Salsolinol　(1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline),　the　endogenous　dopamine-derived　catechol　isoquinolines　whose　structure　is　similar　with　MPTP　(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine),　may　be　a　possible　candidate　of　dopaminergic　neurotoxins　to　elicit　Parkinson＇s　disease　(PD).　Catechol　isoquinolines　can　selectively　target　dopaminergic　neurons,　leading　to　dopaminergic　neuronal　death.　However,　the　formation　and　nosogenesis　of　these　toxins　remains　unclear.　Salsolinol　synthase　is　a　novel　enzyme　which　condensate　dopamine　and　acetaldehyde　to　salsolinol.　It　is　the　first　key　enzyme　in　the　metabolic　pathway　of　catechol　isoquinolines　which　directly　affects　salsolinol　and　its　derivative　metabolism　in　vivo.　It　is　also　one　kind　of　Pictet-Spenglerase,　which　has　been　little　studied　and　need　more　characterization.　PC12　cells　and　rat　brains　were　performed　to　illustrate　the　existence　of　salsolinol　synthase　in　our　study.　The　results　indicate　that　salsolinol　synthase　is　a　low　molecular　weight　protein,　showing　enhanced　activity　with　increase　in　dopamine　concentration.　It　is　suggested　that　salsolinol　synthase　is　sensitive　to　strong　acid　and　stable　to　high-temperature.　In　this　research,　existence　of　salsolinol　synthase　was　confirmed　in　vivo,　and　also　provided　some　new　evidences　to　elucidate　the　endogenous　catechol　isoquinoline　neurotoxin　substances　involved　in　the　pathogenesis　of　PD.