SNAP25 and Parkinson disease: Similar results were observed for SNAP-25, and the increased phosphorylation of SNAP-25 at Ser187 induced by 1.2 mM 4-AP treatment (228.9 ± 45.9%; p < 0.05) was also reduced by the application of PD (89.7 ± 27.7%; p < 0.05).