Adrenal hormone effects on hippocampal excitatory amino acid binding

The influence of short-term adrenalectomy or corticosterone treatment on the binding of glutamate receptor subtypes in the rat hippocampus was explored using the technique of in vitro autoradiography. Analysis of NMDA, kainate and AMPA binding in the hippocampus was conducted on the brains of control, adrenalectomized, and adrenalectomized animals given corticosterone treatment. In addition, serum corticosterone levels were determined by RIA. No striking effects of acute adrenalectomy on the distribution or density of any glutamate receptor subtype were observed in the hippocampus. Adrenalectomy had a small but significant effect on kainate binding in the stratum lucidum and stratum radiatum of CA3 in the first experiment, but no effect in follow-up experiments. Short-term treatment with stress levels of corticosterone had no effect on the binding of NMDA or kainate in any hippocampal subfield. However, a small effect of high doses of corticosterone (CORT) was observed on AMPA binding in one subregion. Although the hippocampus is a target for glucocorticoids and uses excitatory amino acids as a primary neurotransmitter, transient manipulation of adrenal hormone levels did not directly modulate excitatory amino acid receptor binding.