Differential effects of granule cell transplantation on two sprouted axonal systems in granuloprival coeruleocerebellar cultures.

Exposure of coeruleocerebellar cultures to cytosine arabinoside for the first 5 days in vitro destroyed granule cells and induced sprouting of cortical neurites (Purkinje cell recurrent axon collaterals) and catecholaminergic fibers. Transplantation of such granuloprival cultures with kainic acid-treated cerebellar explants as a source of granule cells resulted in a reduction of silver-positive cortical neurites, but not of histofluorescent catecholaminergic axons. Tissue levels of catecholamines were similar in transplanted and nontransplanted cultures. Differences in types of contacts made with target Purkinje cells in vitro may account for the difference in response to granule cell transplantation by the two axonal groups.