Exercise restores β-adrenergic vasorelaxation in aged rat carotid arteries(614 views) Leosco D, Iaccarino G, Cipolletta E, De Santis D, Pisani E, Trimarco V, Ferrara N, Abete P, Sorriento D, Rengo F, Trimarco B
Am J Physiol Heart Circ Physiol American Journal Of Physiology Heart And Circulatory Physiology (ISSN: 0363-6135), 2003; 285(154-1): H369-H369.
Department of Geriatrics, University of Naples Federico II, 80131 Naples, Italy
Department of Internal Medicine, University of Naples Federico II, 80131 Naples, Italy
Department of Gerontology, II University of Naples, 80131 Naples, Italy
Cattedra di Geriatria, Univ. degli Studi Napoli Federico II, Via Sergio Pansini 5, 80131 Naples, Italy
References: Not available.
Exercise restores β-adrenergic vasorelaxation in aged rat carotid arteries
Aging is associated with alterations in β-adrenergic receptor (β-AR) signaling and reduction in cardiovascular responses to β-AR stimulation. Because exercise can attenuate age-related impairment in myocardial β-AR signaling and function, we tested whether training could also exert favorable effects on vascular β-AR responses. We evaluated common carotid artery responsiveness in isolated vessel ring preparations from 8 aged male Wistar-Kyoto (WKY) rats trained for 6 wk in a 5 days/wk swimming protocol, 10 untrained agematched rats, and 10 young WKY rats. Vessels were preconstricted with phenylephrine (10-6 M), and vasodilation was assessed in response to the β-AR agonist isoproterenol (10-10-3 × 10-8 M), the α2-AR agonist UK-14304 (10-9-10-6 M), the muscarinic receptor agonist ACh (10-9-10-6 M), and nitroprusside (10-8-10-5 M). β-AR density and cytoplasmic β-AR kinase (β-ARK) activity were tested on pooled carotid arteries. β-ARK expression was assessed in two endothelial cell lines from bovine aorta and aorta isolated from a 12-wk WKY rat. β-AR, α2-AR, and muscarinic responses, but not that to nitroprusside, were depressed in untrained aged vs. young animals. Exercise training restored β-AR and muscarinic responses but did not affect vasodilation induced by UK-14304 and nitroprusside. Aged carotid arteries showed reduced β-AR number and increased β-ARK activity. Training counterbalanced these phenomena and restored β-AR density and β-ARK activity to levels observed in young rat carotids. Our data indicate that age impairs β-AR vasorelaxation in rat carotid arteries through β-AR downregulation and desensitization. Exercise restores this response and reverts age-related modification in β-ARs and β-ARK. Our data support an important role for β-ARK in vascular β-AR vasorelaxation.
Exercise restores β-adrenergic vasorelaxation in aged rat carotid arteries
No results.
Exercise restores β-adrenergic vasorelaxation in aged rat carotid arteries