[Stationary characteristics of proton receptors in the somatic membrane of sensory neurons in the rat].

Steady-state properties of proton-activated Na+ permeability in the membrane of rat sensory neurons have been investigated under conditions of intracellular perfusion and voltage clamp. The desensitization of this mechanism is found to develop at weakly basic pH levels (pKa 7.15). The desensitization is highly cooperative: its Hill coefficient is close to 7, while for activation it is about 2. Divalent cations (Ca2+ and Mg2+) complete with protons by changing corresponding pKa both for activation and desensitization without affecting the Hill coefficient.