Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Numerous studies reported in the literature indicate that the amygdala is essential for normal pituitary-adrenal function in rodents. In light of discrepancies regarding the nature of this relationship this investigation was undertaken to reevaluate tile influence of the amydala over adrenocortical secretory mechanisms. To this end, plasma corticosterone concentrations were determined after ablation or electrical stimulation of the amygdaloid system. Interruption of the stria terminalis or ventral amygdalofugal pathway as well as large amygdaloid lesions had no effect on resting or stress components of the pituitary-adrenal axis. Stimulation of the arcuate hypothalamic nucleus, amygdala, hippocampus or preoptic area in awake animals resulted in elevated plasma corticosterone levels. Except for the arcuate nucleus,stimulation was associated with hyperactivity and clonic convulsions involving the upper ex­ tremities and head region. In anesthetized rats, stimulation of these same forebrain areas produced plasma corticosterone titers that did not differ from the elevated steroid levels observed after sham stimulation. These results suggest that amygdaloid ablation or stimulation does not compromise pituitary-adrenal function in the rat.