Vasoconstriction by endothelin-1 in resistance and conduit portions of isolated human mesenteric arteries.
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.
Miyauchi
T
T
Department of Internal Medicine, University of Tsukuba, Ibaraki, Japan.
Tomobe
Y
Y
Ishikawa
T
T
Goto
K
K
Sugishita
Y
Y
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*
D019332:Endothelin-1