Does tyrosinase exist in neuromelanin-pigmented neurons in the human substantia nigra?

doi:10.1016/S0304-3940(98)00649-1

Neuroscience Letters

Volume 253, Issue 3, 3 September 1998, Pages 198-200

https://doi.org/10.1016/S0304-3940(98)00649-1 Get rights and content

Abstract

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.

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Acknowledgements

This study was supported by a Grant-in-Aid for Scientific Research on Priority Areas, Ministry of Education, Science, Sports and Culture of Japan to K.I., I.N., A.N. and T.N.

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Although hyperpigmentation diseases such as freckles, melasma, post-inflammatory melanoderma and age spots are not fatal, they have a giant impact on the psychology and quality of life in patients [9,66]. In addition, studies have shown that tyrosinase is also involved in the neuromelanin synthesis in the substantia nigra (SN) of the brain, which has neuroprotective effects by eliminating potential neurotoxic substances like dopaquinone [67–69]. To some extent, tyrosinase is related to Alzheimer's disease and Parkinson's disease (PD), [70].
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Does tyrosinase exist in neuromelanin-pigmented neurons in the human substantia nigra?

Abstract

Section snippets

Acknowledgements

Biochim. Biophys. Acta

Neurosci. Lett.

Neurosci. Lett.

Mol. Brain Res.

Mol. Brain Res.

Extra-cutaneous melanin

Pigment Cell Res.

Generation of reactive oxygen species by tyrosine hydroxylase: a possible contribution to the degeneration of dopaminergic neurons?

J. Neurochem.