Central neurons are depressed by iontophoretic and micropressure application of ethanol and tetrahydropapaveroline.

In an attempt to circumvent the complexities of systemically administered ethanol and tetrahydroisoquinolines (TIQs), iontophoresis and micropressure application were used to test these agents in single rat neurons. Alcohol applied by either method depressed cerebellar Purkinje cells in a concentration-dependent, non-specific, local anesthetic-like manner. Tests of tetrahydropapaveroline.HCl (THP) on neurons from three brain areas also showed depression of spontaneous discharge, although, in contrast to ethanol, little or no local anesthetic-like action was observed, and at equivalent ejection currents or pressures, the THP depressions appeared to be more pronounced. The underlying mechanisms for these responses are unknown.