Salsolinol　is　an　endogenous　neurotoxin　derived　from　dopamine,　and　has　been　proved　to　cause　the　apoptosis　of　the　dopaminergic　neurons　involved　in　the　pathogenesis　of　Parkinson＇s　disease　(PD).　Salsolinol　synthase　is　the　key　enzyme　in　the　biosynthesis　of　salsolinol,　and　its　activity　exists　in　most　regions　of　rat　brain.　However,　the　activity　distribution　and　its　catalyzed　function　in　vivo　are　still　unknown.　On　the　basis　of　the　chromatographic　assay　established　previously,　we　investigated　the　activity　of　salsolinol　synthase　and　salsolinol　production　in　both　cell　and　rat　model　of　PD　induced　by　6-hydroxydopamine　(6-OHDA).　The　results　show　that　the　enzymatic　activity　increases　in　cell　model　and　in　the　striatum　region　of　PD　rat　brain.　Nevertheless,　there　is　a　reduction　of　activity　in　hippocampus,　cortex,　and　midbrain　of　PD　model　when　compared　with　control.　Conversely,　the　level　of　salsolinol　was　significantly　increased　in　the　midbrain　region.　Together,　these　results　indicate　the　relationship　between　the　oxidative　stress　induced　by　6-OHDA　and　the　activity　of　salsolinol　synthase,　suggesting　the　correlation　of　the　endogenous　neurotoxin　and　Parkinson＇s　disease.　Further　research　will　provide　more　evidence　and　clarity　on　the　function　of　Sal　synthase.