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Aging‐induced changes in angiotensin II‐induced contractions and tachyphylaxis of isolated carotid arteries
Author(s) -
Koller Akos,
Toth Peter,
Rozsa Bernadett,
Cseplo Peter,
Hamar Janos,
Vamos Zoltan
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.775.1
Subject(s) - tachyphylaxis , myograph , medicine , angiotensin ii , vasomotor , endocrinology , methoxamine , carotid arteries , vasodilation , renin–angiotensin system , vasoconstriction , blood pressure , receptor , agonist
Angiotensin II (Ang II) is a potent vasoconstrictor, yet the potential aging‐ induced changes in the magnitude of responses have not yet been explored. We hypothesized that aging induces changes in the magnitude of vasomotor responses to Ang II. Thus carotid arteries from newborn (8 days: 8d), young (2 months: 2m) and old (24 months: 24m) rats were isolated and placed in a wire myograph to measure changes in their isometric tension. Two dose response curves to Ang II were obtained in a sequential manner (1‐, and 2‐administration (Adm). Contractions of vessels to 1‐Adm of Ang II in 8d vessels were significantly less compared to those of 2m and 24m, which were similar in magnitude (1.40±0.2 mN and 5.2±0.6 and 5.7±0.39 mN, respectively). Compared to the 1‐Adm, contractions of vessels to 2‐Adm of Ang II were significantly reduced in 2m and 24m vessels (4.4±0.54 and 0.5±0.19mN), whereas it did not change in vessels of 8d rats (1.28±0,2 mN). These findings suggest that in carotid arteries 1) Ang II‐induced contractions increase with age, 2) repeated administration of Ang II elicits tachyphylaxis and the magnitude of tachyphylaxis increases with aging. (Hungarian Nat. Sci. Res. Fund.‐OTKA K71591 , K67984 , AHA Founders Aff., 0555897T)