Influence of aging on the contractile response to endothelin of rat thoracic aorta.
Age-related changes in the contractile response to endothelin-1 and ACh were assessed in thoracic aortas isolated from 2-, 6- and 24-month-old male Fischer 344 rats. In aortic strips with an intact endothelium, the maximal contractile response to endothelin-1 decreased with development to maturity. Removal of the endothelium did not affect the contractile response to endothelin-1. Endothelin-1 did not elicit a relaxant response in phenylephrine-precontracted strips. The ACh-induced relaxation decreased in senescent rats. These results indicate that the contractile response of aortic smooth muscle to endothelin-1 decreases with age, and that the endothelial vasorelaxant factors do not contribute to this age-induced modulation.
Ishihata
A
A
Department of Pharmacology, Yamagata University School of Medicine, Japan.
Katano
Y
Y
Morinobu
S
S
Endoh
M
M
D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D016232:Endothelins / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D014661:Vasoconstriction / Q000187:drug effects*
D016232:Endothelins; D000109:Acetylcholine