| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Cell and Developmental Biology, University of Colorado Health Sciences Center, Denver, CO, USA
* To whom correspondence should be addressed. E-mail: tag{at}biology.usu.edu.
Two-pore domain K+ (K2P) channels encoded by genes KCNK1-17 (K2p1-17) play important roles in regulating cell excitability. We report here that rat taste receptor cells (TRCs) highly express TASK-2 (KCNK5; K2p5.1) and to a much lesser extent TALK-1 (KCNK16; K2p16.1) and TASK-1 (KCNK3; K2p3.1) and suggest potentially important roles for these channels in setting resting membrane potentials and in sour taste transduction. Whole-cell recordings of isolated TRCs demonstrate that a leak K+ (Kleak) current in a subset of TRCs exhibited high sensitivity to acidic extracellular pH similar to reported properties of TASK-2 and TALK-1 channels. A drop in bath pH from 7.4 to 6 suppressed 90% of the current, resulting in membrane depolarization. K+ channel blockers, BaCl2 but not TEA, inhibited the current. Interestingly, resting potentials of these TRCs averaged -70 mV, which closely correlated with the amplitude of the pH-sensitive Kleak, suggesting a dominant role of this conductance in setting resting potentials. RT-PCR assays followed by sequencing of PCR products showed that TASK-1, TASK-2 and a functionally similar channel, TALK-1, were expressed in all three types of lingual taste buds. To verify expression of TASK channels, we labeled taste tissue with antibodies against TASK-1, TASK-2 and TASK-3. Strong labeling was seen in some TRCs with antibody against TASK-2 but not TASK-1 and TASK-3. Consistent with the immunocytochemical staining, quantitative real time PCR assays demonstrated that the message for TASK-2 was expressed at significantly higher levels (10-100X greater) than was TASK-1, TALK-1 or TASK-3. Thus, several K2P channels, and in particular TASK-2, are expressed in rat TRCs where they may contribute to the establishment of resting potentials and sour reception.
This article has been cited by other articles:
|
|
 |
|
  S. Kataoka, R. Yang, Y. Ishimaru, H. Matsunami, J. Sevigny, J. C. Kinnamon, and T. E. Finger The Candidate Sour Taste Receptor, PKD2L1, Is Expressed by Type III Taste Cells in the Mouse Chem Senses, March 1, 2008; 33(3): 243 - 254. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Ishimaru, H. Inada, M. Kubota, H. Zhuang, M. Tominaga, and H. Matsunami Transient receptor potential family members PKD1L3 and PKD2L1 form a candidate sour taste receptor PNAS, August 15, 2006; 103(33): 12569 - 12574. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Bai, H. A. Lacey, S. L. Greenwood, P. N. Baker, M. A. Turner, C. P. Sibley, and G. K. Fyfe TASK Channel Expression in Human Placenta and Cytotrophoblast Cells Reproductive Sciences, January 1, 2006; 13(1): 30 - 39. [Abstract] [PDF]
|
|
|
|
 |
|
 V. Lyall, H. Pasley, T.-H. T. Phan, S. Mummalaneni, G. L. Heck, A. K. Vinnikova, and J. A. DeSimone Intracellular pH Modulates Taste Receptor Cell Volume and the Phasic Part of the Chorda Tympani Response to Acids J. Gen. Physiol., December 27, 2005; 127(1): 15 - 34. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.P. Barfield, C.H. Yeung, and T.G. Cooper Characterization of potassium channels involved in volume regulation of human spermatozoa Mol. Hum. Reprod., December 1, 2005; 11(12): 891 - 897. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Liu, D. R. Hansen, I. Kim, and T. A. Gilbertson Expression and characterization of delayed rectifying K+ channels in anterior rat taste buds Am J Physiol Cell Physiol, October 1, 2005; 289(4): C868 - C880. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. C. Spector and S. P. Travers The representation of taste quality in the Mammalian nervous system. Behav Cogn Neurosci Rev, September 1, 2005; 4(3): 143 - 191. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
