Abnormal expression of voltage-gated sodium channels Nav1.7, Nav1.3 and Nav1.8 in trigeminal neuralgia.
Voltage-gated sodium channels have been implicated in acute and chronic neuropathic pain. Among subtypes, Nav1.7 single mutations can cause congenital indifference to pain or chronic neuropathic pain syndromes, including paroxysmal ones. This channel is co-expressed with Nav1.8, which sustains the initial action potential; Nav1.3 is an embrionary channel which is expressed in neurons after injury, as in neuropathic conditions. Few studies are focused on the expression of these molecules in human tissues having chronic pain. Trigeminal neuralgia (TN) is an idiopathic paroxysmal pain treated with sodium channel blockers. The aim of this study was to investigate the expression of Nav1.3, Nav1.7 and Nav1.8 by RT-PCR in patients with TN, compared to controls. The gingival tissue was removed from the correspondent trigeminal area affected. We found that Nav1.7 was downregulated in TN (P=0.017) and Nav1.3 was upregulated in these patients (P=0.043). We propose a physiopathological mechanism for these findings. Besides vascular compression of TN, this disease might be also a channelopathy.
Siqueira
S R D T
SR
School of Arts, Science and Humanities, University of São Paulo, Brazil. silviadowgan@hotmail.com
Alves
B
B
Malpartida
H M G
HM
Teixeira
M J
MJ
Siqueira
J T T
JT
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D005786:Gene Expression Regulation; D005881:Gingiva / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D062552:NAV1.3 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D010146:Pain / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism*; D014277:Trigeminal Neuralgia / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
D062552:NAV1.3 Voltage-Gated Sodium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568317:SCN10A protein, human; C424715:SCN3A protein, human; C486866:SCN9A protein, human; D015222:Sodium Channels