[Vascular component of the systemic circulatory response to orthostasis]

Under the orthostatic test (OT) pronounced compensation of the initial lowering of the arterial pressure (AP) and insignificant restoration of cardiac output arose in anesthetized cats. An important role of the baroreceptor reflexes from the carotid sinus in the mechanism of AP compensation was established. The response of the resistance anc capacitance vessels to OT was studied by the method of extracorporeal circulation. Quantitative evaluation of the blood pooling in the vascular system under OT was made. Compensatory response of the AP under OT was determined mainly by the reflex vasoconstriction of the resistance vessels, but not by the venomotor reactions.