Pulmonary artery smooth muscle activation attenuates arterial dysfunction during acute pulmonary hypertension.

Acute pulmonary hypertension (PH) may arise with or without an increase in vascular smooth muscle (VSM) tone. Our objective was to determine how VSM activation affects both the conduit (CF) and wall buffering (BF) functions of the pulmonary artery (PA) during acute PH states. PA instantaneous flow, pressure, and diameter of six sheep were recorded during normal pressure (CTL) and different states of acute PH: 1) passively induced by PA mechanical occlusion (PPH); 2) actively induced by intravenous administration of phenylephrine (APH); and 3) a combination of both (APPH).

[The vascular smooth muscle of great arteries: local control site of arterial buffering function?].

Introduction And Objectives: To characterize the viscoelastic properties of the aorta and pulmonary arteries and the effects of vascular smooth muscle activation on arterial buffering function.

Material And Method: Aortic and pulmonary artery pressure and diameter were measured in six anesthetized sheep under baseline conditions, and during arterial hypertension induced by mechanical vascular occlusion (passive), and i.v.

Improved pulmonary artery buffering function during phenylephrine-induced pulmonary hypertension.

The goal of this study was to determine the in vivo pulmonary arterial buffering function (BF) during acute and moderate pulmonary hypertension achieved by phenylephrine-induced smooth muscle activation. Pulmonary pressure (Konigsberg P7) and diameter (sonomicrometry) were measured in nine anesthetized sheep. Transit pulmonary arterial hypertension was induced by mechanical occlusion of the pulmonary artery (HP) and by phenylephrine infusion (5 microg/kg/min) (PHE).