Journal of Applied Physiology, Vol 79, Issue 3 763-770, Copyright © 1995 by American Physiological Society

ARTICLES

In vitro responses of lung arteries to acute hypoxia after NO synthase blockade or chronic hypoxia

G. Q. Teng and G. R. Barer
Department of Medicine and Pharmacology, Royal Hallamshire Hospital, Sheffield, United Kingdom.

Responses to hypoxia of lung arteries (200-350 microns) from control (C) and chronically hypoxic (CH) rats were compared in a myograph before and after blockade of NO synthase with NG-nitro-L-arginine methyl ester (L-NAME). After precontraction with prostaglandin F2 alpha (PGF2 alpha), hypoxia caused a four-phase tension change: brief dilation, transient contraction, prolonged dilation, and slow contraction (we studied the first three phases). In CH rats, the first dilation and first contraction were significantly reduced. After L-NAME, the first dilation was reduced in C rats and abolished in CH rats; thus the first phase is attributable to NO release and is affected by chronic hypoxia. The first contractile phase was significantly reduced by L-NAME in C but not in CH rats, where it was small. Thus NO synthase inhibition inhibits hypoxic constriction in isolated vessels, whereas it enhances hypoxic constriction in perfused lungs. The third dilator phase was unaffected by chronic hypoxia; it was increased after L-NAME in CH rats. Thus, in vitro, responses to hypoxia are complex; there is a balance between two dilator and two constrictor processes.

This article has been cited by other articles:

				REBUTTAL FROM DR. ROBERTSON J Appl Physiol, May 1, 2007; 102(5): 2075 - 2075. [Full Text] [PDF]

				J. B. Gordon, M. A. VanderHeyden, T. R. Halla, E. P. Cortez, G. Hernandez, S. T. Haworth, C. A. Dawson, and J. A. Madden What leads to different mediators of alkalosis-induced vasodilation in isolated and in situ pulmonary vessels? Am J Physiol Lung Cell Mol Physiol, May 1, 2003; 284(5): L799 - L807. [Abstract] [Full Text] [PDF]

				N. Weissmann, M. Nollen, B. Gerigk, H. Ardeschir Ghofrani, R. T. Schermuly, A. Gunther, K. Quanz, L. Fink, J. Hanze, F. Rose, et al. Downregulation of hypoxic vasoconstriction by chronic hypoxia in rabbits: effects of nitric oxide Am J Physiol Heart Circ Physiol, March 1, 2003; 284(3): H931 - H938. [Abstract] [Full Text] [PDF]

				V. Hampl and J. Herget Role of Nitric Oxide in the Pathogenesis of Chronic Pulmonary Hypertension Physiol Rev, October 1, 2000; 80(4): 1337 - 1372. [Abstract] [Full Text] [PDF]

				S. Terraz, F. Baechtold, D. Renard, A. Barsi, A. Rosselet, A. Gnaegi, L. Liaudet, R. Lazor, J.-A. Haefliger, N. Schaad, et al. Hypoxic contraction of small pulmonary arteries from normal and endotoxemic rats: fundamental role of NO Am J Physiol Heart Circ Physiol, April 1, 1999; 276(4): H1207 - H1214. [Abstract] [Full Text] [PDF]

				C. A. Nankervis and C. E. Miller Developmental differences in response of mesenteric artery to acute hypoxia in vitro Am J Physiol Gastrointest Liver Physiol, April 1, 1998; 274(4): G694 - G699. [Abstract] [Full Text] [PDF]