The project aims at obtaining an understanding of the extrinsic regulations, humoral and cellular, that apply to neural tissue during development and adult life. The objective will be pursued by the establishment and investigation of dissociated neural cell systems and cultures mimicking in vitro properties of the source tissues and yet readily susceptible to experimental manipulation. Source tissues will be mainly dorsal root and sympathetic ganglia and spinal cord from embryonic chick and newborn rodent. Particularly investigated will be the role of glia cells in supporting metabolic and culture performances of homologous and heterologous neurons and the similarities between the support provided by glial cell and by mouse submaxillary nerve Growth Factor. Biochemical and metabolic alterations induced by Nerve Growth Factor in ganglionic cells will be studied in detail toward an elucidation of its mechanism of action.