Abstract
In 15 anesthetized dogs, the bronchial arterial flow and bronchopulmonary flow were measured directly by means of two Shipley-Wilson rotameters. About two-thirds of the bronchial arterial flow was collected as bronchopulmonary flow, and the remainder drained into the bronchial veins and ultimately into the right atrium. Stimulation of the sympathetic nerve caused a reduction in bronchial arterial flow but an increase in bronchopulmonary flow. These effects are interpreted to mean that sympathetic stimulation causes constriction of the bronchial veins with shifting of blood into the bronchopulmonary anastomoses. The blood flow effects appear to be unrelated to a primary bronchodilator action or to a primary bronchial arterial constriction. A similar distribution of flow (reduced bronchial artery but increased bronchopulmonary) was also encountered in some cases following bronchial arterial injections of epinephrine, norepinephrine and 5-hydroxytryptamine. A combined increase in both flows was induced by acetylcholine, isoproterenol and histamine. The latter induced reflex bronchoconstriction, bradycardia and hypotension by stimulation of sensory receptors that are mediated by the vagus.
Footnotes
- Received February 18, 1961.
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