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Morphological, immunophenotypical and electrophysiological properties of resting microglia in vitro
Author(s) -
Eder Claudia,
Schilling Tom,
Heinemann Uwe,
Haas Dorit,
Hailer Nils,
Nitsch Robert
Publication year - 1999
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.1999.00852.x
Subject(s) - microglia , astrocyte , biology , major histocompatibility complex , microbiology and biotechnology , integrin alpha m , antigen , downregulation and upregulation , electrophysiology , immunology , chemistry , pathology , neuroscience , central nervous system , inflammation , immune system , biochemistry , medicine , gene
Morphological, immunophenotypical and electrophysiological properties were investigated in isolated cultured murine microglia before and after exposure to astrocyte‐conditioned medium (ACM). Following application of ACM, microglial cells underwent a dramatic shape transformation from an amoeboid appearance to a ramified morphology. In parallel to morphological changes, a downregulation of macrophage surface antigens was observed in microglia exposed to ACM. Staining intensities for major histocompatibility complex (MHC) class II molecules and for the adhesion molecules leukocyte function‐associated antigen‐1 (LFA‐1) and intercellular adhesion molecule‐1 (ICAM‐1) were significantly decreased in ramified microglia 5 days after exposure to ACM. In microglial cells treated daily with ACM over a period of 5 days, the smallest staining intensities for all surface antigens as well as the smallest ramification index as a measure for the highest degree of ramification were determined. In addition, upregulation of delayed rectifier K + currents was observed in microglia exposed to ACM for 1 day or treated daily with ACM for 5 days. In contrast, untreated amoeboid microglia or ramified microglia analysed 5 days after exposure to ACM did not express delayed rectifier K + currents. Analyses of the resting membrane potential and expression levels and properties of inward rectifier K + currents did not reveal any differences between untreated and ACM‐treated microglia. It is suggested that electrophysiological properties of microglia do not strongly correlate with the morphology or the immunophenotype of microglial cells.