Distribution of melanosomes across the retinal pigment epithelium of a hooded rat: implications for light damage

Journal Article · Mon Feb 01 00:00:00 EST 1982 · Invest. Ophthalmol. Visual Sci.; (United States)

OSTI ID:5513200

Howell, W L; Rapp, L M; Williams, T P

Distribution of melanosomes across the retinal pigment epithelium of hooded rats (Long-Evans) is studied at the light microscopic and electron microscopic levels. This distribution is shown to be nonuniform: more melanosomes exist in the periphery than elsewhere and, importantly, there are very few melanosomes in a restricted area of the central portion of the superior hemisphere compared with the corresponding part of the inferior hemisphere. The region with fewest melanosomes is precisely the one that is highly susceptible to light damage. Because this region is the same in both pigmented and albino eyes, the paucity of melanin in this region is not the cause of its great sensitivity to light damage. Nor does light cause the nonuniform distribution of melanin. A possible explanation, involving a proposed vestigial tapetum, is given in order to explain the correlation of melanosome counts and sensitivity to light damage.

• Research Organization: Institute of Molecular Biophysics, Florida State University, Tallahassee
• OSTI ID: 5513200
• Journal Information: Invest. Ophthalmol. Visual Sci.; (United States), Vol. 22:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
MELANIN
TISSUE DISTRIBUTION
RETINA
PHOTOSENSITIVITY
ANIMAL CELLS
ELECTRON MICROSCOPY
RATS
VISIBLE RADIATION
ANIMALS
BODY
BODY AREAS
DISTRIBUTION
ELECTROMAGNETIC RADIATION
EYES
FACE
HEAD
HYDROXY COMPOUNDS
MAMMALS
MICROSCOPY
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PIGMENTS
RADIATIONS
RODENTS
SENSE ORGANS
SENSITIVITY
VERTEBRATES
551000* - Physiological Systems