My labortory studies the role of target-derived factors in the development of neurons and synapses in the peripheral nervous system. The neurotrophins are a well known class of proteins that promote neuronal differentiation and survival. We have determined an additional role for the neurotrophin nerve growth factor (NGF) in the formation and function of synaptic connections between sympathetic neurons and their peripheral targets. We are investigating the molecular and cellular pathways by which NGF and additional target-derived factors determine the number and strength of sympathetic synapses.