[K(+)](e) increase accompanies many pathological states in the CNS and evokes changes in astrocyte morphology and glial fibrillary acidic protein expression, leading to astrogliosis. Changes in the electrophysiological properties and volume regulation of astrocytes during the early stages of astrocytic activation were studied using the patch-clamp technique in spinal cords from 10-day-old rats after incubation in 50 mM K(+). In complex astrocytes, incubation in high K(+) caused depolarization, an input resistance increase, a decrease in membrane capacitance, and an increase in the current densities (CDs) of voltage-dependent K(+) and Na(+) currents. In passive astrocytes, the reversal potential shifted to more positive values and CDs decreased. No changes were observed in astrocyte precursors. Under hypotonic stress, astrocytes in spinal cords pre-exposed to high K(+) revealed a decreased K(+) accumulation around the cell membrane after a depolarizing prepulse, suggesting altered volume regulation. 3D confocal morphometry and the direct visualization of astrocytes in enhanced green fluorescent protein/glial fibrillary acidic protein mice showed a smaller degree of cell swelling in spinal cords pre-exposed to high K(+) compared to controls. We conclude that exposure to high K(+), an early event leading to astrogliosis, caused not only morphological changes in astrocytes but also changes in their membrane properties and cell volume regulation.

• MeSH
• Astrocytes physiology   MeSH
• Potassium pharmacokinetics   MeSH
• Potassium Channels, Voltage-Gated physiology   MeSH
• Glial Fibrillary Acidic Protein metabolism   MeSH
• Gliosis physiopathology   MeSH
• Hypotonic Solutions pharmacology   MeSH
• Immunohistochemistry MeSH
• Hydrogen-Ion Concentration MeSH
• Rats MeSH
• Membrane Potentials drug effects   physiology   MeSH
• Patch-Clamp Techniques MeSH
• Spinal Cord cytology   MeSH
• Osmotic Pressure MeSH
• Rats, Wistar MeSH
• Sodium metabolism   MeSH
• Sodium Channels physiology   MeSH
• Cell Size MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Potassium MeSH
• Potassium Channels, Voltage-Gated MeSH
• Glial Fibrillary Acidic Protein MeSH
• Hypotonic Solutions MeSH
• Sodium MeSH
• Sodium Channels MeSH