Actions of convulsants, 4-aminopyridine and pentylenetetrazole, on the transient outward current of single isolated nodose ganglion neurons.

The actions of 4-aminopyridine (4-AP) and pentylenetetrazole (PTZ) were examined on the transient outward current (IA) of single isolated neurons of the rabbit nodose ganglion. Both agents reduced the amplitude of the current and shortened its duration in a dose-dependent manner. The steady-state inactivation of the IA channel was shifted in a hyperpolarizing direction in the presence of these agents. It is suggested that convulsants such as 4-AP and PTZ modify the IA channels resulting in increased cell excitability possibly contributing to their convulsant action.