[Mesenteric microvessel reactivity in rats in mesenteric shock]

Reactivity of rat mesenterial microvessels was studied during mesenterial shock. The development of the shock was discovered to involve two phases in the changes of microvascular reactivity. The sensitivity of microvessels to adrenaline was increased at the beginning of the shock whereupon it started descending. This phenomenon evidences that vasodilatation occurring at the late stages of the shock development is determined not only by a reduction in the concentration of endogenous adrenaline and noradrenaline but also by a decrease in the sensitivity of microvessels to these agents. The data obtained make it possible to explain the mechanism of steady vasodilatation in response to injection of exogenous adrenaline and noradrenaline, which is seen at the late stages of mesenterial shock.