CHANGES IN GLIAL FIBRILLARY ACIDIC PROTEIN IMMUNOREACTIVITY IN THE RAT FACIAL NUCLEUS FOLLOWING VARIOUS TYPES OF NERVE LESIONS

We report about changes on astrocytes in the facial nucleus of the rat following various types of peripheral nerve lesions. Astrocyte-specif ic glial fibrillary acidic protein (GFAP) was labeled by immunohistoch emistry and served as a marker for these changes. Increased GFAP immun oreactivity was found in the facial nucleus on the lesioned side withi n 2-3 days after axotomy. This change lasted longer (up to 1 year) whe n axon regeneration was prevented or delayed by placing a metal clip o n the proximal nerve stump. Lesion of the trigeminal nerve prior to ax otomy reduced the degree of GFAP immunoreactivity. No side differences were observed after botulinum toxin application.