The Influence of Sympathetic Nervous Control on Blood Flow through the Human Forearm.
Abstract
The role of neurally mediated (sympathetic) vasoconstriction and metabolic dilatation has been examined in both exercising and resting forearms of human volunteers. To examine this competition in the resting forearm, the arms were 'calibrated' for changes in blood flow, integrated e.m.g. and oxygen uptake at low sustained isometric tensions (1-10% MVC). The 'calibrated' arm became the contralateral ('resting') arm during a sustained isometric hand-grip contraction at 33% MVC for 2 min with the opposite arm. There was no significant increase in forearm blood flow in the contralateral arm in two-thirds of both trained and naive subjects. Small increases in flow were matched by increases in e.m.g. activity. The remainder of subjects demonstrated almost a doubling of blood flow in the contralateral arm during the second min of the contraction but this change was also accompanied by appropriate increases in e.m.g. activity. Use of either alpha-adrenergic or beta-adrenergic blocking agents indicated that increased alpha-adrenergic activity mediated changes in vascular resistance during isometric exercise. There was no detectable control of forearm flow exerted by beta-adrenergic receptors.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 27, 1981
- Accession Number
- ADA107834
Entities
People
- A. R. Lind
- C. A. Williams
Organizations
- Saint Louis University