Pergolide potentiates L-DOPA-induced dopamine release in rat striatum after lesioning with 6-hydroxydopamine

We used intrastriatal microdialysis to study the effect of pergolide, a D-1 /D-2 dopamine (DA) receptor agonist on biotransformation of exogenous L-DOP A in hemi-Parkinsonian rats. DA and metabolites were assayed by microbore liquid chromatography. Pergoli de (50 mu g/kg, i.p) caused a 67% and 87% decrease in striatal EC levels of DA in intact and denervated striatum respectively. In intact striatum but not in denervated striatum, pergolide decreased EC levels of 3,4-dihydroxyp henylacetic acid (DOPAC) and homovanillic acid (HVA) (53% and 42% decrease, respectively). L-DOPA (100 mg/kg, i.p.) produced significant increase in E C levels of DA, DOPAC and HVA in intact and denervated striatum with and wi thout local perfusion of 10(-4)M pergolide. In denervated striatum, L-DOPA- induced DA increase was significantly higher in rats with pergolide. Our re sults suggest that, in an animal model of Parkinson's disease, pergolide in association with L-DOPA favors the restoration of striatal EC DA levels.