L-glutamate-stimulated taurine release from rat cerebral cultured astrocytes

✍ Scribed by Y. Koyama; T. Ishibashi; K. Tanaka; Dr. A. Baba

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 596 KB
• Volume: 38
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490380110

✦ Synopsis

Abstract

We characterized L‐glutamate‐stimulated taurine release from cultured astrocytes prepared from rat cerebrum. L‐glutamate (0.5 mM) stimulated release of ^3^H‐labeled and endogenous taurine, where the rate of release reached maximum in 40 min. L‐glutamate increased astrocytic volume [^3^H‐O‐methyl‐D‐glucose (^3^H‐OMG) space] with a similar time course to ^3^H‐taurine release. Quisqualate, L‐aspartate, DL‐homocysteate, and L‐cysteate increased both astrocytic ^3^H‐OMG space and ^3^H‐taurine release from cultured astrocytes, while kainate (1 mM) stimulated ^3^H‐taurine release without affecting astrocytic volume. N‐methyl‐D‐aspartate had no effect on ^3^H‐taurine release and astrocytic volume. Treatment of astrocytes with dibutyryl cAMP reduced the effect of kainate on ^3^H‐taurine release. L‐glutamate‐stimulated ^3^H‐taurine release was attenuated by removal of extracellular Cl^−^ and in hyperosmotic medium, which prevented L‐glutamate‐induced increase in ^3^H‐OMG space of cultured astrocytes. These results indicate that L‐glutamate stimulates taurine release from astrocytes through swelling‐triggered mechanisms and that kainate causes the release through volume‐independent mechanisms. © 1994 Wiley‐Liss, Inc.