Objective: To determine if the magnitude of the force used to induce incisor tooth movement promotes distinct activation in cells in the central amygdala (CEA) and lateral hypothalamus (LH) of rats. Also, the effect of morphine on Fos immunoreactivity (Fos-IR) was investigated in these nuclei. Materials and Methods: Adult male rats were anesthetized and divided into six groups: only anesthetized (control), without orthodontic appliance (OA), OA but without force, OA activated with 30g or 70g, OA with 70g in animals pretreated with morphine (2 mg/kg, intraperitoneal). Three hours after the onset of the experiment the rats were reanesthetized and perfused with 4% paraformaldehyde. The brains were removed and fixed, and sections containing CEA and LH were processed for Fos protein immunohistochemistry. Results:The results show that in the control group, the intramuscular injection of a ketamine/ xylazine mixture did not induce Fos-IR cells in the CEA or in the LH. Again, the without force group showed a little Fos-IR. However, in the 70g group the Fos-IR was the biggest observed (P Ͻ .05, Tukey) in the CEA and LH compared with the other groups. In the 30g group, the Fos-IR did not differ from the control group, the without OA group, and the without force group. Furthermore, pretreatment with morphine in the 70g group reduced Fos-IR in these regions. Conclusions: Tooth movement promotes Fos-IR in the CEA and LH according to the magnitude of the force applied. (Angle Orthod. 2010;80:111-115.)

This study evaluated whether the administration of a NSAID, sodium diclofenac, can promote alterations in the expression of Fos protein in central amygdala (CEA) and the lateral hypothalamus (LH) after 6 h of experimental tooth movement with a controlled force of 70 g, applied to the superior central incisors of rats. Adult male rats were anesthetized and divided into four groups: Control, no orthodontic appliance (OA); OA activated with 70 g; OA activated with 70 g and pretreated with diclofenac sodium (5 mg/kg, intramuscular); and diclofenac sodium alone. Six hours after the onset of the experiment the rats were reanesthetized and perfused with 4% paraformaldehyde. The brains were removed and fixed, and sections containing the CEA and LH were processed for Fos protein immunohistochemistry. The results show that in the control group, intramuscular injection of a ketamine/xylazine mixture did not induce IR-Fos cells in the CEA or LH. However, in the 70 g group, IR-Fos was the strongest observed (P < 0.05, Newman-Keuls) in the CEA and LH compared with the other groups. Furthermore, pretreatment with sodium diclofenac reduced IR-Fos in these regions. Pretreatment with diclofenac sodium reduced Fos protein immunoreactivity in the CEA and LH induced by orthodontic force application. The expression of Fos protein in the CEA and LH is dependent, at least in part, on the inflammatory reaction induced by teeth movement. Diclofenac can be an alternative medication of choice for relief of orthodontic pain.

Dedico este trabalho, A Deus, pois Sua força me fez caminhar entre as adversidades, superar os desafios da vida e alcançar o quanto almejei. Aos meus pais, Paulo e Raquel, fundamentais em minha vida, razão pela qual foi possível conquistar meus objetivos. Devo tudo a vocês! A minha irmã Juliana, companheira de todas as horas, presença certa em todos os momentos. Ao Jorge, pela amizade, carinho, companheirismo e incentivo ao longo dessa caminhada. vi MEUS SINCEROS AGRADECIMENTOS A Profa. Dra. Christie Ramos Andrade Leite Panissi, fonte de inspiração, amizade e dedicação, durante todos estes anos, sendo fundamental para o desenvolvimento deste trabalho; fornecendo, ainda, valiosos ensinamentos que levarei por toda a vida. A Profa. Dra Maria José Alves da Rocha, por me acolher em seu laboratório e por sua valorosa contribuição desde o início do desenvolvimento deste trabalho. A Profa Dra Juliana Mazzonetto Teófilo, pela fundamental colaboração na realização do processamento histológico. Aos professores da banca, pela atenção dispensada na leitura desta dissertação. Aos amigos do laboratório: Alberto, Aline, Amanda, Bruno, Eveline e Priscila, pela amizade e suporte, essenciais à consecução de mais esta etapa de minha busca por conhecimento. Aos funcionários do Biotério I da FORP, Sr. Antônio Sérgio Aparecido Mesca e Sr. Antônio Massaro pelos cuidados com os animais experimentais. A Regiane de Cássia Tirado Damasceno, secretária do Programa de Pós-Graduação de Biologia Oral da FORP-USP e Lucimeire Resende Ribeiro, técnica acadêmica do Departamento de Morfologia, Estomatologia e Fisiologia da FORP-USP, que prestaram inestimável auxílio nos aspectos formais que aqui foram despendidos. A CAPES, PROEX e FAPESP, pelo apoio financeiro.