Abstract
The membrane response to γ-aminobutyric acid (GABA) of locust muscle fibers bathed in "propionate saline" at pH 6.5 is generally biphasic. The slow phase is exponential, and its rate constant (5.5 x 10-3 to 1.0 x 10-2 sec-1) is independent of GABA concentration and relatively insensitive to temperature change (from 26° to 15°). With increasing GABA concentration and temperature, a faster process intervenes. A form of "sensitization" occurs in which the participation of the fast component of the kinetics increases on repeated application of the same GABA concentration. Equilibrium curves of GABA action were obtained at different temperatures, and a van't Hoff plot was constructed. The standard enthalpy change, ΔH°, for the over-all interaction between GABA and receptor is -59.3 kcal/mole.
- Copyright ©, 1973, by Academic Press, Inc.
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