MOTOR DISCOORDINATION AND INCREASED SUSCEPTIBILITY TO CEREBELLAR INJURY IN GLAST MUTANT MICE

To study the function of GLAST, a glutamate transporter highly express ed in the cerebellar Bergmann astrocytes, the mouse GLAST gene was ina ctivated, GLAST-deficient mice developed normally and could manage sim ple coordinated tasks, such as staying on a stationary or a slowly rot ating rod, but failed more challenging task such as staying on a quick ly rotating rod. Electrophysiological examination revealed that Purkin je cells in the mutant mice remained to be multiply innervated by clim bing fibres even at the adult stage, We also found that oedema volumes in the mutant mice increased significantly after cerebellar injury, T hese results indicate that GLAST plays active roles both in the cerebe llar climbing fibre synapse formation and in preventing excitotoxic ce rebellar damage after acute brain injury.