| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
CARDIOVASCULAR |
1 Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843, USA
2 Division of Exercise Physiology, Department of Physiology and Pharmacology, and the Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University School of Medicine, Morgantown, WV 26506, USA
Ageing is associated with increased leg vascular resistance and reductions in leg blood flow during rest and exercise, potentially predisposing older adults to a host of functional and cardiovascular complications. The purpose of these studies was to examine the effects and possible mechanisms of ageing and exercise training on arteriolar adrenergic vasoreactivity. Young and old male Fischer 344 rats were divided into young sedentary (YS), old sedentary (OS), young exercise-trained (YT) or old exercise-trained (OT) groups, where training consisted of chronic treadmill exercise. Isolated soleus (SOL) and gastrocnemius (GAS) muscle arterioles were studied in vitro. Responses to noradrenaline in endothelium-intact and endothelium-denuded arterioles, as well as during nitric oxide synthase (NOS) inhibition were determined. Vasodilator responses to isoproterenol and forskolin were also determined. Results: Noradrenaline-mediated vasoconstriction was increased in SOL arterioles with ageing, and exercise training in old rats attenuated 
-adrenergic vasoconstriction in arterioles from both muscle types. Removal of the endothelium and NOS inhibition eliminated these ageing and training effects. Isoproterenol-mediated vasodilatation was impaired with ageing in SOL and GAS arterioles, and exercise training had little effect on this response. Forskolin-induced vasodilatation was not affected by age. The data demonstrate that ageing augments -adrenergic vasoconstriction while exercise training attenuates this response, and both of these alterations are mediated through an endothelial -receptor-NOS-signalling pathway. In contrast, ageing diminishes 
-receptor-mediated vasodilatation, but this impairment is specific to the smooth muscle. These studies indicate that - and -adrenergic mechanisms may serve to increase systemic vascular resistance with ageing, and that the effects of exercise training on adrenergic vasomotor properties could contribute to the beneficial effects of exercise on cardiovascular disease.
(Received 25 August 2006;
accepted after revision 26 October 2006;
first published online 2 November 2006)
Corresponding author M. D. Delp: Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506, USA. Email: mdelp{at}hsc.wvu.edu
This article has been cited by other articles:
|
|
 |
|
  L. A. Lesniewski, A. J. Donato, B. J. Behnke, C. R. Woodman, M. H. Laughlin, C. A. Ray, and M. D. Delp Decreased NO signaling leads to enhanced vasoconstrictor responsiveness in skeletal muscle arterioles of the ZDF rat prior to overt diabetes and hypertension Am J Physiol Heart Circ Physiol, April 1, 2008; 294(4): H1840 - H1850. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. W. Ramsey, B. J. Behnke, R. D. Prisby, and M. D. Delp Effects of aging on adipose resistance artery vasoconstriction: possible implications for orthostatic blood pressure regulation J Appl Physiol, November 1, 2007; 103(5): 1636 - 1643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Sugawara, H. Komine, K. Hayashi, M. Yoshizawa, T. Otsuki, N. Shimojo, T. Miyauchi, T. Yokoi, S. Maeda, and H. Tanaka Systemic {alpha}-adrenergic and nitric oxide inhibition on basal limb blood flow: effects of endurance training in middle-aged and older adults Am J Physiol Heart Circ Physiol, September 1, 2007; 293(3): H1466 - H1472. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
