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Neural Control of Venous Capacitance Function in Health and Disease
APS Neural Control and Autonimc Regulation Section
Gregory D. Fink
J. V. Tyberg, A. Shoukas, C.C. Pang and G.D. Fink
This symposium will address the question of regulation of vascular
capacitance affects overall control of the circulation. Systemic vascular
capacitance is largely determined by the properties of small veins,
particularly those in the splanchnic organs. Passive changes in vein
diameter can strongly affect vascular capacitance, but this symposium will
focus on active changes in venous smooth muscle activ8ity. This topic has
received relatively little attention in recent years, despite evidence that
abnormal vascular capacitance regulation participates in the etiology of
orthostatic disorders, dialysis-related hypotension, chronic fatigue
syndrome, heart failure, hypertension and other important clinical
problems. Dr. John Tyberg will begin the symposium with an explication of
his novel approach to understanding the interrelationships between venous
capacitance, venous return and cardiac output. Dr. Artin Shoukas will show
how changes in vascular capacitance are key determinants of the overall
circulatory response to activation of the arterial baroreflexes. Both of
theses presentations will emphasize quantitative and model-based approaches
to the topic. Venous smooth muscle activity can be significantly modified
by drugs and hormones with important consequences for regulation of vascular
capacitance. Dr. Catherine Pang will discuss how autonomic and other drugs
modify venous smooth muscle tone as assessed using drug induced changes in
mean circulatory filling pressure in the intact animal. Finally, Dr. Fink
will illustrate fundamental differences in the way sympathetic nerves
control venous versus arterial smooth muscle, and possible implications of
these difference for understanding the etiology of hypertension and other
cardiovascular diseases. A major purpose of this symposium is to
reemphasize the importance of venous capacitance regulation as a way of
identifying new strategies for treating cardiovascular disease.
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