Skip to main content
NCBI home page
British Journal of Pharmacology logoLink to British Journal of Pharmacology
. 1978 May;63(1):197–215. doi: 10.1111/j.1476-5381.1978.tb07790.x

Reversal of the action of amino acid antagonists by barbiturates and other hypnotic drugs

N G Bowery, A Dray
PMCID: PMC1668297  PMID: 206305

Abstract

1 The effects of pentobarbitone (PB) and other sedative/hypnotic drugs have been examined in relation to γ-aminobutyric acid (GABA) in vitro on the superfused isolated superior cervical ganglion of the rat and in vivo on single units in the brain stem of the anaesthetized rat.

2 PB, and other barbiturates, depolarized the ganglion in a dose-dependent manner (threshold concentration 100-300 μM, cf. GABA depolarization threshold 1 μM). The depolarization was reduced in the presence of the selective GABA antagonist (+)-bicuculline methochloride (Bic). Other non-barbiturate sedatives e.g. chlordiazepoxide, amitriptyline, promethazine at concentrations up to 2mM produced no depolarization.

3 PB, tested at concentrations up to 80 μM, produced variable effects on the dose-response curve to GABA. On most occasions a slight potentiation occurred in responses to low concentrations of GABA (below 10 μM) coupled with a depression in the responses to concentrations of GABA greater than 10 μM.

4 Superfusion with PB in the presence of Bic reversed the depression in the response to GABA produced by Bic. This reversal phenomenon occurred at concentrations of PB too low to depolarize the ganglion and was dependent not only on the concentration of PB but also on that of Bic.

5 The reversal potency within an homologous series of barbiturates increased with the size of the alkyl substituent (R2) at C5 on the barbiturate ring. The most potent occurred when the substituent contained 5 carbon atoms (pentobarbitone and amylobarbitone); above this, activity decreased.

6 PB reversed the effects of the other GABA antagonists, tetramethylenedisulphotetramine and isopropyl bicyclophosphate and also the non-selective antagonism produced by strychnine. A concomitant reduction by strychnine of responses to the cholinomimetic, carbachol, was not reversed by PB.

7 Non-barbiturate sedative/hypnotics also reversed the GABA antagonism produced by Bic. The benzodiazepines were effective at lower concentrations than PB (chlordiazepoxide threshold concentration 0.5 μM, cf. PB 5 μM), however, they only produced a partial reversal even at concentrations much higher than the maximally effective concentration of PB.

8 The Bic reversal effect of chloridazepoxide (and other benzodiazepines) lasted many hours after removal from the superfusion solution. By contrast the effect of PB lasted only 15-30 min after its removal.

9 Chlordiazepoxide (30 μM) applied in the absence of Bic did not affect the response to GABA but did reduce the depression produced by the subsequent application of Bic even though the chlordiazepoxide had been removed 40 min earlier.

10 In the rat brain stem in vivo PB, applied iontophoretically in amounts which neither decreased the spontaneous neuronal firing rate nor affected the response to GABA or glycine, reversed the GABA antagonism induced by iontophoretic application of Bic (in all 23 neurones tested). PB also reversed the antagonism produced by strychnine of responses to glycine although this was less readily observed (5 out of 14 neurones tested).

11 Iontophoretic application of other barbiturates and chlordiazepoxide also reversed the effect of Bic. Chlordiazepoxide only produced a partial reversal, as in the isolated ganglion, and no reversal could be demonstrated with flurazepam.

12 Intravenous administration of thiopentone (1.3 mg/kg) pentobarbitone (0.4-5.5 mg/kg) hexobarbitone (0.4-0.8 mg/kg) and clonazepam (0.1-0.2 mg/kg) also reversed the effect of iontophoretically applied Bic. The reversal by clonazepam was of much longer duration than that produced by the barbiturates.

13 It is suggested that the reversal exhibited by PB and the other hypnotics may be explained by assuming that the amino acids and their antagonists bind to the membrane at separate sites. If the reversal agent has particular affinity only for the antagonist binding site then it may displace the antagonist without affecting the receptor.

Full text

PDF
197

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ANDERSON E. G., BONNYCASTLE D. D. A study of the central depressant action of pentobarbital, phenobarbital and diethyl ether in relationship to increases in brain 5-hy-droxytryptamine. J Pharmacol Exp Ther. 1960 Oct;130:138–143. [PubMed] [Google Scholar]
  2. Blaustein M. P. Barbiturates block calcium uptake by stimulated and potassium-depolarized rat sympathetic ganglia. J Pharmacol Exp Ther. 1976 Jan;196(1):80–86. [PubMed] [Google Scholar]
  3. Blaustein M. P. Barbiturates block sodium and potassium conductance increases in voltage-clamped lobster axons. J Gen Physiol. 1968 Mar;51(3):293–307. doi: 10.1085/jgp.51.3.293. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bowery N. G., Brown D. A., Collins J. F. Tetramethylenedisulphotetramine: an inhibitor of gamma-aminobutyric acid induced depolarization of the isolated superior cervical ganglion of the rat. Br J Pharmacol. 1975 Mar;53(3):422–424. doi: 10.1111/j.1476-5381.1975.tb07379.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bowery N. G., Brown D. A. Depolarizing actions of gamma-aminobutyric acid and related compounds on rat superior cervical ganglia in vitro. Br J Pharmacol. 1974 Feb;50(2):205–218. doi: 10.1111/j.1476-5381.1974.tb08563.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Bowery N. G., Dray A. Barbiturate reversal of amino acid antagonism produced by convulsant agents. Nature. 1976 Nov 18;264(5583):276–278. doi: 10.1038/264276a0. [DOI] [PubMed] [Google Scholar]
  7. Bradley P. B., Dray A. Modification of the responses of brain stem neurones to transmitter substances by anaesthetic agents. Br J Pharmacol. 1973 Jun;48(2):212–224. doi: 10.1111/j.1476-5381.1973.tb06907.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Brown D. A., Constanti A. Interaction of pentobarbitone and gamma-aminobutyric acid on mammalian sympathetic ganglion cells. Br J Pharmacol. 1978 May;63(1):217–224. doi: 10.1111/j.1476-5381.1978.tb07791.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Brown D. A., Galvan M. Influence of neuroglial transport on the action of gamma-aminobutyric acid on mammalian ganglion cells. Br J Pharmacol. 1977 Feb;59(2):373–378. doi: 10.1111/j.1476-5381.1977.tb07502.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Choi D. W., Farb D. H., Fischbach G. D. Chlordiazepoxide selectively augments GABA action in spinal cord cell cultures. Nature. 1977 Sep 22;269(5626):342–344. doi: 10.1038/269342a0. [DOI] [PubMed] [Google Scholar]
  11. Corrodi H., Fuxe K., Hökfelt T. The effects of barbiturates on the activity of the catecholamine neurones in the rat brain. J Pharm Pharmacol. 1966 Aug;18(8):556–558. doi: 10.1111/j.2042-7158.1966.tb07932.x. [DOI] [PubMed] [Google Scholar]
  12. Costa E., Guidotti A., Mao C. C. Evidence for involvement of GABA in the action of benzodiazepines: studies on rat cerebellum. Adv Biochem Psychopharmacol. 1975;(14):113–130. [PubMed] [Google Scholar]
  13. Costa E., Guidotti A., Mao C. C., Suria A. New concepts on the mechanism of action of benzodiazepines. Life Sci. 1975 Jul 15;17(2):167–185. doi: 10.1016/0024-3205(75)90501-9. [DOI] [PubMed] [Google Scholar]
  14. Crawford J. M. Anaesthetic agents and the chemical sensitivity of cortical neurones. Neuropharmacology. 1970 Jan;9(1):31–46. doi: 10.1016/0028-3908(70)90045-6. [DOI] [PubMed] [Google Scholar]
  15. Crawford J. M., Curtis D. R. Pharmacological studies on feline Betz cells. J Physiol. 1966 Sep;186(1):121–138. doi: 10.1113/jphysiol.1966.sp008024. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Curtis D. R., Game C. J., Lodge D. Benzodiazepines and central glycine receptors. Br J Pharmacol. 1976 Mar;56(3):307–311. doi: 10.1111/j.1476-5381.1976.tb07643.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Curtis D. R., Lodge D., Johnston G. A., Brand S. J. Central actions of benzodiazepines. Brain Res. 1976 Dec 17;118(2):344–347. doi: 10.1016/0006-8993(76)90723-x. [DOI] [PubMed] [Google Scholar]
  18. Curtis D. R., Lodge D. Pentobarbitone enhancement of the inhibitory action of GABA. Nature. 1977 Dec 8;270(5637):543–544. doi: 10.1038/270543c0. [DOI] [PubMed] [Google Scholar]
  19. Cutler R. W., Dudzinski D. S. Effect of pentobarbital on uptake and release of [3H]GABA and [14C]glutamate by brain slices. Brain Res. 1974 Mar 8;67(3):546–548. doi: 10.1016/0006-8993(74)90504-6. [DOI] [PubMed] [Google Scholar]
  20. Cutler R. W., Markowitz D., Dudzinski D. S. The effect of barbiturates on (3H)GABA transport in rat cerebral cortex slices. Brain Res. 1974 Dec 6;81(2):189–197. doi: 10.1016/0006-8993(74)90935-4. [DOI] [PubMed] [Google Scholar]
  21. Dray A., Straughan D. W. Benzodiazepines: GABA and glycine receptors on single neurons in the rat medulla. J Pharm Pharmacol. 1976 Apr;28(4):314–315. doi: 10.1111/j.2042-7158.1976.tb04163.x. [DOI] [PubMed] [Google Scholar]
  22. ECCLES J. C., SCHMIDT R., WILLIS W. D. PHARMACOLOGICAL STUDIES ON PRESYNAPTIC INHIBITION. J Physiol. 1963 Oct;168:500–530. doi: 10.1113/jphysiol.1963.sp007205. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Eccles J. C., Faber D. S., Táboríková H. The action of a parallel fiber volley on the antidromic invasion of Purkyne cells of cat cerebellum. Brain Res. 1971 Jan 22;25(2):335–356. doi: 10.1016/0006-8993(71)90442-2. [DOI] [PubMed] [Google Scholar]
  24. Evans R. H. GABA-potentiating action of pentobarbitone on the isolated superior cervical ganglion of the rat [proceedings]. J Physiol. 1977 Oct;272(1):49P–50P. [PubMed] [Google Scholar]
  25. Gähwiler B. H. Diazepam and chlordiazepoxide: powerful GABA antagonsits in explants of rat cerebellum. Brain Res. 1976 Apr 30;107(1):176–179. doi: 10.1016/0006-8993(76)90108-6. [DOI] [PubMed] [Google Scholar]
  26. Haefely W., Kulcsár A., Möhler H., Pieri L., Polc P., Schaffner R. Possible involvement of GABA in the central actions of benzodiazepines. Adv Biochem Psychopharmacol. 1975;(14):131–151. [PubMed] [Google Scholar]
  27. Hayward J. N. Physiological and morphological identification of hypothalamic magnocellular neuroendocrine cells in goldfish preoptic nucleus. J Physiol. 1974 May;239(1):103–124. doi: 10.1113/jphysiol.1974.sp010558. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Hunt P., Raynaud J. P. Benzodiazepine activity: is interaction with the glycine receptor, as evidenced by displacement of strychnine binding, a useful criterion? J Pharm Pharmacol. 1977 Jul;29(7):442–444. doi: 10.1111/j.2042-7158.1977.tb11363.x. [DOI] [PubMed] [Google Scholar]
  29. Kozhechkin S. N., Ostrovskay R. U. Are benzodiazepines GABA antagonists? Nature. 1977 Sep 1;269(5623):72–73. doi: 10.1038/269072a0. [DOI] [PubMed] [Google Scholar]
  30. Mitchell J. F. The spontaneous and evoked release of acetylcholine from the cerebral cortex. J Physiol. 1963 Jan;165(1):98–116. doi: 10.1113/jphysiol.1963.sp007045. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Mohler H., Okada T. GABA receptor binding with 3H (+) bicuculline-methiodide in rat CNS. Nature. 1977 May 5;267(5606):65–67. doi: 10.1038/267065a0. [DOI] [PubMed] [Google Scholar]
  32. Nicoll R. A., Eccles J. C., Oshima T., Rubia F. Prolongation of hippocampal inhibitory postsynaptic potentials by barbiturates. Nature. 1975 Dec 18;258(5536):625–627. doi: 10.1038/258625a0. [DOI] [PubMed] [Google Scholar]
  33. Nicoll R. A. Pentobarbital: action on frog motoneurons. Brain Res. 1975 Oct 10;96(1):119–123. doi: 10.1016/0006-8993(75)90582-x. [DOI] [PubMed] [Google Scholar]
  34. Nicoll R. A. Presynaptic action of barbiturates in the frog spinal cord. Proc Natl Acad Sci U S A. 1975 Apr;72(4):1460–1463. doi: 10.1073/pnas.72.4.1460. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Nicoll R. A. The effects of anaesthetics on synaptic excitation and inhibition in the olfactory bulb. J Physiol. 1972 Jun;223(3):803–814. doi: 10.1113/jphysiol.1972.sp009875. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Peck E. J., Miller A. L., Lester B. R. Pentobarbital and synaptic high-affinity receptive sites for gamma-aminobutyric acid. Brain Res Bull. 1976 Nov-Dec;1(6):595–597. doi: 10.1016/0361-9230(76)90087-3. [DOI] [PubMed] [Google Scholar]
  37. Phillis J. W. Acetylcholine release from the cerebral cortex: its role in cortical arousal. Brain Res. 1968 Mar;7(3):378–389. doi: 10.1016/0006-8993(68)90004-8. [DOI] [PubMed] [Google Scholar]
  38. Phillis J. W., Chong G. C. Acetylcholine release from the cerebral and cerebellar cortices: its role in cortical arousal. Nature. 1965 Sep 18;207(5003):1253–1255. doi: 10.1038/2071253a0. [DOI] [PubMed] [Google Scholar]
  39. RICHTER D., CROSSLAND J. Variation in acetylcholine content of the brain with physiological state. Am J Physiol. 1949 Nov;159(2):247–255. doi: 10.1152/ajplegacy.1949.159.2.247. [DOI] [PubMed] [Google Scholar]
  40. Ransom B. R., Barker J. L. Pentobarbital selectively enhances GABA-mediated post-synaptic inhibition in tissue cultured mouse spinal neurons. Brain Res. 1976 Sep 24;114(3):530–535. doi: 10.1016/0006-8993(76)90977-x. [DOI] [PubMed] [Google Scholar]
  41. Sato M., Austin G. M., Yai H. Increase in permeability of the postsynaptic membrane to potassium produced by 'nembutal'. Nature. 1967 Sep 30;215(5109):1506–1508. doi: 10.1038/2151506a0. [DOI] [PubMed] [Google Scholar]
  42. Steiner F. A., Felix D. Antagonistic effects of GABA and benzodiazepines on vestibular and cerebellar neurones. Nature. 1976 Mar 25;260(5549):346–347. doi: 10.1038/260346a0. [DOI] [PubMed] [Google Scholar]
  43. Young A. B., Zukin S. R., Snyder S. H. Interaction of benzodiazepines with central nervous glycine receptors: possible mechanism of action. Proc Natl Acad Sci U S A. 1974 Jun;71(6):2246–2250. doi: 10.1073/pnas.71.6.2246. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Zukin S. R., Young A. B., Snyder S. H. Gamma-aminobutyric acid binding to receptor sites in the rat central nervous system. Proc Natl Acad Sci U S A. 1974 Dec;71(12):4802–4807. doi: 10.1073/pnas.71.12.4802. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from British Journal of Pharmacology are provided here courtesy of The British Pharmacological Society

RESOURCES