MODIFICATION OF ETHANOL INTOXICATION BY DOPAMINE AGONISTS AND ANTAGONISTS

The effects of ethanol on locomotor activity and rotarod performance were measured in the rat. Apomorphine (4 mg/kg s.c.) antagonized and pimozide (0.75-1.50 mg/kg s.c.) enhanced the effects of a 2 g/kg dose of ethanol on rotarod performance. No such interaction was seen with pentobarbital, 25 mg/kg, a dose sufficient to produce an equivalent motor performance deficit. Animals with 6-hydroxydopamine lesions of the substantia nigra were more sensitive to the ethanol-induced impairment of rotarod performance and suppression of locomotor activity than sham-operated controls. The pattern of dopamine depletion in lesioned animals indicated a degree of selectivity of the lesion for the nigrostriatal pathway. Apparently ethanol interferes with dopaminergic transmission and such an interference may be involved in the behavioral effects of ethanol.