PKCγ-positive neurons gate light tactile inputs to pain pathway through pERK1/2 neuronal network in trigeminal neuropathic pain model.
J Oral Facial Pain Headache
; 29(1): 70-82, 2015.
Article
en En
| MEDLINE
| ID: mdl-25635962
ABSTRACT
AIMS:
To explore the possible relationship between protein kinase C gamma (PKCγ) and phosphorylated forms of extracellular signal-regulated kinases 1/2 (pERK1/2) in the rat medullary dorsal horn and the facial hypersensitivity indicative of dynamic mechanical allodynia (DMA) following chronic constriction of the infraorbital nerve (CCI-IoN).METHODS:
A well-established rat model of trigeminal neuropathic pain involving CCI-IoN was used. Facial mechanical hypersensitivity was tested with non-noxious dynamic mechanical stimulation (air-puff), and the medullary dorsal horn was examined immunohistochemically using PKCγ and pERK1/2 as pain markers. Statistical analysis was performed using Student t test or one-way analysis of variance (ANOVA).RESULTS:
Increased PKCγ and pERK1/2 expressions within the medullary dorsal horn were associated with DMA following CCI-IoN. A segmental network composed of PKCγ-positive cells located in medullary dorsal horn laminae II/III, contacting more superficially located pERK1/2-expressing cells, was identified. Ultrastructural analysis confirmed the presence of PKCγ to pERK1/2-positive cells. Moreover, intracisternal administration of the selective PKCγ inhibitor KIG31-I blocked both the DMA and pERK1/2 expression in a dose-dependent manner. Although the number of pERK1/2-positive cells was significantly elevated with air-puff stimulation, DMA rats not receiving air-puff stimulation showed significant pERK1/2 expression, suggesting they were experiencing spontaneous pain.CONCLUSION:
PKCγ cells in the medullary dorsal horn may be involved in DMA following CCI-IoN through the activation of pERK1/2-expressing cells, which then may relay non-nociceptive information to lamina I cells in the medullary dorsal horn.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Tacto
/
Neuralgia del Trigémino
/
Proteína Quinasa C
/
Células del Asta Posterior
/
Quinasas MAP Reguladas por Señal Extracelular
/
Nocicepción
Límite:
Animals
Idioma:
En
Revista:
J Oral Facial Pain Headache
Año:
2015
Tipo del documento:
Article