Details

Autor(en) / Beteiligte

• Zhao, Peng
• Barr, Travis P.
• Hou, Quanzhi
• Dib-Hajj, Sulayman D.
• Black, Joel A.
• Albrecht, Phillip J.
• Petersen, Karin
• Eisenberg, Elon
• Wymer, James P.
• Rice, Frank L.
• Waxman, Stephen G.

Titel

Voltage-gated sodium channel expression in rat and human epidermal keratinocytes: Evidence for a role in pain

Ist Teil von

• Pain (Amsterdam), 2008-09, Vol.139 (1), p.90-105

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2008

Quelle

MEDLINE

Beschreibungen/Notizen

• Keratinocytes are implicated in sensory transduction and can influence nociception, but whether these contribute to chronic pain is not known. In neurons, voltage-gated sodium channels (Na v) are involved in neuropathic pain and are activated by depolarization. Since keratinocytes can also show changes in membrane potential, we used RT-PCR, in situ hybridization, and immunohistochemistry to investigate the expression of sodium channels in these cells. Na v1.1, Na v1.6, and Na v1.8 were localized within keratinocytes in rat epidermis. In addition, sodium channels contribute to the release of ATP from rat keratinocytes in response to increased [K +] o, implicating sodium channels in keratinocyte ligand release and nociception. To examine whether keratinocytes may contribute to human pain states, we analyzed sodium channel expression in human skin biopsies from subjects with complex regional pain syndrome Type 1 (CRPS) and post-herpetic neuralgia (PHN) using immunohistochemistry. Control skin exhibited immunolabeling for Na v1.5, Na v1.6 and Na v1.7. In contrast, painful skin from CRPS and PHN subjects displayed Na v1.1, Na v1.2, and Na v1.8 immunolabeling, in addition to substantially increased signal for Na v1.5, Na v1.6, Na v1.7. These observations lead us to propose that pathological increases in keratinocyte sodium channel expression may contribute to pain by increasing epidermal ATP release, resulting in excessive activation of P2X receptors on primary sensory axons. Consistent with this hypothesis, animal models of neuropathic pain exhibit increases in subcutaneous ATP release and activity of primary sensory neurons, and peripheral administration of P2X antagonists has been shown to reduce neuropathic pain in humans.