Effect of BTS 49465 on hypoxic pulmonary vasoconstriction

Area of Science:

• Pharmacology
• Cardiovascular Physiology

Background:

• Hypoxic pulmonary vasoconstriction (HPV) is a physiological response that increases pulmonary vascular resistance during low oxygen levels.
• Understanding modulators of HPV is crucial for managing conditions like acute respiratory distress syndrome and congenital heart disease.

Purpose of the Study:

• To evaluate the efficacy of BTS 49465 as a pulmonary vasodilator.
• To compare the effects of BTS 49465 on hypoxic pulmonary vasoconstriction with placebo and sodium nitroprusside.

Main Methods:

• A randomized, placebo-controlled study in 10 anesthetized mongrel dogs.
• Measurements included vascular pressures, cardiac output, and arterial blood gases.
• BTS 49465 was administered intravenously and its effects on HPV were monitored over 3.5 hours.

Main Results:

• BTS 49465 significantly reduced pulmonary artery pressure compared to placebo (21.6 +/- 1.3 vs. 27.6 +/- 1.8 torr, p < 0.05).
• The reduction in pulmonary artery pressure was sustained throughout the 3.5-hour study period.
• BTS 49465 showed a trend towards increasing cardiac index, though not statistically significant. Its effects were quantitatively similar to sodium nitroprusside.

Conclusions:

• BTS 49465 is an effective pulmonary vasodilator.
• BTS 49465 successfully ameliorates hypoxic pulmonary vasoconstriction.