Conformation of gamma-aminobutyric acid and its receptors
Sytinsky, I.A.
Biokhimiia 43(5): 771-781
1978
ISSN/ISBN: 0320-9725 PMID: 656501 Document Number: 130871
The preferable conformations of the inhibitory transmitter gamma-aminobutyric acid (GABA) and its specific inhibitor bicuculline are due to the occupation of the GABAreceptor by a part of the bicuculline molecule that is isosteric with the biologically active conformation of GABA. In the present review are described characteristics of sodium-independence receptor sites and evaluated the regional distribution of postsynaptic receptor binding for GABA in the central nervous system. The postsynaptic GABA receptor has been labeled by direct binding of 3H-GABA. The structural analogues and antagonists of GABA were investigated for inhibition of GABA binding. The developmental changes in the activity of glutamic acid decarboxylase, the GABA uptake mechanism and GABA receptor binding in embryo brain were examined. Different models for the GABA-receptor interaction are considered. Data of the stoichiometry of GABA-receptor interactions indicate that the interaction is probabilistic and that 3 molecules of GABA are needed to activate the receptor probabilistically. It was found that 1 molecule of picrotoxin was capable of blocking the interaction with 3 GABA molecules. The hypothetical model of cooperative action of GABA-recepto-inophore complexes involving membrane mobility is also discussed. The transitive complex GABA with ligand binding of Na+, Cl- and the conformational changes of GABA-receptor is proposed.