Role of the nitric oxide/cyclic GMP pathway and extracellular environment in the nitric oxide donor-induced increase in dopamine secretion from PC12 cells: a microdialysis in vitro study.
In vitro microdialysis was used to investigate the mechanism of nitric oxide (NO) donor-induced changes in dopamine (DA) secretion from PC12 cells. Infusion of the NO-donor S-nitroso-N-acetylpenicillamine (SNAP, 1.0 mm) induced a long-lasting increase in DA and 3-methoxytyramine (3-MT) dialysate concentrations. SNAP-induced increases were inhibited either by pre-infusion of the soluble guanylate cyclase (sGC) inhibitor 1H-[1,2,4] oxadiazolo[4,3]quinoxalin-1-one (ODQ, 0.1 mm) or by Ca2+ omission. Ca2+ re-introduction restored SNAP effects. SNAP-induced increases in DA + 3-MT were unaffected by co-infusion of the l-type Ca2+ channel inhibitor nifedipine. The NO-donor (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (NOR-3, 1.0 mm) induced a short-lasting decrease in dialysate DA + 3-MT. Ascorbic acid (0.2 mm) co-infusion allowed NOR-3 to increase dialysate DA + 3-MT. ODQ pre-infusion inhibited NOR-3 + ascorbic acid-induced DA + 3-MT increases. Infusion of high K+ (75 mm) induced a 2.5-fold increase in dialysate DA + 3-MT. The increase was abolished by NOR-3 co-infusion. Conversely, co-infusion of ascorbic acid (0.2 mm) with NOR-3 + high K+ restored high K+ effects. Co-infusion of nifedipine inhibited high K+-induced DA + 3-MT increases. These results suggest that activation of the NO/sGC/cyclic GMP pathway may be the underlying mechanism of extracellular Ca2+-dependent effects of exogenous NO on DA secretion from PC12 cells. Extracellular Ca2+ entry may occur through nifedipine-insensitive channels. NO effects and DA concentrations in dialysates largely depend on both the timing of NO generation and the extracellular environment in which NO is generated.
Serra
Pier Andrea
PA
Department of Pharmacology, University of Sassari, Sassari, Italy.
Rocchitta
Gaia
G
Delogu
Maria R
MR
Migheli
Rossana
R
Taras
Maria G
MG
Mura
Maria P
MP
Esposito
Giovanni
G
Miele
Egidio
E
Desole
Maria S
MS
Miele
Maddalena
M
D015102:3,4-Dihydroxyphenylacetic Acid / Q000032:analysis / Q000378:metabolism; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002470:Cell Survival; D006152:Cyclic GMP / Q000378:metabolism*; D004298:Dopamine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism*; D006719:Homovanillic Acid / Q000032:analysis / Q000378:metabolism; D017551:Microdialysis; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009574:Nitro Compounds / Q000494:pharmacology; D016716:PC12 Cells; D010673:Pheochromocytoma / Q000188:drug therapy / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D026423:S-Nitroso-N-Acetylpenicillamine / Q000494:pharmacology
D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D015102:3,4-Dihydroxyphenylacetic Acid; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; C061872:FK 409; D006152:Cyclic GMP; C001746:3-methoxytyramine; D001205:Ascorbic Acid; D011188:Potassium; D002118:Calcium; D004298:Dopamine; D006719:Homovanillic Acid