Further ivestigations into the relationship between the dopanminergic system ascorbic acid and uric acid in the rat striatum

Levels of dopaminc (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid (AA), dehydroascorbic acid (DHAA), and uric acid were determined in the rat striatum following single apomorphine (1 mg/kg), scopolamine (0.6 mg/kg), pilocarpine (4 mg/kg), or pilocarpine + scopolamine (4 and 0.6 mg/kg, respectively) injections. The decrease in DOPAC levels and in the DOPAC/DA ratio, induced by the pharmacological manipulation, was linearly correlated with the increase in DHAA levels (r = −0.9060, P < 0.05) and with the increase in the DHAAAA ratio (r = −0.9004, P < 0.05), respectively. I dopaminergic activaction or cholinergic inhibition both increase striatal AA oxidation, which is correlated with a decrease in DA turnover.