The neuroprotective agent sipatrigine (BW619C89) potently inhibits the human tandem pore-domain K(+) channels TREK-1 and TRAAK.
We have cloned and functionally expressed the human orthologue of the mouse TRAAK gene. When cDNA for hTRAAK is expressed in either Xenopus oocytes or HEK293 cells it forms a K(+)-selective conductance and hyperpolarises the resting membrane potential. Quantitative mRNA expression analysis using Taqman revealed that hTRAAK mRNA is predominantly present in the central nervous system where it exhibits a regionally diverse pattern of expression. Like the related channel TREK-1, the activity of TRAAK was potentiated by arachidonic acid. The neuroprotective agent sipatrigine (10 microM) inhibited both hTREK-1 (73.3+/-4.4%) and hTRAAK (45.1+/-11.2%) in a reversible, voltage-independent manner. Inhibition of both channels was dose-dependent and for TREK-1 occurred with an IC(50) of 4 microM. The related compound lamotrigine, which is a better anticonvulsant but weaker neuroprotective agent than sipatrigine, was a far less effective antagonist of both channels, producing <10% inhibition at a concentration of 10 microM.
Meadows
H J
HJ
Neuroscience Research, SmithKline Beecham Pharmaceuticals, New Frontiers Science Park, Third Avenue, Harlow, Essex CM19 5AW, UK. helen_j_meadows@sbphrd.com
Chapman
C G
CG
Duckworth
D M
DM
Kelsell
R E
RE
Murdock
P R
PR
Nasir
S
S
Rennie
G
G
Randall
A D
AD
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000502:physiology*; D002460:Cell Line; D005260:Female; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D010879:Piperazines / Q000494:pharmacology*; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D024683:Potassium Channels, Tandem Pore Domain; D011743:Pyrimidines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014982:Xenopus laevis
C503432:KCNK4 protein, human; C503433:Kcnk4 protein, mouse; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D010879:Piperazines; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024683:Potassium Channels, Tandem Pore Domain; D011743:Pyrimidines; D012333:RNA, Messenger; C103742:potassium channel protein TREK-1; C081980:sipatrigine