Analysis of human Nav1.8 expressed in SH-SY5Y neuroblastoma cells.
The tetrodotoxin-resistant voltage-gated sodium channel alpha-subunit Nav1.8 is expressed in nociceptors and has been implicated in chronic pain. Difficulties of heterologous expression have so far precluded analysis of the pharmacological properties of human Nav1.8. To address this we have introduced human Nav1.8 in neuroblastoma SH-SY5Y cells. Voltage-clamp analysis showed that human Nav1.8 generated an inward tetrodotoxin-resistant sodium current with an activating threshold around -50 mV, half maximal activation at -11+/-3 mV and a reversal potential of 67+/-4 mV. These properties closely match those of the endogenous rat tetrodotoxin-resistant sodium current in dorsal root ganglia suggesting that the expressed human channel is in a near physiological conformation. Human Nav1.8 was resistant to tetrodotoxin and activated by the pyrethroid toxin deltamethrin. Both voltage-activated and deltamethrin-activated human Nav1.8 were inhibited by the sodium channel blockers BIII 890 CL, NW-1029, and mexiletine. Inhibition of Nav1.8 by these compounds may underlie their known analgesic effects in animal models.
Dekker
Lodewijk V
LV
Ionix Pharmaceuticals Ltd, 418 Cambridge Science Park, Cambridge CB4 0PA UK. lodewijk.dekker@nottingham.ac.uk
Daniels
Zoe
Z
Hick
Caroline
C
Elsegood
Kathryn
K
Bowden
Sarah
S
Szestak
Tadge
T
Burley
J Russell
JR
Southan
Andy
A
Cronk
David
D
James
Iain F
IF
D000577:Amides / Q000494:pharmacology; D000818:Animals; D017306:Annexin A2 / Q000235:genetics / Q000378:metabolism; D001575:Benzomorphans / Q000494:pharmacology; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020128:Inhibitory Concentration 50; D008564:Membrane Potentials / Q000187:drug effects; D008801:Mexiletine / Q000494:pharmacology; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D009447:Neuroblastoma; D009570:Nitriles / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D011722:Pyrethrins / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D009418:S100 Proteins / Q000235:genetics / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D015222:Sodium Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D014162:Transfection; D000099248:S100 Calcium Binding Protein A10
D000577:Amides; D017306:Annexin A2; D001575:Benzomorphans; D008801:Mexiletine; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; D009570:Nitriles; D011422:Propionates; D011722:Pyrethrins; D012333:RNA, Messenger; D009418:S100 Proteins; D012964:Sodium; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013779:Tetrodotoxin; D000099248:S100 Calcium Binding Protein A10; C408069:BIII 890 CL; C475054:NW 1029; C568317:SCN10A protein, human; C568319:Scn10a protein, rat; C017180:decamethrin