Author/Editor		Costa Calejo, Ana-Isabel; Jorgačevski, Jernej; Rituper, Boštjan; Guček, Alenka; Pereira, Patrícia M.; Santos, Manuel A. S.; Potokar, Maja; Vardjan, Nina; Kreft, Marko; Goncalves, Paula P.; Zorec, Robert
Title		Hyperpolarization-activated cyclic nucleotide-gated channels and cAMP-dependent modulation of exocytosis in cultured rat lactotrophs
Type		članek
Vol. and No.		Letnik 34, št. 47
Publication year		2014
Volume		str. 15638-15647
ISSN		0270-6474 - The Journal of neuroscience : the official journal of the Society for Neuroscience
Language		eng
Abstract		Hormone and neurotransmitter release from vesicles is mediated by regulated exocytosis, where an aqueous channel-like structure, termed a fusion pore, is formed. It was recently shown that second messenger cAMP modulates the fusion pore, but the detailed mechanisms remain elusive. In this study, we asked whether the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which are activated by cAMP, are involved in the regulation of unitary exocytic events. By using the Western blot technique, a real-time PCR, immunocytochemistry in combination with confocal microscopy, and voltage-clamp measurements of hyperpolarizing currents, we show that HCN channels are present in the plasma membrane and in the membrane of secretory vesicles of isolated rat lactotrophs. Single vesicle membrane capacitance measurements of lactotrophs, where HCN channels were either augmented by transfection or blocked with an HCN channel blocker (ZD7288), show modulated fusion pore properties. We suggest that the changes in local cation concentration, mediated through HCN channels, which are located on or near secretory vesicles, have an important role in modulating exocytosis.
Keywords		HCN channels exocytosis RT-PCR HCN kanali eksocitoza RT-PCR