Effects of acute and chronic exercise on vasoconstrictor responsiveness of rat abdominal aorta

• Published in: Journal of applied physiology (1985) Vol. 87; no. 5; pp. 1752 - 1757
• Main Authors: Spier, Scott A, Laughlin, M. Harold, Delp, Michael D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.11.1999; American Physiological Society
• Subjects: Adrenergic alpha-Agonists - pharmacology; Anatomy & physiology; Animals; Aorta, Abdominal - physiology; Arginine Vasopressin - pharmacology; Biological and medical sciences; Blood vessels; Blood vessels and receptors; Exercise; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; Isometric Contraction - physiology; Male; Norepinephrine - pharmacology; Oxidation-Reduction; Phenylephrine - pharmacology; Physical Exertion - physiology; Potassium Chloride - pharmacology; Rats; Rats, Sprague-Dawley; Receptors, Adrenergic - physiology; Receptors, Adrenergic, alpha-1 - drug effects; Receptors, Adrenergic, alpha-1 - physiology; Rodents; Space life sciences; Vasoconstriction - physiology; Vasoconstrictor Agents - pharmacology; Vertebrates: cardiovascular system; Physical exercise; Agonist; Rat; Rodentia; Vasoconstriction; Smooth muscle; Artery; Endothelium; Vasomotricity; Vertebrata; Mammalia; Blood vessel; Aorta; Vasoconstrictor agent; Circulatory system; Adaptation; NASA Discipline Musculoskeletal; Non-NASA Center
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1999.87.5.1752

1  Departments of Health and Kinesiology and Medical Physiology, Texas A&M University, College Station, Texas 77843; and 2  Departments of Veterinary Biomedical Sciences and Physiology, and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211 Reductions in blood pressure that are associated with exercise training have been hypothesized to be the result of a sustained postexertional vascular alteration following single bouts of exercise. The purpose of this study was to determine whether a decrease in vascular sensitivity to vasoconstrictor agonists occurs after a single bout of exercise and whether this vascular alteration is sustained through various periods of exercise training. Vascular responses of abdominal aortic rings to norepinephrine (NE; 10 9 -10 4 M) were determined in vitro. Aortas were isolated from sedentary rats immediately after rats performed a single bout of treadmill exercise (30 m/min for 1 h); 24 h after the last exercise bout in rats exercised for 1 day; and 1, 2, 4, and 10 wk of training at 30 m/min, 60 min, 5 days/wk. Sensitivity to NE was only diminished after 10 wk of training. This diminished vascular sensitivity to NE was abolished with the removal of the endothelial cell layer. Furthermore, there were no reductions in developed tension or vascular sensitivity to the vasoconstrictor agonists KCl (10-100 mM), phenylephrine (10 8 -10 4 M), and arginine vasopressin (10 9 -10 5 M) in vessels either with or without the endothelial layer after a single bout of exercise. These data indicate that a single bout of exercise does not diminish aortic responsiveness to vasoconstrictor agonists and thus is not responsible for the diminished contractile responsiveness that occurs between 4 and 10 wk of moderate-intensity exercise training in rats. This vascular adaptation to exercise training appears to be mediated through an endothelium-dependent mechanism. exercise; norepinephrine; vascular smooth muscle