Characterization of 3H-GABA receptor binding to rat brain synaptosomal membranes: effect of non GABAergic compounds.
Characteristics of 3H-GABA binding to rat brain synaptic membranes in vitro have been investigated. The specific binding of 3H-GABA displays saturation kinetics. Only one single population of receptor sites was found (Km = 31.3 nM) with a concentration of 2.09 pmol/mg protein. Only GABA agonists show inhibitory effect on the binding, whereas GABA antagonists, GABA-uptake inhibitors, and inhibitors of GAD and GABA-T are without effect. The order of potencies for GABA agonists are: Muscimol greater than GABA greater than or equal to 4,5-dihydromuscimol greater than 3-aminoproprane sulphonic acid greater than isoguvacine greater than THIP greater than 3-hydroxy-GABA greater than imidazol-4-acetic acid. Agonists and antagonists from other neurone systems as well as neuroleptics and benzodiazepines had no or only a very slight potency in the binding test.
D000818:Animals; D001921:Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D011956:Receptors, Cell Surface; D005680:gamma-Aminobutyric Acid