L-DOPA DOES NOT FACILITATE NITRIC-OXIDE PRODUCTION IN THE RAT STRIATUM AND SUBSTANTIA-NIGRA - IN-VIVO MICRODIALYSIS STUDY

Using in vivo microdialysis and flow-injection, we evaluated the produ ction of nitric oxide (NO) in the striatum and substantia nigra of fre ely moving rats in response to challenge doses of L-dihydroxyphenylala nine (L-DOPA) by measuring the NO metabolite levels of nitrate and nit rite. The dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) concentr ations also were determined in the same perfusates. Intraperitoneal in jection of L-DOPA produced a significant, dose-dependent increase in t he extracellular levels of dopamine and DOPAC in these areas, but did not modify the extracellular levels of the NO metabolites. An acute do se of L-DOPA does not appear to facilitate NO production in the rat st riatum and substantia nigra. (C) 1998 Elsevier Science Inc.