Identification of mouse type-2-like astrocytes: demonstration of glutamate and GABA transmitter activated responses.
We have identified mouse type-2-like astrocytes and examined some of their electrophysiological properties. Cultures were prepared from P4 mouse neopallia. We demonstrate that mouse type-2-like astrocytes can be identified using the following criteria: presence of glial fibrillary acidic protein (GFAP), presence of chondroitin sulfate polysaccharide, and presence of gamma-aminobutyric acid (GABA). A2B5-binding is not a sufficient criterion to identify O2A lineage cells in mouse neopallial glial cultures since the monoclonal antibody A2B5 binds not only to O2A lineage cells but also to a subpopulation of large, flat type-1-like astrocytes. Mouse type-2-like astrocytes have resting membrane potentials of -76.2 +/- 2.1 mV-i.e., similar to that of mouse type-1-like astrocytes. The input resistance of 44.2 +/- 0.5 M omega is an order of magnitude greater than that of type-1-like astrocytes suggesting the type-2-like astrocytes are not extensively electrically coupled either to each other or to type-1-like astrocytes. Glutamate application caused an 8.8 +/- 1.7 mV depolarization of type-2-like astrocytes. Application of glutamate to barium treated astrocytes caused a fast depolarization with a peak amplitude of 21.4 +/- 1.8 mV; the cells repolarized from this peak by about 10 mV and upon removal of glutamate returned to its pre-glutamate value. Application of GABA caused a transient depolarization of 14.0 +/- 1.7 mV. The presence of barium resulted in a steady-state GABA-induced depolarization of 10.3 +/- 2.0 mV. Neither SITS nor beta-alanine interfered with the amplitude of the glutamate and GABA responses.
Department of Physiology, University of Saskatchewan, Saskatoon, Canada.
N S
NS
Magoski
W
W
Walz
B H
BH
Juurlink
D000818:Animals; D000917:Antibody Formation; D001253:Astrocytes / Q000378:metabolism*; D002478:Cells, Cultured; D004594:Electrophysiology; D005904:Glial Fibrillary Acidic Protein / Q000276:immunology / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism*; D018698:Glutamic Acid; D007150:Immunohistochemistry; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005904:Glial Fibrillary Acidic Protein; D005971:Glutamates; D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid