Skip to main content
Article thumbnail
Location of Repository

CO2-dependent opening of an inwardly rectifying K+ channel

By Robert T. R. Huckstepp and Nicholas Dale

Abstract

CO2 chemosensing is a vital function for the\ud maintenance of life that helps to control acid–base balance.\ud Most studies have reported that CO2 is measured via its\ud proxy, pH. Here we report an inwardly rectifying channel,\ud in outside-out excised patches from HeLa cells that was\ud sensitive to modest changes in PCO2 under conditions of\ud constant extracellular pH. As PCO2 increased, the open\ud probability of the channel increased. The single-channel\ud currents had a conductance of 6.7 pS and a reversal\ud potential of –70 mV, which lay between the K+ and Cl–\ud equilibrium potentials. This reversal potential was shifted\ud by +61 mV following a tenfold increase in extracellular\ud [K+] but was insensitive to variations of extracellular [Cl–].\ud The single-channel conductance increased with extracellular\ud [K+]. We propose that this channel is a member of the\ud Kir family. In addition to this K+ channel, we found that\ud many of the excised patches also contained a conductance\ud carried via a Cl–-selective channel. This CO2-sensitive Kir\ud channel may hyperpolarize excitable cells and provides a\ud potential mechanism for CO2-dependent inhibition during\ud hypercapnia

Topics: QP
Publisher: Springer
Year: 2011
OAI identifier: oai:wrap.warwick.ac.uk:34583

Suggested articles

Citations

  1. (2006). A strategy for determining arterial blood gases on the summit of Mt.
  2. (2001). An alternative approach to the identification of respiratory central chemoreceptors in the brainstem. Respir Physiol 129:141–157 Pflugers Arch - doi
  3. (1997). Carbon dioxide regulates the tonic activity of locus coeruleus neurons by by modulating a proton- and polyamine-sensitive inward rectifier potassium current. doi
  4. (2004). Cellular mechanisms involved in CO2 and acid signalling in chemosensitive neurons.
  5. (1995). Characterization of single potassium channels in mouse pancreatic acinar cells. doi
  6. (1999). Chloride channels and salivary gland function. doi
  7. (2000). CO2 inhibits specific inward rectifier K + channels by decreases in intraand extracellular pH. doi
  8. (2010). CO2-dependent opening of connexin 26 and related β connexins. doi
  9. (2001). CO2/HCO3 –-responsive soluable adenylyl cyclase as a putative metabolic sensor. Trends Endocrinol Metab 12:366–370 344 Pflugers Arch - doi
  10. (2010). Connexin hemichannel-mediated CO2-dependent release of ATP in the medulla oblongata contributes to central respiratory chemosensitivity. doi
  11. (1998). Contribution of Ca 2+-activated K + channels to central chemosensitivity in cultivated neurons of fetal rat medulla. doi
  12. (1987). Data transformations for improved display and fitting of single-channel dwell time histograms. doi
  13. (2006). Differential control of central cardiorespiratory interactions by hypercapnia and the effect of prenatal nicotine. doi
  14. (2006). Effects of electrical stimulation of the medullary raphé nuclei on respiratory movement in rats. doi
  15. (2004). Expression and coexpression of CO2-sensitive Kir channels in brainstem neurons of rats. doi
  16. (2008). Expression of inwardly rectifying K + channels in the carotid body of rat. doi
  17. (2010). Inwardly rectifying potassium channels: their structure, function, and physiological roles. Physiol Rev 90:291–366 doi
  18. (1997). Inwardly rectifying, voltagedependent and resting potassium currents in rat pancreatic acinar cells in primary culture. doi
  19. (2001). Maxi K + channels co-localised with CFTR in the apical membrane of an exocrine gland acinus: possible involvement in secretion. doi
  20. (2003). Multiple targets of chemosensitive signaling in locus coeruleus neurons: role doi
  21. (2006). Regulation of ROMK (Kir1.1) channels: new mechanisms and aspects. doi
  22. (2004). Respiratory control by ventral surface chemoreceptor neurons in rats. doi
  23. (2005). Response of membrane potential and intracellular pH to hypercapnia in neurons and astrocytes from rat retrotrapezoid nucleus. doi
  24. (2005). Retrotrapezoid nucleus: a litmus test for the identification of central chemoreceptors. doi
  25. (2004). Serotonergic neurons as carbon dioxide sensors that maintain pH homeostasis. doi
  26. (2003). SK4/IK1-like channels mediate TEA-insensitive, Ca 2+-activated K + currents in bovine parotid acinar cells. doi
  27. (2000). Soluble adenylyl cyclase as an evoultionary conserved bicarbonate sensor.
  28. (2007). TASK channels determine pH sensitivity in select respiratory neurons but do not contribute to central respiratory chemosensitivity. doi
  29. (2008). The doi
  30. (2009). The amygdala isa chemosensor that detects carbon dioxide and acidosis to elicit fear behavior.
  31. (1995). Transduction of chemostimuli by the type 1 carotid body cell. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.