Pulmonary Hypertension in Dogs Induced by Injection of Lycopodium Spores Into the Pulmonary Artery, With Special Reference to the Absence of Vasomotor Reflexes

Abstract

Lycopodium spores were injd. through an indwelling catheter into the pulmonary arterial tree of anesthetized dogs. Injns. into the main pulmonary artery and into a pulmonary end artery caused a rise in pulmonary artery blood pressure. This rise was absent when a ligature was placed around the artery containing the catheter. Comparable results were obtained in isolated perfused lungs. As the pulmonary artery pressure rose, so did the pulmonary end artery pressure and the pulmonary arteriolar resistance. Vagotomy, bilateral anterior rhizotomy and thoracic sympathectomy did not prevent the development of pulmonary hypertension. It was concluded that localized embolism does not cause generalized vasoconstriction.