Haloperidol effects on Na current in acutely isolated rat retinal ganglion cells

Suppressive effects of haloperidol, one of the neuroleptic compounds that acts on the transient Na current (INa,t) were studied in freshly isolated 5-10-day-old rat retinal ganglion cells using a whole-cell patch clamp technique. High doses of haloperidol reversibly and dose dependently (2-200 mumol ) reduced the peak amplitude of INa,t. The half-inhibition dose was 27.1 mumol. The inactivation curve of INa,t was shifted toward a hyperpolarizing direction by about 42% when the amplitude was suppressed with 20 mumol haloperidol. This indicates that haloperidol suppression of INa,t is probably affected through changes in the inactivation of Na channels.