TRPC1 and Parkinson disease: In contrast to TRPC1 levels, TRPC3 levels are not altered in SNpc DA neurons in PD patients (Sun et al., 2017) although their levels are increased by the compensatory effect of decreased TRPC1 in 1-methyl-4-phenyl-1,2,3,6-tetrahyrdropyridine (MPTP)-induced PD-like conditions (Selvaraj et al., 2009).