Training effects on the regional blood flow response to exercise in myocardial infarcted rats

1992 ◽  
Vol 262 (6) ◽  
pp. H1846-H1852 ◽  
Author(s):  
T. I. Musch ◽  
C. T. Nguyen ◽  
H. V. Pham ◽  
R. L. Moore

The regional blood flow (BF) response to submaximal exercise was determined for sedentary and trained myocardial infarcted (MI) rats. Training consisted of treadmill running (10% grade, 30 m/min) for 1 h/day, 5 days/wk for 12-14 wk and produced decreases in resting heart rate and increases in maximal O2 uptake and endurance capacity. BF determined at 2 and 6 min of exercise (via radiolabeled microspheres) demonstrated that trained rats maintained greater BF to organs found in the abdominal region when compared with their sedentary counterparts. BF to the total hindlimb musculature at 2 min of exercise was greater in sedentary rats when compared with their trained counterparts and was the consequence of greater BF to 10 of the 27 muscle or muscle parts investigated. At 6 min of exercise, BF to the total hindlimb musculature was similar between trained and sedentary rats, as BF in 9 of 27 muscles or muscle parts investigated decreased from 2 to 6 min of exercise for the sedentary group. In general, the BF patterns within and among the individual muscles of the hindlimb were different between the two groups. Trained rats tended to maintain greater BF to the predominantly red muscles, whereas the sedentary rats maintained greater BF to the predominantly white muscles at 6 min of exercise. In conclusion, the training-induced changes in BF found in this study are similar to those found previously for normal rats, and they demonstrate that endurance training produces changes in the regional distribution of BF during exercise in MI rats.

1987 ◽  
Vol 62 (4) ◽  
pp. 1724-1732 ◽  
Author(s):  
T. I. Musch ◽  
G. C. Haidet ◽  
G. A. Ordway ◽  
J. C. Longhurst ◽  
J. H. Mitchell

The effect of training on the regional blood flow response to maximal exercise was investigated in the foxhound. Training consisted of 8–12 wk of treadmill running at 80% of maximal heart rate 1 h/day for 5 days/wk and resulted in a 31% increase in maximal O2 consumption, a 28% increase in maximal cardiac output, and a 23% decrease in systemic vascular resistance during maximal exercise. Blood flow to the heart, diaphragm, brain, skin, and 9 of 10 muscles investigated was similar during maximal exercise pre- and posttraining; however, blood flow to the gastrocnemius muscle was greater posttraining than it was pretraining. Blood flow to the stomach, small intestine, and pancreas decreased during maximal exercise pre- and posttraining; however, blood flow to the large intestine, spleen, liver, adrenal glands, and kidneys decreased during maximal exercise only posttraining. In addition, a larger decrease in blood flow to the stomach during maximal exercise was found posttraining compared with pretraining. These results demonstrate that blood flow to skeletal muscle, the kidneys, and the splanchnic region of the foxhound during maximal exercise can be significantly altered by dynamic exercise training.


1987 ◽  
Vol 63 (6) ◽  
pp. 2269-2277 ◽  
Author(s):  
T. I. Musch ◽  
D. B. Friedman ◽  
K. H. Pitetti ◽  
G. C. Haidet ◽  
J. Stray-Gundersen ◽  
...  

The regional blood flow response to progressive treadmill exercise was measured with radioactive microspheres in 25 untrained mongrel dogs. Incremental increases in work intensity resulted in corresponding increases in blood flows to the gracilis, gastrocnemius, semimembranosus, and semitendinosus muscles of the hindlimb and to the heart. During maximal exercise, blood flow was greatest in the semimembranosus muscle and lowest in the semitendinosus muscle (342 and 134 ml–1.100 g tissue-1.min-1, respectively). Exercise produced a decrease in blood flow to the temporalis muscle, which was classified as nonlocomotive in function. Blood flows to the stomach, pancreas, and large intestine decreased at the lowest exercise work load and remained diminished throughout the continuum to maximal exercise. Blood flows to the small intestine and spleen were maintained during submaximal exercise but were reduced by 50% at maximal O2 consumption (VO2max). No changes in blood flows to the kidneys, adrenal glands, liver, and brain were found. These results demonstrate that 1) renal blood flow is maintained at resting levels during exercise in untrained dogs; 2) blood flow changes in the various organs of the splanchnic region of dogs during exercise are heterogeneous; and 3) blood flows to the working skeletal muscles of dogs progressively increase with increasing work loads up to VO2max.


1979 ◽  
Vol 237 (6) ◽  
pp. H705-H712 ◽  
Author(s):  
J. R. Hales ◽  
L. B. Rowell ◽  
R. B. King

Radioactive microspheres (containing six different nuclide labels) were used to measure blood flow (BF) to most major organs of eight conscious baboons during heat stress. Cardiac output (CO), arterial mean pressure, and arterial PO2, PCO2, and pH did not change, but heart rate increased and stroke volume fell as body temperature increased by as much as 2.56 degrees C. Skin BF increased in all regions sampled so that the fraction of CO distributed to skin (not including feet and hands) increased from 3% (control) to 14%. Increased skin BF was compensated for by decreases in splanchnic (intestines, stomach, pancreas, and spleen) (35%), renal (27%), and possibly muscle BF. There was no change in BF to the brain, spinal cord, coronary, or subcutaneous adipose tissue during heating. Therefore, baboons show a generalized redistribution of BF during heat stress, so that increments in skin BF are provided without increases in CO, whereas man depends on changes in both; despite this latter difference between the baboon and man, the similarity in magnitude of the splanchnic and renal vasoconstriction between the two primates may indicate that the baboon would be a suitable animal model for investigations into mechanisms of changes in regional blood flow in man during heat stress.


1983 ◽  
Vol 1 (6) ◽  
pp. 1391-1395 ◽  
Author(s):  
Steven R. Goldsmith ◽  
Gary S. Francis ◽  
T. Barry Levine ◽  
Jay N. Cohn

1983 ◽  
Vol 130 (1) ◽  
pp. 194-195
Author(s):  
M.J. Mäntylä ◽  
J.T. Toivanen ◽  
M.A. Pitkänen ◽  
A.H. Rekonen

1982 ◽  
Vol 242 (5) ◽  
pp. R434-R440
Author(s):  
T. McKean

Beavers (Castor canadensis) and nutria (Myocastor coypus) were anesthetized with halothane and catheters placed in the left ventricle, aorta and pulmonary artery, right ventricle or right atrium. The animals were strapped to a board and following recovery from anesthesia the following measurements were taken: regional distribution of blood flow, cardiac output, O2 consumption, arterial and venous blood gases, and pH. The animal was then immersed in 15-20 degrees C water for up to 2.75 min (nutria) or 4 min (beaver) and the measurements repeated. Heart rate and cardiac output decreased by 80 and 75%, respectively. Arterial and venous oxygen partial pressure and content fell as did pH whereas CO2 pressures rose during diving. Oxygen consumption at rest was 124 and 102% of that predicted on the basis of body mass for the beaver and nutria, respectively. Rate of decline of O2 stores during diving decreased by 93% in beavers and 89% in nutria compared to the predive value. Regional blood flow decreased to all organs except the adrenals, heart, and lungs. Blood flow to the brain increased during diving.


1962 ◽  
Vol 203 (2) ◽  
pp. 266-270 ◽  
Author(s):  
Robert W. Bullard ◽  
Gordon E. Funkhouser

The local organ or tissue blood flows during the process of arousal from hibernation have been estimated in the 13-lined ground squirrel by the Sapirstein method, which consists of the measurement of the regional distribution of injected rubidium 86. The studies demonstrated that during arousal there is a confinement of blood flow to the thoracic regions. After the heart rate has attained 100 beats/min, blood flow increases to the anterior portions of the animal. At the arousal level characterized by a heart rate of 200 beats/min, blood flow to anterior and thoracic tissue had attained levels almost equal to control flows. Posterior tissue flows were still much lower than control flows. The centralization of blood flow to thoracic and anterior tissues did not occur in the rat in the hypothermic state.


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