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The effects of norepinephrine (NE) and acetylcholine (ACh) on isometric force generation were studied in isolated helical strips of intrapulmonary arteries (IPA) and veins (IPV) (3-5 mm diam) from lungs of dog, sheep, swine, and man. Cummalative dose-effect relationships (10-minus8-10-minus 4 M) were determined. All strips contracted in a dose-related fashion when exposed to NE but responses of sheep and swineIPV were weak. Acetylcholine relaxed canine IPA and contracted human IPA, CANINEIPV, and sheep IPV in a dose-related manner. Sheep IPA and swine IPA and IPV were unresponsive to ACh. Human IPV were relaxed by ACh but this effect wasreversed at the highest concentration (10 minus 4 M) tested. All vascular stripscontracted well in a potassium-rich (127 mM) bathing medium. It is concluded thatintrapulmonary lobar vessels from man, dog, swine, and sheep are responsive to autonomicneurohormones but that quantitative as well as qualitative differences exist.

Propofol has significant vasodilator activity in the pulmonary vascular bed of the rat but responses to propofol are not mediated or modulated by the release of nitric oxide, opening of K + ATP channels, or the release of vasodilator cyclooxygenase products.