Competitive interaction of beta-guanidino propionic acid and gamma-aminobutyric acid on the muscle fibre of the crayfish.
1. The interaction of beta-guanidino propionic acid and gamma-aminobutyric acid has been investigated on the crayfish muscle by measurement of the membrane conductance.2. The increase in membrane conductance produced by GABA is depressed by beta-guanidino propionic acid. This antagonist acts in a competitive way as shown by the shift of log dose-response curves and by the results of tests for competitive interaction (method of Schild (1947); Lineweaver and Burk's plot).3. Perfusion of GABA was shown to induce a receptor desensitization. As a consequence, the slope of the dose-response curve plotted in Hill's co-ordinates increases when care is taken to minimize this phenomenon. The significance of this slope for establishing the real number of GABA molecules binding with the GABA receptor is discussed.
D000613:Aminobutyrates / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D003445:Crustacea; D003864:Depression, Chemical; D004553:Electric Conductivity / Q000187:drug effects; D006146:Guanidines / Q000494:pharmacology*; D009210:Myofibrils / Q000187:drug effects*; D010477:Perfusion; D011422:Propionates / Q000494:pharmacology*; D011955:Receptors, Drug
D000613:Aminobutyrates; D006146:Guanidines; D011422:Propionates; D011955:Receptors, Drug