KCNQ1/KCNE1 K⁺ channel and P2Y₄ receptor are co-expressed from the time of birth in the apical membrane of rat strial marginal cells

Abstract

Conclusion. KCNQ1/KCNE1 K⁺ channels and P2Y₄ receptors are expressed in the apical membrane of rat strial marginal cells from postnatal day 1 (P1) and maintained throughout development. Objectives. The purpose of the present study was to investigate the developmental expression of KCNQ1/KCNE1 K⁺ channel and of P2Y₄, which is an important metabotropic regulator of KCNQ1/KCNE1 K⁺ channel in strial marginal cells. Materials and Methods. Sprague-Dawley rats at different stages of development (P1, P3, P5, P7, P14, and P21) were studied. The spiral ligament with the stria vascularis was detached from the cartilaginous or bony cochlea and prepared for a voltage-sensitive vibrating probe and immunohistochemistry. Results. Chromanol 293B, a blocker of KCNQ1/KCNE1 K⁺ channel, inhibited short-circuit currents (I_sc) from P1 to P21. Similarly, I_sc were found to be decreased by uridine 5′-triphosphate at all ages. The antagonist profiles indicated that the apical P2Y receptor is P2Y₄ subtype. KCNQ1, KCNE1, and P2Y₄ were immunolocalized in the apical region of stria vascularis at P1.

• KCNQ1/KCNE1 K⁺ channel
• P2Y₄
• strial marginal cell
• cochlea
• rat
• voltage-sensitive vibrating probe