Hypertension is the single most important contributing factor to both coronary heart disease and stroke, the two leading causes of death in the United States. Nonfatal and fatal cardiovascular diseases including coronary heart disease, ventricular arrhythmias and stroke, as well as renal disease and all-cause mortality increase progressively with higher levels of arterial pressure. In addition, both arterial and cardiopulmonary baroreflexes are less effective in controlling the circulation in hypertensive subjects. Cardiovascular mortality increases progressively with reduced baroreflex sensitivity. A limited number of studies performed with hypertensive subjects reported that endurance exercise training increased the sensitivity of the arterial baroreflex. An increased baroreflex gain may have cardioprotective effects and could be beneficial to patients at high risk for sudden cardiac death. A reduction in the incidence of sudden cardiac death among postinfarction patients participating in a multifactorial intervention program that included exercise has been reported. Therefore, this proposal is designed to determine the effect of endurance exercise training on the arterial and cardiopulmonary baroreflex regulation of the cardiovascular system in hypertensive rats. Specifically, the interaction of the arterial and cardiopulmonary baroreflex on the regulation of sympathetic nerve activity, regional blood flow, arterial pressure, heart rate and hormonal regulation (renin and arginine vasopressin) at rest and during exercise will be studied in sedentary and exercise trained hypertensive rats. The influence of peripheral (afferent activity) and central mechanisms in mediating the autonomic adaptations associated with exercise training will also be examined. These studies will provide a better understanding of the regulation of the neurohumoral drive to the circulation, the effect of exercise training on this regulation and the influence of central and peripheral mechanisms in mediating the autonomic adaptations associated with exercise training in hypertensive rats.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL058414-04
Application #
6184206
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1997-08-20
Project End
2002-07-31
Budget Start
2000-08-01
Budget End
2002-07-31
Support Year
4
Fiscal Year
2000
Total Cost
$199,016
Indirect Cost
Name
Wayne State University
Department
Physiology
Type
Schools of Medicine
DUNS #
001962224
City
Detroit
State
MI
Country
United States
Zip Code
48202
DiCarlo, S E; Collins, H L; Rodenbaugh, D W et al. (2002) Daily exercise reduces measures of heart rate and blood pressure variability in hypertensive rats. Clin Exp Hypertens 24:221-34
Collins, Heidi L; DiCarlo, Stephen E (2002) TENS attenuates response to colon distension in paraplegic and quadriplegic rats. Am J Physiol Heart Circ Physiol 283:H1734-9
Rao, Sumangala P; Collins, Heidi L; DiCarlo, Stephen E (2002) Postexercise alpha-adrenergic receptor hyporesponsiveness in hypertensive rats is due to nitric oxide. Am J Physiol Regul Integr Comp Physiol 282:R960-8
Collins, Heidi L; Dicarlo, Stephen E (2002) Acute exercise reduces the response to colon distension in T(5) spinal rats. Am J Physiol Heart Circ Physiol 282:H1566-70
Lawson, D M; Duke, J L; Zammit, T G et al. (2001) Recovery from carotid artery catheterization performed under various anesthetics in male, Sprague-Dawley rats. Contemp Top Lab Anim Sci 40:18-22
Collins, H L; Kim, J K; DiCarlo, S E (2001) Sino-aortic denervation alters the hemodynamic response to exercise in hypertensive rats. Clin Exp Hypertens 23:657-66
Collins, H L; Rodenbaugh, D W; DiCarlo, S E (2001) Central blockade of vasopressin V(1) receptors attenuates postexercise hypotension. Am J Physiol Regul Integr Comp Physiol 281:R375-80
Howard, M G; Collins, H L; Dicarlo, S E (2000) Post-exercise elevations in sympathetic nerve activity and baroreflex function in normotensive rabbits. Clin Exp Hypertens 22:431-44
Collins, H L; Rodenbaugh, D W; DiCarlo, S E (2000) Daily exercise attenuates the development of arterial blood pressure related cardiovascular risk factors in hypertensive rats. Clin Exp Hypertens 22:193-202
Collins, H L; Rodenbaugh, D W; Dicarlo, S E (2000) Daily exercise attenuated the sympathetic component of the spontaneous arterial baroreflex control of heart rate in hypertensive rats. Clin Exp Hypertens 22:607-22

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