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Gap junction coupling confers isopotentiality on astrocyte syncytium
Author(s) -
Ma Baofeng,
Buckalew Richard,
Du Yixing,
Kiyoshi Conrad M.,
Alford Catherine C.,
Wang Wei,
McTigue Dana M.,
Enyeart John J.,
Terman David,
Zhou Min
Publication year - 2016
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.22924
Subject(s) - syncytium , biology , astrocyte , gap junction , neuroscience , coupling (piping) , microbiology and biotechnology , cell , central nervous system , genetics , engineering , mechanical engineering , intracellular
Astrocytes are extensively coupled through gap junctions into a syncytium. However, the basic role of this major brain network remains largely unknown. Using electrophysiological and computational modeling methods, we demonstrate that the membrane potential ( V M ) of an individual astrocyte in a hippocampal syncytium, but not in a single, freshly isolated cell preparation, can be well‐maintained at quasi‐physiological levels when recorded with reduced or K + free pipette solutions that alter the K + equilibrium potential to non‐physiological voltages. We show that an astrocyte's associated syncytium provides powerful electrical coupling, together with ionic coupling at a lesser extent, that equalizes the astrocyte's V M to levels comparable to its neighbors. Functionally, this minimizes V M depolarization attributable to elevated levels of local extracellular K + and thereby maintains a sustained driving force for highly efficient K + uptake. Thus, gap junction coupling functions to achieve isopotentiality in astrocytic networks, whereby a constant extracellular environment can be powerfully maintained for crucial functions of neural circuits. GLIA 2016;64:214–226