The acid-sensing ion channel 2 (ASIC2) of ciliated cells in the developing rat nasal septum.

The airway epithelium is exposed to an acidic environment in certain conditions. The acid-sensing ion channel 2 (ASIC2) belongs to the epithelial amiloride-sensitive sodium channel and degenerin (ENaC/DEG) family and is expressed on cilia of the respiratory epithelium. The aim of this study was to detect the expression of ASIC2 in the nasal septum in the embryonic stage of the rat. ASIC2 expression was not observed in the primary cilium but was found in some cilia on embryonic day 17 (E17). After E18, all cilia showed ASIC2 immunoreactivity. RT-PCR analysis revealed that ASIC2b, a subtype of ASIC2, was expressed in the nasal septum while ASIC2a was not. Quantitative Real-time RT-PCR studies indicated that the expression level of ASIC2 mRNA was highest on E21, just before birth. These results imply that ASIC2 plays little part in the development of the nasal septum epithelium. On the other hand, ASIC2, especially ASIC2b, may function for the survival and retention of ciliated cells of the nasal septum against dynamic changes in the pH environment at birth.