Electrophysiological effects of cocaine on central monoaminergic neurons

The electrical activity of three different single, identified, spontaneously firing central neurons was monitored by extracellular microelectrodes. Intravenous cocaine administration (0.25-2 mg/kg) elicited an activation of cerebellar Purkinje neurons (PN) and an inhibition of serotonergic dorsal raphe (DRN) and noradrenergic locus coeruleus (LC) neurons. These effects were not temporally correlated with the increase in mean arterial pressure elicited by the intravenous administration of cocaine. In addition, the administration of procaine, a structurally related local anesthetic, did not significantly affect any of the three central neurons studied. Our results suggest that cocaine has potent effects on the activity of DRN, LC and PN neurons, which are not directly related to its cardiovascular or local anesthetic actions.