1-GABA(A)Rs play partial roles in the hypnotic, EEG sleep, anticonvulsant effects, and anxiolytic-like of zolpidem and diazepam. These studies also indicate that α1-GABA(A)Rs play a more prominent role in mediating the discriminative stimulus, reinforcing, hyperphagic, and withdrawal effects of zolpidem and BZs in primates than in rodents. CONCLUSIONS The psychopharmacological data from both rodents and non-human primates suggest that zolpidem has a unique pharmacological profile when compared with classic BZs. The literature reviewed here provides an important framework for studying the role of different GABA(A)R subtypes in the behavioral effects of BZ-type drugs and helps guide the development of new pharmaceutical agents for disorders currently treated with BZ-type drugs.
Collapse
|
8
|
Okamoto R, Itoh Y, Murata Y, Kobayashi D, Hosoi M, Mine K. Reduction of group II metabotropic glutamate receptors during development of benzodiazepine dependence. Pharmacology 2013; 91:145-52. [PMID: 23392308 DOI: 10.1159/000346440] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 12/11/2012] [Indexed: 11/19/2022]
Abstract
Prolonged use of benzodiazepines often leads to dependence and withdrawal syndrome. However, the cellular mechanisms underlying benzodiazepine dependence have not been fully clarified. Several investigators have shown an involvement of metabotropic glutamate receptors (mGluRs) in the pathophysiology of dependence or withdrawal. This study was performed to elucidate the role of mGluRs in benzodiazepine dependence. Withdrawal signs were precipitated in mice by flumazenil injection (25 mg/kg) after continuous subcutaneous infusion of benzodiazepines for 7 days, and the effects of several Gi-coupled receptor ligands on forskolin-stimulated cyclic AMP accumulation were examined in the cerebral cortex of mice. The mRNA expression for mGluRs was determined by RT-PCR. A single injection of flumazenil precipitated typical withdrawal signs such as tail elevation and tremor in mice treated with diazepam or alprazolam, but not quazepam. The inhibitory effect of nonselective mGluR ligands on adenylate cyclase activity was diminished in mice that showed signs of benzodiazepine withdrawal. The mRNA expression levels of mGluR2 and mGluR3 were lowered in the cerebral cortex of mice pretreated with diazepam or alprazolam. Our findings suggest that the reduction in the expression of group II mGluRs subunits may be involved in the development of benzodiazepine dependence.
Collapse
Affiliation(s)
- Ritsuko Okamoto
- Department of Psychosomatic Medicine, Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka, Japan
| | | | | | | | | | | |
Collapse
|
9
|
Fraser LM, Brown RE, Hussin A, Fontana M, Whittaker A, O'Leary TP, Lederle L, Holmes A, Ramos A. Measuring anxiety- and locomotion-related behaviours in mice: a new way of using old tests. Psychopharmacology (Berl) 2010; 211:99-112. [PMID: 20454890 DOI: 10.1007/s00213-010-1873-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2009] [Accepted: 04/19/2010] [Indexed: 12/14/2022]
Abstract
RATIONALE Batteries of tests that are thought to measure different aspects of anxiety-related behaviour are used to characterise mice after genetic or pharmacological manipulation. However, because of the potentially confounding effects of repeated testing and natural intra-individual variations in behaviour over time, subjecting mice to a succession of tests is not ideal. OBJECTIVES The aim of this study was to investigate, in mice, the utility of an integrated apparatus that combines three classical tests of anxiety, the open field, elevated plus maze (EPM) and light/dark box. METHODS Mice from four different strains (CD-1, BALB/cJ, DBA/2J, C57BL/6J) were used in a series of five experiments where their behaviour was observed for 15 min in the integrated apparatus. Responses to anxiety-modulating drugs and 2-day repeated testing were evaluated. RESULTS CD-1 mice explored the apparatus thoroughly, providing measures from all areas throughout the entire testing session. Factor analysis showed that measures of locomotion and anxiety-related behaviour were dissociable. BALB/cJ, DBA/2J and C57BL/6J showed markedly different behavioural profiles, largely consistent with previous studies examining individual tests. Avoidance of aversive environments did not increase with repeated testing. In CD-1 mice, the anxiolytics diazepam and alprazolam (4 and 2 mg/kg, respectively) increased the approach towards the EPM open arms. Alprazolam also had sedative effects, whereas the anxiogenic pentylenetetrazole had no effects. CONCLUSIONS These findings suggest that the triple test is sensitive to genetic/pharmacological influences on anxiety and locomotion and that, by providing quasi-simultaneous measures from three different apparatuses, it may represent an alternative to the use of test batteries.
Collapse
Affiliation(s)
- Leanne M Fraser
- Psychology Department and Neuroscience Institute, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J1
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Starting insomnia treatment: the use of benzodiazepines versus z-hypnotics. A prescription database study of predictors. Eur J Clin Pharmacol 2008; 65:295-301. [DOI: 10.1007/s00228-008-0565-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 08/29/2008] [Indexed: 10/21/2022]
|
11
|
Yildirim Y, Akcay Y, Ozyilkan O, Celasun B. Prostate small cell carcinoma and skin metastases: a rare entity. Med Princ Pract 2008; 17:250-2. [PMID: 18408396 DOI: 10.1159/000117801] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 09/23/2007] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES To report a rare case of small cell carcinoma of the prostate with unusual skin metastasis. CLINICAL PRESENTATION AND INTERVENTIONS A 60-year-old was evaluated for difficulty in urinating. Abdominal computed tomography scans revealed a prostatic mass invading the surrounding tissues and multiple perirectal, periprostatic, para-aortic and pericaval lymph nodes. Needle biopsy specimens showed both small cell carcinoma and adenocarcinoma. He was treated with combination chemotherapy: cisplatin and etoposide and bilateral orchiectomy. After six cycles of the chemotherapy, disease progressed and the patient did not respond to salvage therapy; hence, palliative care was instituted. During the follow-up, papillary lesions were observed in the scrotal skin; biopsy showed metastatic small cell carcinoma. CONCLUSION Small cell carcinoma of the prostate is an aggressive disease with a highly metastatic potential; but skin metastases are very uncommon. It has poor prognosis despite therapy. Management resembles that of small cell carcinoma of the lung.
Collapse
Affiliation(s)
- Yesim Yildirim
- Department of Medical Oncology, Baskent University, Ankara, Turkey.
| | | | | | | |
Collapse
|
12
|
Fahey JM, Pritchard GA, Reddi JM, Pratt JS, Grassi JM, Shader RI, Greenblatt DJ. The effect of chronic lorazepam administration in aging mice. Brain Res 2006; 1118:13-24. [PMID: 16989785 DOI: 10.1016/j.brainres.2006.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Revised: 02/14/2006] [Accepted: 08/05/2006] [Indexed: 11/21/2022]
Abstract
To assess benzodiazepine tolerance in aged animals, lorazepam or vehicle was administered chronically to male Crl: CD-1(ICR)BR mice. Pharmacodynamic and neurochemical endpoints were examined on days 1 and 14 of drug administration. There was no age-related significant difference in plasma lorazepam levels. Young and middle-aged animals demonstrated behavioral tolerance to lorazepam, while the aged animals showed a similar trend which failed to reach significance. In addition, aged animals also showed a trend toward tolerance to the anticonvulsant effects of lorazepam. There were no changes in alpha1 mRNA levels in cortex or hippocampus following administration of lorazepam when compared to vehicle-treated animals in any age group. Aged animals, however, had an initial increase in alpha1 mRNA expression in cortex and hippocampus on day 1 of vehicle treatment followed by decreased expression on day 14. These age-related changes were abolished by lorazepam administration. In summary, age-related sensitivity to the effects of lorazepam was not demonstrated in the present study. However, comparison of these data to other studies indicates that the effect of chronic benzodiazepine treatment may be specific to the benzodiazepine administered, the technique used to quantify mRNA expression changes, the subunits of the GABA(A) receptor investigated and the brain region analyzed. The phenomenon of benzodiazepine sensitivity in the elderly is an area of research which remains controversial and may well be compound specific. Determining benzodiazepines that do not produce pharmacodynamic sensitivity, such as lorazepam, may allow more careful prescribing and dosing of these drugs, and perhaps even the development of specific agents which could avoid this sensitivity.
Collapse
Affiliation(s)
- Jeanne M Fahey
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine and the Division of Clinical Pharmacology, Tufts-New England Medical Center, Boston, MA 02111, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Hellión-Ibarrola MC, Ibarrola DA, Montalbetti Y, Kennedy ML, Heinichen O, Campuzano M, Tortoriello J, Fernández S, Wasowski C, Marder M, De Lima TCM, Mora S. The anxiolytic-like effects of Aloysia polystachya (Griseb.) Moldenke (Verbenaceae) in mice. JOURNAL OF ETHNOPHARMACOLOGY 2006; 105:400-8. [PMID: 16386395 DOI: 10.1016/j.jep.2005.11.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 09/16/2005] [Accepted: 11/18/2005] [Indexed: 05/05/2023]
Abstract
The aim of the present work is to demonstrate the putative sedative and anxiolytic-like effects of a hydro-ethanolic extract obtained from the aerial parts of Aloysia polystachya (Verbenaceae) in male mice using several behavioural assays. Groups of male mice orally treated with doses of 1.0, 10.0 and 100.0 mg/kg of the extract did not show any significant alteration of their locomotor activity, body temperature or motor coordination. The same treatment increased the duration of the sleeping time induced by 30.0 mg/kg i.p. of sodium pentobarbital. However, the sleeping time induced by ethyl ether was not modified by the oral administration of the extract, not confirming the putative sedative effect of the plant. The ethanolic extract also significantly increased the percentage of both entries (1.0 and 100.0 mg/kg) and the time spent (10.0 and 100.0 mg/kg) into the open arms of the elevated plus maze (EPM). Nevertheless, the binding of (3)H-flunitrazepam ((3)H-FNZ) to the benzodiazepine binding site (BDZ-bs), in washed crude synaptosomal membranes from rat cerebral cortex, was not affected by the semi-purified components from Aloysia polystachya. These results indicate an anxiolytic-like profile of action for the extract of Aloysia polystachya without sedative side effect, being this activity probably mediated by other mechanism than BDZ-bs modulation at the GABA(A) receptors.
Collapse
Affiliation(s)
- M C Hellión-Ibarrola
- Laboratory of Psychopharmacology, Department of Pharmacology, Facultad de Ciencias Químicas, Universidad Nacional de Asunción, Campus Universitario, P.O. Box 1055, San Lorenzo, Paraguay.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Pomara N, Willoughby LM, Ritchie JC, Sidtis JJ, Greenblatt DJ, Nemeroff CB. Sex-related elevation in cortisol during chronic treatment with alprazolam associated with enhanced cognitive performance. Psychopharmacology (Berl) 2005; 182:414-9. [PMID: 16001108 DOI: 10.1007/s00213-005-0088-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 05/13/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE There is evidence of more widespread use and abuse of benzodiazepines (BZPs) among elderly women. However, factors underlying this observation are poorly understood but could be related to more intense withdrawal reactions, which are a major risk factor for continued BZP use. We previously reported elevations in interdose morning plasma cortisol levels in healthy elderly individuals after chronic treatment with alprazolam, possibly consistent with increased hypothalamic-pituitary-adrenal (HPA) axis activity and drug withdrawal. In this study, we examined sex-related differences in this population. METHOD Twenty-five cognitively intact healthy elderly (13 women and 12 men) participated in a parallel, double-blind, placebo-controlled study that included a group that received acute and chronic (3 weeks) treatment with alprazolam (0.5 mg b.i.d.). RESULTS Elderly women, but not men, experienced significant elevations in interdose morning plasma cortisol levels over 3 weeks of chronic treatment with alprazolam (0.5 mg b.i.d.) compared to placebo. In addition, higher morning plasma cortisol levels were significantly associated with better cognitive performance but not with higher plasma drug levels or greater degree of tolerance development to an acute alprazolam challenge. CONCLUSION Elderly females experienced a greater interdose activation of the HPA axis during treatment with therapeutic doses of alprazolam than men, which could be related to drug withdrawal.
Collapse
Affiliation(s)
- Nunzio Pomara
- Geriatric Psychiatry Program, Nathan S. Kline Institute, Orangeburg, NY, 10962, USA.
| | | | | | | | | | | |
Collapse
|
15
|
Barbanoj MJ, Clos S, Romero S, Morte A, Giménez S, Lorenzo JL, Luque A, Dal-Ré R. Sleep laboratory study on single and repeated dose effects of paroxetine, alprazolam and their combination in healthy young volunteers. Neuropsychobiology 2005; 51:134-47. [PMID: 15838185 DOI: 10.1159/000085206] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
AIMS To evaluate the potential interaction of 20 mg paroxetine and 1 mg alprazolam (early morning once-daily administration) on polysomnographic (PSG) sleep and subjective sleep and awakening quality, both after a single intake and after reaching a steady-state concentration. METHODS Twenty-two (11 for the PSG) healthy young volunteers of both sexes with no history of sleep disturbances (Pittsburgh Sleep Quality Index <5) participated in a double-blind, double-dummy, placebo-controlled, repeated-dose, 4-period, cross-over study. All volunteers received all 4 treatment sequences: paroxetine-alprazolam placebo (PAP); paroxetine placebo-alprazolam (PPA); paroxetine-alprazolam (PA), and paroxetine placebo-alprazolam placebo (PLA), in a randomized order. Each treatment was administered over 15 consecutive days, with a treatment-free interval of 7 days prior to the subsequent study period. In each experimental period, one PSG sleep study was performed on the 1st night (single-dose effects) and another study was performed on the 15th night (repeated-dose effects). Additionally, two other PSG studies were assessed: an adaptation recording, and a control night recording. All-night PSG recordings were obtained following standard procedures. Each 30-second period was scored according to the criteria of Rechtschaffen and Kales by means of an automatic sleep analysis system: Somnolyzer 24x7. A self-rating scale for sleep and awakening quality and early morning behavior was completed no later than 15 min after awakening over the 15 days of each experimental intervention. General lineal models (treatment/time) were applied separately to each variable. RESULTS (1) No significant effects were observed in any sleep variables when control nights were compared with the 1st night with PLA. (2) Sleep continuity: After PAP a clear awakening effect was seen both in the first and second evaluations, mainly in wake time, movement time, number of awakenings and stage-1 duration. After PPA an evident hypnotic effect was observed on night 1. This effect was mainly observed in maintenance variables and slightly in sleep initiation variables; it had decreased by night 15. After PA an intermediate behavior in the variables related to sleep continuity was seen, highlighting the absence of the tolerance phenomenon observed when PPA was administered alone. (3) Sleep architecture: The most important effects in REM sleep were observed after PAP; an increase in REM latency and decreases in REM sleep. PAP also induced decreases in the number of non-REM and REM periods and increases in the average duration of non-REM periods and sleep cycles. PA presented a similar pattern to PAP, and PPA similar to PLA. In relation to non-REM sleep, PA showed more stage-2 and less slow-wave sleep (SWS). (4) Subjective perception: No significant differences were observed between treatments while they were being taken, but impairments in subjective sleep quality, awaking quality, latency and efficiency were seen, mainly after PA but also after PPA discontinuations. CONCLUSION The combination of PAP and PPA presented an intermediate pattern in relation to sleep continuity, with less awaking effect than PAP alone and less hypnotic effect than PPA alone, and without developing tolerance. The PAP and PPA combination also showed a similar effect to PAP on REM sleep and was the treatment with the longest stage 2 and shortest SWS. No subjective sleep and awakening effects were seen during drug intake but subjective withdrawal reports were seen after abrupt interruption. The high agreement rate for the epoch-by-epoch comparison between automatic and human scoring confirms the validity of the Somnolyzer 24x7 and thus facilitates sleep studies in neuropsychopharmacological research.
Collapse
Affiliation(s)
- Manuel J Barbanoj
- Centre d'Investigació de Medicaments, Institut de Recerca, Servei de Farmacologia Clínica, Hospital de la Santa Creu i Sant Pau, Barcelona, España.
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Aburawi SM, Elhwuegi AS, Ahmed SS, Saad SF, Attia AS. Behavioral effects of acute and chronic triazolam treatments in albino rats. Life Sci 2003; 73:3095-107. [PMID: 14550850 DOI: 10.1016/s0024-3205(03)00612-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previous behavioral studies on triazolam (TZ), which are small in number, could only speculate about tolerance to the anxiolytic effect of TZ, as the experiments did not cover sufficient time (of 4 to 7 days) for tolerance to develop. Therefore longer time for chronic TZ administration is used. We investigated the effects of TZ on motor activity and exploratory behavior using plus maze and open field. Three experiments were conducted. In the first, five groups of rats were acutely treated with different doses of TZ (0.25 mg/kg-4.0 mg/kg). In the second set of experiments, rats were treated chronically with a single daily dose of TZ (started with 0.25 mg/kg and increased by time to 1.0 mg/kg) for 5 weeks (representing clinical use). In the third, rats were treated chronically with three daily doses of TZ (started with 0.25 mg/kg and increased by time to 0.5 mg/kg) for 20 days (mimicking drug abuse). Acute TZ administration produced dose dependent anxiolytic effects and a decrease in motor activity with higher doses. Chronically treated rats, either once daily or three times daily doses, showed tolerance to both anxiolytic and sedative effects of TZ. It may be concluded that tolerance to the anxiolytic and sedative effects of TZ would develop after chronic administration either with clinical use or its abuse.
Collapse
Affiliation(s)
- S M Aburawi
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Great Alfateh University, PO Box 84593, Tripoli, Libya.
| | | | | | | | | |
Collapse
|
17
|
Prut L, Belzung C. The open field as a paradigm to measure the effects of drugs on anxiety-like behaviors: a review. Eur J Pharmacol 2003; 463:3-33. [PMID: 12600700 DOI: 10.1016/s0014-2999(03)01272-x] [Citation(s) in RCA: 2088] [Impact Index Per Article: 99.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The open field is a very popular animal model of anxiety-like behavior. An overview of the literature on the action elicited by effective or putative anxiolytics in animal subjected to this procedure indicates that classical treatments such as benzodiazepine receptor full agonists or 5-HT(1A) receptor full or partial agonists elicit an anxiolytic-like effect in this procedure in most cases (approximately 2/3). However, compounds (triazolobenzodiazepines such as adinazolam and alprazolam, selective serotonin reuptake inhibitors) that have a different spectrum of therapeutic efficacy in anxiety disorders such as panic attacks, generalized anxiety disorder or obsessive-compulsive disorder were poorly effective as anxiolytics in the open field test, suggesting that this paradigm may not model features of anxiety disorders. The procedure is also relevant for the study of compounds endowed with anxiogenic effects, as such effects were detected after treatments with benzodiazepine receptor inverse agonists or with corticotropin releasing factor (CRF) receptor agonists.
Collapse
Affiliation(s)
- Laetitia Prut
- EA3248, Psychobiologie des Emotions, Faculte des Sciences et Techniques, Universite Francois Rabelias, Parc de Grandmont Avenue Monge, 37200 Tours, France
| | | |
Collapse
|
18
|
Schmitt U, Lüddens H, Hiemke C. Behavioral analysis indicates benzodiazepine-tolerance mediated by the benzodiazepine binding-site at the GABA(A)-receptor. Prog Neuropsychopharmacol Biol Psychiatry 2001; 25:1145-60. [PMID: 11444682 DOI: 10.1016/s0278-5846(01)00166-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
1. GABA(A)-receptor induced changes in locomotion and anxiety-like behaviors were studied in rats using an open-field and an elevated plus-maze. Acute and chronic doses of the benzodiazepine diazepam without and in combination with the GABA uptake inhibitor SKF-89976A were investigated. 2. Fifty-six male rats of the strain PVG/OlaHsd (PVG; 180-200 g body wt) were used to assess the influence of the benzodiazepine binding-site to the development of tolerance. Rats were divided into six groups: The first receiving saline (0.9%), the second and third diazepam (10.0 mg/kg) daily for 23 days with or without an acute challenge of 2.0 mg/kg diazepam. The fourth group received diazepam (10.0 mg/kg) daily and acutely SKF-89976A (15.0 mg/kg) plus diazepam and the fifth and sixth group received acute treatment with diazepam (2.0 mg/kg) or SKF-89976A (15.0 mg/kg). 3. Under chronic treatment with diazepam the animals became tolerant to acute doses of diazepam in activity and anxiety-related behaviors. Acute treatment with SKF-89976A increased exploration. Parameters expressing anxiolytic-like behaviors were increased, too, but not all of them significantly. In diazepam tolerant animals SKF-89976A produced anxiolytic-like behaviors 4. We conclude that the BZ- and not the GABA-binding site at the GABA(A)-receptor is involved in the development of BZ-tolerance.
Collapse
Affiliation(s)
- U Schmitt
- Department of Psychiatry, University of Mainz, Germany
| | | | | |
Collapse
|
19
|
Arnot MI, Davies M, Martin IL, Bateson AN. GABA(A) receptor gene expression in rat cortex: differential effects of two chronic diazepam treatment regimes. J Neurosci Res 2001; 64:617-25. [PMID: 11398186 DOI: 10.1002/jnr.1115] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diazepam is widely prescribed as an anxiolytic but its therapeutic application is limited because with daily use tolerance develops to certain aspects of its pharmacological profile. We compared the effects of two dosing paradigms on GABA(A) receptor gene expression and benzodiazepine binding characteristics. Equivalent daily doses of 15 mg/kg/day diazepam were delivered either via constant infusion or daily subcutaneous injection for 14 days. The two distinct treatment regimes produced significantly different changes in GABA(A) receptor alpha4-, beta2-, beta3- and gamma1-subunit mRNA steady-state levels. Similar changes in the GABA enhancement of flunitrazepam binding and the BZ3/BZ2 subtype ratio determined ex vivo were produced, however, significant differences were found in [(3)H]-Ro 15-4513 binding between cortical tissue from diazepam injected animals compared with diazepam infused animals. Our data suggest that it is the diurnal fluctuations in receptor occupancy that are responsible for the different effects produced by these two dosing regimes.
Collapse
Affiliation(s)
- M I Arnot
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | | | | | | |
Collapse
|
20
|
Fahey JM, Pritchard GA, Grassi JM, Pratt JS, Shader RI, Greenblatt DJ. Pharmacodynamic and receptor binding changes during chronic lorazepam administration. Pharmacol Biochem Behav 2001; 69:1-8. [PMID: 11420062 DOI: 10.1016/s0091-3057(01)00507-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To assess pharmacodynamic and neurochemical aspects of tolerance, lorazepam (2 mg/kg/day), or vehicle was administered chronically to male Crl: CD-1(ICR)BR mice via implantable osmotic pump. Open-field behavior, benzodiazepine receptor binding in vitro, receptor autoradiography, and muscimol-stimulated chloride uptake were examined at both 1 and 14 days. Open-field activity was depressed in lorazepam-treated animals on Day 1. On Day 14, open-field parameters were indistinguishable from those of vehicle-treated animals, indicating behavioral tolerance. Benzodiazepine binding, as determined by the specific binding of [125I]diazepam, was also decreased in cortex on Day 14. Hippocampal binding was unchanged following chronic lorazepam exposure. Apparent affinity in cortical membrane preparations was unchanged, indicating that altered ligand uptake was due to decreased receptor number. Muscimol-stimulated chloride uptake into cortical synaptoneurosomes from lorazepam-treated animals was not significantly different on Day 1 or Day 14 compared to vehicle-treated animals. These results confirm that down-regulation of benzodiazepine receptor binding is closely associated with behavioral tolerance to benzodiazepines. These observed changes in binding are not necessarily associated with robust changes in receptor function.
Collapse
Affiliation(s)
- J M Fahey
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA
| | | | | | | | | | | |
Collapse
|
21
|
Fahey JM, Pritchard GA, Grassi JM, Pratt JS, Shader RI, Greenblatt DJ. In situ hybridization histochemistry as a method to assess GABA(A) receptor subunit mRNA expression following chronic alprazolam administration. J Psychopharmacol 1999; 13:211-8. [PMID: 10512074 DOI: 10.1177/026988119901300301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Previous work in our laboratory has demonstrated region-specific effects for chronic alprazolam on binding and function at the GABA(A) receptor. The present study evaluated regional changes in mRNA expression of several subunits of the GABA(A) receptor following chronic alprazolam administration that might underlie these effects. Mice received alprazolam (2 mg/kg/day) or vehicle via subcutaneously implanted osmotic pumps for 1, 7, 14 or 28 days. In situ hybridization histochemistry was performed on tissue sections using [35S]dATP oligonucleotide probes corresponding to the alpha1 and gamma2 subunits of the GABA(A) receptor. Specific hybridization was clearly demonstrated and alpha1 subunit mRNA expression in frontoparietal cortex (layers II-IV) on day 1 of infusion was reduced in animals receiving alprazolam compared to vehicle. On subsequent days, there were no alterations in the levels of alpha1 subunit mRNA in the frontoparietal cortex, hippocampus or dentate gyrus. Expression of gamma2 subunit mRNA was increased on day 1 in the frontoparietal cortex (layer VI), hippocampus and dentate gyrus. mRNA expression was also increased in the dentate gyrus on day 28 of infusion. Comparison of the present study with the results of chronic treatment with other benzodiazepines clearly demonstrates that the pattern of mRNA subunit alterations obtained is both treatment- and region-specific. This makes a definitive conclusion regarding benzodiazepines and their interactions with GABA(A) receptors difficult at best.
Collapse
Affiliation(s)
- J M Fahey
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine and the Division of Clinical Pharmacology, New England Medical Center, Boston, MA, USA
| | | | | | | | | | | |
Collapse
|
22
|
Fujita M, Woods SW, Verhoeff NP, Abi-Dargham A, Baldwin RM, Zoghbi SS, Soares JC, Jatlow PA, Krystal JH, Rajeevan N, Charney DS, Seibyl JP, Innis RB. Changes of benzodiazepine receptors during chronic benzodiazepine administration in humans. Eur J Pharmacol 1999; 368:161-72. [PMID: 10193652 DOI: 10.1016/s0014-2999(99)00013-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Changes of central type GABA(A)/benzodiazepine receptors during 24-day per-oral administration of alprazolam (2 mg/day) were measured with single photon emission computed tomography (SPECT) in nine healthy human subjects. Receptor densities were measured on days -4 (baseline), 3, 10, 17 and 24. Comparison of baseline and day 3 SPECT images was used to assess receptor occupancy; comparisons of the four scans on medication were used to assess alterations in receptor levels. Clinical effects were evaluated by subjective ratings of mood and the Hopkins verbal learning test. Alprazolam induced sedation associated with a 16% receptor occupancy. Unoccupied receptor levels decreased 10% from day 3 to day 10 but then normalized to baseline values by day 17. Clinical effects showed corresponding changes 1-2 weeks after the changes in the receptor. Thus, the decrease of benzodiazepine receptor densities may be one of the major mechanisms for tolerance development in humans.
Collapse
Affiliation(s)
- M Fujita
- Department of Psychiatry, Yale University School of Medicine, West Haven, CT 06516, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Pokk P, Zharkovsky A. Small platform stress attenuates the anxiogenic effect of diazepam withdrawal in the plus-maze test. Behav Brain Res 1998; 97:153-7. [PMID: 9867240 DOI: 10.1016/s0166-4328(98)00036-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of stress on the behavioural changes caused by diazepam withdrawal was studied in mice. Diazepam (2.5 mg/kg) or vehicle was injected intraperitoneally twice a day for 2 weeks. When the last vehicle or diazepam injection had been administered to the mice, 12 h later, the mice were subjected to small platform stress exposure or left in their home cages. Small platform stress was induced by placing mice on small platforms (3.5 cm diameter) surrounded by water for 24 h. This experimental model contains several factors of stress like rapid eye movement (REM) sleep deprivation, isolation, immobilization and falling into the water. The plus-maze test was carried out with stressed mice as well as with mice not subjected to stress. Small platform stress induced an anxiolytic effect and diazepam withdrawal--an anxiogenic effect in the plus-maze test. Small platform stress also attenuated the anxiogenic effect of diazepam withdrawal. On the basis of this data it was proposed that small platform stress counteracts the anxiogenic effect of diazepam withdrawal in the plus-maze test. It was also proposed that the effect of stress on the signs of benzodiazepine withdrawal depends on the characteristics and duration of stress.
Collapse
Affiliation(s)
- P Pokk
- Department of Pharmacology, Faculty of Medicine, University of Tartu, Estonia
| | | |
Collapse
|
24
|
Medina JH, Viola H, Wolfman C, Marder M, Wasowski C, Calvo D, Paladini AC. Overview--flavonoids: a new family of benzodiazepine receptor ligands. Neurochem Res 1997; 22:419-25. [PMID: 9130252 DOI: 10.1023/a:1027303609517] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Benzodiazepines (BDZs) are the most widely prescribed class of psychoactive drugs in current therapeutic use, despite the important unwanted side-effects that they produce such as sedation, myorelaxation, ataxia, amnesia, ethanol and barbiturate potentiation and tolerance. Searching for safer BDZ-receptor (BDZ-R) ligands we have recently demonstrated the existence of a new family of ligands which have a flavonoid structure. First isolated from plants used as tranquilizers in folkloric medicine, some natural flavonoids have shown to possess a selective and relatively mild affinity for BDZ-Rs and a pharmacological profile compatible with a partial agonistic action. In a logical extension of this discovery various synthetic derivatives of those compounds, such as 6,3'-dinitroflavone were found to have a very potent anxiolytic effect not associated with myorelaxant, amnestic or sedative actions. This dinitro compound, in particular, exhibits a high affinity for the BDZ-Rs (Ki = 12-30 nM). Due to their selective pharmacological profile and low intrinsic efficacy at the BDZ-Rs, flavonoid derivatives, such as those described, could represent an improved therapeutic tool in the treatment of anxiety. In addition, several flavone derivatives may provide important leads for the development of potent and selective BDZ-Rs ligands.
Collapse
Affiliation(s)
- J H Medina
- Instituto de Biologia Celular y Neurociencias, Facultad de Medicina, UBA, Paraguay, Buenos Aires, Argentina
| | | | | | | | | | | | | |
Collapse
|
25
|
Hutchinson MA, Smith PF, Darlington CL. The behavioural and neuronal effects of the chronic administration of benzodiazepine anxiolytic and hypnotic drugs. Prog Neurobiol 1996; 49:73-97. [PMID: 8817699 DOI: 10.1016/0301-0082(96)00011-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Benzodiazepine anxiolytic and hypnotic drugs are some of the most widely prescribed drugs in the Western world. Despite this fact, the mechanisms that underlie the development of tolerance to, and dependence upon, benzodiazepines are poorly understood. The aim of this review is to summarize and critically evaluate the experimental evidence relating to the chronic behavioural and neuronal effects of benzodiazepines. Behavioural studies in animals generally indicate that tolerance gradually develops to the muscle relaxant, ataxic, locomotor and anticonvulsant effects of benzodiazepines. The evidence relating to the development of tolerance to the anxiolytic effects of benzodiazepines is less clear. The literature on the possible mechanisms of benzodiazepine tolerance and dependence is large, highly complex and difficult to interpret. The effect of chronic benzodiazepine treatment varies enormously as a function of the benzodiazepine used and the treatment schedule employed. Many studies have demonstrated a down-regulation of benzodiazepine binding sites, although affinity is usually unchanged. The evidence relating to the number and affinity of GABAA binding sites is unclear. Some studies suggest that chronic benzodiazepine administration results in a reduction in the number of Cl- channels associated with the GABAA receptor complex, although it is not clear that the efficacy of the GABA binding site in operating the Cl- channel necessarily changes. There is, however, substantial evidence to support the hypothesis that chronic benzodiazepine treatment results in a reduction in the coupling between the GABAA and benzodiazepine binding sites (the "functional uncoupling hypothesis"). Although some electrophysiological studies suggest that chronic benzodiazepine treatment results in a subsensitivity to GABA, this effect seems to be highly area-specific.
Collapse
Affiliation(s)
- M A Hutchinson
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | | | | |
Collapse
|
26
|
Ramsey-Williams VA, Wu Y, Rosenberg HC. Comparison of anticonvulsant tolerance, crosstolerance, and benzodiazepine receptor binding following chronic treatment with diazepam or midazolam. Pharmacol Biochem Behav 1994; 48:765-72. [PMID: 7938133 DOI: 10.1016/0091-3057(94)90344-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In a previous study, rats treated chronically with flurazepam were tolerant to the anticonvulsant action of some benzodiazepines (BZs), but not others (34). To determine if this differential crosstolerance was unique to flurazepam, rats were treated chronically with diazepam or midazolam, and tested for tolerance to the anticonvulsant actions of diazepam, midazolam, clonazepam, and clobazam. Regional benzodiazepine receptor binding in brain was also studied. In contrast to previous findings with flurazepam, 1 week treatment with diazepam or with midazolam did not cause tolerance. Rats treated with diazepam for 3 weeks were tolerant to diazepam, clonazepam, clobazam, and midazolam. In contrast, rats treated 3 weeks with midazolam were tolerant to diazepam and midazolam, but not clobazam or clonazepam. Neither diazepam nor midazolam treatment for 3 weeks altered BZ binding in cerebral cortex, cerebellum, or hippocampus. The effects of chronic BZ treatment depended not only on the BZ given chronically, but also on the BZ used to evaluate these effects, suggesting drug-specific interactions of different BZs with their receptors.
Collapse
|
27
|
Burke TF, Miller LG, Moerschbaecher JM. Acute effects of benzodiazepines on operant behavior and in vivo receptor binding in mice. Pharmacol Biochem Behav 1994; 48:69-76. [PMID: 7913233 DOI: 10.1016/0091-3057(94)90500-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Lorazepam and alprazolam produced dose-dependent decreases in the rate of fixed-ratio (FR) 20 schedules of food presentation in which either a nose-poke or a lever-press defined the operant and under a fixed-interval (FI) 2-min lever-press schedule of food presentation. In contrast, under FI 2-min and differential reinforcement of low response rate (DRL) 20-s schedules of nose-poke responding for food, intermediate doses of alprazolam produced increases in response rate. Lorazepam, however, only decreased overall response rates under the FI schedule and produced some increases in responding under the DRL schedule. Acute in vivo benzodiazepine receptor binding experiments showed that low to intermediate doses of alprazolam produced significant increases in the binding of [3H]flumazenil in all brain areas tested, while lorazepam produced increases in the brain stem only. The acute effects on binding produced by both drugs were positively and significantly correlated with their acute effects on response rate only under the FR lever-press procedure. These results indicate that the effects of benzodiazepines on in vivo binding may be related to their effects on FR lever-press responding.
Collapse
Affiliation(s)
- T F Burke
- Department of Pharmacology, Louisiana State University Medical Center, New Orleans 70112-1393
| | | | | |
Collapse
|
28
|
Wolffgramm J, Mikolaiczyk C, Coper H. Acute and subchronic benzodiazepine-barbiturate-interactions on behaviour and physiological responses of the mouse. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1994; 349:279-86. [PMID: 8208306 DOI: 10.1007/bf00169294] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Female NMRI mice were pretreated for 2 weeks with diazepam (D: 20 mg/kg/day), secobarbital (S: 23 mg/kg/day), or combination (D+S: 19 mg/kg/day, each) by means of the drinking fluid. A fourth group remained untreated. One day after this period the mice received an i.p. injection of one out of 16 drug combinations (crossover design: 0, 2, 4, 6 mg/kg D combined with 0, 6, 12, 18 mg/kg S). Open field behaviour, motor performance, and rectal body temperature were measured. In non-pretreated animals, D and S induced immobility, impairment of coordination and hypothermia in a dose-dependent manner. Excitation appeared after low doses of D (2 mg/kg) and high doses of S (12-18 mg/kg). Acute interactions between D and S were studied by means of isobolographic analysis. Dose-additivity indicating a common mechanism of action was confirmed for immobility, impairment of coordination, and hypothermia whereas excitation revealed a non-additive interaction and was reduced after combined administrations. After chronic pretreatment, the mode of acute drug interaction (dose-additive and non-additive, resp.) remained unchanged. Shifts of the isoboles indicated tolerance, cross-tolerance or sensitization. There was an asymmetry concerning the pretreatment with D and S. Chronic administration of D induced a tolerance to D in regard to all responses and a sensitization to S-effected motor incordination. Chronic administration of S sensitized the sedative and hypothermic responses to acute D. Metabolic tolerance could not account for the subchronic effects since distinct functional responses were concerned in different ways.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J Wolffgramm
- Institut für Neuropsychopharmakologie, Freie Universität Berlin, Germany
| | | | | |
Collapse
|
29
|
Effectiveness of flumazenil (RO 15-1788) in the treatment of benzodiazepine withdrawal. Curr Ther Res Clin Exp 1993. [DOI: 10.1016/s0011-393x(05)80679-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
30
|
Torchin CD, Kapetanovic IM, Kupferberg HJ. A system for testing the development and reversal of anticonvulsant tolerance to benzodiazepines in mice. Epilepsy Res 1993; 16:27-35. [PMID: 7902275 DOI: 10.1016/0920-1211(93)90036-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tolerance to the anticonvulsant effects of benzodiazepines limits their use in epilepsy treatment. Animal models producing tolerance have been developed, but they require repetitive injections over several days or use silastic capsules which must be made for each drug and do not provide a constant infusion rate. Alzet 2001 osmotic pumps deliver at a constant rate (1 microliter/h) and dosage can be easily adjusted. Various solvents, PEG 400, propylene glycol, 2% Tween, 50% DMSO, saline, Molecusol, and 0.5% methyl cellulose, were tried and found unsuitable because benzodiazepines were not maintained in solution or proconvulsant activity was seen. Tetraglycol was chosen as it did not demonstrate these shortcomings. Anticonvulsant activity was evaluated by PTZ i.v. tail infusion using forelimb clonus as the endpoint. This study describes a simple method for testing the development of tolerance and its reversal with flumazenil or ZK 93426. At 72 h of pump infusion with diazepam or flunitrazepam, tolerance to anticonvulsant activity was evident. Acute treatment with flumazenil or ZK 93426 reversed this tolerance. When flumazenil or ZK 93426 was given to diazepam tolerant mice, this reversal was complete. In flunitrazepam tolerant mice reversal with flumazenil was partial, but significant. When flumazenil was chronically coinfused with diazepam or flunitrazepam, anticonvulsant activity was antagonized. Similarly, when ZK 93426 was coinfused with diazepam, anticonvulsant activity was antagonized. The method described is suitable for screening putative anticonvulsant drugs for development of tolerance and the reversal of tolerance by other compounds.
Collapse
Affiliation(s)
- C D Torchin
- Preclinical Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | | | | |
Collapse
|
31
|
Chaves ML, Bianchin M, Peccin S, Rotta F, Jardim C, Gianlupi A, Eidt L. Chronic use of benzodiazepines and cognitive deficit complaints: a risk factor study. ITALIAN JOURNAL OF NEUROLOGICAL SCIENCES 1993; 14:429-35. [PMID: 7904262 DOI: 10.1007/bf02339172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Benzodiazepines produce an anterograde amnesia after acute administration but whether their chronic use is hazardous to memory processes remains unclear. The present study analyses the risk of increasing cognitive complaints with chronic benzodiazepine use. Subjects seeking medical assistance at the General Internal Medicine Outpatient Clinic of Hospital de Clinicas de Porto Alegre, were interviewed before seeing physicians. They were asked about use of benzodiazepines, history of neurological and psychiatric diseases, use of alcohol, and deficits in remembering and learning as well as age, sex and level of education. Age (over 51 years), low level of education, a history of neurological and psychiatric diseases and use of benzodiazepines showed significant associations with cognitive complaints. After a conditional logistic regression analysis, benzodiazepine use lost its association with memory complaints. These data support the hypothesis that the chronic use of benzodiazepines does not carry a risk for cognitive deficits complaints.
Collapse
Affiliation(s)
- M L Chaves
- Neurology Service, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | | | | | | | | |
Collapse
|
32
|
Owens MJ, Vargas MA, Nemeroff CB. The effects of alprazolam on corticotropin-releasing factor neurons in the rat brain: implications for a role for CRF in the pathogenesis of anxiety disorders. J Psychiatr Res 1993; 27 Suppl 1:209-20. [PMID: 8145178 DOI: 10.1016/0022-3956(93)90029-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Considerable evidence indicates that corticotropin-releasing factor (CRF) is responsible for integrating not only the endocrine, but the autonomic and behavioral responses of an organism to stress. We have investigated the effects of the anxiolytic triazolobenzodiazepine, alprazolam, on the activity of the hypothalamic-pituitary-adrenal (HPA) axis and of CRF neurons following acute and chronic administration. In addition, because many of the signs and symptoms observed in animals and humans following abrupt discontinuation of benzodiazepines resemble those of the stress response, we examined the effect of alprazolam withdrawal on CRF neurons and HPA axis activity. Alprazolam decreases CRF concentrations in the locus coeruleus 0.5-3.0 hours following acute injection. Similarly, chronic (14 days) alprazolam administration also results in decreased CRF concentrations in the locus coeruleus. CRF concentrations return to control values 24 hours following abrupt alprazolam withdrawal. Moreover, abrupt alprazolam withdrawal results in increased plasma ACTH and corticosterone concentrations and decreased anterior pituitary CRF receptor concentrations 24 hours following drug discontinuation. Thus, abrupt alprazolam withdrawal profoundly activates the HPA axis. These indices of HPA axis activity return to control values by 48 hours post-withdrawal. These actions of alprazolam on CRF neurons are opposite to those observed following acute or chronic stress. These results support the hypothesis that CRF-containing neurons innervating the locus coeruleus may be involved in the pathogenesis of anxiety, and in the actions of clinically efficacious anxiolytics.
Collapse
Affiliation(s)
- M J Owens
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322
| | | | | |
Collapse
|
33
|
Byrnes JJ, Miller LG, Greenblatt DJ, Shader RI. Chronic benzodiazepine administration. XII. Anticonvulsant cross-tolerance but distinct neurochemical effects of alprazolam and lorazepam. Psychopharmacology (Berl) 1993; 111:91-5. [PMID: 7870939 DOI: 10.1007/bf02257412] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tolerance to the sedative and anticonvulsant effects of benzodiazepines has been reported, but cross-tolerance among benzodiazepines is poorly characterized. To evaluate cross-tolerance between lorazepam and alprazolam in a reliable anticonvulsant pharmacodynamic model, we treated mice with either drug for 14 days, and with the two drugs sequentially for 7 days each. Pentylenetetrazole-induced seizure thresholds were similar in mice treated for 14 days with lorazepam or alprazolam, 2 mg/kg/day. For both compounds, a discontinuation effect characterized by reduced seizure threshold occurred at 4 days after discontinuation. Substitution of alprazolam for lorazepam after 1 week, and vice versa, did not interrupt tolerance. [3H]flumazenil binding in vivo was downregulated in cortex after 14 days of either drug. However, binding was also reduced in hippocampus for lorazepam but not for alprazolam. Substitution of alprazolam for lorazepam resulted in downregulation in cortex only, similar to lorazepam alone. Conversely, substitution of lorazepam for alprazolam led to binding changes similar to lorazepam alone. These data demonstrate cross-tolerance to the convulsant effects of pentylenetetrazole between lorazepam and alprazolam. However, effects of the two compounds on benzodiazepine receptor binding in hippocampus remain distinct.
Collapse
Affiliation(s)
- J J Byrnes
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA
| | | | | | | |
Collapse
|
34
|
Kaplan GB, Cotreau MM, Greenblatt DJ. Effects of benzodiazepine administration on A1 adenosine receptor binding in-vivo and ex-vivo. ACTA ACUST UNITED AC 1992; 44:700-3. [PMID: 1359103 DOI: 10.1111/j.2042-7158.1992.tb05502.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The adenosine receptor has been implicated in the central mechanism of action of benzodiazepines. The specific binding of an A1-selective adenosine antagonist radioligand, [3H]8-cyclopentyl-1,3-dipropylxanthine, was measured in-vivo in mice treated with alprazolam (2 mg kg-1, i.p.), lorazepam (2 mg kg-1, i.p.) and vehicle. Binding studies were performed in-vivo and ex-vivo in mice receiving continuous infusion of alprazolam (2 mg kg-1 day-1), lorazepam (2 mg kg-1 day-1) and vehicle by mini-osmotic pumps for 6 days. Continuous infusion of alprazolam and lorazepam significantly decreased specific binding by 34 and 53%, respectively, compared with vehicle treatment (P less than 0.01). Single doses of alprazolam and lorazepam induced a similar trend in specific binding in-vivo (P = 0.07). There were no alterations in A1-receptor density (Bmax) or affinity (Kd) in cortex, hippocampus or brainstem in ex-vivo studies. Benzodiazepine treatment may diminish A1- receptor binding in-vivo by inhibiting adenosine uptake or by direct occupancy of the A1 adenosine receptor recognition site.
Collapse
Affiliation(s)
- G B Kaplan
- Department of Psychiatry, Tufts University School of Medicine, Boston, MA
| | | | | |
Collapse
|
35
|
Miller LG, Heller J. Chronic exposure to a benzodiazepine partial agonist does not alter GABAA receptor function in cultured neurons. Eur J Pharmacol 1991; 199:111-3. [PMID: 1654264 DOI: 10.1016/0014-2999(91)90644-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The benzodiazepine partial agonist Ro16-6028 does not lead to GABAA receptor downregulation in vivo. To assess effects of this compound in vitro, cultured neurons were exposed to Ro16-6028, 1 and 10 microM. GABA-dependent chloride uptake was unaffected at either dose of Ro16-6028 from 2 to 10 days, in contrast to decreased function observed with clonazepam, 1 microM, at 10 days, Ro16-6028 exposure did not alter GABA-independent chloride uptake, total neuronal protein, or cellular protein synthesis.
Collapse
Affiliation(s)
- L G Miller
- Department of Psychiatry, Tufts University School of Medicine, Boston, MA
| | | |
Collapse
|
36
|
Kang I, Miller LG. Decreased GABAA receptor subunit mRNA concentrations following chronic lorazepam administration. Br J Pharmacol 1991; 103:1285-7. [PMID: 1653067 PMCID: PMC1908383 DOI: 10.1111/j.1476-5381.1991.tb09781.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Chronic benzodiazepine administration has been associated with alterations in binding and function at the GABAA receptor. To evaluate effects of chronic benzodiazepine exposure on messenger RNA (mRNA) concentrations for several GABAA receptor subunits, we treated mice with lorazepam, 2 mg kg-1 daily for 1-28 days and evaluated mRNAs for the alpha 1 and gamma 2 subunits by Northern hybridization. In cerebral cortex, concentrations of mRNA for the alpha 1 and gamma 2 subunits were unchanged from vehicle or control after 1-10 days of lorazepam. However, after 14 days of treatment mRNA concentrations for both subunits decreased to approximately 50% of control values and remained decreased at 28 days. In contrast, no significant alterations were observed for either subunit mRNA in hippocampus or cerebellum over the same time course. Alterations in mRNAs in cortex occur after the development of tolerance and receptor downregulation in this model.
Collapse
Affiliation(s)
- I Kang
- Dept. of Psychiatry, Tufts Univ. School of Medicine, Boston, MA
| | | |
Collapse
|
37
|
Abstract
Chronic benzodiazepine administration is associated with the development of tolerance and dependence. To evaluate the cellular mechanisms for these phenomena the authors developed a mouse model of chronic benzodiazepine exposure. The benzodiazepine agonists lorazepam, alprazolam, and clonazepam produced tolerance in this system, which was associated in each case with benzodiazepine and GABAA receptor downregulation. After discontinuation, a syndrome that included increased motor activity and receptor upregulation occurred with each of these compounds. A benzodiazepine antagonist, flumazenil, and an inverse agonist, FG 7142, were associated with receptor upregulation and increased activity during chronic administration. In contrast, a partial agonist (Ro16-6028) did not produce tolerance or receptor changes. Similar results were obtained in a culture system for clonazepam, flumazenil, and FG 7142. The increase in receptor binding after lorazepam discontinuation may be due to enhanced receptor synthesis. Changes in gene expression for GABAA receptor subunits also occur with chronic lorazepam administration, and they follow alterations in binding.
Collapse
Affiliation(s)
- L G Miller
- Division of Clinical Pharmacology, Tufts University School of Medicine, Boston, MA
| |
Collapse
|
38
|
Cittadini A, Lader M. Lack of effect of a small dose of flumazenil in reversing short-term tolerance to benzodiazepines in normal subjects. J Psychopharmacol 1991; 5:220-7. [PMID: 22282559 DOI: 10.1177/026988119100500307] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Twelve normal volunteers received two courses of 7 days of either lorazepam (2 mg every morning; six subjects) or oxazepam (30 mg every morning; six subjects). After one of the courses, 0.2 mg of flumazenil was injected, after the other placebo, using a balanced design and double-blind procedures. A test dose of the lorazepam or oxazepam was administered the day after the flumazenil or placebo. A battery of physiological and psychological tests was applied before and after the dose of benzodiazepine on days 1, 4, 8 and 10. The benzodiazepines had the expected effects on the EEG, and event-related potentials (ERP), impaired several psychological tests and induced drowsiness and relaxation. Some tolerance was seen with respect to anxiolytic effects, some EEG and ERP variables and some psychological tests, but not those of memory. Tolerance tended to be more apparent in the subjects given lorazepam than in the oxazepam-treated subjects. No effects of the small dose of flumazenil in reversing tolerance were apparent.
Collapse
Affiliation(s)
- A Cittadini
- Clinica Psichiatrica I, Universita degli Studi di Pisa, via Roma 55, 56100 Pisa, Italy
| | | |
Collapse
|
39
|
Galpern WR, Lumpkin M, Greenblatt DJ, Shader RI, Miller LG. Chronic benzodiazepine administration. VII. Behavioral tolerance and withdrawal and receptor alterations associated with clonazepam administration. Psychopharmacology (Berl) 1991; 104:225-30. [PMID: 1652144 DOI: 10.1007/bf02244183] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Clonazepam administration may lead to tolerance and "withdrawal" syndromes in clinical use. To assess the effects of this drug in a mouse model, we administered clonazepam (1.5 mg/kg/day) for 1-14 days and evaluated open-field activity, cortical clonazepam concentrations, and binding and function at the GABAA receptor. We also evaluated the same parameters at 1, 2, 4 and 7 days after discontinuation of 7 days of clonazepam administration. During chronic treatment, tolerance developed to the effects of clonazepam on motor activity at 7 days and persisted to 14 days. Cortical clonazepam concentrations did not change significantly during this period. Benzodiazepine receptor binding in vivo was decreased in cortex at days 7 and 14 of clonazepam, but was unchanged in other regions. Binding determined in vitro was also decreased at these points. TBPS (t-butylbicyclophosphorothionate) binding in cortex was slightly, but not significantly, decreased. Muscimol-stimulated chloride uptake was also decreased at days 7 and 14. After clonazepam discontinuation, open-field activity returned to control values at 1 day but was increased above baseline at 4 days. Benzodiazepine binding in vivo and in vitro, as well as TBPS binding, were increased at 4 days. Muscimol-stimulated chloride uptake was also increased at this point. These results indicate that chronic clonazepam administration is associated with tolerance to motoric effects, with discontinuation effects, and with receptor alterations in a mouse model. Clonazepam is similar to other benzodiazepines in this regard.
Collapse
Affiliation(s)
- W R Galpern
- Department of Psychiatry, New England Medical Center, Boston, MA 02111
| | | | | | | | | |
Collapse
|
40
|
Galpern WR, Miller LG, Greenblatt DJ, Shader RI. Differential effects of chronic lorazepam and alprazolam on benzodiazepine binding and GABAA-receptor function. Br J Pharmacol 1990; 101:839-42. [PMID: 1964820 PMCID: PMC1917851 DOI: 10.1111/j.1476-5381.1990.tb14167.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
1. Chronic benzodiazepine administration has been associated with tolerance and with downregulation of gamma-aminobutyric acidA (GABAA)-receptor binding and function. However, effects of individual benzodiazepines on brain regions have varied. 2. To compare the effects of chronic lorazepam and alprazolam, we have administered these drugs to mice for 1 and 7 days (2 mg kg-1 day-1) and determined benzodiazepine receptor binding in vivo with and without administration of CL 218,872, 25 mg kg-1 i.p., and GABA-dependent chloride uptake in 3 brain regions at these time points. 3. Benzodiazepine binding was decreased in the cortex and hippocampus at day 7 compared to day 1 of lorazepam, with an increase in CL 218,872-resistant (Type 2) sites in both regions. Maximal GABA-dependent chloride uptake was also decreased in the cortex and hippocampus at day 7. 4. Binding was decreased only in the cortex after 7 days of alprazolam, with no significant change in Type 2 binding. Maximal GABA-dependent chloride uptake was also decreased only in the cortex. 5. These data suggest that the effects of chronic benzodiazepine administration on the GABAA-receptor may be both region-specific and receptor subtype-specific.
Collapse
Affiliation(s)
- W R Galpern
- Department of Psychiatry, Tufts University School of Medicine, Boston, MA
| | | | | | | |
Collapse
|
41
|
Greenblatt DJ, Miller LG, Shader RI. Neurochemical and pharmacokinetic correlates of the clinical action of benzodiazepine hypnotic drugs. Am J Med 1990; 88:18S-24S. [PMID: 1968714 DOI: 10.1016/0002-9343(90)90281-h] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Benzodiazepine derivatives are presumed to exert their pharmacologic activity via interaction with specific molecular recognition sites, termed benzodiazepine receptors, within the brain. The various benzodiazepines used in clinical practice differ considerably in their intrinsic receptor affinity, but the qualitative character of the drug-receptor interaction is similar or identical among this class of drugs. All benzodiazepines are lipophilic (lipid-soluble) substances that relatively rapidly cross the blood-brain barrier and equilibrate with brain tissue. After equilibrium is attained, a constant brain:plasma ratio is maintained, such that plasma concentrations proportionately reflect concentrations of drug in brain. Brain concentrations are proportional to the extent of receptor occupancy, which in turn determines the acute behavioral effect. Clinical differences among benzodiazepines largely reflect differences in pharmacokinetic properties. The onset of action after single oral doses reflects the rate of absorption from the gastrointestinal tract, whereas the duration of action is determined by the rate and extent of drug distribution to peripheral tissues, as well as by the rate of elimination and clearance. During multiple dosage, long half-life drugs accumulate, with the concurrent possibility of daytime sedation. However, a benefit of long half-life drugs is that rebound insomnia on abrupt termination is unlikely. Short half-life drugs accumulate minimally and have a lower likelihood of producing daytime sedation. However, they may be more likely to produce rebound insomnia on abrupt discontinuation.
Collapse
Affiliation(s)
- D J Greenblatt
- Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts 02111
| | | | | |
Collapse
|
42
|
Lopez F, Miller LG, Greenblatt DJ, Chesley S, Schatzki A, Shader RI. Chronic administration of benzodiazepines--V. Rapid onset of behavioral and neurochemical alterations after discontinuation of alprazolam. Neuropharmacology 1990; 29:237-41. [PMID: 1691458 DOI: 10.1016/0028-3908(90)90007-e] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Discontinuation of chronic treatment with alprazolam may cause a characteristic clinical syndrome. To assess the basis of this syndrome, mice were treated with alprazolam, 2 mg/kg, for 7 days, a regimen associated with the development of tolerance and downregulation of receptors. Effects on motor activity and the binding and function of GABA receptors were evaluated 1, 2, 4 and 7 days after discontinuation. Motor activity was similar to controls 1 day after cessation of alprazolam, increased from days 2 to 4 after-alprazolam, and returned to control values by 7 days. The binding of benzodiazepines in vivo and in vitro was increased in the cortex 2 and 4 days after alprazolam and in the hypothalamus at 4 days after alprazolam. Binding returned to control values in all areas by 7 days. Binding at the chloride channel, using [35S]t-butylbicyclophosphorothionate, was not significantly altered after discontinuation. Muscimol-stimulated uptake of [36Cl-] in cortical synaptoneurosomes was increased at 4 days after alprazolam, compared to days 1, 2 and 7. Thus, behavioral and neurochemical alterations was associated with the discontinuation of alprazolam. These alterations were qualitatively similar to those observed following discontinuation of lorazepam but occurred more rapidly and with differing regional specificity.
Collapse
Affiliation(s)
- F Lopez
- Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts
| | | | | | | | | | | |
Collapse
|