The effects of amphetamine and pilocarpine on the release of ascorbic and uric acid in several rat brain areas.

Linear sweep voltammetry was used to investigate the effects of amphetamine (which enhances the release of dopamine) and/or pilocarpine (a cholinergic agonist) on the release of ascorbic acid and uric acid in brain areas differing in dopamine and acetylcholine concentrations. In caudate, nucleus accumbens, and hippocampus, the magnitude of the amphetamine-induced increase in ascorbic acid was roughly correlated with dopamine content of the brain area tested. Cingulate cortex was a notable exception; the increase in ascorbic acid was greater than that in nucleus accumbens. Pilocarpine produced the greatest increase in ascorbic acid in cingulate cortex, even though cingulate cortex has the lowest acetylcholine concentration of the brain areas tested. Except for cingulate cortex, the ascorbic acid data were consistent with the hypothesis that amphetamine and pilocarpine release different pools of ascorbic acid. The uric acid data were consistent with the hypothesis that amphetamine and pilocarpine release the same pool of uric acid. The unexpected findings in cingulate cortex may point to an important role of ascorbic acid in this brain area.