Analysis of ion channel expression by astrocytes in red nucleus brain stem slices of the rat
✍ Scribed by Garnik Akopian; Elena Kuprijanova; Klaus Kressin; Christian Steinhäuser
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 200 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0894-1491
No coin nor oath required. For personal study only.
✦ Synopsis
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 S100b, suggesting an astroglial origin. Depolarizing voltage steps activated transient and delayed rectifier K 1 currents as well as Na 1 currents. In addition, a subset of cells expressed Ba 21 sensitive inward rectifier K 1 currents activated by hyperpolarization. All ''complex'' glial cells analyzed possessed ionotropic glutamate receptors of the a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) subtype, while functional kainate and N-methyl-D-aspartate (NMDA) receptors could not be detected. Receptor activation blocked outward rectifying K 1 currents, similar to previous observations in glial cells of the hippocampus and the corpus callosum.