ASTROCYTIC GAP-JUNCTIONS REMAIN OPEN DURING ISCHEMIC CONDITIONS

Gap junctions are highly conductive channels that allow the direct tra nsfer of intracellular messengers such as Ca2+ and inositol triphospha te (IP3) between interconnected cells, In brain, astrocytes are couple d extensively by gap junctions. We found here that gap junctions among astrocytes in acutely prepared brain slices as well as in culture rem ained open during ischemic conditions, Uncoupling first occurred after the terminal loss of plasma membrane integrity. Gap junctions therefo re may link ischemic astrocytes in an evolving infarct with the surrou ndings. The free exchange of intracellular messengers between dying an d potentially viable astrocytes might contribute to secondary expansio n of ischemic lesions.