Time course of substance P expression in dorsal root ganglia following complete spinal nerve transection.
J Comp Neurol
; 497(1): 78-87, 2006 Jul 01.
Article
en En
| MEDLINE
| ID: mdl-16680762
ABSTRACT
Recent evidence suggests that substance P (SP) is up-regulated in primary sensory neurons following axotomy and that this change occurs in larger neurons that do not usually produce SP. If this is so, then the up-regulation may allow normally neighboring, uninjured, and nonnociceptive dorsal root ganglion (DRG) neurons to become effective in activating pain pathways. By using immunohistochemistry, we performed a unilateral L5 spinal nerve transection on male Wistar rats and measured SP expression in ipsilateral L4 and L5 DRGs and contralateral L5 DRGs at 1-14 days postoperatively (dpo) and in control and sham-operated rats. In normal and sham-operated DRGs, SP was detectable almost exclusively in small neurons (< or =800 microm2). After surgery, the mean size of SP-positive neurons from the axotomized L5 ganglia was greater at 2, 4, 7, and 14 dpo. Among large neurons (>800 microm2) from the axotomized L5, the percentage of SP-positive neurons increased at 2, 4, 7, and 14 dpo. Among small neurons from the axotomized L5, the percentage of SP-positive neurons was increased at 1 and 3 dpo but was decreased at 7 and 14 dpo. Thus, SP expression is affected by axonal damage, and the time course of the expression is different between large and small DRG neurons. These data support a role for SP-producing, large DRG neurons in persistent sensory changes resulting from nerve injury.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Traumatismos de la Médula Espinal
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Sustancia P
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Regulación de la Expresión Génica
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Ganglios Espinales
Límite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Año:
2006
Tipo del documento:
Article
País de afiliación:
Estados Unidos