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Table 1 Summary of sodium channel distribution and potential involvement in pain conditions

From: Are voltage-gated sodium channels on the dorsal root ganglion involved in the development of neuropathic pain?

Channel Distribution in normal DRG Inflammatory pain Neuropathic pain Effect of manipulation on behavioral consequences Human disorders
   mRNA Protein mRNA Protein Antisense/siRNA Knock out  
1.1 High in large cells, low in small cells Unchanged (carrageenan) Unchanged (carrageenan) Decreased (SNI, SNL) N/A N/A N/A Migraine, epilepsy
1.2 Very low in most conditions Unchanged (carrageenan) Unchanged (carrageenan) Decreased (SNI, SNL) N/A N/A N/A Epilepsy
1.3 Extremely low in adult DRG Increased (carrageenan) Increased (carrageenan) Increased (SNI, SNL) Increased (SNI, SNL) Effective on SCI and CCI, but no effect on SNI No effect on acute, inflammatory, or neuropathic pain Accumulates in neuromas of human painful neuropathy
1.6 High in large cells, low in small cells Unchanged (carrageenan) Unchanged (carrageenan) Decreased (SNI, SNL) N/A N/A N/A N/A
1.7 Predominantly in small cells Increased (carrageenan, CFA) Increased (carrageenan, CFA) Decreased (SNI, SNL) Decreased (SNA, SNI, and SNL) Effective on CFA Effective on acute and inflammatory pain; no effect on neuropathic pain Decreased in human injured DRG; accumulates in neuromas; mutations: PE, PEPD, and CIP
1.8 Exclusively in small cells Increased (carrageenan) Increased (carrageenan) Decreased (SNI, SNL) Decreased in L5 DRG (SNL, SNI) but increased in L4 DRG and sciatic nerve Effective on CFA, SNL, and CCI Effective on inflammatory pain; no effect on neuropathic pain Accumulates in neuromas of human painful neuropathy
1.9 Selectively expressed in small cells Increased (CFA), unchanged (carrageenan) Unchanged (carrageenan) Decreased (SNA, SNI, and SNL) Decreased (SNA, SNI, and SNL) No effect on SNL Effective on inflammatory pain; no effect on neuropathic pain N/A
  1. Abbreviations: CCI, chronic constrictive injury; CFA, complete Freund's adjuvant; CIP, channelopathy-associated insensitivity to pain; DRG, dorsal root ganglion; N/A, not applicable; PE, primary erythermalgia; PEPD, paroxysmal extreme pain disorder; SCI, spinal cord injury; SNA, sciatic nerve axotomy; SNI, spared nerve injury; SNL, spinal nerve ligation.