Vitamin D Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin D, including details on sources, melanin, benefits, deficiency, supplements, calcium absorption.

Vitamin D upregulates expression of ECaC1 mRNA in semicircular canal.

Yamauchi D, Raveendran NN, Pondugula SR, Kampalli SB, Sanneman JD, Harbidge DG, Marcus DC

Cellular Biophysics Laboratory, Department of Anatomy and Physiology, Kansas State University, Manhattan, KS 66506, USA.

The low luminal Ca2+ concentration of mammalian endolymph in the vestibular labyrinth is required for normal balance. We found transcripts in primary cultures of semicircular canal duct (SCCD) epithelial cells from neonatal rats representing a complete transport system for transepithelial absorption of Ca2+ that is comprised of the epithelial Ca2+ channels ECaC1 (CaT2, TRPV5) and ECaC2 (CaT1, TRPV6), calbindin (calbindin-D9k, calbindin-D28k), Na+/Ca2+ exchanger (NCX1, NCX2, and NCX3), and plasma membrane Ca2+-ATPase (PMCA1, PMCA3, and PMCA4) by RT-PCR. Further, vitamin D receptor was also expressed in SCCD and it was found by quantitative RT-PCR that incubation for 24 h with 1,25-dihydroxyvitamin D3 upregulated the expression of ECaC1, calbindin-D9k, and calbindin-D28k. These observations provide evidence for the first time of an ECaC-based Ca2+ transport system in SCCD that could maintain the low Ca2+ concentration in vestibular endolymph.

Published 10 May 2005 in Biochem Biophys Res Commun, 331(4): 1353-7.
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