ISOPROTERENOL PREVENTS ETHANOL-INDUCED MICROVASCULAR STASIS AND DEEP HISTOLOGIC INJURY IN RAT GASTRIC-MUCOSA

The effect of topical isoproterenol (5.8 X 10(-5) M) on the microvascu lar stasis and histologic injury produced in the rat gastric mucosa by absolute ethanol was investigated using in vivo microscopic and histo logic techniques. Our findings show that in control animals, absolute ethanol applied to the gastric mucosa caused a rapid decrease in micro vascular bloodflow, leading to complete stasis by 3 min. In contrast, prior treatment of the gastric mucosa with topical isoproterenol incre ased microvascular blood flow initially and then maintained microvascu lar flow in the majority of microvessels studied after the application of absolute ethanol. Treatment with topical isoproterenol also reduce d the histologic injury score and percent mucosal necrosis caused by a bsolute ethanol. Pretreatment of animals with a beta-adrenergic antago nist propranolol (2 mg/kg subcutaneously), completely blocked these pr otective effects. We observed no systemic effects attributable to the topical use of isoproterenol. These results indicate that prior treatm ent of the gastric mucosa with topical isoproterenol maintains microva scular blood flow and reduces the deep histologic injury in the stomac h caused by 100% ethanol.