Lee K, Dixon A K, Rowe I C, Ashford M L, Richardson P J
Department of Pharmacology, University of Cambridge, England.
J Neurochem. 1996 Jun;66(6):2562-71. doi: 10.1046/j.1471-4159.1996.66062562.x.
The coexpression of sulphonylurea binding sites and ATP-sensitive K+(KATP) 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 KATP channels and charybdotoxin-sensitive, large-conductance calcium-activated K+ BKCa 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 KATP channels are functionally linked in the motor cortex and that they are both selectively expressed in nerve terminals, where the KATP channel may serve to limit glutamate release under conditions of metabolic stress.
在大鼠运动皮层中检测了磺酰脲结合位点与ATP敏感性钾离子通道（KATP通道）的共表达情况，该区域是中枢神经系统中磺酰脲结合密度较高的区域。在神经元细胞体上未检测到这些通道，但通过对运动皮层融合神经末梢进行膜片钳记录，检测到了磺酰脲敏感性KATP通道以及对蝎毒素敏感的大电导钙激活钾离子通道（BKCa通道）。亚细胞分级分离显示，高亲和力磺酰脲结合位点在神经末梢部分富集，而格列本脲可增加分离神经末梢中不依赖钙的谷氨酸外流。得出的结论是，神经元磺酰脲受体与KATP通道在运动皮层中存在功能联系，且它们都在神经末梢中选择性表达，在代谢应激条件下，KATP通道可能用于限制谷氨酸释放。
