[Action of cyclic N6-monobutyryladenosine-3':5'-monophosphate (mb-cAMP) on cell on cell and explant cultures of the PNS and CNS in vitro].

Chick embryo trigeminal ganglia of nine days and hippocampus excised from fetal rats between the sixteenth and eighteenth day of gestation were cultivated in cell- and explantcultures in Maximow-chambers. The cultures were placed in a medium containing 2 mM, 1 mM, 0.2 mM or 0.02 mM cyclic N6-Monobutyryladenosin-3':5'-monophosphat (mb-cAMP). The cultures of the PNS, the trigeminal ganglai show after 48 h by 1 mM mb-cAMP longer nerve fibers and a increased nerve fiber index. Smaller concentration did not change significant nerve fiber growth. Cell- and explantcultures of the hippocampus show a stimulation of the nerve fiber growth and the nerve fiberindex by concentration of 0.02 mM mb-cAMP. After ten days in vitro the nerve cells degenerated by higher concentrations.