Inhaled nitric oxide: Dose response and the effects of blood in the isolated rat lung

G. F. Rich, C. M. Roos, S. M. Anderson, D. C. Urich, M. O. Daugherty, Roger A Johns

Research output: Contribution to journalArticle

Abstract

Inhaled nitric oxide (NO) is a vasodilator selective to the pulmonary circulation. Using isolated rat lungs, we determined the dose-response relationship of NO and the role of blood in mediating pulmonary vasodilation and selectivity. Inhaled 20, 50, 100, and 1,000 ppm NO attenuated (P <0.001) hypoxic pulmonary vasoconstriction by 16.1 ± 4.9, 22.6 ± 6.8, 28.4 ± 3.5, and 69.3 ± 4.2%, respectively. Inhaled 13, 34, 67, and 670 ppm NO attenuated the increase in pulmonary arterial pressure secondary to angiotensin II more (P <0.001) in Greenberg-Bohr buffer- (GB) than in blood-perfused lungs (51.7 ± 9.9, 71.9 ± 8.9, 78.2 ± 5.3, and 91.9 ± 2.1% vs. 14.3 ± 4.1, 23.8 ± 4.6, 28.4 ± 3.8, and 55.5 ± 5.9%, respectively). Samples from GB- but not blood-perfused lungs contained NO (93.0 ± 26.3 nM). Intravascular NO attenuated the response to angiotensin II more (P <0.001) in GB- (with and without plasma) than in blood- (hematocrit = 41 and 5%) perfused lungs (75.6 ± 6.4 and 70.9 ± 4.8% vs. 22.2 ± 2.4 and 39.4 ± 7.6%). In conclusion, inhaled NO produces reversible dose-dependent pulmonary vasodilation over a large range of concentrations. Inhaled NO enters the circulation, but red blood cells prevent systemic vasodilation and also a significant amount of pulmonary vasodilation.

Original languageEnglish (US)
Pages (from-to)1278-1284
Number of pages7
JournalJournal of Applied Physiology
Volume75
Issue number3
Publication statusPublished - 1993
Externally publishedYes

    Fingerprint

Keywords

  • angiotension II
  • endothelium-derived relaxing factor
  • hypoxic pulmonary vasoconstriction
  • pulmonary vascular resistance

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Rich, G. F., Roos, C. M., Anderson, S. M., Urich, D. C., Daugherty, M. O., & Johns, R. A. (1993). Inhaled nitric oxide: Dose response and the effects of blood in the isolated rat lung. Journal of Applied Physiology, 75(3), 1278-1284.