An electrophysiological study on the effects of BDNF and FGF2 on voltage dependent Ca(2+) currents in developing human striatal primordium.

Over the past decades, studies in both Huntington's disease animal models and pilot clinical trials have demonstrated that replacement of degenerated striatum and repair of circuitries by grafting fetal striatal primordium is feasible, safe and may counteract disease progression. However, a better comprehension of striatal ontogenesis is required to assess the fetal graft regenerative potential. During neuronal development, neurotrophins exert pleiotropic actions in regulating cell fate and synaptic plasticity. In this regard, brain-derived neurotrophic factor (BDNF) and fibroblast growth factor 2 (FGF2) are crucially implicated in the control of fate choice of striatal progenitor cells. In this study, we intended to refine the functional features of human striatal precursor (HSP) cells isolated from ganglionic eminence of 9-12week old human fetuses, by studying with electrophysiological methods the effect of BDNF and FGF2 on the membrane biophysical properties and the voltage-dependent Ca(2+) currents. These features are particularly relevant to evaluate neuronal cell functioning and can be considered reliable markers of the developmental phenotype of human striatal primordium. Our results have demonstrated that BDNF and FGF2 induced membrane hyperpolarization, increased the membrane capacitance and reduced the resting total and specific conductance values, suggesting a more efficient control of resting ionic fluxes. Moreover, the treatment with both neurotrophins enhanced N-type Ca(2+) current amplitude and reduced L- and T-type ones. Overall, our data indicate that BDNF and FGF2 may help HSP cells to attain a more functionally mature phenotype.