CILIARY NEUROTROPHIC FACTOR ENHANCES THE SURVIVAL OF PURKINJE-CELLS IN-VITRO

We have examined the effects of ciliary neurotrophic factor (CNTF) on the development of rat Purkinje cells in vitro. Cerebellar cells, deri ved from embryonic day 16 rat fetuses, were found to respond rapidly t o CNTF treatment by induction of c-Fos protein, such that 40% of the c ells were immunopositive after 60 min. Treatment with low doses of CNT F (10 - 100 pg/ml) for 8 days resulted in an similar to 1.6-fold incre ase in the number of Purkinje cells, identified by immunohistochemical staining for calbindin. Immunohistochemical staining for other Purkin je cell markers-cyclic-GMP-dependent protein kinase and the low-affini ty nerve growth factor receptor-verified increased Purkinje cell survi val following CNTF treatment. in addition, CNTF increased specific hig h-affinity GABA uptake by 45%, and the number of GABAergic neurons by 70%. A maximal increase in the number of Purkinje cells and GABA-uptak e was only achieved if CNTF was added within 48 h of plating the cells , further suggesting that CNTF enhances Purkinje cell survival in vitr o. These results taken together strongly support a direct effect of CN TF in promoting the survival of Purkinje cells and possibly other GABA ergic cerebellar neurons.