LESION-SPECIFIC PATTERN OF IMMUNOCYTOCHEMICAL DISTRIBUTION OF GROWTH-ASSOCIATED PROTEIN B-50 (GAP-43) IN THE CEREBELLUM OF WEAVER AND PCD-MUTANT MICE - LACK OF B-50 INVOLVEMENT IN NEUROPLASTICITY OF PURKINJE-CELL TERMINALS

The growth-associated protein B-50 (GAP-43) is thought to play a major role in the development and regeneration of neurons. The participatio n of B-50 in neuronal plasticity is well documented, especially for mo noaminergic systems, However, such an important role for B-50 in GABAe rgic systems has not been substantiated to date. This study was perfor med to obtain detailed information about the identity of B-50 immunopo sitive axons and terminals in the cerebellum and to test the involveme nt of this protein during plastic changes as observed in the projectio ns of GABAergic Purkinje cells to the lateral vestibular nucleus (LVN) . For this purpose mutant mice with specific cerebellar cell loss were used, Weaver mutants (B6CBA wv/wv), PCD-mutants (B6C3Fe pcd/pcd), and their corresponding wild-type mice were investigated with immunocytoc hemical and immunoblot procedures at the age of 8-23 days and 5-6 mont hs using polyclonal and monoclonal antibodies to B-50. Substantial dif ferences in B-50 distribution were detected between normals and mutant s and between young and adult animals. These results demonstrate that the labeling of B-50 is mainly related to the outgrowth of parallel fi bers and to a minor degree on the ingrowth of non-GABAergie cerebellar afferents. There was no immunocytochemical indication that B-50 is re lated to Purkinje cells or accompanies the plasticity of the GABAergic innervation of the LVN. (C) 1994 Wiley-Liss, Inc.