Modulation of dopamine uptake by nitric oxide in cultured mesencephalic neurons.
Strong evidence obtained from in vivo and ex-vivo studies suggests the existence of interaction between dopaminergic and nitrergic systems. Some of the observations suggest a possible implication of nitric oxide (NO) in dopamine (DA) uptake mechanism. The present work investigated the interaction between both systems by examining the effect of an NO donor, sodium nitroprusside (SNP), associated with the indirect DA agonist, amphetamine (AMPH) on tritiated DA uptake in cultures of embryonic mesencephalic neurons. Consistent with the literature, both AMPH (1, 3 and 10 microM) and SNP (300 microM and 1 mM) inhibited DA uptake in a dose-dependent manner. In addition, the inhibition of DA uptake by AMPH (1 and 3 microM) was significantly increased by the previous addition of SNP (300 microM). The implication of NO in this interaction was supported by the fact that the free radical scavenger N-acetyl-L-Cysteine (500 microM) significantly increased DA uptake and completely abolished the effect of SNP, leaving unaffected that from AMPH on DA uptake. Further, double-labeling immunohistochemistry showed the presence of tyrosine hydroxylase- (TH, marker for dopaminergic neurons) and neuronal NO synthase- (nNOS, marker for NO containing neurons) expressing neurons in mesencephalic cultures. Some dopaminergic neurons also express nNOS giving further support for a pre-synaptic interaction between both systems. This is the first work demonstrating in mesencephalic cultured neurons a combined effect of an NO donor and an indirect DA agonist on specific DA uptake.
Salum
Cristiane
C
Department Physiology, FORP, University of São Paulo, Ribeirão Preto, SP, Brazil. crisalum@uol.com.br
Raisman-Vozari
Rita
R
Michel
Patrik P
PP
Gomes
Margarete Zanardo
MZ
Mitkovski
Miso
M
Ferrario
Juan E
JE
Ginestet
Laure
L
Del Bel
Elaine A
EA
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology; D007150:Immunohistochemistry; D008636:Mesencephalon / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D015415:Biomarkers; D018491:Dopamine Agonists; D016166:Free Radical Scavengers; D020030:Nitric Oxide Donors; D009599:Nitroprusside; D009569:Nitric Oxide; D000661:Amphetamine; D052248:Nitric Oxide Synthase Type I; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine