Effects of estrogen on potassium-stimulated acetylcholine release in the hippocampus and overlying cortex of adult rats.

In vivo microdialysis techniques were used to examine the effects of estrogen on potassium-stimulated acetylcholine release in the hippocampus and overlying cortex of adult, ovariectomized rats. Estrogen treatment resulted in a significant increase in the percent change in acetylcholine release induced by potassium relative to controls, particularly after prolonged (90 min) exposure to high potassium. The data suggest that estrogen may help to maintain cholinergic function under conditions where cholinergic afferents to the hippocampal formation and cortex are challenged or impaired.