Association between cell swelling and glycogen content in cultured astrocytes

Treatment of cultured rat astrocytes with hypotonic media or with 1 mM glut amate for 90 min caused cell swelling and a significant increase in glycoge n content. Conversely, treatment with hypertonic media caused cell shrinkag e with a corresponding decrease in astrocyte glycogen, which was proportion al to the increasing osmolality of the hypertonic media. The glutamate rece ptor antagonist, MK-801, lowered both the glutamate-induced swelling and gl ycogen increase. These findings demonstrate a correlation between changes i n cell volume and astrocyte glycogen content. This may explain the increase d astrocytic glycogen observed in many neuropathological conditions where a strocyte swelling occurs. Because glycogen, represents the largest energy r eserve in the central nervous system, a swelling-induced disturbance in gly cogen metabolism may lead to abnormal glialneuronal interactions resulting in impaired brain bioenergetics. (C) 2000. Published by Elsevier Science Lt d. All rights reserved.