No Evidence for a General Change in Contractile Responsiveness of the Mesenteric Artery With Aging
- 1 January 1995
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journals of Gerontology: Series A
- Vol. 50A (1) , B20-B25
- https://doi.org/10.1093/gerona/50a.1.b20
Abstract
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 μM 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 LJ46619, 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.Keywords
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