TRPC1 and Parkinson disease: A study in SH-SY5Y cells demonstrated that TRPC1 protein expression becomes down-regulated in these cells following incubation with salsolinol (Bollimuntha et al., 2006), a neurotoxin endogenously found in the nigrostriatal cells and cerebrospinal fluid samples of patients with PD (Moser et al., 1995; Maruyama et al., 1996).