Ca(2+)-ATPases in the cochlear duct.
Differing levels of the Ca(2+)-ATPase enzymes that reside on the plasma membrane (PM) and on the endoplasmic reticulum (ER) were identified in individual rat cochlear tissues by the use of a semi-quantitative enzyme-linked immunosorbent assay (ELISA). Unlike other studies, a specific antibody to PM Ca(2+)-ATPase was used to detect significantly greater levels (about 2x) of PM Ca(2+)-ATPase in the stria vascularis (SV) than that in the spiral ligament (SL) and organ of Corti (OC) tissues. Similarly, levels of ER Ca(2+)-ATPase were also significantly higher in the SV than in the SL and OC tissues. The presence of ER Ca(2+)-ATPase in the tissues of the SV has not been demonstrated previously. Given the importance of Ca2+ homeostasis in the inner ear, the statistically significantly higher densities of both PM and ER Ca(2+)-ATPase measured in the SV relative to the SL and OC regions would indicate tissue-specific responses to fluctuations in systemic and local Ca2+ concentrations.
Curtis
L M
LM
Department of Anatomy, J. Hillis Miller Health Science Center, University of Florida, USA.
Garg
L C
LC
Rarey
K E
KE
D000818:Animals; D000911:Antibodies, Monoclonal; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003053:Cochlear Duct / Q000201:enzymology*; D005110:Extracellular Space / Q000201:enzymology; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000201:enzymology; D008297:Male; D009925:Organ of Corti / Q000201:enzymology; D051381:Rats; D012044:Regression Analysis; D013316:Stria Vascularis / Q000201:enzymology
D000911:Antibodies, Monoclonal; D000252:Calcium-Transporting ATPases