title: Vasoconstriction by endothelin-1 in resistance and conduit portions of isolated human mesenteric arteries.
abstract: Although physiological processes related to vascular function differ greatly between resistance arteries and conduit arteries, it is not known whether the effects of endothelin-1 on these arteries differ in humans. In the present study, the conduit portion and the resistance portion of isolated human mesenteric arteries were suspended in a Krebs-Ringer solution. Norepinephrine and endothelin-1 produced concentration-dependent contractions in both portions. The EC50 value of norepinephrine in the resistance portion (3.7 x 10(-7) M, n = 8) did not differ from that in the conduit portion (3.4 x 10(-7) M, n = 7). However, the EC50 value of endothelin-1 in the resistance portion (3.0 x 10(-9) M, n = 8) was significantly lower than that in the conduit portion (1.1 x 10(-8) M, n = 7, P < 0.05). Although the maximum response to norepinephrine in the resistance portion (calculated as the percentage of 50 mM KCl-induced contraction) did not differ from that in the conduit portion, the maximum response to endothelin-1 in the resistance portion was significantly greater than that in the conduit portion. These results indicate that endothelin-1 induces more potent constriction in resistance portion than in conduit portion in isolated human mesenteric arteries.
authors.affiliation: Department of Internal Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Miyauchi
authors.forename: Y
authors.initials: Y
authors.lastname: Tomobe
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: K
authors.initials: K
authors.lastname: Goto
authors.forename: Y
authors.initials: Y
authors.lastname: Sugishita
mesh_terms: D000328:Adult; D000368:Aged; D019332:Endothelin-1 / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D019332:Endothelin-1