CACNA1D and Parkinson disease: However, it is unknown whether the kinase can regulate the activity of other CaV channel subtypes, such as CaV1.3 (L-type), which play a significant role in the excitability of dopaminergic neurons in the substantia nigra pars compacta (SNc) and whose dysregulation contributes to neurodegeneration in Parkinson’s disease (PD).