Nonselective Voltage-Gated Ionic Channels in Type II Taste Cells

摘要

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