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Analysis of ion channel expression by astrocytes in red nucleus brain stem slices of the rat
Author(s) -
Akopian Garnik,
Kuprijanova Elena,
Kressin Klaus,
Steinhäuser Christian
Publication year - 1997
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/(sici)1098-1136(199703)19:3<234::aid-glia6>3.0.co;2-z
Subject(s) - biology , kainate receptor , ampa receptor , glutamate receptor , neuroscience , patch clamp , neuroglia , depolarization , astrocyte , ion channel , microbiology and biotechnology , receptor , biophysics , electrophysiology , biochemistry , central nervous system
The red nucleus (RN) has been widely used to study the formation and remodeling of synaptic connections during development and in post‐lesion plasticity. Since glial cells are thought to contribute to synaptic plasticity, and information on functional properties of brain stem glia is missing, we analyzed voltage‐gated ion channels as well as glutamate receptors expressed by glial cells of the RN. The patch‐clamp technique was applied to identified cells in acute brain stem slices of 5‐ to 12‐day‐old rats. Based on their pattern of membrane currents, two types of glial cells could be distinguished. A first type was characterized by passive, symmetrical currents. The second population of cells, which was the focus of the present study, expressed a complex pattern of voltage‐gated channels. These cells could be labeled with antibodies against glutamine synthetase and S100β, suggesting an astroglial origin. Depolarizing voltage steps activated transient and delayed rectified K + currents as well as Na + currents. In addition, a subset of cells expressed Ba 2+ sensitive inward rectifier K − currents activated by hyperpolarization. All “complex” glial cells analyzed possessed ionotropic glutamate receptors of the α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazoleprorionic acid (AMPA) subtype, while functional kainate and N‐methyl‐D‐aspartate (NMDA) receptors could not be detected. Receptor activation blocked outward rectifying K + currents, similar to previous observations in glial cells of the hippocampus and the corpus callosum. GLIA 19:234–246, 1997. © 1997 Wiley‐Liss, Inc.