GABA, depressants and chloride ions affect the rate of dissociation of 35S-t-butylbicyclophosphorothionate binding

G. Maksay, M. K. Ticku

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The dissociation of 35S-TBPS was studied from binding sites of rat cerebral cortex. Monophasic dissociation plots became polyphasic and accelerated in the presence of micromolar concentrations of GABA suggesting the involvement of low (or super-low) affinity GABA receptors. The presence of the depressants etazolate, R(-)MPPB and ethanol resulted in similarly accelerated dissociation patterns. In contrast, the convulsants S(+)MPPB and pentamethylenetetrazol did not significantly affect the dissociation of TBPS. Dissociation initiated by dilution was not affected either by an excess of picrotoxin or by varying the equilibrium occupancy of the TBPS sites. These findings rule out the possibility of a kinetic cooperativity for the binding of convulsants. The removal of chloride ions also enhanced the rate of TBPS dissociation. Kinetic heterogeneity of the TBPS binding sites can be interpreted with allosteric interactions mediated by various sites at the GABA receptor complex coupled to different states of the chloride ionophore.

Original languageEnglish
Pages (from-to)2173-2180
Number of pages8
JournalLife Sciences
Volume37
Issue number23
DOIs
Publication statusPublished - Dec 9 1985

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gamma-Aminobutyric Acid
Chlorides
Ions
Convulsants
GABA Receptors
Etazolate
Binding Sites
Picrotoxin
Ionophores
Kinetics
Cerebral Cortex
Ethanol
Dilution
tert-butylbicyclophosphorothionate
Rats
1-methyl-5-phenyl-5-propylbarbituric acid

ASJC Scopus subject areas

  • Pharmacology

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GABA, depressants and chloride ions affect the rate of dissociation of 35S-t-butylbicyclophosphorothionate binding. / Maksay, G.; Ticku, M. K.

In: Life Sciences, Vol. 37, No. 23, 09.12.1985, p. 2173-2180.

Research output: Contribution to journalArticle

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