GLUCOCORTICOIDS PROMOTE LOCALIZED ACTIVITY OF RAT HIPPOCAMPAL CA1 PYRAMIDAL NEURONS IN BRAIN-SLICES

The effects of glucocorticoids on rat hippocampal CA1 pyramidal neurons were studied using brain slice preparations. At 10 days after bilateral adrenalectomy, a localized region of CA1 showed a drastic reduction of excitability induced by CA3 stimulation as compared to control. The region of CA1 most effected was 1.4-2.0 mm from the most rostral side of the hippocampus. Upon perfusion of corticosterone, the response to synaptic activation was reduced in this region in slices from adrenalatomized animals increased rapidly toward control values, volatile responses in other regions were unaffected. These results suggest that glucocorticoid receptors are concentrated in restricted regions of hippocampus and that these receptors have important roles in regulation of synaptic excitability.