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The High‐Affinity Sulphonylurea Receptor Regulates K ATP Channels in Nerve Terminals of the Rat Motor Cortex
Author(s) -
Lee Kevin,
Dixon Alistair K.,
Rowe Iain C. M.,
Ashford Michael L. J.,
Richardson Peter J.
Publication year - 1996
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1996.66062562.x
Subject(s) - motor nerve , neuroscience , motor cortex , chemistry , receptor , biophysics , microbiology and biotechnology , biology , biochemistry , stimulation
The coexpression of sulphonylurea binding sites and ATP‐sensitive K + (K ATP ) channels was examined in the rat motor cortex, an area of the CNS exhibiting a high density of sulphonylurea binding. These channels were not detected on neuronal cell bodies, but sulphonylurea‐sensitive K ATP channels and charybdotoxin‐sensitive, large‐conductance calcium‐activated K + BK Ca channels were detected by patch clamping of fused nerve terminals from the motor cortex. Subcellular fractionation revealed that high‐affinity sulphonylurea binding sites were enriched in the nerve terminal fraction, whereas glibenclamide increased calcium‐independent glutamate efflux from isolated nerve terminals. It is concluded that neuronal sulphonylurea receptors and K ATP channels are functionally linked in the motor cortex and that they are both selectively expressed in nerve terminals, where the K ATP channel may serve to limit glutamate release under conditions of metabolic stress.