Evidences for involvement of nitric oxide in the gastroprotective effect of bromocriptine and cyclosporin A on water immersion stress-induced gastric lesions.
Previous studies have been shown that the adrenergic system involves in gastric secretion and pathogenesis of peptic lesion and activation of alpha(2)-adrenoceptors located on the vagus nerve inhibits gastric acid secretion. Bromocriptine, a dopamine receptor agonist, also has alpha(2) agonistic effect and prevents indomethacin-induced gastric ulcer. alpha(2)-Adrenoceptors involve in the release of nitric oxide which has cytoprotective activity in gastric mucosa. Cyclosporin A (CsA) has also been suppressed stress-induced gastric mucosal lesions, dose dependently. The object of this study was to clarify the interaction between the anti-ulcer effect of bromocriptine (2, 4, 8 mg kg(-1)) or cyclosporin A (5, 10, 20 mg kg(-1)) and nitric oxide. Intraperitoneal injections of bromocriptine and cyclosporin A prevented water immersion stress-induced gastric ulcer in rats. L-Nitro-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, increased stress-induced lesions while L-arginine, a precursor of nitric oxide, decreased these lesions. In conclusion, increasing level of nitric oxide by bromocriptine and cyclosporin A may be one of the contributory factors in their protective effects on gastric mucosa.
Samini
Morteza
M
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran.
Moezi
Leila
L
Jabarizadeh
Naghmeh
N
Tavakolifar
Bahareh
B
Shafaroodi
Hamed
H
Dehpour
Ahmad R
AR
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology / Q000627:therapeutic use*; D016572:Cyclosporine / Q000494:pharmacology / Q000627:therapeutic use*; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D013276:Stomach Ulcer / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013312:Stress, Physiological / Q000188:drug therapy* / Q000378:metabolism
D009569:Nitric Oxide; D001971:Bromocriptine; D016572:Cyclosporine