Protective effect of carbidopa on hydroxyl radical generation in the rat striatum by dopamine.
The effect of L-3,4-dihydroxyphenylalanine (L-DOPA) on the generation of hydroxyl free radicals (.OH) was investigated using striatal microdialysis technique. Salicylic acid in Ringer's solution (0.5 nmol.microliters-1.min-1) was infused directly through a microdialysis probe to detect the generation of .OH as reflected by the formation of dihydroxybenzoic acids (DHBA) in the striatum. When L-DOPA (0.1 mM; 1 microliter.min-1) was infused in the rat brain, the level of 3,4-dihydroxyphenylacetic acid (DOPAC) gradually increased in a time-dependent manner. In addition, a marked elevation of DHBA was observed. However, in the presence of carbidopa, a decarboxylase inhibitor, the elevation in DHBA formation was not observed. These results suggest that carbidopa may suppress the .OH generation by dopamine (DA).
Obata
T
T
Department of Pharmacology, Oita Medical University, Japan.
Yamanaka
Y
Y
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D002230:Carbidopa / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D006878:Hydroxides; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012980:Sodium Salicylate / Q000494:pharmacology
D016861:Cyclooxygenase Inhibitors; D015259:Dopamine Agents; D005609:Free Radicals; D006878:Hydroxides; D018696:Neuroprotective Agents; D015102:3,4-Dihydroxyphenylacetic Acid; D007980:Levodopa; C031356:hydroxide ion; D002230:Carbidopa; D004298:Dopamine; D012980:Sodium Salicylate