ASTROCYTE PROLIFERATION IN CULTURE FOLLOWING EXPOSURE TO POTASSIUM-ION

FOLLOWING brain injury astrocytes swell acutely and proliferate therea fter. To investigate the direct relationship between swelling and prol iferation, cultured astroglial cells were exposed to 60 mM K+ ion or h ypo-osmolar (205 mOsm) electrolyte solution for 1 h to cause transient swelling. Proliferation was assessed by bromodeoxyuridine (BrdU) upta ke 24 and 96 h later. The cells were double-labelled with antibodies t o glial fibrillary acidic protein (GFAP) and BrdU. At 96 h the GFAP im munoreactive cells exposed to K+ exhibited 44.9% uptake versus 27.0% a nd 21.1% for control and hypo-osmolar exposed cells, respectively. We conclude that swelling of astroglia in vitro does not induce cell prol iferation but transient depolarization following exposure to high K+ d oes induce