Involvement of adenosine triphosphate-sensitive K+ channels in glucose-sensing in the rat solitary tract nucleus

The presence of adenosine triphosphate-sensitive (ATP-sensitive) K+ channel s (K-ATP channels) in the caudal nucleus tractus solitarii (NTS), and their possible involvement in glucose-sensing, were assessed by extracellular re cording of neuronal activity in rat hindbrain slices. In 21 out of 36 recor ded cells, firing was increased by sulfonylureas and decreased by K+ channe l opener (KCO), indicating the existence of K-ATP channels in the caudal NT S. In seven out of the nine neurons activated by a 2 mM increase in the glu cose level, the effects of sulfonylureas and KCO were consistent with the i nvolvement of K-ATP channels in the glucose response. Conversely, the mecha nism(s) underlying the response of glucose-depressed neurons remains to be clarified. Finally, the presence of K-ATP channels was also detected in som e neurons that were unresponsive to a 2 mM change in the glucose level. Thu s, K-ATP channels were pharmacologically identified in the caudal NTS, wher e they may be partly involved in glucose sensing. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.