Vagal control of pulmonary blood flow inAmbystoma mexicanum

✍ Scribed by De Saint-Aubain, M. L.

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: English
• Weight: 396 KB
• Volume: 221
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402210205

✦ Synopsis

Abstract

Through direct observations on Ambystoma mexicanum it is found that the pulmonary artery contracts during stimulation of the vagus nerve and during acetylcholine treatment. In addition, contraction of the artery is a response to lung deflation and also occurs when the vagus fibers from the lung wall are sectioned; lung inflation and atropine treatment produce dilatation of the artery. Hypercapnia and noradrenaline had no effect on pulmonary vasomotor tone. The constrictor is located between the ductus Botalli and the lung, where histological examination showed a concentrically arranged layer of smooth muscle cells. It is suggested that the vagus nerve contains afferent fibers from stretch receptors in the lung wall inhibiting the vasomotor tone in the pulmonary artery. It is further suggested that the pulmonary vasoconstrictor in A. mexicanum is homologous to the vasoconstrictor previously found in a similar location in anurans and reptiles.