PENTOBARBITAL INDUCES FOS IN ASTROCYTES - INCREASED EXPRESSION FOLLOWING PICROTOXIN AND SEIZURES

Fos immunoreactivity was observed in astrocytes identified by immunore activity to glial fibrillary acidic protein, 1.5 h following intraveno us pentobarbitone anesthesia (20-30 mg/kg). Fos-positive astrocytes we re seen only in the hilus of the hippocampus. Pentobarbitone administe red after picrotoxin but without seizures resulted in an increase in b oth the intensity of Fos labeling and areal distribution of Fos-positi ve hilar astrocytes. Pentobarbitone administered after single picrotox in-induced seizures resulted in an increased number of Fos immunoreact ive astrocytes in the hilus and other hippocampal regions and their pr esence in the upper layers of Fr1, Fr2, cingulate, visual, and perirhi nal cortex, Our observations that Fos is expressed in astrocytes follo wing pentobarbitone, provides support for the current view that glial cell processes can be activated by pentobarbitone stimulation of GABA( a) receptor-chloride channels. (C) 1996 Academic Press, Inc.