Effect of Cabergoline, a Long-Acting dopamine D₂ Agonist, on Reserpine-Treated Rodents

Abstract

We studied the characterization of cabergoline, a new ergot alkaloid derivative and a selective dopamine D₂ receptor agonist, in comparison to bromocriptine and pergolide in reserpine-treated rodents. Cabergoline (0.25-1.0 mg/kg, s.c.) improved dose-dependently the reserpine-induced akinesia that was assessed on the locomotor activity, and the efficacy lasted longer than those of bromocriptine (1.25-5.0 mg/kg, s.c.) or pergolide (0.0625-0.5 mg/kg, s.c.). Cabergoline (ED₅₀=1.10 mg/kg, at 4 h after the administration of drugs) also reversed catalepsy, the failure to correct an externally imposed posture, and its efficacy was stronger and longer than bromocriptine (ED₅₀=4.65 mg/kg, at 4 h). Further, reserpine-induced rigidity was improved equally by cabergoline (0.125-1.0 mg/kg, i.v.) and bromocriptine (1.0 mg/kg, i.v.). When cabergoline was administered together with 3-(3, 4-dihydroxyphenyl)-L-alanine (L-DOPA), the effects were additive. Our results indicate that the long-lasting effects of cabergoline could be beneficial for treating Parkinson's disease.