No evidence for a general change in contractile responsiveness of the mesenteric artery with aging.
Rings of human mesenteric artery (1-3 mm diameter) suspended in Krebs solution were contracted (maximal contraction relative to KCl 80 mM = 100%) by the thromboxane mimetic U46619 (190 +/- 10%), noradrenaline (162 +/- 9%), angiotensin II (107 +/- 11%), and 5-hydroxytryptamine (5-HT) (96 +/- 10%). Reducing extracellular Ca2+ strongly inhibited the maximal contraction to angiotensin II and 5-HT and moderately inhibited the maximal contraction to noradrenaline, but had less effect on the maximal contraction to U46619 (contraction in Ca2+ 1.3 microM was reduced to 24 +/- 5, 20 +/- 3, 38 +/- 4 and 52 +/- 4% respectively of the contraction in 2.5 mM Ca2+). Reducing extracellular Ca2+ lowered sensitivity to 5HT, angiotensin II, and U46619, but did not alter sensitivity to noradrenaline. The EC50 and maximal contraction for each of the 4 agonists did not change with patient age at 2.5 mM Ca2+ or in reduced extracellular Ca2+. It is concluded that aging does not affect the responsiveness of mesenteric arterial smooth muscle to physiological vasoconstrictors.
McDonald
A
A
Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, Scotland.
MacDonald
E
E
Fulton
J D
JD
Wadsworth
R M
RM
Scott
P J
PJ
Howie
K A
KA
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000375:Aging / Q000502:physiology*; D000804:Angiotensin II / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013928:Thromboxane A2 / Q000031:analogs & derivatives / Q000494:pharmacology; D014661:Vasoconstriction; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D011450:Prostaglandin Endoperoxides, Synthetic; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D012701:Serotonin; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D002118:Calcium; D009638:Norepinephrine