In vivo voltammetric determination of the kinetics of dopamine metabolism in the rat.

In vivo voltammetry at carbon paste electrodes placed in the striatum of chloral hydrate-anesthetized rats was used to monitor changes in extracellular 3,4-dihydroxyphenylacetic acid (DOPAC) following 1-min periods of electrical stimulation of the ascending nigro-striatal pathways. Statistical analysis of resultant changes in DOPAC allows simultaneous determination of the rate constants for the turnover of both dopamine (DA) (0.046/min) and DOPAC (0.053/min.). The data demonstrate that there are substantial temporal differences between neuronal release of DA and changes in striatal DOPAC levels. This should be considered when metabolite measurements are used as an index of neurotransmitter activity.