title: Opening of pannexin- and connexin-based channels increases the excitability of nodose ganglion sensory neurons.
abstract: Satellite glial cells (SGCs) are the main glia in sensory ganglia. They surround neuronal bodies and form a cap that prevents the formation of chemical or electrical synapses between neighboring neurons. SGCs have been suggested to establish bidirectional paracrine communication with sensory neurons. However, the molecular mechanism involved in this cellular communication is unknown. In the central nervous system (CNS), astrocytes present connexin43 (Cx43) hemichannels and pannexin1 (Panx1) channels, and the opening of these channels allows the release of signal molecules, such as ATP and glutamate. We propose that these channels could play a role in glia-neuron communication in sensory ganglia. Therefore, we studied the expression and function of Cx43 and Panx1 in rat and mouse nodose-petrosal-jugular complexes (NPJcs) using confocal immunofluorescence, molecular and electrophysiological techniques. Cx43 and Panx1 were detected in SGCs and in sensory neurons, respectively. In the rat and mouse, the electrical activity of vagal nerve increased significantly after nodose neurons were exposed to a Ca(2+)/Mg(2+)-free solution, a condition that increases the open probability of Cx hemichannels. This response was partially mimicked by a cell-permeable peptide corresponding to the last 10 amino acids of Cx43 (TAT-Cx43CT). Enhanced neuronal activity was reduced by Cx hemichannel, Panx1 channel and P2X7 receptor blockers. Moreover, the role of Panx1 was confirmed in NPJc, because in those from Panx1 knockout mice showed a reduced increase of neuronal activity induced by Ca(2+)/Mg(2+)-free extracellular conditions. The data suggest that Cx hemichannels and Panx channels serve as paracrine communication pathways between SGCs and neurons by modulating the excitability of sensory neurons.
authors.affiliation: Facultad de Medicina, Centro de Fisiología Celular e Integrativa, Clínica Alemana Universidad del Desarrollo Santiago, Chile ; Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: Mauricio A
authors.initials: MA
authors.lastname: Retamal
authors.affiliation: Laboratorio de Fisiología Celular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile.
authors.forename: Julio
authors.initials: J
authors.lastname: Alcayaga
authors.affiliation: Facultad de Medicina, Centro de Fisiología Celular e Integrativa, Clínica Alemana Universidad del Desarrollo Santiago, Chile.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Verdugo
authors.affiliation: KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine Leuven, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Bultynck
authors.affiliation: Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University Ghent, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Leybaert
authors.affiliation: Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile.
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Sáez
authors.affiliation: Facultad de Ciencias Biológicas y Facultad de Medicina, Universidad Andrés Bello Santiago, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Fernández
authors.affiliation: Facultad de Medicina, Centro de Genética Humana, Clínica Alemana Universidad del Desarrollo Santiago, Chile.
authors.forename: Luis E
authors.initials: LE
authors.lastname: León
authors.affiliation: Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile Santiago, Chile ; Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto Milenio Valparaíso, Chile.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Sáez
keywords: connexon; glial satellite cells; nodose ganglia; peripheral glial cells; sensory ganglia