Single-Channel Recording of TASK-3-like K Channel and Up-Regulation of TASK-3 mRNA Expression after Spinal Cord Injury in Rat Dorsal Root Ganglion Neurons.
Single-channel recordings of TASK-1 and TASK-3, members of two-pore domain K(+) channel family, have not yet been reported in dorsal root ganglion (DRG) neurons, even though their mRNA and activity in whole-cell currents have been detected in these neurons. Here, we report single-channel kinetics of the TASK-3-like K(+) channel in DRG neurons and up-regulation of TASK-3 mRNA expression in tissues isolated from animals with spinal cord injury (SCI). In DRG neurons, the single-channel conductance of TASK-3-like K(+) channel was 33.0+/-0.1 pS at -60 mV, and TASK-3 activity fell by 65+/-5% when the extracellular pH was changed from 7.3 to 6.3, indicating that the DRG K(+) channel is similar to cloned TASK-3 channel. TASK-3 mRNA and protein levels in brain, spinal cord, and DRG were significantly higher in injured animals than in sham-operated ones. These results indicate that TASK-3 channels are expressed and functional in DRG neurons and the expression level is up-regulated following SCI, and suggest that TASK-3 channel could act as a potential background K(+) channel under SCI-induced acidic condition.
Jang
Inseok
I
Department of Thoracic Surgery, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju 660-751, Korea.
La
Jun-Ho
JH
Kim
Gyu-Tae
GT
Lee
Jeong-Soon
JS
Kim
Eun-Jin
EJ
Lee
Eun-Shin
ES
Kim
Su-Jeong
SJ
Seo
Jeong-Min
JM
Ahn
Sang-Ho
SH
Park
Jae-Yong
JY
Hong
Seong-Geun
SG
Kang
Dawon
D
Han
Jaehee
J