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: 95/4/1638    most recent 01168.2002v1 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 (2) Citing Articles via Google Scholar Google Scholar Articles by Symons, J. D. Articles by Ensunsa, J. L. Search for Related Content PubMed PubMed Citation Articles by Symons, J. D. Articles by Ensunsa, J. L.

Improved coronary vascular function evoked by high-intensity treadmill training is maintained in arteries exposed to ischemia and reperfusion

¹College of Health, University of Utah, Salt Lake City, Utah 84112; ²School of Human Sciences, Waseda University, Tokyo, Japan 169-8050; and³Department of Nutrition, University of California, Davis, California 95616

Submitted 18 December 2002 ; accepted in final form 6 May 2003

We hypothesized that myocardial contractile function and coronary arterial function are greater after ischemia and reperfusion in high-intensity treadmill-trained vs. sedentary rats. Rats performed 10 x 4-min bouts of treadmill running consisting of 2 min at 13 m/min + 2 min at 45-60 m/min (Etr) or were sedentary (Sed) for 12 wk. Animals then were instrumented to measure left ventricular (LV) contractility in response to three 15-min coronary occlusion (O) and 5-min reperfusion (R) cycles (Isc) or a sham operation (Sham). After the Isc and Sham protocols, hearts were excised and coronary arterial (105 µm ID) function was evaluated by using isometric techniques. LV developed pressure, the first derivative of LV pressure at a developed pressure of 40 mmHg, and systolic blood pressure were not different between Etr (n = 14) and Sed (n = 7) rats before or after the Sham protocol. Furthermore, hemodynamic variables were similar in Etr (n = 14) and Sed (n = 13) animals before the Isc protocol and were depressed to the same degree by the three O-R cycles. Therefore, Etr did not alter myocardial contractile function in rats that were (i.e., Isc) or were not (i.e., Sham) exposed to ischemia and reperfusion. Acetylcholine-evoked relaxation (10^-8 to 3 x 10^-5 M) was greater (P < 0.05) in coronary arteries from Sham-Etr vs. Sham-Sed animals (5 of 8 doses tested) and Isc-Etr vs. Isc-Sed rats (3 of 8 doses tested). Maximal relaxation produced by sodium nitroprusside (10^-4 M) was similar among groups. Vasocontractile responses produced by KCl (10-100 mM) and endothelin-1 (10^-11-10^-4 M) were greater (P < 0.05) in the presence vs. the absence of nitric oxide synthase inhibition (10^-6 M N^G-monomethyl-L-arginine) in vessels from Sham-Etr but not Sham-Sed rats and from Isc-Etr but not Isc-Sed rats. These findings suggest that Etr-evoked improvements in coronary function are maintained in small arteries even when exposed to ischemia and reperfusion.

endothelium; vascular smooth muscle; exercise; myocardial function; endothelin-1; sodium nitroprusside; acetylcholine; N^G-monomethyl-L-arginine; rats

This article has been cited by other articles:

				Q.-J. Zhang, S. L. McMillin, J. M. Tanner, M. Palionyte, E. D. Abel, and J. D. Symons Endothelial nitric oxide synthase phosphorylation in treadmill-running mice: role of vascular signalling kinases J. Physiol., August 1, 2009; 587(15): 3911 - 3920. [Abstract] [Full Text] [PDF]

				J. D. Symons, J. C. Rutledge, U. Simonsen, and R. A. Pattathu Vascular dysfunction produced by hyperhomocysteinemia is more severe in the presence of low folate Am J Physiol Heart Circ Physiol, January 1, 2006; 290(1): H181 - H191. [Abstract] [Full Text] [PDF]

				J. L. Ensunsa, J. D. Symons, L. Lanoue, H. R. Schrader, and C. L. Keen Reducing Arginase Activity via Dietary Manganese Deficiency Enhances Endothelium-Dependent Vasorelaxation of Rat Aorta Experimental Biology and Medicine, December 1, 2004; 229(11): 1143 - 1153. [Abstract] [Full Text] [PDF]