[Mechanisms involving the endothelium in reaction of reactive hyperemia]

The experiments on anesthetized dogs and on test-preparations of isolated vascular rings of femoral artery used for detection of appearance of vasoactive substances in venous blood demonstrated that the response of reactive hyperemia is accompanied by the appearance of vasodilation substances in the blood, the concentration of which taking into account the reaction of relaxation of vascular preparation, increases with the occlusion duration. Chemical inhibition of endothelium of a studied bed by saponin essentially decreases the reactive hyperemia and relaxation of test-preparation. The rise of pressure in an overlapped part of a bed and the decrease in the deformation of endothelium with the help of dimerized glutaraldehyde treatment affected the hyperemia and vascular preparation reaction in the similar way. We concluded that the reaction of reactive hyperemia is the result of the vasoactive substances secretion by endothelium in response to a decrease in intravascular pressure.