The influence of sex and menstrual cycle over the pain and electromyographic activity of masticatory muscles in subjects with temporomandibular disorders

Orientador: Maria Cecilia Ferraz de Arruda VeigaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: A mialgia mastigatória, é um dos principais sintomas em pacientes com disfunção temporomandibular (DTM); entretanto, sua patofisiologia ainda é pouco compreendida. Por isso, os objetivos deste trabalho foram investigar o efeito do sexo e do ciclo menstrual na atividade eletromiográfica (EMG) de pacientes com DTM, e a sensibilidade dolorosa, assim como os aspectos psicológicos destes mesmos pacientes. As respostas avaliadas, foram comparadas com as respostas do grupo controle. Os grupos DTM, foram compostos por 30 mulheres com ciclo menstrual regular; e por 23 homens. Os grupos controle, foram compostos por 30 mulheres com ciclo menstrual regular e por 30 homens, ambos sem DTM ou outras dores crÃ'nicas. Os voluntários foram avaliados, com base no Critério Diagnóstico de Pesquisa para DTM, (RDC/TMD) tanto para dor miofascial, como para artralgia (Eixo I). Os voluntários preencheram a Escala do Grau de Dor CrÃ'nica (GCPS), e as escalas de depressão e de sintomas físicos não-específicos (somatização) do RDC/TMD (Eixo II). A atividade EMG no repouso, foi registrada bilateralmente, nos músculos temporal anterior e músculos masseteres. A raiz quadrada da média (RMS) foi gerada a partir dos sinais EMG e foram normalizados, a partir dos valores obtidos durante a contração voluntária máxima. Os resultados mostraram diferenças EMG apenas nos músculos do lado esquerdo dos homens com DTM. Não houve diferenças significativas na atividade EMG dos músculos mastigatórios entre mulheres com e sem DTM. A dor miofascial foi maior na fase menstrual, comparada com as outras fases do ciclo menstrual. Além disso, as mulheres com DTM apresentaram maior GCPS, maior grau de depressão (moderado a severo), e pontuaram maiores itens de somatização (moderado a severo), comparado aos homens com DTM. Concluiu-se portanto, que: 1) Os homens com DTM apresentaram maior atividade EMG nos músculos do lado esquerdo da face, onde a dor foi mais prevalente. Não houve alteração na atividade EMG dos músculos mastigatórios de mulheres com DTM, sugerindo que existam diferenças sexuais nas respostas musculares induzidas pela dor; 2) a dor por DTM, é freqüentemente acompanhada por aspectos psicológicos, como depressão e somatização, principalmente em mulheresAbstract: The masticatory myalgia is one of the most common symptoms in temporomandibular disorder (TMD) patients; however, its pathophysioloy is poorly understood. Thus, the aims of this study were to investigate the effect of sex and pain on electromyographic activity (EMG); the effect of menstrual cycle phases on EMG activity; the influence of menstrual cycle on pain sensitivity; and the psychological aspects of TMD and control group. TMD cases were 30 normally cycling women; and 23 men. Controls were 30 normally cycling women and 30 men, without TMD or other chronic pains. The subjects were assessed based on Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) for both myofascial pain and arthralgia (Axis I). Subjects completed the RDC/TMD (Axis II), for Graded Chronic Pain Scale (GCPS), and measures of depression and nonspecific physical symptoms. EMG signals at rest were recorded bilaterally from the anterior temporal and masseter muscles. The root mean square (RMS) were computed from the EMG signals and normalized to the values obtained during maximal voluntary contractions. The results showed that were EMG differences only on the menâ?¿s TMD left masticatory muscles. There were no statistically significant differences in the EMG activity of masticatory muscles between women with and without TMD. The myofascial pain was significantly higher in menstrual phase compared with all of other phases of the menstrual cycle. Moreover, TMD women experienced higher GCPS, more moderately to severely graded depression, and scored greater moderate and severe somatization items than men TMD patients. It was concluded that: 1) The TMD men, presented higher EMG activity on the left side of the face, where pain was more prevalent. There was no significantly differences in EMG activity of womenâ?¿s TMD masticatory muscles, which indicates that the pain-induced changes in muscular responses could differ in men and women; 2) TMD pain is frequently accompanied by psychological aspects, like depression and somatization mainly in womenDoutoradoFisiologia OralDoutor em Odontologi

Influence of ethanol and morphine on pain perception evoked by deep tissue injury

O objetivo deste estudo foi avaliar o efeito do etanol e da morfina sobre as respostas comportamentais nociceptivas provocadas pelo teste da formalina na ATM de ratos (Teste da formalina na ATM). No experimento 1, os animais receberam uma solução de etanol 6,5 % ou água comum para beber durante 4 e 10 dias, antes da realização do teste da formalina na ATM. No grupo tratado por 4 dias, observou-se analgesia significativa ao teste da formalina, enquanto que no grupo tratado por 10 dias esse efeito não ocorreu, demonstrando o desenvolvimento de tolerância aos efeitos antinociceptivos do etanol. No experimento 2, os animais foram submetidos ao regime crônico de etanol (6,5% por 10 dias) e o grupo controle recebeu água comum para beber. Após esse período, foi administrado morfina (10 mg/kg i.p.) 30 minutos antes da realização do teste da formalina na ATM. A morfina teve o mesmo efeito analgésico nos 2 grupos, demonstrando que o tratamento com etanol não foi capaz de alterar a potência analgésica da morfina. Os resultados mostraram que o etanol é capaz de alterar as respostas nociceptivas relacionadas à dor proveniente de tecidos profundos, como a ATM, e a ausência de interação entre o etanol e a morfina indica que a analgesia induzida pelo etanol é mediada por mecanismos não-opióides.The aim of this study was to evaluate the effect of ethanol and morphine on nociceptive behavioral responses evoked by the injection of formalin into the temporomandibular joint region of rats (the TMJ formalin test). In experiment 1, animals were given an ethanol solution (6.5%) or tap water to drink for 4 and 10 days, before the procedure for TMJ pain. In the group treated for 4 days, significant analgesia was observed in the TMJ formalin test, whereas the group treated for 10 days did not show this effect, revealing the development of tolerance to ethanol antinociceptive effects. In experiment 2, animals were submitted to chronic regimen of ethanol (6.5% for 10 days) and the control group was given tap water to drink. After this period, morphine (10 mg/kg i.p.) was administrated 30 minutes before the TMJ formalin test. Morphine had the same analgesic effect in both groups, showing that the treatment with ethanol was not able to alter the analgesic potency of morphine. The results showed that ethanol can affect nociceptive behavioral responses related to pain from deep tissues, like the TMJ, and the absence of interaction between ethanol and morphine suggest that ethanol-induced analgesia was mediated by nonopiate mechanisms

Envolvimento do receptor opioide kapa na modulação da dor induzida pela formalina na ATM de ratas prenhas e na fase estro

Orientador: Maria Cecilia Ferraz de Arruda VeigaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaMestrad

Influence of ethanol and morphine on pain perception evoked by deep tissue injury A influência do etanol e da morfina sobre a percepção dolorosa provocada por injúria tecidual profunda

The aim of this study was to evaluate the effect of ethanol and morphine on nociceptive behavioral responses evoked by the injection of formalin into the temporomandibular joint region of rats (the TMJ formalin test). In experiment 1, animals were given an ethanol solution (6.5%) or tap water to drink for 4 and 10 days, before the procedure for TMJ pain. In the group treated for 4 days, significant analgesia was observed in the TMJ formalin test, whereas the group treated for 10 days did not show this effect, revealing the development of tolerance to ethanol antinociceptive effects. In experiment 2, animals were submitted to chronic regimen of ethanol (6.5% for 10 days) and the control group was given tap water to drink. After this period, morphine (10 mg/kg i.p.) was administrated 30 minutes before the TMJ formalin test. Morphine had the same analgesic effect in both groups, showing that the treatment with ethanol was not able to alter the analgesic potency of morphine. The results showed that ethanol can affect nociceptive behavioral responses related to pain from deep tissues, like the TMJ, and the absence of interaction between ethanol and morphine suggest that ethanol-induced analgesia was mediated by nonopiate mechanisms.<br>O objetivo deste estudo foi avaliar o efeito do etanol e da morfina sobre as respostas comportamentais nociceptivas provocadas pelo teste da formalina na ATM de ratos (Teste da formalina na ATM). No experimento 1, os animais receberam uma solução de etanol 6,5 % ou água comum para beber durante 4 e 10 dias, antes da realização do teste da formalina na ATM. No grupo tratado por 4 dias, observou-se analgesia significativa ao teste da formalina, enquanto que no grupo tratado por 10 dias esse efeito não ocorreu, demonstrando o desenvolvimento de tolerância aos efeitos antinociceptivos do etanol. No experimento 2, os animais foram submetidos ao regime crônico de etanol (6,5% por 10 dias) e o grupo controle recebeu água comum para beber. Após esse período, foi administrado morfina (10 mg/kg i.p.) 30 minutos antes da realização do teste da formalina na ATM. A morfina teve o mesmo efeito analgésico nos 2 grupos, demonstrando que o tratamento com etanol não foi capaz de alterar a potência analgésica da morfina. Os resultados mostraram que o etanol é capaz de alterar as respostas nociceptivas relacionadas à dor proveniente de tecidos profundos, como a ATM, e a ausência de interação entre o etanol e a morfina indica que a analgesia induzida pelo etanol é mediada por mecanismos não-opióides

Effects of ethanol on deep pain evoked by formalin injected in TMJ of rat

It has been reported that ethanol can alter nociceptive sensitivity from superficial tissues, such as skin and subcutaneous region. However, the influence of ethanol on deep pain conditions is not understood. The aim of this study was to demonstrate the acute, chronic and ethanol withdrawal effects on nociceptive behavioral responses induced by the injection of formalin into the temporomandibular joint (TMJ) region of rats. In experiment 1, rats were injected with ethanol (2,5 g/Kg, i.p.) or an equal volume of saline 15 min before the administration of formalin (1.5%) into the TMJ. Rats pretreated with ethanol showed a decrease in nociceptive behavioral responses. In experiment 2, rats were given an ethanol solution (6.5%) or tap water to drink for 4 and 10 days. On day 4, the animals (ethanol group) showed amounts of analgesia when submitted to the TMJ formalin test. Tolerance to the antinociceptive effects was observed on day 10. Behavioral hyperalgesia was verified 12 hr after withdrawal in another group that drank ethanol for 10 days. These results show that ethanol can affect the nociceptive responses related to deep pain evoked by the TMJ formalin test.It has been reported that ethanol can alter nociceptive sensitivity from superficial tissues, such as skin and subcutaneous region. However, the influence of ethanol on deep pain conditions is not understood. The aim of this study was to demonstrate the acute, chronic and ethanol withdrawal effects on nociceptive behavioral responses induced by the injection of formalin into the temporomandibular joint (TMJ) region of rats. In experiment 1, rats were injected with ethanol (2,5 g/Kg, IP) or an equal volume of saline 15 min before the administration of formalin (1,5%) into the TMJ. Rats pretreated with ethanol showed a decrease in nociceptive behavioral responses. In experiment 2, rats were given an ethanol solution (6,5%) or tap water to drink for 4 and 10 days. On day 4, the animals (ethanol group) showed amounts of analgesia when submitted to the TMJ formalin test. Tolerance to the antinociceptive effects was observed on day 10. Behavioral hyperalgesia was verified 12 hr after withdrawal in another group that drank ethanol for 10 days. These results show that ethanol can affect the nociceptive responses related to deep pain evoked by the TMJ formalin test73263351336

Nociception- And Anxiety-like Behavior In Rats Submitted To Different Periods Of Restraint Stress.

The aim of this study was to evaluate the effect of acute, sub-chronic and chronic stress on nociception induced by formalin injection in rats' temporomandibular joint (TMJ). It was evaluated the relation between blood levels of adrenocorticotropin, corticosterone, the levels of anxiety and nociceptive responses recorded after different stress protocols. Animals were initially submitted to acute restraint stress (15; 30 min and 1 h), or exposed to sub-chronic (3 days-1 h/day) or chronic stress (40 days-1 h/day). Then, animals were (1) killed immediately to collect blood for hormonal determinations; or (2) submitted to the elevated plus-maze to evaluate anxiety; or (3) submitted to the TMJ formalin test to evaluate nociception. It was also evaluated the role of serotoninergic and opioid systems in nociceptive changes induced by stress. For this, the serotonin-selective reuptake inhibitor (fluoxetine 10 mg/kg) and the opioid agonist (morphine 1-5 mg/kg) were administered before the nociception test. All stress protocols significantly raised the levels of ACTH or corticosterone, as well as the anxiety behavior. In relation to nociception, the chronic stressed animals showed an increase in nociceptive responses (hyperalgesia). In this group, there was a reduction in the morphine analgesic effects, suggesting dysfunction in the endogenous opioid system. Fluoxetine had an analgesic effect in both stressed and control groups, although this effect was more evident in the stressed group. It was concluded that stress-induced hyperalgesia may result from changes in the serotoninergic and opioid systems, which can explain, at least in part, the important link between stress and orofacial pain.87643-