POSSIBLE PRESENCE OF THE ATP-SENSITIVE K+ CHANNEL IN ISOLATED SPINAL DORSAL HORN NEURONS OF THE RAT

The ATP-sensitive K+ channel (K-ATP channel) is a K+ channel inhibited by cytoplasmic ATP. It was originally found in cardiac cells and recently in neuronal cells. Here, we present evidence indicating that the K-ATP channel also exists in spinal dorsal horn neurons: membrane currents were recorded by whole-cell voltage-clamp in spinal dorsal horn neurons isolated from young rats. The outward current was augmented by K-ATP channel activators nicorandil and minoxidil and reduced by the blocker glibenclamide. This glibenclamide-induced change in the current was augmented when the intracellular ATP was lowered and the reversal potential was shifted according to the external K+ concentration.