GLIAL Bfgf AND S100 IMMUNOREACTIVITIES INCREASE IN ASCENDING DOPAMINE PATHWAYS FOLLOWING STRIATAL 6-OHDA-INDUCED PARTIAL LESION OF THE NIGROSTRIATAL SYSTEM: A STEROLOGICAL ANALYSIS

S100, a calcium-binding protein, and basic fibroblast growth factor (bFGF, FGF-2) are found predominantly in astrocytes in the central nervous system. Those molecules show trophic properties to neurons and are upregulated after brain lesions. The present study investigated the changes in the S100b and bFGF immunoreactivities after a partial lesion of the rat midbrain ascending dopamine pathways induced by intrastriatal injection of 6-hydroxydopamine (6-OHDA). Stereological method revealed increases in the estimated total number and density of bFGF immunoreactive astroglial profiles in the ipsilateral pars compacta of the substantia nigra (SNc) and ventral tegmental area (VTA). Increases in the counts of astroglial S100b immunoreactive profiles were found in the striatum, SNc, and VTA mainly ipsilateral but also in the contralateral nuclei. These results open up the possibility that interactions between astroglial S100b and bFGF may be relevant to paracrine events related to repair and maintenance of remaining dopamine neurons following striatal 6-OHDA induced partial lesion of ascending midbrain dopamine pathway.