The effect of haloperidol on the ionic currents in the voltage-clamped node of Ranvier.

Haloperidol (Haldol) selectively inhibits sodium currents at the voltage-clamped node of Ranvier at concentrations ranging from 0.013 to 13 muM. The action potential is reduced or abolished while the membrane potential is not significantly changed. The dose-response curve is described by a Langmuir adsorption isotherm with an apparent dissociation constant of 6 X 10(-7) M. Sodium current time-to-peak and the permeability-voltage relationship are not affected, although at higher concentrations the inactivation time constant is slightly increased. Potassium currents are not altered except at 13 muM where there is an occasional nonsystematic effect. Leakage currents are not changed at any concentration.