Is myofascial pain of the temporal muscles relieved by oral sumatriptan? A cross-over pilot study
ABSTRACT There is evidence that serotonin may be implicated in the pathophysiology of myofascial pain (MFP). Because of this, we used oral sumatriptan (Imitrex, Glaxo), a peripherally acting agonist of 5-HT1D receptors, in a double-blind, randomized, placebo-controlled double crossover pilot study of 7 patients with episodic MFP of the temporalis muscles. The results showed that there was a significant reduction in pain intensity and increase in pain relief over time with both the active medication and the placebo, but no significant difference between treatments. All but 1 patient reported that they are not interested in retaking the same medication. These data suggest that oral sumatriptan may not be the drug of choice in the control of episodic MFP.
- SourceAvailable from: Ik-Soon Jang
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- "However, it should be noted that mechanisms operating at room temperature might be not the same as those prevailing at physiological temperature. Triptans, such as sumatriptan, naratriptan and zolmitriptan , have a selective analgesic action on some types of cranial pain, including migraine and cluster headache (Ekbom et al., 1995; Ahn and Basbaum, 2005), but not facial or somatic pain (Dao et al., 1995; Antonaci et al., 1998). In peripheral tissues, the anti-migraine action of triptans is mainly mediated by both 5-HT1B and 5-HT1D receptors. "
ABSTRACT: Although 5-HT(1B) receptors are expressed in trigeminal sensory neurons, it is still not known whether these receptors can modulate nociceptive transmission from primary afferents onto medullary dorsal horn neurons. Primary afferent-evoked EPSCs were recorded from medullary dorsal horn neurons of rat horizontal brain stem slices using a conventional whole-cell patch clamp technique under a voltage-clamp condition. CP93129, a selective 5-HT(1B) receptor agonist, reversibly and concentration-dependently decreased the amplitude of glutamatergic EPSCs and increased the paired-pulse ratio. In addition, CP93129 reduced the frequency of spontaneous miniature EPSCs without affecting the current amplitude. The CP93129-induced inhibition of EPSCs was significantly occluded by GR55562, a 5-HT(1B/1D) receptor antagonist, but not LY310762, a 5-HT(1D) receptor antagonist. Sumatriptan, an anti-migraine drug, also decreased EPSC amplitude, and this effect was partially blocked by either GR55562 or LY310762. On the other hand, primary afferent-evoked EPSCs were mediated by the Ca(2+) influx passing through both presynaptic N-type and P/Q-type Ca(2+) channels. The CP93129-induced inhibition of EPSCs was significantly occluded by ω-conotoxin GVIA, an N-type Ca(2+) channel blocker. The present results suggest that the activation of presynaptic 5-HT(1B) receptors reduces glutamate release from primary afferent terminals onto medullary dorsal horn neurons, and that 5-HT(1B) receptors could be, at the very least, a potential target for the treatment of pain from orofacial tissues.British Journal of Pharmacology 03/2012; 167(2):356-67. DOI:10.1111/j.1476-5381.2012.01964.x · 4.99 Impact Factor
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- "Estudo do impacto da enxaqueca na severidade da dor miofascial da musculatura mastigatória Dao et al. 6 , em 1995, analisando uma amostra composta por pacientes com enxaqueca, relataram melhora dos sintomas de dor muscular após administração de dihidroergotamina-45 ou um triptano, ambas as medicações para tratamento abortivo de enxaquecas. Entretanto, em populações com dor orofacial, especialmente com DMF, há relatos do contrário 7 . "
ABSTRACT: OBJETIVO: comparar a severidade da dor subjetiva e objetiva, além de outras características associadas entre pacientes com dor miofascial com e sem o diagnóstico adicional de enxaqueca. MÉTODOS: foram selecionados 203 pacientes, com idade média de 40,3 anos (89,2% do sexo feminino), que se apresentaram à Clínica de Dor Orofacial da Universidade da Califórnia, Los Angeles, EUA todos com diagnóstico primário de dor miofascial. Pacientes com diagnóstico secundário de enxaqueca foram incluídos (n=83) e formaram o grupo 2. O teste de Mann-Whitney foi utilizado para comparar o grupo 1 (dor miofascial) com o 2 (dor miofascial + enxaqueca) quanto à intensidade de dor à palpação e subjetiva, através de Escalas Analógicas Visuais (EAV). Também com o auxílio de EAV, foram comparados estado de humor, problemas com a função, qualidade do sono e incapacidade. Em todos os testes foi adotado um nível de significância de 5%. RESULTADOS: o grupo 2 apresentou níveis de dor à palpação muscular estatisticamente maiores que o grupo 1 (p<0,05). Ao se analisar a intensidade de dor subjetiva obtida através da EAV, o grupo 2 apresentou níveis maiores de dor subjetiva (EAV) em todas as medições, com significância estatística para "dor no momento" e "dor máxima" (p<0,05). Da mesma maneira, o grupo 2 mostrou níveis maiores, obtidos através da EAV, de problemas com humor, incapacidade, problemas com a função mandibular e problemas com sono/descanso, sendo que apenas o último apresentou significância estatística (p<0,05). CONCLUSÕES: a comorbidade enxaqueca exerce forte impacto na severidade da dor e na qualidade de vida de pacientes que apresentam diagnóstico primário de dor miofascial.08/2011; 16(4):103-110. DOI:10.1590/S2176-94512011000400017
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- "However, because 5-HT 1D receptors are present on nociceptors throughout the body, it is surprising that triptans are reportedly effective treatments for only migraine and cluster headache (Ekbom et al., 1995). They are apparently not useful for other primary headache disorders (Antonaci et al., 1998), or other painful disorders of the head (Dao et al., 1995; Harrison et al., 1997), and are not used in the treatment of somatic pain conditions. "
ABSTRACT: The anti-migraine action of "triptan" drugs involves the activation of serotonin subtype 1D (5-HT1D) receptors expressed on "pain-responsive" trigeminal primary afferents. In the central terminals of these nociceptors, the receptor is concentrated on peptidergic dense core vesicles (DCVs) and is notably absent from the plasma membrane. Based on this arrangement, we hypothesized that in the resting state the receptor is not available for binding by a triptan, but that noxious stimulation of these afferents could trigger vesicular release of DCVs, thus externalizing the receptor. Here we report that within 5 min of an acute mechanical stimulus to the hindpaw of the rat, there is a significant increase of 5-HT1D-immunoreactivity (IR) in the ipsilateral dorsal horn of the spinal cord. We suggest that these rapid immunohistochemical changes reflect redistribution of sequestered receptor to the plasma membrane, where it is more readily detected. We also observed divergent changes in 5-HT1D-IR in inflammatory and nerve-injury models of persistent pain, occurring at least in part through the regulation of 5-HT1D-receptor gene expression. Finally, we found that 5-HT1D-IR is unchanged in the spinal cord dorsal horn of mice with a deletion of the gene encoding the neuropeptide substance P. This result differs from that reported for the partial differential-opioid receptor, which is also sorted to DCVs, but is greatly reduced in preprotachykinin mutant mice. We suggest that a "pain"-triggered regulation of 5-HT1D-receptor expression underlies the effectiveness of triptans for the treatment of migraine. Moreover, the widespread expression of 5-HT1D receptor in somatic nociceptive afferents suggests that triptans could, in certain circumstances, treat pain in nontrigeminal regions of the body.The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 09/2006; 26(32):8332-8. DOI:10.1523/JNEUROSCI.1989-06.2006 · 6.75 Impact Factor