Expression and activity of the nitric oxide synthase isoenzymes in the spinal trigeminal subnucleus caudalis following carrageenan-induced arthritis in the rat TMJ / Expressão e atividade das isoenzimas oxido nitrico sintase no subnucleo caudal do nucleo espinal do nervo trigemeo durante artrite na articulação temporomandibular do rato

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Nitric oxide has been implicated in hyperalgesia modulation accompanying peripheral inflammation. In this study, we analyzed the effects of carrageenan-induced arthritis (CIA) in the unilateral temporomandibular joint (TMJ) on immunoreactivity and activity of the neuronal nitric oxide synthase (nNOS) in the caudal part of the rat spinal trigeminal nucleus (Sp5C) during the acute, chronic and chronic-active phases. In addition, double immunohistochemistry was used to verify Fos induction in nNOS neurons. The number of nNOS-like immunoreactive (nNOS-LI) neurons in the Sp5C was elevated and we observed a slight bilaterally increase in numbers of these neurons in the acute, chronic and chronic-active phases of CIA when compared to the respective sham groups, although the difference was less than statistically significant. A discrete percentage of nNOS-LI neurons expressed Fos immunoreactivity in all experimental groups. In addition, Ca2+-dependent NOS activity in the ipsilateral Sp5C was significantly higher (P<0.05) in the chronic phase than in the acute phase, chronic-active phase or in the sham group animals. In conclusion, since there was a large population of nNOS-LI neurons in the rat Sp5C, nitric oxide seems to play an important role in nociceptive processing under normal conditions. Furthermore, changes in Ca2+-dependent NOS activity in chronic arthritis show that NOS may play a role in the Sp5C central nociceptive mechanism during long-term TMJ arthritis

ASSUNTO(S)

temporomandibular temporomandibular joint oxido nitrico arthritis artrite nitric oxide articulação

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