CILIARY NEUROTROPHIC FACTOR, UNLIKE NERVE GROWTH-FACTOR, SUPPORTS NEURITE OUTGROWTH BUT NOT SYNAPSE FORMATION BY ADULT LYMNAEA NEURONS

The nerve growth factor (NGF) family and ciliary neurotrophic factor ( CNTF) support survival and/or neurite outgrowth of many cell types, Ho wever, it is not known whether the neurite outgrowth induced by neurot rophic factors results in the formation of synapses, We tested NGF and CNTF for their ability to induce neurite outgrowth and synapse format ion in vitro by interneurons from the mollusc Lymnaea, Dopaminergic an d peptidergic interneurons survived in the absence of neurotrophic fac tors but exhibited robust outgrowth in response to both NGF and CNTF. Chemical synapses formed between these interneurons and their target n eurons cultured in NGF, but synapses were absent in CNTF, Survival, ne urite outgrowth, and synaptogenesis are therefore differentially regul ated in these neurons. (C) 1996 John Wiley & Sons, Inc.