Promotion and inhibition of neurite regeneration in cultured neurons

The majority of neurons belonging to the central nervous system of the mollusc Planorbarius corneus is capable of neurite regeneration in vitro only in presence of factors released from the periesophageal ganglionic ring. Even each individual ganglion produces unknown stimulating factors sufficient for a complete neurite regeneration. The percentage of neurons showing neurite regeneration is nearly the same independent of ganglionic type and it increases following a rise in the concentration of promoting factors. We identified by RIA an insulin -like molecule among the released substances. Adding antisera against molluscan insulin -like neuropeptides to the culture medium we obtained an almost complete inhibition of neurite regeneration when the factors are released by cerebral or pedal ganglia. No inhibition occurs if the neural factors are released by visceroparietal ganglia.