The Effects of Peripheral Chemosympathectomy and Adrenalectomy Upon Blood Pressure Responses of the Rat to Footshock Under Varying Conditions: Evidence for Behavioral Effects on Patterning of Sympathetic Nervous System Responses.

A significant decrease in blood pressure is observed after shock-induced fighting in intact rats. In rats treated with intravenous 6-hydroxydopamine, a drug that selectively destroys peripheral sympathetic nerve endings when given by this route, this blood pressure response is reversed to a significant increase. In contrast, adrenalectomy converts a slight increase in blood pressure after intact rats are shocked alone in the cage into a significant decrease. These alterations in blood pressure response suggest that the sympathetic response to a stressful stimulus is not an all or none response, but, rather, consists of a patterned activation depending upon the behavioral response available. The current physiological findings are consistent with neuroendocrine research in which coping behavior is found associated with a predominant norepinephrine release by the sympathetic nervous system, and stress without available coping responses is associated with release also of epinephrine. [ABSTRACT FROM AUTHOR]