NERVE GROWTH-FACTOR PROMOTES NEURITE OUTGROWTH IN GUINEA-PIG MYENTERIC PLEXUS GANGLIA

Nerve growth factor (NGF) has important developmental actions in both central and peripheral nervous systems. Primary cultures of neonatal g uinea pig myenteric plexus ganglia were used to examine the ability of NGF to stimulate morphological development in enteric neurons. NGF, i n the presence of a serum-free medium, produced dose-dependent increas es in neurite density, significant at 1 ng/ml and maximal at 100 ng/ml (4.5-fold increase vs. control). Maximum neurite length was also sign ificantly increased at 1 ng/ml, with maximal effects at 100 ng/ml. Coi ncubation of NGF (50 ng/ml) with monoclonal NGF antibodies abolished i ncreases in both neurite density (128 +/- 19 processes/mm for control, 369 +/- 19 for NGF, 183 +/- 28 for NGF + monoclonal antibodies) and n eurite length. Exposure of enteric neurons to low concentrations of NG F (1 ng/ml) was also associated with increased mRNA levels for cytoske letal genes. alpha-Tubulin mRNA levels were increased 3.9 +/- 0.7 time s basal at 48 h. mRNA levels for microtubule-associated protein 2 were increased threefold at 48 h of NGF incubation. NGF demonstrates activ ities in cultured enteric ganglia that stimulate morphological develop ment.