Avtor/Urednik		Robert, A; Lancaster, C; Olafsson, AS; Gilbertson-Beadling, S; Zhang, W
Naslov		Gastric adaptation to the ulcerogenic effec of aspirin
Tip		članek
Vir		Exp Clin Gastroenterol
Vol. in št.		Letnik 1, št. 1
Leto izdaje		1991
Obseg		str. 73-81
Jezik		eng
Abstrakt		We report a defense machanism for the stomach, called "gastric adaptation". It is the property of the gastric mucosa to become adapted to the ulcerogenic effect of aspirin (ASA) upon continued administration of the drug. It is based on the following observations made in rats. 1. Whereas a single oral administration ASA combined with exposure to cold temperature produced many severe, bleeding gastric erosions within one hour, repeated daily treatment for 4-14 days using the same regimen of ASA + cold produced fewer lesions, and the reduction in lesions was related to the number of treatments with ASA. The average number of lesions per stomach decreased from 39 (ASA given once) to 6 and 3 after 4 and 14 days, respectively, of continued daily administration. 2. The resistence to ulcer formation persisted for 10 days following a 4-day treatment. 3. The threshold dose of ASA + cold that induced adaptation was 25 mg/kg given daily, and full adaptation occurred at 50 mg/kg. 4. The adaptation induced by a 4-day treatment with ASA + cold was not overcome by high doses of ASA, although such doses, given only once to naive rats, were maximally ulcerogneic. 5. In order for adaptation to develop, ASA had to be given orally; parenteral (subcutaneous) administration for 4 days was ineffective. The present data demonstrate the existence of physiological mechanism by which the stomach can defend itself from irritating drugs. Adaptation is not due to a reduction in gastric acid secretion. It is not due either to a decreased effectiveness of the inhibitory action of ASA on prostaglandin cyclooxygense, since the ability of the gastric mucosa to synthesize prostaglandins remained depressed during prolonged treatment with ASA. We hypothesize that the local gastric irritation caused by the first treatment with ASA + cold may be responsable for the subsequent adaptation. It may trigger the formation of substance(s) that in turn increase mucosal resistance to damage.(trunc.)
Deskriptorji		GASTRIC MUCOSA ASPIRIN COLD FASTING DOSE-RESPONSE RELATIONSHIP, DRUG STOMACH ULCER GASTRIC ACID RATS, INBRED STRAINS RATS