DIFFUSIBLE FACTORS FROM RAT ARCUATE NUCLEUS AND BROCA DIAGONAL BAND NUCLEUS INCREASE SIZE AND NEURITE OUTGROWTH, RESPECTIVELY, OF CULTURED MELANIN-CONCENTRATING HORMONE-CONTAINING NEURONS

Using a co-culture model, we showed that diffusible factors from arcua te nucleus (AN) specifically increased the number and the size of hypo thalamic neurons producing melanin-concentrating hormone (MCH). In thi s model neurite outgrowth and contacts between MCH neurons and dopamin ergic neurons were also prominently increased, as compared to control lateral areas of the posterior hypothalamus (LH) primary cultures. The se effects were mediated in part by AN glia but also by neurons of bot h fetal and adult AN. AN glia produced diffusible factor(s) mainly res ponsible for an important MCH neurite outgrowth and expressed inhibiti ng factors, preventing the adhesion of LH cells on AN glial cells. Fur thermore, we report here a nerve growth factor-like effect from Broca' s diagonal band on MCH hypothalamic neurons.