The cellular localization of glutamate-aspartate transporter (GLAST) mRNA expression within the rat facial nucleus was investigated with the aid of in situ hybridization. Hybridization signals for GLAST mRNA were almost undetectable in the facial nucleus of sham-operated animals. However the signals were seen 3 days sfter transection of the facial nerve in the nucleus of the affected side. These signals intensified at 1 or 2 weeks and lasted at least 5 weeks. Microautoradiograms showed that non-neuronal cells in the facial nucleus expressed signals of GLAST mRNA on the side of the injury. These findings suggest that GLAST can be expressed in astrocytes in the facial nucleus, and that GLAST may enhance the removal of extracellular glutamate and thus reduce the vulnerability of damaged neurons of the facial nucleus.