The importance of the capacitive properties of the systemic vascular bed has been recognized for some time: this property is involved in the regulation of cardiac output, since it affects the filling pressure of the right heart. This proposal aims at investigating the mechanism(s) by which the circulatory system may change capacitive properties and filling pressure to the right heart via the carotid sinus baroreceptor reflex. We will investigate what particular organ or organs significantly contribute to the changes of overall capacitive function of the systemic vascular bed via the baroreceptor reflex by eliminating specific regions one at a time. Those regions which were found to significantly contribute to overall capacitive function will then be studied in detail using two-port analysis techniques to describe the resistance and capacitance changes by the reflex system. The liver and spleen will be given special attention in an additional series of experiments concerning capacitive property of the systemic vascular bed. In parallel with the above studies we will investigate the resistive and capacitive property of the entire heart-lung compartment. In an additonal set of experiments we will investigate the capacitive and resistive property of the pulmonary vascular bed and their modifications by the barorecptor reflex. In a final set of experiments we will investigate baroreceptor reflex control of capacitive function in unanesthetized chronically instrumented dogs. The chronic dog experiments will be repeated after they are anesthetized and the data compared. Finally, experiments similar to the acute experiments will be performed in these same dogs.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HL019039-20
Application #
2215209
Study Section
Special Emphasis Panel (NSS)
Project Start
1976-06-01
Project End
1999-03-31
Budget Start
1996-04-01
Budget End
1999-03-31
Support Year
20
Fiscal Year
1996
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Biomedical Engineering
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Thompson-Torgerson, Caitlin S; Champion, Hunter C; Santhanam, Lakshmi et al. (2009) Cyclohexanone contamination from extracorporeal circuits impairs cardiovascular function. Am J Physiol Heart Circ Physiol 296:H1926-32
McKeown, K P; Shoukas, A A (1998) Chronic isolation of carotid sinus baroreceptor region in conscious normotensive and hypertensive rats. Am J Physiol 275:H322-9
Potts, J T; McKeown, K P; Shoukas, A A (1998) Reduction in arterial compliance alters carotid baroreflex control of cardiac output in a model of hypertension. Am J Physiol 274:H1121-31
Potts, J T; Hatanaka, T; Shoukas, A A (1996) Effect of arterial compliance on carotid sinus baroreceptor reflex control of the circulation. Am J Physiol 270:H988-1000
Hatanaka, T; Potts, J T; Shoukas, A A (1996) Invariance of the resistance to venous return to carotid sinus baroreflex control. Am J Physiol 271:H1022-30
Shigemi, K; Brunner, M J; Shoukas, A A (1994) Alpha- and beta-adrenergic mechanisms in the control of vascular capacitance by the carotid sinus baroreflex system. Am J Physiol 267:H201-10
Shoukas, A A (1993) Overall systems analysis of the carotid sinus baroreceptor reflex control of the circulation. Anesthesiology 79:1402-12
Rose, W C; Shoukas, A A (1993) Two-port analysis of systemic venous and arterial impedances. Am J Physiol 265:H1577-87
Haase, E B; Shoukas, A A (1992) Blood volume changes in microcirculation of rat intestine caused by carotid sinus baroreceptor reflex. Am J Physiol 263:H1939-45
Lash, J M; Haase, E; Shoukas, A A (1992) Systemic responses to carotid occlusion in the anesthetized rat. J Appl Physiol 72:1247-54

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