[Development of the reactivity of the microcirculatory system of the rat mesentery during sexual maturation].

Biomicroscopy was employed to study the time-course of microcirculatory reactivity in rat mesentery under the influence of adrenaline solution from the 3d to the 13th week of development. Variation in the microcirculatory reactivity in the mesentery in ontogenesis is associated with an increase in the sensitivity of microvessels to the action of vasoactive substances and with the organization of the microcirculatory bed becoming more complicated. Three stages were revealed in the development of microvascular reactivity in the course of formation of mesenterial microcirculation: early (3-5 weeks), characterized by relatively low sensitivity of microvessels; intermediate (7-8 weeks) marked by a progressive increase in microvascular sensitivity; mature (starting from the 13th week) characterized by the appearance of the definitive reaction pattern.