Hostname: page-component-76fb5796d-2lccl Total loading time: 0 Render date: 2024-04-28T06:51:11.230Z Has data issue: false hasContentIssue false

Selective Antagonism of GABAA Receptor Subtypes: An In Vivo Approach to Exploring the Therapeutic and Side Effects of Benzodiazepine–Type Drugs

Published online by Cambridge University Press:  07 November 2014

Abstract

Benzodiazepines (BZs) are clinically used as anxiolytic, hypnotic, anticonvulsant, and antispasmodic drugs. Research using transgenic mouse models has suggested that the effects of BZs involve multiple subtypes of the γ-aminobutyric acid type A (GABAA) receptor, identified by specific α subunits (α1, α2, α3, α5). This review discusses the experimental uses of β-carboline-3-carboxylate-t-butyl ester (βCCT), a drug that binds preferentially to the GABAA α1 subtype but exerts no action (ie, is a pharmacologic antagonist at the GABAA α1 subtype receptor). βCCT blocks the anxiolytic-like effects of BZs, although studies in primates suggests this antagonism may reflect multiple receptor populations. βCCT antagonized the ataxic but not muscle relaxant effects of BZs, a finding that implicates the GABAA α1 subtype receptor in ataxia but not muscle relaxation. The potential clinical utility of βCCT is discussed, both in terms of treatment (ie, hepatic encephalopathy) and as a diagnostic imaging agent. Altogether, these results indicate that subtype-selective antagonists represent a useful approach to studying receptor mechanisms underlying the behavioral effects of BZ-type drugs.

Type
Review Article
Copyright
Copyright © Cambridge University Press 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Griffiths, RR, Weerts, EM. Benzodiazepine self-administration in humans and laboratory animals—implications for problems of long-term use and abuse. Psychopharmacobgy (Berl). 1997;134:137.Google Scholar
2. Argyropoulos, SV, Sandford, JJ, Nutt, DJ. The psychobiology of anxiolytic drugs. Part 2: Pharmacological treatments of anxiety. Pharmacol Ther. 2000;88:213227.CrossRefGoogle ScholarPubMed
3. Möhler, H, Fritschy, JM, Rudolph, U. A new benzodiazepine pharmacology. J Pharmacol Exp Ther. 2002;300:28.CrossRefGoogle ScholarPubMed
4. National Institute on Drug Abuse. Prescription Drugs: Abuse and Addiction. National Institute on Drug Abuse Research Report Series, National Institutes of Health Pub No. 01-4881; 2001.Google Scholar
5. Smith, KM, Larive, LL, Romanelli, F. Club drugs: methylenedioxymethamphetamine, flunitrazepam, ketamine hydrochloride, and gamma-hydroxybutyrate. Am J Health Syst Pharm. 2002;59:10671076.CrossRefGoogle ScholarPubMed
6. Costa, E, Auta, J, Grayson, DR, et al. GABAA receptors and benzodiazepines: a role for dendritic resident subunit mRNAs. Ncuropharmacology. 2002;43:925937.Google Scholar
7. McKernan, RM, Whiting, PJ. Which GABAA-receptor subtypes really occur in the brain? Trends Neurosci. 1996;19:139143.Google Scholar
8. Whiting, PJ. The GABAA receptor gene family: new opportunities for drug development. Curr Opin Drag Discov Devel. 2003;6:648657.Google Scholar
9. Rudolph, U, Crestani, F, Möhler, H. GABA(A) receptor subtypes: dissecting their pharmacological functions. Trends Pharmacol Sci. 2001;22:188194.CrossRefGoogle ScholarPubMed
10. Atack, JR. Anxioselective compounds acting at the GABA(A) receptor benzodiazepine binding site. Curr Drug Targets CNS Neurol Disord. 2003;2:213232.Google Scholar
11. McKernan, RM, Rosahl, TW, Reynolds, DS, et al. Sedative but not anxiolytic properties of benzodiazepines are mediated by the GABA(A) receptor alphal subtype. Nat Neurosci. 2000;3:587592.Google Scholar
12. Griebel, G, Perrault, G, Simiand, J, et al. SL651498: an anxioselective compound with functional selectivity for alpha2- and alpha3-containing gamma-aminobutyric acid(A) (GABA(A)) receptors. J Pharmacol Exp Ther. 2001;298:753768.Google Scholar
13. Albaugh, PA, Marshall, L, Gregory, J, et al. Synthesis and biological evaluation of 7,8,9,10-tetrahydroirnidazo[1,2-c]pyrido[3,4-e]pyrimdin-5(6H)-ones as functionally selective ligands of the benzodiazepine receptor site on the GABA(A) receptor. J Med Chem. 2002;45:50435051.Google Scholar
14. Shannon, HE, Guzman, F, Cook, JM. beta-Carboline-3-carboxylate-t-butyl ester: a selective BZ1 benzodiazepine receptor antagonist. Life Sci. 1984;35:22272236.Google Scholar
15. Huang, Q, Cox, ED, Gan, T, et al. Studies of molecular pharmacophore/receptor models for GABAA/benzodiazepine receptor subtypes: bind affinities of substituted beta-carbolines at recombinant alpha x beta 3 gamma 2 subtypes and quantitative structure-activity relationship studies via a comparative molecular field analysis. Drug Des Discov. 1999;16:5576.Google Scholar
15. Cox, ED, Hagen, TJ, McKernan, RM, Cook, JM. BZ1 receptor subtype specific ligands. Synthesis and biological properties of ~CCt, a BZ1 receptor subtype specific antagonist. Med Chem Res. 1995;5:710718.Google Scholar
16. Huang, Q, He, X, Ma, C, et al. Pharmacophore/receptor models for GABA(A)/BzR subtypes (alpha1beta3gamma2, alpha5beta3gamma2, and alpha6beta3gamma2) via a comprehensive ligand-mapping approac. J Med Chem. 2000;43:7195.CrossRefGoogle Scholar
17. Griebel, G, Perrault, G, Letang, V, et al. New evidence that the pharmacological effects of benzodiazepine receptor ligands can be associated with activities at different BZ (omega) receptor subtypes. Psychopharmacology (Berl). 1999;146:205213.CrossRefGoogle ScholarPubMed
18. Atack, JR, Smith, AJ, Emms, F, McKernan, RM. Regional differences in the inhibition of mouse in vivo [3H]Ro 15-1788 binding reflect selectivity for alpha 1 versus alpha 2 and alpha 3 subunit-containing GABAA receptors. Neuropsychopharmacology. 1999;20:255262.CrossRefGoogle ScholarPubMed
19. Wisden, W, Herb, A, Wieland, H, Keinanen, K, Luddens, H, Seeburg, PH. Cloning, pharmacological characteristics and expression pattern of the rat GABAA receptor alpha 4 subunit. FEBS Lett. 1991;289:227230.Google Scholar
20. Fritschy, JM, Möhler, H. GABAA-receptor heterogeneity in the adult rat brain: differential regional and cellular distribution of seven major subunits. J Comp Neurol. 1995;359:154194.CrossRefGoogle ScholarPubMed
21. June, HL, Foster, KL, McKay, PF, et al. The reinforcing properties of alcohol are mediated by GABA(Al) receptors in the ventral pallidum. Neuropsychopharmacology. 2003;28:21242137.Google Scholar
22. Crestani, F, Martin, JR, Möhler, H, Rudolph, U. Mechanism of action of the hypnotic zolpidem in vivo. Br J Pharmacol. 2000;131:12511254.Google Scholar
23. Belzung, C, Le Guisquet, AM, Griebel, G. Beta-CCT, a selective BZ-omegal receptor antagonist, blocks the anti-anxiety but not the amnesic action of chlordiazepoxide in mice. Behav Pharmacol. 2000;11:125131.CrossRefGoogle Scholar
24. Platt, DM, Rowlett, JK, Spealman, RD, Cook, J, Ma, C. Selective antagonism of the ataxic effects of zolpidem and triazolam by the GABAA/alpha1-preferring antagonist beta-CCt in squirrel monkeys. Psychopharmacobgy (Berl). 2002;164:151159.Google Scholar
25. Rowlett, JK, Spealman, RD, Lelas, S, Cook, JM, Yin, W. Discriminative stimulus effects of zolpidem in squirrel monkeys: role of GABA(A)/alpha1 receptors. Psychopharmacology (Berl). 2003;165:209215.Google Scholar
26. Carroll, M, Woods, JE II, Seyoum, RA, June, HL. The role of the GABAA α1 subunit in mediating the sedative and anxiolytic properties of benzodiazepines. Alcoholism Clin Exp Res. 1991;25:12A.Google Scholar
27. Lippa, AS, Coupet, J, Greenblatt, EN, Klepner, CA, Beer, B. A synthetic non-benzodiazepine ligand for benzodiazepine receptors: a probe for investigating neuronal substrates of anxiety. Pharmacol Biochem Behav. 1979;11:99106.Google Scholar
28. Rowlett, JK, Tornatzky, W, Cook, JM, Ma, C, Miczek, KA. Zolpidem, triazolam, and diazepam decrease distress vocalizations in mouse pups: differential antagonism by flumazenil and beta-Carboline-3-carboxylate-t-buty1 ester (beta-CCt). J Pharmacol Exp Ther. 2001;297:247253.Google Scholar
29. Rudolph, U, Crestani, F, Benke, D, et al. Benzodiazepine actions mediated by specific gamma-aminobutyric acid(A) receptor subtypes. Nature. 1999;401:796800.Google Scholar
30. Löw, K, Crestani, F, Keist, R, et al. Molecular and neuronal substrate for the selective attenuation of anxiety. Science. 2000;290:131134.Google Scholar
31. Griebel, G, Perrault, G, Simiand, J, et al. SL651498, a GABAA receptor agonist with subtype-selective efficacy, as a potential treatment for generalized anxiety disorder and muscle spasms. CNS Drug Rev. 2003;9:320.Google Scholar
32. Crestani, F, Low, K, Keist, R, Mandelli, M, Mohler, H, Rudolph, U. Molecular targets for the myorelaxant action of diazepam. Mol Pharmacol. 2001;59:442445.Google Scholar
33. Facklam, M, Schoch, P, Bonetti, EP, et al. Relationship between benzodiazepine receptor occupancy and functional effects in vivo of four ligands of differing intrinsic efficacies. J Pharmacol Exp Ther. 1992;261:11141121.Google Scholar
34. Paronis, CA, Cox, ED, Cook, JM, Bergman, J. Different types of GABA(A) receptors may mediate the anticonflict and response rate-decreasing effects of zaleplon, zolpidem, and midazolam in squirrel monkeys. Psychopharmacology (Berl). 2001;156:461468.Google Scholar
35. Evans, SM, Funderburk, FR, Griffiths, RR. Zolpidem and triazolam in humans: behavioral and subjective effects and abuse reliability. J Pharmacol Exp Ther. 1990;255:12461255.Google Scholar
36. Verster, JC, Volkerts, ER, Verbaten, MN. Effects of alprazolam on driving ability, memory functioning and psychomotor performance: a randomized, placebo-controlled study. Neuropsychopharmacology. 2002;27:260269.Google Scholar
37. de Visser, SJ, van der Post, JP, de Waal, PP, Cornet, F, Cohen, AF, van Gerven, JM. Biomarkers for the effect of benzodiazepines in healthy volunteers. Br J Clin Pharmacol. 2003;55:3950.CrossRefGoogle ScholarPubMed
38. Hoffman, EJ, Warren, EW. Flumazenil: a benzodiazepine antagonist. Clin Pharm. 1993;12:641656.Google ScholarPubMed
39. Goulenok, C, Bernard, B, Cadranel, JF, et al. Flumazenil vs. placebo in hepatic encephalopathy in patients with cirrhosis: a meta-analysis. Aliment Pharmacol Ther. 2002;16:361372.Google Scholar
40. Ruscito, BJ, Harrison, NL. Hemoglobin metabolites mimic benzodiazepines and are possible mediators of hepatic encephalopathy. Blood. 2003;102:15251528.Google Scholar
41. Malizia, AL. Receptor binding and drug modulation in anxiety. Eur Neuropsychopharmacol. 2002;12:561574.Google Scholar
42. Goethals, I, Wiele, C, Boon, P, Dierckx, R. Is central benzodiazepine receptor imaging useful for the identification of epileptogenic foci in localization-related epilepsies? Eur J Nucl Med Mol Imaging. 2003;30:325328.Google Scholar
43. Hammers, A, Koepp, MJ, Richardson, MP, Hurlemann, R, Brooks, DJ, Duncan, JS. Grey and white matter flumazenil binding in neocortical epilepsy with normal MRI. A PET study of 44 patients. Brain. 2003;126(pt 6):13001318.Google Scholar
44. Dumont, F, Waterhouse, RN, Montoya, JA, et al. Synthesis and in vivo evaluation of [11C]zolpidem, an imidazopyridine with agonist properties at central benzodiazepine receptors. Nucl Med Biol. 2003;30:435439.CrossRefGoogle ScholarPubMed
45. Lingford-Hughes, A, Hume, SP, Feeney, A, et al. Imaging the GABA-benzodiazepine receptor subtype containing thealpha5-subunit in vivo with [11C]Ro15-4513 positron emission tomography. J Cereb Blood Flow Metab. 2002;22:878889.Google Scholar