Author/Editor		Wu, Zhen-Yong; Križančić Bombek, Lidija; Rupnik, Marjan
Title		AMPA receptors regulate exocytosis and insulin release in pancreatic [beta] cells
Type		članek
Vol. and No.		Letnik 13, št. 8
Publication year		2012
Volume		str. 1124-1139
ISSN		1398-9219 - Traffic (Copenhagen, Denmark)
Language		eng
Abstract		Ionotropic glutamate receptors (iGluRs) are expressed in islets and insulinomacells and involved in insulin secretion. However, the exact roles that iGluRs play in ? cells remain unclear. Here, we demonstrated that GluR2-containing ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) were expressed in mouse ? cells. Glutamate application increased both cytosolic calcium and the number of docked insulin-containing granules, which resulted in augmentation of depolarization-induced exocytosis and high-glucose-stimulated insulin release. While glutamate application directly depolarized ? cells, it also induced an enormous depolarization when K(ATP) channels were available. Glutamate application reduced the conductance of K(ATP) channels and increased voltage oscillations. Moreover, actions of AMPARs were absent in Kir6.2 knock-out mice. The effects of AMPARs on K(ATP) channels were mediated by cytosolic cGMP. Taken together, our experiments uncovered a novel mechanism by which AMPARs participate in insulin release.
Descriptors		Islets of Langerhans Pancreas Physiology