AJP - Heart and Circulatory Physiology, Vol 264, Issue 5 1454-H1459, Copyright © 1993 by American Physiological Society

ARTICLES

PAF increases capillary pressure but not vascular permeability in isolated blood-perfused canine lungs

T. Shibamoto, Y. Yamaguchi, T. Hayashi Jr, Y. Saeki, M. Kawamoto and S. Koyama
Department of Physiology, Shinshu University School of Medicine, Nagano, Japan.

We determined the effects of platelet-activating factor (PAF) on pulmonary vascular resistance, lung weight, and microvascular permeability in isolated canine lungs perfused at constant pressure with autologous blood. PAF caused a dose-dependent increase in total pulmonary vascular resistance (Rt) and pulmonary capillary pressure assessed as double-occlusion pressure. PAF (33 micrograms; n = 7) caused a 10-fold increase in Rt and a decrease in precapillary-to-postcapillary vascular resistance ratio from 0.97 +/- 0.10 to 0.38 +/- 0.03, suggesting predominant pulmonary venoconstriction. Shortly after PAF, lung weight decreased transiently and then increased, reaching a plateau above baseline (112.5 +/- 1.6%) at 30 min. In lungs perfused in the antidromic direction from the pulmonary vein to the artery (n = 5), PAF (33 micrograms) produced marked precapillary vasoconstriction, consistent with pulmonary venoconstriction, and a remarkable and sustained decrease in lung weight below baseline by 30 min. Vascular permeability, measured 30 min after PAF using the capillary filtration coefficient and isogravimetric capillary pressure, did not change significantly from baseline. Thus we conclude that PAF produces lung weight gain by means of an increase in capillary pressure predominantly due to pulmonary venoconstriction without significant changes in vascular permeability in isolated blood-perfused canine lungs.

This article has been cited by other articles:

				Y. Gao and J. U. Raj Role of veins in regulation of pulmonary circulation Am J Physiol Lung Cell Mol Physiol, February 1, 2005; 288(2): L213 - L226. [Abstract] [Full Text] [PDF]

				Y. Gao, S. Dhanakoti, E. M. Trevino, F. C. Sander, A. M. Portugal, and J. U. Raj Effect of oxygen on cyclic GMP-dependent protein kinase-mediated relaxation in ovine fetal pulmonary arteries and veins Am J Physiol Lung Cell Mol Physiol, September 1, 2003; 285(3): L611 - L618. [Abstract] [Full Text] [PDF]

				L. C. Clavijo, M. B. Carter, P. J. Matheson, M. A. Wilson, W. B. Wead, and R. N. Garrison PAF increases vascular permeability without increasing pulmonary arterial pressure in the rat J Appl Physiol, January 1, 2001; 90(1): 261 - 268. [Abstract] [Full Text] [PDF]

				C. L. Ivey, A. H. Stephenson, and M. I. Townsley Involvement of cytochrome P-450 enzyme activity in the control of microvascular permeability in canine lung Am J Physiol Lung Cell Mol Physiol, October 1, 1998; 275(4): L756 - L763. [Abstract] [Full Text] [PDF]

				T. Miyahara, T. Shibamoto, H.-G. Wang, and S. Koyama Role of circulating blood components and thromboxane in anaphylactic vasoconstriction in isolated canine lungs J Appl Physiol, November 1, 1997; 83(5): 1508 - 1516. [Abstract] [Full Text] [PDF]

				Y. Gao, H. Zhou, and J. U. Raj Endothelium-Derived Nitric Oxide Plays a Larger Role in Pulmonary Veins Than in Arteries of Newborn Lambs Circ. Res., April 1, 1995; 76(4): 559 - 565. [Abstract] [Full Text]