RESUMEN
Certain compounds such as prostaglandins, atropine, cimetidine and carotenes are able to prevent the development of gastric mucosal damage produced in experimental animals or in man by intragastric administration of necrotizing agents such as indomethacin without significantly inhibiting gastric acid secretion. The clinical background of this gastric cytoprotection and its importance for man is not yet known, although the beneficial effects of these compounds have been demonstrated in human therapy. In the present study, carried out in 66 healthy human subjects, it was found that vitamin A at a dose of 100,000 IU i.m., atropine at 0.125 mg i.m., and cimetidine at 12.5 mg i.m., which doses do not inhibit the gastric basal secretion nor the maximal secretory response to pentagastrin stimulation, each prevented the gastric microbleeding produced by the oral application of indomethacin. It is concluded that this gastric cytoprotection, characteristic of prostaglandins but extending to atropine, cimetidine and vitamin A, holds good in man as well as experimental animals. Thus the potential clinical significance of gastric cytoprotection induced by these compounds may be considerable.
Asunto(s)
Atropina/farmacología , Cimetidina/farmacología , Mucosa Gástrica/efectos de los fármacos , Indometacina/antagonistas & inhibidores , Vitamina A/farmacología , Relación Dosis-Respuesta a Droga , Jugo Gástrico/metabolismo , Hemorragia/inducido químicamente , Humanos , Pentagastrina/farmacología , Tasa de Secreción/efectos de los fármacosRESUMEN
Swimming of the rats in the water below body temperature (23 degrees C) for a period of 5 hours resulted in a number of acute haemorrhagic lesions, principally erosions, in the glandular part of the stomach. The objective of this study was to establish the possible roles of some hormonal, biochemical and metabolic factors in the pathogenesis of stress ulcer produced in rats forced to swim. It was found that (i) prior ligation of the pylorus caused a considerable decrease of both the incidence and the severity of the ulcers resulting from the swim-stress, (ii) a significant decrease of the gastric secretion and rectal temperature resulted during the swim-stress condition, (iii) metabolic acidosis developed during the forced swimming period, (iv) considerable increases of the plasma corticosterone and blood glucose concentration also developed, (v) the gastric mucosal level of cAMP also increased, and (vi) a prior period of starvation increased the incidence and severity of the acute ulcers resulting from the swim-stress. It was concluded that various humoral, biochemical and metabolic factors play important roles in the development of stress ulceration in rats forced to swim.
Asunto(s)
Úlcera Gástrica/etiología , Estrés Fisiológico/metabolismo , Animales , Corticosterona/sangre , AMP Cíclico/análisis , Femenino , Ácido Gástrico/metabolismo , Masculino , Ratas , Ratas Endogámicas , Úlcera Gástrica/metabolismo , NataciónRESUMEN
Plasma concentration, hepatic uptake and biliary excretion of intravenously administered rose bengal was determined in rats pretreated with phenobarbital (50 mg/kg) daily, for four days). After an initial (0--16 min) rapid fall in plasma rose bengal concentration caused by hepatic uptake of the dye, the curves in control and pretreated rats did not differ from each other either after administration of a small (5 mg/kg) or a large (50 mg/kg) dose. Hepatic rose bengal concentration was significantly lower in pretreated animals than in the control group. Since liver weight was higher in the phenobarbital pretreated animals than in the controls, the total amount of rose bengal taken up by the liver did not differ in the two groups. The biliary excretion of low dose (5 mg/kg) rose bengal was significantly higher in phenobarbital pretreated than in the control rats but with doses of 50 mg/kg and 100 mg/kg no difference was observed. These doses of rose bengal diminished the increased bile flow caused by phenobarbital.