Recently, we have identified two astrocytic subpopulations in the cortex of GFAP-EGFP mice, in which the astrocytes are visualized by the enhanced green-fluorescent protein (EGFP) under the control of the human glial fibrillary acidic protein (GFAP) promotor. These astrocytic subpopulations, termed high response- (HR-) and low response- (LR-) astrocytes, differed in the extent of their swelling during oxygen-glucose deprivation (OGD). In the present study we focused on identifying the ion channels or transporters that might underlie the different capabilities of these two astrocytic subpopulations to regulate their volume during OGD. Using three-dimensional confocal morphometry, which enables quantification of the total astrocytic volume, the effects of selected inhibitors of K⁺ and Cl⁻ channels/transporters or glutamate transporters on astrocyte volume changes were determined during 20 minute-OGD in situ. The inhibition of volume regulated anion channels (VRACs) and two-pore domain potassium channels (K(2P)) highlighted their distinct contributions to volume regulation in HR-/LR-astrocytes. While the inhibition of VRACs or K(2P) channels revealed their contribution to the swelling of HR-astrocytes, in LR-astrocytes they were both involved in anion/K⁺ effluxes. Additionally, the inhibition of Na⁺-K⁺-Cl⁻ co-transporters in HR-astrocytes led to a reduction of cell swelling, but it had no effect on LR-astrocyte volume. Moreover, employing real-time single-cell quantitative polymerase chain reaction (PCR), we characterized the expression profiles of EGFP-positive astrocytes with a focus on those ion channels and transporters participating in astrocyte swelling and volume regulation. The PCR data revealed the existence of two astrocytic subpopulations markedly differing in their gene expression levels for inwardly rectifying K⁺ channels (Kir4.1), K(2P) channels (TREK-1 and TWIK-1) and Cl⁻ channels (ClC2). Thus, we propose that the diverse volume changes displayed by cortical astrocytes during OGD mainly result from their distinct expression patterns of ClC2 and K(2P) channels.

• MeSH
• Astrocytes cytology   drug effects   metabolism   MeSH
• Models, Biological MeSH
• Chloride Channels metabolism   MeSH
• Potassium Channels metabolism   MeSH
• Glial Fibrillary Acidic Protein metabolism   MeSH
• Glucose deficiency   MeSH
• K Cl- Cotransporters MeSH
• Oxygen MeSH
• Humans MeSH
• Membrane Transport Modulators pharmacology   MeSH
• Cerebral Cortex cytology   MeSH
• Mice, Transgenic MeSH
• Mice MeSH
• Sex Characteristics MeSH
• Gene Expression Regulation drug effects   MeSH
• Sodium-Potassium-Chloride Symporters metabolism   MeSH
• Gene Expression Profiling MeSH
• Symporters metabolism   MeSH
• In Vitro Techniques MeSH
• Cell Size drug effects   MeSH
• Vesicular Glutamate Transport Proteins metabolism   MeSH
• Green Fluorescent Proteins metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Chloride Channels MeSH
• Potassium Channels MeSH
• enhanced green fluorescent protein MeSH Browser
• Glial Fibrillary Acidic Protein MeSH
• Glucose MeSH
• Oxygen MeSH
• Membrane Transport Modulators MeSH
• Sodium-Potassium-Chloride Symporters MeSH
• Symporters MeSH
• Vesicular Glutamate Transport Proteins MeSH
• Green Fluorescent Proteins MeSH