title: In vitro vascular reactivity to endothelin: a comparison between young and old normotensive and hypertensive rats.
abstract: In this study we have investigated whether the vascular smooth muscle of a large capacitance artery of spontaneously hypertensive rats (SHR) is hyperresponsive to endothelin-1 and whether the arterial responsiveness to endothelin-1 is affected by aging. Isometric contractions of spirally cut aortic strips from SHR of 11, 22, 33 and 44 weeks of age and from age-matched WKY were measured in parallel. The vessels from SHR did not exhibit a greater responsiveness to endothelin-1 than those from WKY. No difference of responsiveness to the peptide was found among the arteries isolated from WKY of different ages. In contrast, a progressive decrease of responsiveness to endothelin-1 with aging was observed in SHR. This finding seems to be specific for endothelin-1, since the responsiveness to norepinephrine was unchanged. The significant decrease of aortic responsiveness in SHR with aging might be due to chronic hypertension and indicate desensitization to endothelin-1. The latter might be related to chronic in vivo hyperproduction of endothelin, either genetically determined or related to the hypertension-induced endothelial damage.
authors.affiliation: Department of Pharmacology, University of Padova, Italia.
authors.forename: G
authors.initials: G
authors.lastname: Cargnelli
authors.forename: G
authors.initials: G
authors.lastname: Rossi
authors.forename: S
authors.initials: S
authors.lastname: Bova
authors.forename: A C
authors.initials: AC
authors.lastname: Pessina
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D016232:Endothelins / Q000494:pharmacology* / Q000502:physiology; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D016232:Endothelins; D009638:Norepinephrine