Regarding the relationship between calcium channels and PD pathogenesis, SN DA neurons are reported to be autonomous pacemakers that fire action potentials in the absence of excitatory synaptic input; this pacemaker activity is mainly regulated by the L-type calcium channel CaV1.3, as revealed by an animal model (Surmeier et al., 2005). This evidence concerns the gene CACNA1D and Parkinson disease.