[The antiulcer effect of corticosteroids and the blood flow in the gastric mucosa].

Intravital microfilming by means of dark-field contact epiobjective was used for investigation of the role of gastric microcirculation in antiulcerogenic action of corticosteroids in rats. Microvascular volume blood flow velocity was calculated from measurements of red cell velocity and vessel diameters. There was compared gastric submucosal and mucosal microcirculation as well as gastric ulceration after water-immersion stress in rats with normal function of hypothalamo-pituitary-adrenocortical (HPA) axis and in rats with insufficiency of corticosteroid production, induced by blockade of the HPA axis. The 3h stress induced gastric ulcerations, dilatation of mucosal microvessels and a significant decrease of volume blood flow in submucosal microvessels. These changes were greater in rats with blockade of HPA axis than in animals with normal corticosteroid production. Replacement corticosterone therapy decreased the effects of HPA axis blockade. Thus corticosteroids which are produced during stress restricted the reduction of volume blood flow in submucosal microvessels, the dilatation of mucosal microvessels as well as gastric ulcerations. These findings indicate that corticosteroids exert their antiulcerogenic action via the mechanism of improvement of gastric microcirculation.