Endothelin-activated calcium signaling in enteric glia derived from neonatal guinea pig

The American Journal of Physiology
W ZhangMichael W Mulholland

Abstract

The ability of guinea pig enteric glia to respond to endothelins was examined using fura 2-based digital microscopy in glial cells derived from guinea pig taenia coli. Each isoform of endothelin (ET-1, ET-2, ET-3) evoked dose-dependent and equipotent increases in intracellular Ca2+ concentration ([Ca2+]i) and in percentage of cells responding, 4alaEt-1, an ETB receptor agonist, elicited similar [Ca2+]i increments. BQ-788, an ETB antagonist, inhibited [Ca2+]i responses to endothelin. Preincubation of glia with U-73122 a phospholipase C inhibitor, abolished the [Ca2+]i response to ET-3 exposure. Thapsigargin also eliminated ET-3-evoked Ca2+ signaling. The inositol 1,4,5-trisphosphate (IP3) receptor antagonist heparin, introduced into glial cells by radio frequency electroporation, blocked [Ca2+]i responses to ET-3 (100 nM) in 63% of glia. Sustained elevation in [Ca2+]i was abolished by removal of Ca2+ from the buffer and inhibited 85. -3% by Ni2+ (1 mM). Preincubation of glia with 100 nM phorbol 12-myristate 13-acetate (24 h) also inhibited sustained increments in [Ca2+]i by 87%. The presence of IP3 receptors in enteric glia was confirmed by immunofluorescent confocal microscopy.

Citations

Apr 14, 2000·American Journal of Physiology. Gastrointestinal and Liver Physiology·M HananiT Pannicke
Jun 22, 2018·American Journal of Physiology. Gastrointestinal and Liver Physiology·Ninotchska M DelvalleBrian D Gulbransen
Dec 5, 2002·Glia·Julie CabarrocasRoland S Liblau

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