Melanin in the inner ear: micromorphological and microanalytical investigations.

Abstract

Melanin-pigments are found in various parts of the inner ear, especially in the neighbourhood of those epithelia that are believed to be involved in the secretion and/or absorption of endolymphatic fluid. Microprobe analysis (LAMMA, X-ray) measurements were performed in different parts of the inner ear in tissues containing melanin. The tissues were shock-frozen, freeze-dried and embedded in Earle's medium (Spurr). The semi-thin sections used for microprobe analysis were cut dry in a conventional ultramicrotome and mounted on copper grids. Experimental manipulation of the endolymph ionic composition (increased Na+) stimulated the migration of melanosomes from the perinuclear region into the dendritic processes and the rearrangement of the dendritic processes in a close vicinity of the presumably transporting epithelia. The intracellular ion measurements showed the affinity of divalent ions for melanin (Mg++, Ca++, Sr++ and Ba++). It is proposed that melanin represents a physiologically important "reservoir" for essential trace elements and by its binding/release may play a key role in the enzymatically controlled processes of ionic pumps.

• Authors: A Meyer zum Gottesberge-Orsulakova
• Journal: Acta histochemica. Supplementband (Acta Histochem Suppl) Vol. 32 Pg. 245-53 ( 1986) ISSN: 0567-7556 [Print] Germany
• PMID: 3085158 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Melanins

Topics

• Animals
• Cytoplasmic Granules (analysis, ultrastructure)
• Dendrites (analysis, ultrastructure)
• Ear, Inner (analysis, innervation, ultrastructure)
• Electron Probe Microanalysis (methods)
• Guinea Pigs
• Male
• Melanins (analysis)
• Melanocytes (analysis, ultrastructure)