Immunohistochemical localization of phospholipase C isozymes in mature and developing gerbil cochlea

• Published in: Neuroscience 2001-01, Vol.102 (2), p.451-459
• Main Authors: Okamura, H., Spicer, S.S., Schulte, B.A.
• Format: Article
• Language: English
• Subjects: Aging - metabolism; Animals; Biological and medical sciences; Cochlea - enzymology; Cochlea - growth & development; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Female; Fundamental and applied biological sciences. Psychology; Gerbillinae; Immunohistochemistry; inner ear; intracellular signaling; ion transport; Isoenzymes - metabolism; Male; Meriones unguiculatus; spiral ganglion; Type C Phospholipases - metabolism; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(00)00456-5

The possibility that phospholipase C contributes to intracellular signaling in the cochlea was investigated by immunostaining for eight different isoforms of the enzyme. In the mature gerbil cochlea, expression of the isozymes varied widely among different cell types. The phospholipase C-β1 isoform was detected in inner and outer hair cells, and spiral ganglion neurons where it may participate in regulating Ca 2+ flux. The β3 isozyme was expressed in epithelial cells thought to mediate lateral and medial circulation of potassium. The β2 isozyme was present in border, inner phalangeal and Hensen cells, the stria vascularis, and suprastrial and supralimbal fibrocytes where it also may be involved in regulating ion transport activities. The phospholipase C-γ isozymes were expressed in supporting cells, the stria vascularis, and certain fibrocytes where they possibly participate in activating tyrosine kinase and modulating ion conductances. The δ2 isoform was found in pillar, outer sulcus and strial marginal cells as well as spiral ganglion neurons and their radial processes. Documentation of changes in the expression pattern of phospholipase C isoforms during postnatal development and knowledge of their distribution in several positive control tissues provided further data for speculation about the biologic significance of the cochlear reactivity. The results demonstrate a wide diversity of isozyme distribution in the cochlea and suggest that the enzymes affect activities of various cochlear cell types in different ways.