IDENTIFICATION OF ATP-SENSITIVE K+ CHANNEL IN SPINY NEURONS OF RAT CAUDATE-NUCLEUS

On the somata of GABAergic spiny neurons in the caudate nucleus of th rat an ATP-sensitive K+ channel (K-ATP-channel) was identified. The K-ATP-currents in cell-attached patches were activated both by energy-depleting conditions (200 mu M cyanide) and by diazoxide (300 mu M) and were reversibly blocked by tolbutamide (EC(50) = 5 mu M). In inside-out patch membranes both ATP (1 mM) and its non-hydrolyzable analog AMP-PNP (adenylylimidodi-phosphate; EC(50) = 27 mu M) reversibly inhibited channel activity. These results demonstrate that the K-ATP-channel in spiny neurons displays properties characteristic of K-ATP-channel in hippocampal, neocortical and nigral neurons and in pancreatic beta-cells.