Autonomic Influences on Peripheral Circulatory and Thermal Responses to Cold,
ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
Pagination or Media Count:
The effects of bilateral denervations of the lumbar sympathetic chain, vagus nerves, and sacral ventral roots on peripheral circulatory and thermal responses during local cold exposure of a cat hindlimb were determined. Cold exposure apparently produced a peripheral vasocinstriction mediated by a somatosympathetic reflex and local mechanisms. Interruption of the L3 sympathetic hain ipsilateral as well as contralateral to the cold-exposed hindlimb produced a marked reduction in vascular resistance, a femoral arterial hyperemia, and a warming of the footpad and increased heat loss from the footpad. These responses were acute suggesting that local mechanisms can predominate in the absence of neurogenic mechanisms to restore peripheral vasoconstriction. Interruption of the vagus nerves and sacral ventral roots had little effect on the peripheral circulatory and thermal responses to cold. This study identified the primary autonomic pathway mediating peripheral vasoconstriction during cold exposure as the efferent sympathetic nerves.
- Stress Physiology