A novel acid-sensitive K+ channel in rat dorsal root ganglia neurons.
Recent studies have suggested that acid-sensitive background K+ channels such as TASK-1 and TASK-3, members of two-pore domain K+ (K2P) channel family, express and contribute to extracellular acidification-induced responses in dorsal root ganglia (DRG) neurons. However, it has remained to address whether other acid-sensitive background K+ channels are functionally expressed in DRG neurons. Here we characterized biophysical and pharmacological properties of a novel acid-sensitive background K+ channel in DRG neurons isolated from neonatal rats. We recorded an 80-pS K+ channel with a weak inward rectification current-voltage relationship in cell-attached patches in 150mM KCl bath solution. The 80-pS K+ channel was inhibited by extracellular low pH (pHo 6.3). Interestingly, the channel was similar to TASK-2 cloned from mouse and rat in biophysical and pharmacological properties. However, extracellular alkaline condition which activates TASK-2 channel, failed to activate the 80-pS K+ channel. Lidocaine and quinine more inhibited the channel activity of 80-pS K+ channel than that of TASK-2 channel. Our results suggest that the acid-sensitive 80-pS K+ channels may regulate resting membrane potential and may play a critical role in various processes such as cell metabolism, pH, and pain sensation in DRG neurons.
La
Jun-Ho
JH
Medical Research Center for Neural Dysfunction, Department of Physiology, College of Medicine and Institute of Health Sciences, Gyeongsang National University, 90 Chilam-dong, Jinju, Gyeongnam, South Korea.
Kang
Dawon
D
Park
Jae-Yong
JY
Hong
Seong-Geun
SG
Han
Jaehee
J
D000143:Acids / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D004558:Electric Stimulation / Q000379:methods; D005727:Ganglia, Spinal / Q000166:cytology*; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods; D024683:Potassium Channels, Tandem Pore Domain / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D014162:Transfection / Q000379:methods
D000143:Acids; C498740:Kcnk5 protein, rat; D024683:Potassium Channels, Tandem Pore Domain