[Blocking of proton-activated sodium permeability of the membranes of trigeminal ganglion neurons in the rat by organic cations].

The effect of amiloride, 2- and 4-aminopyridines, tetraethylammonium, guanidine on proton-induced membrane permeability was investigated in perfused neurons from rat trigeminal ganglia. When applied externally these substances produced a rapid and reversible blocking action on the inwardly directed proton-induced current. The degree of blocking increased with hyperpolarization and with a decrease in the intracellular concentration of permeable cations. The initially linear current-voltage relationship became nonlinear. Amyloride with effective concentrations between 10(-6)-10(-4) M was the most potent blocker among the substances tested.