EXERCISE TRAINING ENHANCES ENDOTHELIUM-DEPENDENT RELAXATION OF PORCINE CORONARY ARTERIES DISTAL TO CHRONIC CORONARY OCCLUSION

Shock ◽  
1999 ◽  
Vol 11 (Supplement) ◽  
pp. 56 ◽  
Author(s):  
K L Griffin ◽  
M L Mattox ◽  
B D Larkin ◽  
M H Laughlin ◽  
J L Parker
Keyword(s):  
Exercise Training ◽  
Coronary Arteries ◽  
Coronary Occlusion ◽  
Chronic Coronary Occlusion ◽  
Endothelium Dependent Relaxation

Exercise training restores adenosine-induced relaxation in coronary arteries distal to chronic occlusion

2000 ◽  
Vol 278 (6) ◽  
pp. H1984-H1992 ◽  
Author(s):  
Cristine L. Heaps ◽  
Michael Sturek ◽  
Julie A. Rapps ◽  
M. Harold Laughlin ◽  
Janet L. Parker
Keyword(s):  
Coronary Artery ◽  
Exercise Training ◽  
Sodium Nitroprusside ◽  
Coronary Arteries ◽  
Coronary Occlusion ◽  
Circumflex Coronary Artery ◽  
Miniature Swine ◽  
Chronic Occlusion ◽  
Chronic Coronary Occlusion ◽  
Camp And Cgmp

We previously reported that canine collateral-dependent coronary arteries exhibit impaired relaxation to adenosine but not sodium nitroprusside. In contrast, exercise training enhances adenosine sensitivity of normal porcine coronary arteries. These results stimulated the hypothesis that chronic coronary occlusion and exercise training produce differential effects on cAMP- versus cGMP-mediated relaxation. To test this hypothesis, Ameroid occluders were surgically placed around the proximal left circumflex coronary artery (LCx) of female Yucatan miniature swine 8 wk before initiating sedentary or exercise training (treadmill run, 16 wk) protocols. Relaxation to the cAMP-dependent vasodilators adenosine (10− 7 to 10− 3 M) and isoproterenol (3 × 10− 8 to 3 × 10− 5 M) were impaired in collateral-dependent LCx versus nonoccluded left anterior descending (LAD) arterial rings isolated from sedentary but not exercise-trained pigs. Furthermore, adenosine-mediated reductions in simultaneous tension and myoplasmic free Ca2+ were impaired in LCx versus LAD arteries isolated from sedentary but not exercise-trained pigs. In contrast, relaxation in response to the cAMP-dependent vasodilator forskolin (10− 9 to 10− 5 M) and the cGMP-dependent vasodilator sodium nitroprusside (10− 9 to 10− 4 M) was not different in LCx versus LAD arteries of sedentary or exercise-trained animals. These data suggest that chronic occlusion impairs receptor-dependent, cAMP-mediated relaxation; receptor-independent cAMP- and cGMP-mediated relaxation were unimpaired. Importantly, exercise training restores cAMP-mediated relaxation of collateral-dependent coronary arteries.

scholarly journals Exercise training enhances multiple mechanisms of relaxation in coronary arteries from ischemic hearts

2013 ◽  
Vol 305 (9) ◽  
pp. H1321-H1331 ◽  
Author(s):  
Rachel R. Deer ◽  
Cristine L. Heaps
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Coronary Artery ◽  
Nitric Oxide Synthase ◽  
Exercise Training ◽  
Coronary Arteries ◽  
Vascular Function ◽  
Channel Inhibition ◽  
Oxide Synthase ◽  
Endothelium Dependent Relaxation

Exercise training of coronary artery disease patients is of considerable interest, since it has been shown to improve vascular function and, thereby, enhance blood flow into compromised myocardial regions. However, the mechanisms underlying exercise-induced improvements in vascular function have not been fully elucidated. We tested the hypothesis that exercise training increases the contribution of multiple mediators to endothelium-dependent relaxation of coronary arteries in the underlying setting of chronic coronary artery occlusion. To induce gradual occlusion, an ameroid constrictor was placed around the proximal left circumflex coronary artery in Yucatan miniature swine. At 8 wk postoperatively, pigs were randomly assigned to sedentary or exercise (treadmill, 5 days/wk) regimens for 14 wk. Exercise training significantly enhanced the contribution of nitric oxide, prostanoids, and large-conductance Ca2+-dependent K+ (BKCa) channels to endothelium-dependent, bradykinin-mediated relaxation in nonoccluded and collateral-dependent arteries. Combined nitric oxide synthase, prostanoid, and BKCa channel inhibition ablated the enhanced relaxation associated with exercise training. Exercise training significantly increased nitric oxide levels in response to bradykinin in endothelial cells isolated from nonoccluded and collateral-dependent arteries. Bradykinin treatment significantly increased PGI2 levels in all artery treatment groups and tended to be further enhanced after nitric oxide synthase inhibition in exercise-trained pigs. No differences were found in whole cell BKCa channel currents, BKCa channel protein levels, or arterial cyclic nucleotide levels. Although redundant, upregulation of parallel vasodilator pathways appears to contribute to enhanced endothelium-dependent relaxation, potentially providing a more refined control of blood flow after exercise training.

CHRONIC CORONARY OCCLUSION, EXERCISE TRAINING, AND PLASMA LIPIDS IN MINIATURE SWINE

2001 ◽  
Vol 33 (5) ◽  
pp. S214
Author(s):  
K Wooten ◽  
S E. Martin ◽  
J L. Parker ◽  
M Mattox ◽  
J Fogarty ◽  
...  
Keyword(s):  
Exercise Training ◽  
Coronary Occlusion ◽  
Plasma Lipids ◽  
Miniature Swine ◽  
Chronic Coronary Occlusion

Vasomotor Function of Pig Coronary Arteries after Chronic Coronary Occlusion

2003 ◽  
Vol 41 (4) ◽  
pp. 600-608 ◽  
Author(s):  
Jinsheng Li ◽  
Hector De Leon ◽  
Takafumi Ueno ◽  
Jianhua Cui ◽  
Patrick K. Coussement ◽  
...  
Keyword(s):  
Coronary Arteries ◽  
Coronary Occlusion ◽  
Vasomotor Function ◽  
Chronic Coronary Occlusion ◽  
Pig Coronary Arteries

Chronic exercise training does not alter pulmonary vasorelaxation in normal pigs

2000 ◽  
Vol 88 (6) ◽  
pp. 2008-2014 ◽  
Author(s):  
Lynelle R. Johnson ◽  
M. Harold Laughlin
Keyword(s):  
Nitric Oxide ◽  
Exercise Training ◽  
Pulmonary Artery ◽  
Coronary Occlusion ◽  
Pulmonary Arteries ◽  
Chronic Exercise ◽  
Maximal Contraction ◽  
Endothelial Denudation ◽  
Oxide Synthase ◽  
Endothelium Dependent Relaxation

Exercise training increases acetylcholine-induced pulmonary vasorelaxation in pigs with coronary occlusion. The present study tested the hypothesis that chronic exercise training enhances endothelium-mediated vasorelaxation in pulmonary arteries from normal pigs. Yucatan miniswine exercised for 16 wk on a treadmill (Ex); control pigs (Sed) remained in pens. Pulmonary artery rings (2- to 3-mm OD) were studied using standard isometric techniques. Contractile responses to 80 mM KCl and norepinephrine (NE) were determined. Vessels were constricted with levels of NE that resulted in half-maximal contraction to examine endothelium-dependent relaxation to ACh and endothelium-independent relaxation to sodium nitroprusside in the presence and absence of nitric oxide synthase inhibition, cyclooxygenase inhibition, and endothelial denudation. Arteries from Ex pigs developed increased contraction to 80 mM KCl, but the response to NE did not differ between groups. Endothelium-dependent and endothelium-independent responses did not differ between Sed and Ex in the presence or absence of pharmacological inhibitors or denudation. We conclude that chronic exercise training does not alter endothelium-dependent or endothelium-independent vasorelaxation responses of pulmonary arteries from normal pigs.

scholarly journals Exercise training increases basal tone in arterioles distal to chronic coronary occlusion

2006 ◽  
Vol 290 (3) ◽  
pp. H1128-H1135 ◽  
Author(s):  
Cristine L. Heaps ◽  
Mildred L. Mattox ◽  
Katherine A. Kelly ◽  
Cynthia J. Meininger ◽  
Janet L. Parker
Keyword(s):  
Nitric Oxide ◽  
Exercise Training ◽  
Coronary Occlusion ◽  
External Solution ◽  
Nitric Oxide Production ◽  
Miniature Swine ◽  
Oxide Production ◽  
Chronic Coronary Occlusion ◽  
Basal Tone ◽  
Coronary Arterioles

Endurance exercise training increases basal active tone in coronary arteries and enhances myogenic tone in coronary arterioles of control animals. Paradoxically, exercise training has also been shown to augment nitric oxide production and nitric oxide-mediated relaxation in coronary arterioles. The purpose of the present study was to examine the effect of exercise training on basal active tone of arterioles (∼150 μm ID) isolated from the collateral-dependent region of hearts exposed to chronic coronary occlusion. Ameroid occluders were surgically placed around the proximal left circumflex coronary artery of miniature swine. Arterioles were isolated from both the collateral-dependent and nonoccluded myocardial regions of sedentary (pen confined) and exercise-trained (treadmill run; 14 wk) pigs. Coronary tone was studied in isolated arterioles using microvessel myographs and standard isometric techniques. Exposure to nominally Ca2+-free external solution reduced resting tension in all arterioles; decreases were most profound ( P < 0.05) in arterioles from the collateral-dependent region of exercise-trained animals. Furthermore, nitric oxide synthase (NOS) inhibition ( Nω-nitro-l-arginine methyl ester; 100 μM) unmasked markedly increased nitric oxide-sensitive tone in arterioles from the collateral-dependent region of exercise-trained swine. Blockade of K+ channels revealed significantly enhanced K+ channel contribution to basal tone in collateral-dependent arterioles of exercise-trained pigs. Protein content of endothelial NOS (eNOS) and phosphorylated eNOS (pS1179), determined by immunoblot, was elevated in arterioles from exercise-trained animals with the greatest effect in collateral-dependent vasculature. Taken together, we demonstrate the interaction of opposing exercise training-enhanced arteriolar basal active tone, nitric oxide production, and K+ channel activity in chronic coronary occlusion, potentially enhancing the capacity to regulate blood flow to collateral-dependent myocardium.

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