SYMPATHETIC NERVOUS SYSTEM AND INTEGRATIVE VASCULAR CONTROL

Abstract

Regulation of vascular resistance of skeletal muscle vessels (arterioles) in humans at rest and during exercise depends on two major regulatory systems: (I) systemic control which consists of both neural and humoral regulation, (II) local control by (IIa) myogenic regulation (intrinsic mechanism of smooth muscle cells), (IIb) vasoactive factors (endothelium-derived substances as well as metabolites from tissue)and (IIc) muscle pump action (mechanical influence as well as metabolic). When sympathetic innervation is absent or augmented integrated vascular control at rest and during exercise will be affected. How this affects the regulation of the vascular resistance at rest and during exercise and what the effect is on other factors like endothelium-derived substances (nitric oxide; NO) and local metabolic factors like adenosine is not clear and will be the central theme of this symposium. The purpose of the symposium is to provide an overview of the effects of absent or augmented sympathetic innervation on the integrated vascular control at rest and during exercise. This question will be addressed from different points of view, i.e., animal studies, studies in which the receptors are blocked, studies in which the sympathetic innervation in humans is altered (elderly) or absent because of a disease (spinal cord-injured patients, sympathectomized patients). The focus of the symposium will be: what can we learn about integrative vascular control from the similarities and the contradictions between these different models or conditions?