(-)-Stepholidine promotes proliferation and neuronal differentiation of rat embryonic striatal precursor cells in vitro

The present study investigated the influence of (-)-stepholidine, an effective dopamine D-1 receptor agonist and D-2 receptor antagonist, on the development of neural precursor cells. Incubation of striatal neural precursor cells with stepholidine resulted in significant increase in the number of proliferating precursor cell spheres when in the presence of fibroblast growth factor-2. This action can be blocked by application of haloperidol. Treatment with stepholidine also increased the number of microtubule-associated protein-2-immunoreactive cells in the cultures and promoted marked increases in tyrosine hydroxylase expression. These findings suggest that stepholidine is involved in the regulation of proliferation of precursor cells. The effect appears to be mediated by dopamine receptors. Stepholidine also promotes the differentiation of precursor cells, however, this action may be independent of its effect on dopaminergic receptors.