[Biphasic (ulcer-forming and ulcer-preventing) effect of adrenaline in rats].
Adrenaline-induced gastric ulceration was studied in rats. Adrenaline in high doses caused gastric ulcer, which was completely blocked by pretreatment with alpha-blockers (phenoxybenzamine, dibenamine), but not by pretreatment with propranolol or atropine, nor by vagotomy, hypophysectomy or adrenalectomy. After successive administration of adrenaline, once daily for 7 days, however, no gastric ulcer was observed. Recovery from the ulcerogenic action of adrenaline was seen after 4 weeks withdrawal. Pretreatment with a small dose of adrenaline inhibited the ulcerogenic action of a high dose of adrenaline. Pretreatment with reserpine, pyrogallol or iproniazid inhibited the action of adrenaline. It is concluded that adrenaline has a biphasic effect on gastric ulceration, the ulcerogenic action is due to its alpha-action and antiulcerogenic effect is due to development of tachyphylaxis.
D000315:Adrenalectomy; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D007016:Hypophysectomy; D007490:Iproniazid / Q000494:pharmacology; D008297:Male; D011748:Pyrogallol / Q000494:pharmacology; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D013276:Stomach Ulcer / Q000139:chemically induced / Q000517:prevention & control; D014628:Vagotomy
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D006634:Histamine H1 Antagonists; D011748:Pyrogallol; D001285:Atropine; D012110:Reserpine; D007490:Iproniazid; D004837:Epinephrine