Further evidence for the predominance of a(1D)-adrenoceptors in arteries of normotensive and spontaneously hypertensive rats
Por:
Ibarra M., López-Guerrero J.J., Villalobos-Molina R.
Publicada:
1 ene 1998
Resumen:
Noradrenaline is involved in hyperreactivity of vascular smooth muscle from spontaneously hypertensive rats (SHR). We investigated the functional ?a1-adrenoceptor subtype(s) present among arteries of SHR and Wistar Kyoto normotensive (WKY) rats, that could explain the observed hyperreactivity. We studied concentration-responses to noradrenaline, oxymetazoline or methoxamine (?(1D)-, ?(1A)- and ?(1A)/?(1D) adrenoceptor agonists, respectively) in rings of carotid, aorta, mesenteric and caudal, endothelium-denuded arteries from 6 months WKY and SHR rats. Noradrenaline selectivity was carotid ? aorta > mesenteric > caudal; whereas oxymetazoline selectivity was caudal > mesenteric > carotid ? aorta from both strains; methoxamine did not show any difference between arteries. pD2 values for noradrenaline in aortic and carotid rings of SHR were higher than those from WKY (P < 0.05). In contrast, caudal artery from SHR was hyporesponsive compared with WKY (P < 0.05). These data support the contention that ?(1D)-adrenoceptors occur in the carotid, aorta and mesenteric arteries, meanwhile ?(1A)-adrenoceptors occur in caudal and mesenteric arteries of both strains.
Filiaciones:
Ibarra M.:
Secc. de Terap. Experimental, Depto. de Farmacologia y Toxicologia, CINVESTAV-IPN, Mexico D.F. 16020, Mexico
López-Guerrero J.J.:
Secc. de Terap. Experimental, Depto. de Farmacologia y Toxicologia, CINVESTAV-IPN, Mexico D.F. 16020, Mexico
Villalobos-Molina R.:
Secc. de Terap. Experimental, Depto. de Farmacologia y Toxicologia, CINVESTAV-IPN, Mexico D.F. 16020, Mexico
Apartado Postal 22026, Mexico D.F. 14000, Mexico
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