ANTERIOR HYPOTHALAMIC-STIMULATION DECREASES SERUM IMMUNOGLOBULIN-G CONCENTRATIONS

lNeuroimmunological research has indicated that hypothalamic structure s play an important role in the modulation of immunoresponsivity. We r eport that electrical stimulation of the anterior hypothalamus decreas es the concentration of Immunoglobulin G (IgG) in rat serum. Male Spra gue-Dawley rats were randomly assigned to either an anterior or dummy electrode group. Following the determination of baseline IgG concentra tions animals were placed in an operant chamber where electrical stimu lation was delivered to animals in the anterior group. Animals in the dummy electrode group were placed in an operant chamber but received n o brain stimulation through the attached cable. IgG concentrations wer e determined for each animal 3, 6, 12, and 24 hours following each ses sion in the operant chamber. Poststimulation measurement periods were counterbalanced across animals to control for possible order effects. A significant decrease in IgG concentrations was found between animals in the anterior group and animals in the dummy electrode group. An an alysis was also performed to assess the effects of repeated measuremen ts on IgG concentrations. As compared to the dummy electrode group, th e anterior group displayed significantly higher IgG concentrations as a function of the number of measurements. The results of the present s tudy indicate that anterior hypothalamic activity can change IgG conce ntrations without antigenic challenge and the relevance of this findin g as applied to current research in Health Psychology is discussed.