Does tyrosinase exist in neuromelanin-pigmented neurons in the human substantia nigra?
It is controversial whether tyrosinase is involved in the neuromelanin-biosynthetic pathway. We examined tyrosinase-immunoreactivity in human substantia nigra neurons which contain neuromelanin pigments, using antibodies against human tyrosinase and human tyrosine hydroxylase. In human melanoma, the antibody to tyrosinase showed intense immunoreactivity while there was no immunoreactivity with antibody to tyrosine hydroxylase. In the human midbrain pigmented neurons, however, we could detect no tyrosinase-immunoreactivity while the neurons were strongly immunoreactive to tyrosine hydroxylase. The present results suggest that tyrosinase is not involved in the main pathway of neuromelanin biosynthesis.
Ikemoto
K
K
Department of Anatomy, Fujita Health University, School of Medicine, Toyoake, Japan. kikemoto@fujita-hu.ac.jp
Nagatsu
I
I
Ito
S
S
King
R A
RA
Nishimura
A
A
Nagatsu
T
T
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008543:Melanins / Q000032:analysis; D008545:Melanoma / Q000737:chemistry / Q000473:pathology; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000032:analysis*; D009474:Neurons / Q000737:chemistry* / Q000166:cytology; D010858:Pigmentation; D013378:Substantia Nigra / Q000737:chemistry* / Q000166:cytology*; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D008543:Melanins; C014121:neuromelanin; D014446:Tyrosine 3-Monooxygenase; D014442:Monophenol Monooxygenase