The influence of nerve growth factor, potassium depolarization and dibutyryl (cyclic) adenosine 3',5'-monophosphate on explant cultures of chick embryo sympathetic ganglia.

Optimal nerve growth factor (NGF) and potassium concentrations for the culture of explants of single chick embryo sympathetic ganglia in Leighton tubes are described. NGF increases ganglionic monoamine oxidase (MAO; E.C.1.4.3.4) activity in a dose dependent fashion with maximum effects at a concentration of about 8 U/ml NGF. Peak activity compares closely with values seen in chick ganglia in vivo. Potassium-induced depolarization (45 mM K-+) also increases MAO activity; but the extent of the increase depends upon (NGF concentration, for there is little or no increase at high NGF concentrations. Dibutyryl adenosine 3',5'-cyclic monophosphoric acid (db cyclic AMP) can mimic the potassium-induced increase in MAO.