Serotonin,Pulmonary Hypertension,and Airway Constriction in the Anesthetized Dog 1

Abstract

Summary

Serotonin (10-500 μg) was infused into the pulmonary circulation of anesthetized, spontaneously breathing dogs and the effect on pulmonary hemodynamics [pulmonary artery pressure (P _pa), left atrial pressure (P _la), the pulmonary artery-left atrial pressure gradient (P _pa-P _la)] and pulmonary mechanics [pulmonary resistance (R _L) and compliance (C _L)] was determined. Pulmonary arterial hypertension, manifested by an increase in P _pa and P _pa-P_la with no change in P _la, was caused by small doses of serotonin (30-100 μg) which had no measurable effect on R _l and C _l. These findings are consistent with the hypothesis that serotonin causes pulmonary arterial hypertension as a result of active pulmonary vasoconstriction rather than as a result of changes in the mechanical properties of the lungs.