Immunohistochemical demonstration of expression of tyrosine hydroxylase in cerebellar Purkinje cells of the human and mouse.

We demonstrated the expression of tyrosine hydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT) in cerebellar Purkinje cells of human and mouse brains by immunohistochemistry. At the age of 8 months, vermal Purkinje cells in the human cerebellum were immunoreactive with anti-TH or anti-human specific PNMT antiserum. We also found TH-positive Purkinje cells in the mouse brain. TH immunoreactivity first appeared in the Purkinje cells in the caudal vermis from postnatal day 8 (P8), and enlarged numbers between P13 and P15. After gradual reduction to P19, the TH-positive Purkinje cells again multiplied the number from the age of 4 weeks, and maintained in a large number up to old stage. At the age of 11 months, the other groups of TH-positive Purkinje cells appeared in the flocculus and paraflocculus of the mouse cerebellum.