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Effects of aging on vasoconstrictor and mechanical properties of rat skeletal muscle arteriolesExercise capacity and skeletal muscle blood flow during exercise are reduced with advancing age. This reduction in blood flow capacity may be related to increased reactivity of skeletal muscle resistance vessels to vasoconstrictor stimuli. The purpose of this study was to test the hypothesis that aging results in increased vasoconstrictor responses of skeletal muscle resistance arterioles. First-order (1A) arterioles (90-220 microm) from the gastrocnemius and soleus muscles of young (4 mo) and aged (24 mo) Fischer-344 rats were isolated, cannulated, and pressurized via hydrostatic reservoirs. Vasoconstriction in response to increases in norepinephrine (NE; 1 x 10(-9)-1 x 10(-4) M) and KCl (20-100 mM) concentrations and increases in intraluminal pressure (10-130 cmH(2)O) were evaluated in the absence of flow. Responses to NE and KCl were similar in both soleus and gastrocnemius muscle arterioles from young and aged rats. In contrast, active myogenic responses to changes in intraluminal pressure were diminished in soleus and gastrocnemius arterioles from aged rats. To assess whether alterations in the mechanical properties of resistance arterioles underlie altered myogenic responsiveness, passive diameter responses to pressure and mechanical stiffness were evaluated. There was no effect of age on the structural behavior (passive pressure-diameter relationship) or stiffness of arterioles from either the soleus or gastrocnemius muscles. These results suggest that aging does not result in a nonspecific decrease in vasoconstrictor responsiveness of skeletal muscle arterioles. Rather, aging-induced adaptations of vasoreactivity of resistance arterioles appear to be limited to mechanisms that are uniquely involved in the signaling of the myogenic response.
Document ID
20040088379
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Muller-Delp, Judy
(College Station Texas 77843, United States)
Spier, Scott A.
Ramsey, Michael W.
Lesniewski, Lisa A.
Papadopoulos, Anthony
Humphrey, J. D.
Delp, Michael D.
Date Acquired
August 21, 2013
Publication Date
May 1, 2002
Publication Information
Publication: American journal of physiology. Heart and circulatory physiology
Volume: 282
Issue: 5
ISSN: 0363-6135
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: AG-19248-01
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Musculoskeletal
Non-NASA Center

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