Phentolamine block of KATP channels is mediated by Kir6.2.

ABSTRACT: The ATP-sensitive K+-channel (KATP channel) plays a key role in insulin secretion from pancreatic beta cells. It is closed both by glucose metabolism and the sulfonylurea drugs that are used in the treatment of noninsulin-dependent diabetes mellitus, thereby initiating a membrane depolarization that activates voltage-dependent Ca2+ entry and insulin release. The beta cell KATP channel is a complex of two proteins: Kir6.2 and SUR1. The former is an ATP-sensitive K+-selective pore, whereas SUR1 is a channel regulator that endows Kir6.2 with sensitivity to sulfonylureas. A number of drugs containing an imidazoline moiety, such as phentolamine, also act as potent stimulators of insulin secretion, but their mechanism of action is unknown. We have used a truncated form of Kir6.2, which expresses

SUBMITTER: Proks P 

PROVIDER: S-EPMC23609 | biostudies-literature | 1997 Oct

REPOSITORIES: biostudies-literature