This hypothesis is further supported by the finding that NCX3, apart from its expression at the plasma membrane level, is also detectable on the outer mitochondrial level, where it plays a role in the regulation of mitochondrial calcium efflux in physiological and in pathological conditions such as ischemia and PD [10,31,41,42], and that NCX1 activation represents a neuroprotective mechanism in ischemic conditions [43,44]. This evidence concerns the gene SLC8A3 and Parkinson disease.