Rat tooth pulp cells elicit neurite growth from trigeminal neurones and express mRNAs for neurotrophic factors in vitro.

Molecular factors control the developmental ingrowth of axons to the tooth pulp. Here we examine the ability of pulpal cells to induce neurite outgrowth from neonatal rat trigeminal neurones (TGNs) in vitro. We found that TGNs emitted neurites and formed networks of branches in relation to pulpal cells. Neurones co-cultured with a mixture of pulpal cells and 3T3 fibroblasts formed networks exclusively in relation to the pulpal cells. Cultivated pulpal cells and pulpal tissue produced mRNAs for all neurotrophins and members of the glial cell line-derived neurotrophic factor family. Hence, rat pulpal cells have neuritogenic effects on single TGNs in vitro, that may be associated with secretion of neurotrophic factors.