HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 102/2/803    most recent 00498.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Mueller, P. J. Search for Related Content PubMed PubMed Citation Articles by Mueller, P. J.

HIGHLIGHTED TOPIC
Neural Changes Associated with Training

Exercise training attenuates increases in lumbar sympathetic nerve activity produced by stimulation of the rostral ventrolateral medulla

Dalton Cardiovascular Research Center and Department of Biomedical Sciences, University of Missouri-Columbia, Columbia, Missouri

Submitted 1 May 2006 ; accepted in final form 4 October 2006

Exercise training (ExTr) has been associated with blunted activation of the sympathetic nervous system in several animal models and in some human studies. Although these data are consistent with the hypothesis that ExTr reduces the incidence of cardiovascular diseases via reduced sympathoexcitation, the mechanisms are unknown. The rostral ventrolateral medulla (RVLM) is important in control of sympathetic nervous system activity in both physiological and pathophysiological states. The purpose of the present study was to test the hypothesis that ExTr results in reduced sympathoexcitation mediated at the level of the RVLM. Male Sprague-Dawley rats were treadmill trained or remained sedentary for 8–10 wk. RVLM microinjections were performed under Inactin anesthesia while mean arterial pressure, heart rate, and lumbar sympathetic nerve activity (LSNA) were recorded. Bilateral microinjections of the GABA_A antagonist bicuculline (5 mM, 90 nl) into the RVLM increased LSNA in sedentary animals (169 ± 33%), which was blunted in ExTr animals (100 ± 22%, P < 0.05). Activation of the RVLM with unilateral microinjections of glutamate (10 mM, 30 nl) increased LSNA in sedentary animals (76 ± 13%), which was also attenuated by training (26 ± 2%, P < 0.05). Bilateral microinjections of the ionotropic glutamate receptor antagonist kynurenate (40 mM, 90 nl) produced small increases in mean arterial pressure and LSNA that were similar between groups. Results suggest that ExTr may reduce increases in LSNA due to reduced activation of the RVLM. Conversely, we speculate that the relatively enhanced activation of LSNA in sedentary animals may be related to the increased incidence of cardiovascular disease associated with a sedentary lifestyle.

sympathetic nerve activity; treadmill training; microinjection

This article has been cited by other articles:

				K. T. Higa-Taniguchi, J. V. C. Felix, and L. C. Michelini Brainstem oxytocinergic modulation of heart rate control in rats: effects of hypertension and exercise training Exp Physiol, November 1, 2009; 94(11): 1103 - 1113. [Abstract] [Full Text] [PDF]

				P. J. Mueller Influence of sedentary versus physically active conditions on regulation of plasma renin activity and vasopressin Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2008; 295(3): R727 - R732. [Abstract] [Full Text] [PDF]