Nonselective voltage-gated ionic channels in type II taste cells

In cells of different types outward voltage-gated (VG) ion currents are generally carried by potassium ions. However, in mouse type II taste cells these currents persist when K⁺-selective ion channels are inhibited. In this study, we examined the ion channels that provide a pathway for atypical VG outward currents in type II taste cells. These channels are found to be weakly selective and permeabile to large molecules such as NMDG, gluconate, and ATP. According to non-stationary fluctuation analysis, single channel conductance is about 200 pS. The data obtained suggest that the nonselective ion channels are similar to hemichannels formed by connexins, the gap-junction proteins, in the plasma membrane of vertebrate cells.