Contraction of the rabbit pulmonary artery by isoproterenol
Abstract
Isoproterenol (Iso) 1μM relaxed, while 3μM contracted the smooth muscle of isolated rabbit pulmonary artery. The constrictive effect of Iso was blocked by both phentolamine 95μM and phenoxyhenzamine 13 μM and enhanced by propranolol 100μM. These results implied that Iso 1 μM gave a β-receptor stimulating effect, while Iso 3μM showed an α-receptor stimulating effect. Iso 3 μM also contracted the vas deferens of guinea pigs. This fact implied that acted in α1 receptor.
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