Reactive astrocytes show enhanced inwardly rectifying K+ currents in situ

Injury and diseases of the nervous system can induce astrocytes to form ten acious glial scars. We induced focal cortical freeze-lesions in neonatal ra ts and examined scars histologically and electrophysiologically in tissue s lices isolated 2-3 weeks after lesioning. Lesions displayed marked gliosis, characterized by upregulation of GFAP labeling. Reactive astrocytes surrou nding the scar showed marked hypertrophy, enlarged cell bodies and extended processes frequently terminating with endfeet-like structures on blood ves sels. These reactive astrocytes showed enhanced expression of inwardly rect ifying K+ (K-IR) channels, widely believed to be an important pathway for a strocytic K+ buffering. These results suggest that a subpopulation of react ive astrocytes along a glial scar might be instrumental in buffering K+ awa y from the lesion. NeuroReport 11:3151-3155 (C) 2000 Lippincott Williams & Wilkins.