PT - JOURNAL ARTICLE AU - Altiere, R J AU - Douglas, J S AU - Gillis, C N TI - Potassium chloride- and norepinephrine-induced contractile responses in rabbit pulmonary blood vessels. DP - 1983 Mar 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 572--578 VI - 224 IP - 3 4099 - http://jpet.aspetjournals.org/content/224/3/572.short 4100 - http://jpet.aspetjournals.org/content/224/3/572.full SO - J Pharmacol Exp Ther1983 Mar 01; 224 AB - Responses to KCl and norepinephrine (NE) were examined with ring segments of right extrapulmonary artery, intrapulmonary artery and intrapulmonary vein isolated from rabbit lung. From concentration-response curves to KCl, optimal applied loads were determined to be 5 g for right extrapulmonary artery and intrapulmonary artery and 500 mg for intrapulmonary vein. Both individual and cumulative concentration-response curves to KCI and NE were performed. All gave reproducible results; however, tissues were more sensitive to cumulative addition of either contractile agent. Of three successive cumulative NE concentration-response curves, second and third curves were most reproducible in relation to both sensitivity to NE and maximal force development. Cumulative NE concentration-response curves also exhibited a triphasic pattern, consisting of an initial contractile response (10(-10) to 10(-6) M NE) followed by relaxation or reversal of contractile force development (10(-6) to 10(-4) M NE), then a second contractile response at concentrations of NE greater than 10(-4) M. This response pattern was most prominent in intrapulmonary vessels and was absent in rabbit aorta.