Brain natriuretic peptide inhibits hypoxic pulmonary hypertension in rats

James R. Klinger, Rod R. Warburton, Linda Pietras, Nicholas S. Hill
1998 Journal of applied physiology  
Brain natriuretic peptide inhibits hypoxic pulmonary hypertension in rats. J. Appl. Physiol. 84(5): [1646][1647][1648][1649][1650][1651][1652] 1998.-Brain natriuretic peptide (BNP) is a pulmonary vasodilator that is elevated in the right heart and plasma of hypoxia-adapted rats. To test the hypothesis that BNP protects against hypoxic pulmonary hypertension, we measured right ventricular systolic pressure (RVSP), right ventricle (RV) weight-to-body weight (BW) ratio (RV/ BW), and percent
more » ... and percent muscularization of peripheral pulmonary vessels (%MPPV) in rats given an intravenous infusion of BNP, atrial natriuretic peptide (ANP), or saline alone after 2 wk of normoxia or hypobaric hypoxia (0.5 atm). Hypoxiaadapted rats had higher hematocrits, RVSP, RV/BW, and %MPPV than did normoxic controls. Under normoxic conditions, BNP infusion (0.2 and 1.4 µg/h) increased plasma BNP but had no effect on RVSP, RV/BW, or %MPPV. Under hypoxic conditions, low-rate BNP infusion (0.2 µg/h) had no effect on plasma BNP or on severity of pulmonary hypertension. However, high-rate BNP infusion (1.4 µg/h) increased plasma BNP (69 Ϯ 8 vs. 35 Ϯ 4 pg/ml, P Ͻ 0.05), lowered RV/BW (0.87 Ϯ 0.05 vs. 1.02 Ϯ 0.04, P Ͻ 0.05), and decreased %MPPV (60 vs. 74%, P Ͻ 0.05). There was also a trend toward lower RVSP (55 Ϯ 3 vs. 64 Ϯ 2, P ϭ not significant). Infusion of ANP at 1.4 µg/h increased plasma ANP in hypoxic rats (759 Ϯ 153 vs. 393 Ϯ 54 pg/ml, P Ͻ 0.05) but had no effect on RVSP, RV/BW, or %MPPV. We conclude that BNP may regulate pulmonary vascular responses to hypoxia and, at the doses used in this study, is more effective than ANP at blunting pulmonary hypertension during the first 2 wk of hypoxia. pulmonary circulation; anoxia; atrial natriuretic peptide; brain natriuretic peptide 8750-7587/98 $5.00
doi:10.1152/jappl.1998.84.5.1646 pmid:9572812 fatcat:6bmywj2c7ngq5mmzwqjpfj6r5e