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1.
The Korean Journal of Physiology and Pharmacology ; : 211-216, 2008.
Artigo em Inglês | WPRIM | ID: wpr-728385

RESUMO

TREK (TWIK-RElated K+ channels) and TRAAK (TWIK-Related Arachidonic acid Activated K+ channels) were expressed in COS-7 cells, and the channel activities were recorded from inside-out membrane patches using holding potential of -40 mV in symmetrical 150 mM K+ solution. Intracellular application of an oxidizing agent, 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB), markedly decreased the activity of the TREK2, and the activity was partially reversed by the reducing agent, dithiothreitol (DTT). In order to examine the possibility that the target sites for the oxidizing agents might be located in the C-terminus of TREK2, two chimeras were constructed: TREK2 (1-383)/TASK3C and TREK2 (1-353)/TASK3C. The channel activity in the TREK2 (1-383)/TASK3C chimera was still inhibited by DTNB, but not in the TREK2 (1-353)/TASK3C chimera. These results indicate that TREK2 is inhibited by oxidation, and that the target site for oxidation is located between the amino acid residues 353 and 383 in the C-terminus of the TREK2 protein.


Assuntos
Animais , Ácido Araquidônico , Quimera , Células COS , Ácido Ditionitrobenzoico , Ditiotreitol , Membranas , Oxidantes
2.
The Korean Journal of Physiology and Pharmacology ; : 245-251, 2008.
Artigo em Inglês | WPRIM | ID: wpr-728380

RESUMO

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.


Assuntos
Animais , Humanos , Ratos , Acidose , Encéfalo , Células Clonais , Grupos Diagnósticos Relacionados , Gânglios Espinais , Concentração de Íons de Hidrogênio , Cinética , Neurônios , RNA Mensageiro , Medula Espinal , Traumatismos da Medula Espinal , Raízes Nervosas Espinhais , Regulação para Cima
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