Corticosteroids limit the decrease in blood flow velocity in the microvessels of the gastric submucosal layer during stress in rats

: To evaluate the influence of stress and corticosteroids on blood flow velocity in gastric submucosal microvessels it was used intravital microfilming by means of a dark-field contact epiobjective. The plasma filled "gap" in the continuous erythrocyte flow were used as the markers to measure linear blood flow velocity. In unstressed rats the linear blood flow velocity was equal to 2.0 +/- 0.08 mm/sec (156 microvessels, 6.4 +/- 0.14 micron in diameter), calculated volume blood flow--(6.9 +/- 0.48) x 10(-5) microliters/sec. Stress (water immersion and restraint) led to a decrease of blood flow velocity in microvessels to more than double. A stress-induced decrease of blood flow velocity was more greater in rats with insufficient corticosteroid production. The linear velocity of blood flow of these rats was lowered to 0.6 +/- 0.06 mm/sec, volume blood flow to (1.6 +/- 0.21) x 10(-5) microliters/sec. Replacement corticosterone therapy increased the blood flow velocity. It was concluded that stress decreases blood flow in microvessels of gastric submucosa. The results revealed that glucocorticoids take part in normalization of blood flow of gastric microvessels during stress and this action can provide antiulcerogenic effect of corticosteroids which was shown by us previously.