Inwardly rectifying potassium (Kir) channels play key roles in functions, including maintaining the resting membrane potential and regulating the action potential duration in excitable cells. Using in situ whole-cell recordings, we investigated Kir currents in mouse fungiform taste bud cells (TBCs) and immunologically identified the cell types (type I-III) expressing these currents. We demonstrated that Kir currents occur in a cell-type-independent manner. The activation potentials we measured were -80 to -90 mV, and the magnitude of the currents increased as the membrane potentials decreased, irrespective of the cell types. The maximum current densities at -120 mV showed no significant differences among cell types (p>0.05, one-way ANOVA). The density of Kir currents was not correlated with the density of either transient inward currents or outwardly rectifying currents, although there was significant correlation between transient inward and outwardly rectifying current densities (p<0.05, test for no correlation). RT-PCR studies employing total RNA extracted from peeled lingual epithelia detected mRNAs for Kir1, Kir2, Kir4, Kir6, and Kir7 families. These findings indicate that TBCs express several types of Kir channels functionally, which may contribute to regulation of the resting membrane potential and signal transduction of taste.

• MeSH
• Action Potentials MeSH
• Taste Buds metabolism   MeSH
• Potassium metabolism   MeSH
• Potassium Channels, Inwardly Rectifying genetics   metabolism   MeSH
• Epithelium metabolism   MeSH
• Membrane Potentials MeSH
• RNA, Messenger genetics   MeSH
• Patch-Clamp Techniques methods   MeSH
• Mice MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Potassium MeSH
• Potassium Channels, Inwardly Rectifying MeSH
• RNA, Messenger MeSH