Sympathetic modulation of hypoxic pulmonary vasoconstriction in intact dogs.
Open Access
- 1 May 1997
- journal article
- Published by Oxford University Press (OUP) in Cardiovascular Research
- Vol. 34 (2) , 384-392
- https://doi.org/10.1016/S0008-6363(97)00028-X
Abstract
Background: The effects of the sympathetic nervous system on hypoxic pulmonary vasoconstriction (HPV) have been reported variably. We studied the effects of adrenergic receptor blockade and epidural blockade on HPV in 32 pentobarbital-anaesthetised intact dogs. Methods: Pulmonary arterial flow–pressure relationships were determined in hyperoxia and hypoxia, at baseline and after α-blockade (phentolamine 2 mg/kg + 50 μg·kg−1·h−1), β-blockade (propranolol 2 mg/kg), αβ-blockade, epidural blockade (lignocaine 20 mg/kg), and αβ- plus epidural blockade. Results: At reference flow of 3.5 l·min−1·m−2, the mean hypoxic response (hypoxia-induced increase in transpulmonary pressure gradient, each n=8) changed from 6.0±0.9 to 3.5±1.0 mmHg after α-blockade, from 5.8±0.9 to 7.3±0.7 mmHg after β-blockade, from 4.1±0.8 to 9.0±1.4 mmHg after αβ-blockade, and from 3.4±1.0 to 4.3±0.9 mmHg after epidural blockade (all PConclusions: In pentobarbital-anaesthetised dogs, (1) HPV is attenuated by α- and enhanced by β-, αβ- and epidural blockade, and (2) epidural blockade has no significant adrenergic-unrelated effect on the pulmonary vasculature.Keywords
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