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Taste receptor cells express pH-sensitive leak K+ channels
1Cell and Developmental Biology, University of Colorado Health Sciences Center at Fitzsimons, Aurora, Colorado 80045, USA.
Journal of Neurophysiology
|July 9, 2004
Summary
Rat taste receptor cells express TASK-2 and other K2P channels, which are crucial for setting resting membrane potentials and sour taste perception. These findings highlight the role of specific potassium channels in taste signaling.
Area of Science:
- Physiology
- Molecular Biology
- Neuroscience
Background:
- Two-pore domain potassium (K2P) channels, encoded by KCNK1-17 genes, are vital for regulating cellular excitability.
- Taste receptor cells (TRCs) in the tongue are responsible for detecting different tastes, including sour.
Purpose of the Study:
- To investigate the expression and function of K2P channels, particularly TASK-2, in rat taste receptor cells.
- To determine the role of these channels in establishing resting membrane potentials and sour taste transduction.
Main Methods:
- Whole-cell patch-clamp recordings were performed on isolated rat TRCs.
- Extracellular pH was manipulated to assess the sensitivity of potassium currents.
- RT-PCR and immunocytochemistry were used to verify the expression of TASK channel subtypes.
Main Results:
- A subset of TRCs exhibited a pH-sensitive leak potassium (Kleak) current, suppressed by acidic pH, consistent with TASK-2 and TALK-1 channel properties.
- This pH-sensitive current significantly influenced the resting membrane potential of TRCs, averaging -70 mV.
- RT-PCR and immunocytochemistry confirmed high expression of TASK-2 in rat TRCs, with lower expression of TASK-1 and TALK-1.
Conclusions:
- TASK-2, along with other K2P channels, is expressed in rat TRCs.
- These K2P channels, especially TASK-2, likely play a significant role in setting resting membrane potentials in TRCs.
- TASK-2 and related channels may be involved in the transduction of sour taste signals.
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