Desenvolvimento de um modelo comportamental de dor na ATM de ratos : participação dos receptores H1

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

The TMJ pain conditions are poorly understood. Considering that the subcutaneous formalin injection has been widely used as an experimental model for studying pain mechanisms, the aim of this study was to characterize the nociceptive behavioral responses induced by the formalin injection into the TMJ region of rats and verify the role of the peripheral Hl histaminergic receptor in this response. For this, NaCl 0.9 % (50 `mu´l) or different concentrations of formalin (0.5, 1.5, 2.5 or 5 %) was administrated into the TMJ region and pyrilamine (50, 100, 200 or 400 `mu´g; 25 `mu´l), a selective Hl receptor antagonist, or NaCl 0.9 % (25 `mu´l) was coadministrated with formalin 5 % (25 `mu´l). The nociceptive behavioral responses characterized by rubbing the periarticular region and shaking the head quickly were quantified for 45 minutes and taken together as a quantitative nociceptive behavioral measure. The formalin injection into the TMJ region produced significant nociceptive behavioral responses from the concentration of 1.5 % when compared to the NaCl 0.9% injection. These responses were significantly reduced by the co-administration of pyrilamine from the concentration of 100 `mu´g. In addition, these responses were significantly reduced toa by the co-administration of QX-314 2 % and formalin into the TMJ region and by the intraperitoneal morphin administration (4mg/kg; 10ml/kg). This study demonstrates that the formalin injection into the TMJ region of rats produces quantitative nociceptive behaviors constituting a new behavioral model of TMJ pain. The data provide evidence that the endogenous histamine acting via peripheral HI histamine receptor subtype plays an important role in these formalin-induced nociceptive behavioral responses

ASSUNTO(S)

articulação temporomandibular formaldeido dor

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