Differential pulse voltammetry in the anaesthetized rat: identification of ascorbic acid, catechol and indoleamine oxidation peaks in the striatum and frontal cortex.

1 Differential pulse voltammetric scans recorded using graphite paste working electrodes implanted in the striatum and frontal cortex of anaesthetized rats exhibited up to three distinct oxidation peaks at potentials between -0.1 and +0.5 V. 2 The first peak at about +0.12 V was selectively increased by the micro-infusion of ascorbic acid (5 X 10(-6) M) close to the surface of the working electrode implanted in either the striatum or the frontal cortex. 3 The second peak at about +0.22 V was selectively increased by micro-infusing either dopamine or 3,4-dihydroxyphenylacetic acid, (5 X 10(-6) M). 4 The third peak at approximately + 0.35 V was selectively increased in a dose-related manner by the micro-infusion of either 5-hydroxytryptamine, (7.5 X 10(-6) M to 7.5 X 10(-5) M) or 5-hydroxyindole-3-acetic acid, (2.5 X 10(-5) M to 6 X 10(-4) M). 5 The results show that differential pulse voltammetry can be used to obtain qualitative and quantitative information about catechol and indoleamine neurones in vivo.