Topical isoproterenol protects the rat gastric mucosa from ethanol-induced injury.
This study evaluated the effects of topical isoproterenol, a beta-adrenergic agonist, on the morphologic damage produced in the gastric mucosa by ethanol. The orogastric instillation of 100% ethanol in rats resulted in gross lesion formation and deep histologic injury in the gastric mucosa. Animals pretreated with oral isoproterenol (50 micrograms/kg, 500 micrograms/kg, 50 mg/kg) showed dose-dependent protection from both the gross and the histologic mucosal injury (P less than 0.01, ANOVA). Pretreatment with propranolol (2 mg/kg/sec) but not indomethacin (5 mg/kg/sec) blocked this protective effect. Isoproterenol had no effect on ethanol-induced mast cell degranulation as both mucosal and submucosal mast cell counts were significantly and equally decreased in all groups treated with 100% ethanol (P less than 0.05). These findings show that topical isoproterenol protects the rat gastric mucosa from both the gross and the histologic injury caused by 100% ethanol. This protection is mediated by a beta-adrenergic receptor mechanism as it can be blocked by prior treatment with propranolol, but does not involve stabilization of mucosal or submucosal mast cell membranes.
Howard
T J
TJ
Research Service, West Los Angeles Veterans Administration Medical Center, California.
Passaro
E
E
Guth
P H
PH
D000287:Administration, Topical; D000818:Animals; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D005753:Gastric Mucosa / Q000187:drug effects* / Q000473:pathology; D007545:Isoproterenol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008407:Mast Cells / Q000473:pathology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D000431:Ethanol; D011433:Propranolol; D007545:Isoproterenol