alpha-Sialylcholesterol enhances the depolarization-induced release of acetylcholine and glutamate in rat hippocampus: in vivo microdialysis study.

The effects of alpha-sialylcholesterol (alpha-SC), a synthetic ganglioside analogue, on synaptic neurotransmission were studied using in vivo microdialysis technique. Application of alpha-SC through a microdialysis probe enhanced high potassium-evoked release of acetylcholine and glutamate in the hippocampal CA3 region of Wistar rats. The experiments using synaptosomes and FM1-43, a fluorescent styryl dye used for studies of neurotransmitter release mechanisms, showed that alpha-SC increased depolarization-induced loss of dye but it did not evoke the dye loss at resting condition. These results indicate that alpha-SC promotes a depolarization-induced exocytotic neurotransmitter release in the brain under in vivo conditions. Application of alpha-SC increased the level of glutamate but not that of acetylcholine, suggesting that alpha-SC affects spontaneous glutamate release and/or transport system at the brain region.