Na⁺ and K⁺ Dependence of L-Glutamate-Induced Suppression of Astrocyte Stellation in Culture

Abstract

We have recently found that L-glutamate suppresses astrocyte stellation induced by various stimuli, and that this effect of L-glutamate is mimicked by transportable glutamate uptake inhibitors. To test the possible role of the glutamate transporter in the regulation of astrocyte morphology, we investigated the Na⁺ and K⁺ dependence of this effect of L-glutamate. In astrocyte cultures obtained from the cerebral cortex of neonatal rats, the L-glutamate-induced suppression of astrocyte stellation was significantly attenuated in a low-Na⁺/high-K⁺ medium and by the Na⁺-K⁺ pump inhibitor ouabain. These results support that astrocyte morphology is affected by the activity of the Na⁺-dependent glutamate transporter.