Effects of electrical stimulation or local anesthesia of the rabbit's hypothalamus on the acute phase response

The effects of electrical stimulation of the rostral hypothalamic region on the acute phase response (APR) were examined in rabbits. As indicators of APR, we measured changes in the plasma concentrations of iron, zinc, copper, and fibrinogen and changes in the red and white blood cell counts. Electrical stimulation of the rostral hypothalamic region near the preoptic and anterior hypothalamic region did not induce any aspect of the APR. However, stimulation near the anteroventral portion of the third ventricle (AV3V) induced responses that were, in part, opposite to those observed in the APR: an increase in the plasma concentration of zinc and a decrease in the circulating leukocyte count. Microinjections of procaine into the brain regions near the AV3V did not induce any changes in the plasma levels of trace metals and fibrinogen but increased the circulating leukocyte count. These results suggest that nonspecific stimulation or inhibition of the rostral hypothalamic region does not induce APR.