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Updated: Sep 3, 2026

Measuring Near Plasma Membrane and Global Intracellular Calcium Dynamics in Astrocytes
Published on: April 27, 2009
Volume regulation in astrocytes: a role for taurine as an osmoeffector
H Pasantes Morales1, A Schousboe
1Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F.
Abstract:
Astrocytes in culture regulate their volume under anisosmotic conditions by as yet unclear mechanisms. In a number of other cells this process involves a loss of intracellular osmotically active solutes, including taurine. The possibility that taurine participates as an osmoeffector in astrocytes was examined in cultured astrocytes exposed to hyposmolar conditions. Astrocytes responded to decreases in osmolarity by rapid swelling followed by a volume regulatory phase. Hyposmotic conditions induced a dramatic increase of 3H-taurine efflux, with a time course corresponding to the cell volume regulatory phase. Decreasing osmolarity from 310 to 254, 198 or 150 m osmoles resulted in the release of 8.2%, 17%, and 54%, respectively, of 3H-taurine previously accumulated by astrocytes. Endogenous taurine concentration decreased 64%. The efflux of 3-H GABA, 3H-glycine, or 3H-D-aspartate was much less affected under similar conditions. These results suggest a role for taurine as an osmoeffector in astrocytes.
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