PMID: 1201488Oct 1, 1975Paper

Contractile responses of canine isolated pulmonary lobar arteries and veins to norepinephrine, serotonin, and tyramine

Canadian Journal of Physiology and Pharmacology
P D JoinerA L Hyman

Abstract

Isolated helical strips of canine intrapulmonary lobar arteries and veins (about 4 mm in diameter) undergo dose-related tension development when exposed to increasing concentrations (10(-8) - 10(-3) M) of norepinephrine (NE), serotonin or 5-hydroxytryptamine (5-HT) and tyramine (Tyr). Venous segments were generally more sensitive while the maximum tension development was greater in the arterial strips, probably owing to their greater thickness. Both strips were more sensitive to 5-HT than NE and only responded to Tyr at high concentrations. Norepinephrine and 5-HT were nearly equally efficacious, whereas Tyr was less so. Responses to the latter were slow to develop, exhibited tachyphylaxis, and were greatly inhibited by phentolamine (10(-8) M), an alpha-adrenergic blocker. Exposure to cocaine (10(-5) M) enhanced submaximal NE responses, inhibited Tyr contractions and had no consistent effect on 5-HT responses. Phentolamine (10(-8) M) was also found to inhibit NE responses without altering 5-HT probably acts on other receptors. Tyramine may, in part, act directly on alpha-adrenergic receptors but may also release NE from surviving adrenergic nerve terminals in the preparation. Cocaine inhibits this effect and potentiates respons...Continue Reading

Citations

Jan 1, 1978·Microvascular Research·C SuJ A Bevan
Sep 1, 1984·The Journal of Clinical Investigation·M D McGoon, P M Vanhoutte
Apr 1, 1984·Environmental Health Perspectives·R P DiAugustine, K S Sonstegard
May 15, 2001·American Journal of Physiology. Lung Cellular and Molecular Physiology·E D MichelakisS L Archer

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