Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson’s Disease

Stefania Romeo; Daniela Di Camillo; Alessandra Splendiani; Marta Capannolo; Cristina Rocchi; Gabriella Aloisi; Irene Fasciani; Giovanni U. Corsini; Eugenio Scarnati; Luca Lozzi; Roberto Maggio

doi:10.1155/2014/317879

The Scientific World Journal (Jan 2014)

Eyes as Gateways for Environmental Light to the Substantia Nigra: Relevance in Parkinson’s Disease

Stefania Romeo,
Daniela Di Camillo,
Alessandra Splendiani,
Marta Capannolo,
Cristina Rocchi,
Gabriella Aloisi,
Irene Fasciani,
Giovanni U. Corsini,
Eugenio Scarnati,
Luca Lozzi,
Roberto Maggio

Affiliations

Stefania Romeo: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Daniela Di Camillo: Department of Physical and Chemical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
Alessandra Splendiani: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Marta Capannolo: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Cristina Rocchi: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Gabriella Aloisi: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Irene Fasciani: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Giovanni U. Corsini: Department of Translational Research and New Technology in Medicine, University of Pisa, 56126 Pisa, Italy
Eugenio Scarnati: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy
Luca Lozzi: Department of Physical and Chemical Sciences, University of L’Aquila, 67100 L’Aquila, Italy
Roberto Maggio: Biotechnological and Applied Clinical Sciences Department, University of L’Aquila, 67100 L’Aquila, Italy

DOI: https://doi.org/10.1155/2014/317879
Journal volume & issue: Vol. 2014

Abstract

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Recent data indicates that prolonged bright light exposure of rats induces production of neuromelanin and reduction of tyrosine hydroxylase positive neurons in the substantia nigra. This effect was the result of direct light reaching the substantia nigra and not due to alteration of circadian rhythms. Here, we measured the spectrum of light reaching the substantia nigra in rats and analysed the pathway that light may take to reach this deep brain structure in humans. Wavelength range and light intensity, emitted from a fluorescent tube, were measured, using a stereotaxically implanted optical fibre in the rat mesencephalon. The hypothetical path of environmental light from the eye to the substantia nigra in humans was investigated by computed tomography and magnetic resonance imaging. Light with wavelengths greater than 600 nm reached the rat substantia nigra, with a peak at 709 nm. Eyes appear to be the gateway for light to the mesencephalon since covering the eyes with aluminum foil reduced light intensity by half. Using computed tomography and magnetic resonance imaging of a human head, we identified the eye and the superior orbital fissure as possible gateways for environmental light to reach the mesencephalon.

Published in The Scientific World Journal

ISSN: 2356-6140 (Print); 1537-744X (Online)
Publisher: Hindawi Limited
Country of publisher: United Kingdom
LCC subjects: Technology; Medicine; Science
Website: https://onlinelibrary.wiley.com/journal/8086

About the journal