Ionic mechanisms in glutamate-induced astrocyte swelling: Role of K+ influx

✍ Scribed by Alex S. Bender; Arne Schousboe; Winfried Reichelt; Michael D. Norenberg

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 434 KB
• Volume: 52
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/(sici)1097-4547(19980501)52:3<307::aid-jnr7>3.0.co;2-h

✦ Synopsis

L-Glutamate (L-GLU) induced astrocyte swelling in a time-and concentration-dependent, as well as Na ؉and Ca 2؉ -dependent, and Cl --independent manner. Swelling was prevented by MK-801, cystine, and ouabain. Since L-GLU swelling is ionically dependent, we determined the role of various ions in such swelling. Our results indicate that K ؉ uptake plays a major role in the mechanism of L-GLU-induced astrocyte swelling. Like swelling, K ؉ uptake is dependent on Ca 2؉ and Na ؉ , but not on Cl -. Likewise, K ؉ uptake was inhibited by MK-801, cystine, and ouabain. The K ؉ channel blockers, Ba 2؉ and tetraethylammonium, partially prevented L-GLU-induced swelling. In addition to K ؉ channels, K ؉ influx may also be mediated through Na ؉ /K ؉ -ATPase, as its activity is increased by L-GLU uptake along with the required Na ؉ . Taken together, the data suggest that K ؉ influx plays a key role in the mechanism of L-GLU-mediated astrocyte swelling.