2018 Group Project 3
| Projects 2018: 1 Adrenal Medulla | 3 Melanocytes | 4 Cardiac | 5 Dorsal Root Ganglion |
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Melanocytes
Introduction
History
Tissue Organ Structure and Function
Skin
Ears
Melanocytes are mainly present in the cochlea, vestibular organ and endolymphatic sac:
In the cochlea of humans: Melanocytes are found in the vascularised epithelial tissue in the intermediate layer of the stria vascularis and the modiolus, between the marginal and basal cell layers [1]. During development, marginal layer cuboidal epithelium develops processes which interdigitate with the intermediate melanocytes and basal cells [2]. Based on studies performed on mice models, it is thought that melanocytes are important for the development of the endocochlear potential (EP), produced by strial cells. Intermediate melanocytes conduct K+, which plays an important role in sound conductance, as it flows from the endolymph into the ciliated epithelial cells of the ear via mechano-electrical channels. This influx of K+ is driven by a combination of the membrane potential of these ciliated epithelial cells, and the EP. A study on guinea pig models showed that blocking the K+ channels of melanocytes produces a lower EP [3]. This study agrees with evidence showing that mice deficient in cochlea melanocytes have a lower EP, requiring a greater sound stimulus to produce an action potential [4].
Eyes
Heart
CNS
Embryonic Origins
Development Time Course
Molecular Mechanisms/ Factors/ Genes
Animal Models
Current Research
Abnormalities
Glossary
- ↑ Meyer zum Gottesberge AM. (1988). Physiology and pathophysiology of inner ear melanin. Pigment Cell Res. , 1, 238-49. PMID: 3070525
- ↑ Steel KP & Barkway C. (1989). Another role for melanocytes: their importance for normal stria vascularis development in the mammalian inner ear. Development , 107, 453-63. PMID: 2612372
- ↑ Takeuchi S, Kakigi A, Takeda T, Saito H & Irimajiri A. (1996). Intravascularly applied K(+)-channel blockers suppress differently the positive endocochlear potential maintained by vascular perfusion. Hear. Res. , 101, 181-5. PMID: 8951443
- ↑ Cable J, Huszar D, Jaenisch R & Steel KP. (1994). Effects of mutations at the W locus (c-kit) on inner ear pigmentation and function in the mouse. Pigment Cell Res. , 7, 17-32. PMID: 7521050
