Catecholamine effects on pulmonary blood vessels in strangulation

Guinea pigs were killed by strangulation to investigate the vasomotor of pulmonary congestion by asphyxia. The noradrenaline uptake by the endothelial cells of the pulmonary arteries and capillaries was observed by fluorescence histochemistry, peroxidase-anti-peroxidase (PAP) immunocytochemistry, and autoradiography. By radioassay, the volumes of noradrenaline uptake by the pulmonary arteries and capillaries in the strangulation group were at a significantly higher level than in the control groups. Many myoendothelial junctions were observed at the sites of constricted arteries, and the invasive noradrenaline was clearly observed in the myoendothelial junction. The mechanism of the pulmonary vasoconstriction in strangulation is due to the fact that the plasma noradrenaline, increased by asphyxia, invades the endothelial cells of pulmonary arteries and capillaries and causes the vasoconstriction.