L-arginine produces NO-independent increases in dopamine efflux in rat striatum.
The effect of L-arginine (L-ARG; 10-100 mM) on dopamine efflux from rat striatum was investigated using in vivo microdialysis. L-ARG (50 mM-100 mM), but not D-arginine (100 mM) nor L-citrulline (100 mM), produced a biphasic effect on dopamine efflux with an initial small reduction, followed by a large sustained increase. The effect of L-ARG was not prevented by nitric oxide synthase inhibition with NG-nitro-L-arginine methyl ester or 7-nitroindazole monosodium salt. Efflux of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) was reduced by L-ARG (10-100 mM), D-arginine (100 mM) and L-citrulline (100 mM). These data suggest that changes in dopamine, DOPAC and HVA efflux produced by high concentrations of L-ARG occur independently of NO, and that the use of high L-ARG concentrations are inappropriate when investigating the role of NO in striatum.
Silva
M T
MT
Neurodegenerative Diseases Research Centre, Biomedical Sciences Division, King's College London, UK.
Rose
S
S
Hindmarsh
J G
JG
Jenner
P
P
Marsden
C D
CD
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001120:Arginine / Q000494:pharmacology*; D002956:Citrulline / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006719:Homovanillic Acid / Q000378:metabolism; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism
D004791:Enzyme Inhibitors; D007191:Indazoles; D015102:3,4-Dihydroxyphenylacetic Acid; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester; D004298:Dopamine; D006719:Homovanillic Acid