Interpretations of Voltammetry in the Striatum Based on Chromatography of Striatal Dialysate

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Abstract
A comparison is made of chronoamperometric data recorded from the human striatum and chromatographic data obtained from extracellular striatal perfusate. Three cases are considered: the initial sampling period in which a decline in the observed oxidation current occurs; the effect of haloperidol, a dopamine receptor blocker; and the effect of amphetamine. The perfusate is analyzed for ascorbic acid (AA), the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). Using the relative response of these compounds at a carbon epoxy or carbon paste electrode, and the relative concentration of each in the extracellular fluid, the expected changes in oxidation currents for the 3 cases mentioned are calculated. The decline in oxidation current during the initial sampling period is due primarily to a decrease in ascorbic acid. Different electroactive components of the extracellular fluid are the cause of changing oxidation currents under different stimulus conditions.