Potassium Channel Activators Decrease Endogenous Glutamate Release from Rat Cerebellar Slices

Overview

Journal Amino Acids

Specialty Biochemistry

Date 2013 Nov 5

PMID 24186325

Authors

B G Dickie

J A Davies

Affiliations

Soon will be listed here.

Abstract

The effects of the sulphonylurea activators of ATP-sensitive potassium channels (K(+) ATP), cromakalim and pinacidil, on the evoked-release of endogenous glutamate from superfused slices of rat cerebellum was examined. K(+)-stimulated release was Ca(2+)-dependent, whereas tetrapentylammonium (TPeA)-evoked release occurred both in the presence and absence of Ca(2+), but was significantly greater in Ca(2+)-free medium. The Ca(2+)-dependent TPeA and K(+)-evoked release of glutamate was inhibited by both cromakalim and pinacidil in a concentration-dependent fashion. However, although cromakalim markedly reduced Ca(2+)-independent TPeA-evoked release, pinacidil was ineffective. In addition, the vehicle for cromakalim, ethanol, markedly potentiated both Ca(2+)-dependent and -independent TPeA-evoked release, but not K(+)-evoked release. Despite a high concentration of sulphonylurea binding sites and a dense glutamatergic innervation, the concentrations of K(+) ATP channel activators required to inhibit stimulus-evoked release from the cerebellum are higher than those reported to inhibit glutamate release or reduce neuronal activity in other parts of the CNS.

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