The location of photodegradable nitric oxide store in the mouse stomach fundus.
The aim of this study was to investigate the location of photodegradable nitric oxide (NO) store using a pharmacological approach in mouse gastric fundus. The ultraviolet light irradiation (UV; 360 nm, 60 s), electrical field stimulation (EFS; 4 Hz, 25 V, 1 ms, 15s-train), exogenous nitric oxide (NO; 10 microM), nitroglycerin (100 microM) and isoproterenol (5 nM) induced relaxation in mouse gastric fundus preparations in the absence or presence of an intact mucosa. The NO scavenger, haemoglobin (20 microM), significantly inhibited the relaxation of intact and denuded mucosa stomach fundus to UV light irradiation, EFS and NO, but not to nitroglycerin and isoproterenol. The superoxide anion generator, pyrogallol (50 microM), inhibited relaxation of intact and denuded mucosa stomach fundus induced by UV light irradiation, EFS, NO, but not to nitroglycerin and isoproterenol. The inhibition observed with pyrogallol was prevented by exogenous Cu/Zn superoxide dismutase (SOD; 100 U/ml), a membrane impermeable antioxidant. The Cu/Zn SOD inhibitor, diethyldithiocarbamic acid (DETCA; 8 mM), inhibited the relaxation of intact and denuded mucosa stomach fundus to UV light irradiation, EFS, NO and nitroglycerin but not those to isoproterenol. Exogenous SOD (100 U/ml) partially prevented the inhibitory effect of DETCA on relaxation to UV light irradiation, EFS, NO but not to nitroglycerin. DETCA-induced inhibition of the nitroglycerin-induced relaxation was partially prevented by the cell-permeable polyethylene-glycol-superoxide dismutase (100 U/ml). These results indicate that photodegradable NO store is, at least in part, unlikely to be within smooth muscle cells, and furthermore, that UV light-induced relaxation is not dependent on gastric mucosal layer.
Ogülener
Nuran
N
Department of Pharmacology, Faculty of Medicine, Cukurova University, 01330 Adana, Turkey. ogulener@cu.edu.tr
Döndas
Naciye Yaktubay
NY
Secilmi
Ata
A
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D005748:Gastric Fundus / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D005753:Gastric Mucosa / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D006454:Hemoglobins / Q000494:pharmacology; D008297:Male; D051379:Mice; D009126:Muscle Relaxation / Q000187:drug effects / Q000528:radiation effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009569:Nitric Oxide / Q000494:pharmacology / Q000502:physiology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011748:Pyrogallol / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D014466:Ultraviolet Rays
D000975:Antioxidants; D006454:Hemoglobins; D011748:Pyrogallol; D013481:Superoxides; D009569:Nitric Oxide; D011092:Polyethylene Glycols; D013482:Superoxide Dismutase; C063471:polyethylene glycol-superoxide dismutase