Journal of Applied Physiology, Vol 69, Issue 5 1836-1842, Copyright © 1990 by American Physiological Society
Selective pulmonary vasodilation with ATP-MgCl2 during pulmonary hypertension in lambs
J. R. Fineman, M. R. Crowley and S. J. Soifer
Department of Pediatrics, University of California, San Francisco 94143.
We investigated the effects of infusions of ATP-MgCl2 on the circulation in
11 spontaneously breathing newborn lambs during pulmonary hypertension
induced either by the infusion of U-46619, a thromboxane A2 mimetic, or by
hypoxia. During pulmonary hypertension induced by U-46619, ATP-MgCl2
(0.01-1.0 mg.kg-1.min-1) caused a significant dose-dependent decrease in
pulmonary arterial pressure (12.4-40.7%, P less than 0.05), while systemic
arterial pressure decreased only at the highest doses (P less than 0.05).
Left atrial infusions of ATP-MgCl2 caused systemic hypotension without
decreasing pulmonary arterial pressure. During hypoxia-induced pulmonary
hypertension, ATP-MgCl2 caused a similar significant dose-dependent
decrease in pulmonary arterial pressure (12.0-41.1%, P less than 0.05),
while systemic arterial pressure decreased only at high doses (P less than
0.05). Regression analysis showed selectivity of the vasodilating effects
of ATP-MgCl2 for the pulmonary circulation during pulmonary hypertension
induced either by U-46619 or hypoxia. ATP-MgCl2 is a potent vasodilator
with a rapid metabolism that allows for selective vasodilation of the
vascular bed first encountered (pulmonary or systemic). We conclude that
infusions of ATP-MgCl2 may be clinically useful in the treatment of
children with pulmonary hypertension.
