Kinetic cooperative effect of glycine receptor agonists and antagonists on the dissociation of strychnine binding.
The dissociation of [3H]strychnine binding was studied in synaptosomal membranes of rat spinal cord. Dissociation elicited by 100-fold dilution was accelerated by completely displacing concentrations of glycinergic agents. The rank order of acceleration was iso-THAZ < strychnine approximately taurine < R 5135 < avermectin b1a approximately beta-alanine << glycine (THAZ, 5,6,7,8-tetrahydro-4H-isoxazolo-(3,4-d)azepin-3-ol). The accelerating effects were correlated with the changes of entropy (r = 0.93) but not with the changes of free energies (r = 0.06) of their binding. Half-maximal acceleration was elicited by 58 microM glycine. The accelerating effects of glycine and beta-alanine were attenuated by the antagonists.
Maksay
G
G
Department of Molecular Pharmacology, Hungarian Academy of Sciences, Budapest.
D000818:Animals; D005998:Glycine / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter / Q000037:antagonists & inhibitors / Q000187:drug effects*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism; D013331:Strychnine / Q000378:metabolism*; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism
D018009:Receptors, Glycine; D017981:Receptors, Neurotransmitter; D013331:Strychnine; D005998:Glycine