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Microglial K + channel expression in young adult and aged mice
Author(s) -
Schilling Tom,
Eder Claudia
Publication year - 2015
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.22776
Subject(s) - microglia , inward rectifier potassium ion channel , biology , depolarization , neocortex , neuroglia , hyperpolarization (physics) , entorhinal cortex , neuroscience , potassium channel , microbiology and biotechnology , endocrinology , ion channel , medicine , central nervous system , chemistry , inflammation , immunology , hippocampus , receptor , biochemistry , organic chemistry , nuclear magnetic resonance spectroscopy
The K + channel expression pattern of microglia strongly depends on the cells' microenvironment and has been recognized as a sensitive marker of the cells' functional state. While numerous studies have been performed on microglia in vitro , our knowledge about microglial K + channels and their regulation in vivo is limited. Here, we have investigated K + currents of microglia in striatum, neocortex and entorhinal cortex of young adult and aged mice. Although almost all microglial cells exhibited inward rectifier K + currents upon membrane hyperpolarization, their mean current density was significantly enhanced in aged mice compared with that determined in young adult mice. Some microglial cells additionally exhibited outward rectifier K + currents in response to depolarizing voltage pulses. In aged mice, microglial outward rectifier K + current density was significantly larger than in young adult mice due to the increased number of aged microglial cells expressing these channels. Aged dystrophic microglia exhibited outward rectifier K + currents more frequently than aged ramified microglia. The majority of microglial cells expressed functional BK‐type, but not IK‐ or SK‐type, Ca 2+ ‐activated K + channels, while no differences were found in their expression levels between microglia of young adult and aged mice. Neither microglial K + channel pattern nor K + channel expression levels differed markedly between the three brain regions investigated. It is concluded that age‐related changes in microglial phenotype are accompanied by changes in the expression of microglial voltage‐activated, but not Ca 2+ ‐activated, K + channels. GLIA 2015;63:664–672