ABSTRACT
ABSTRACT The most recently identified serotonin (5-HT) receptor is the 5-HT7 receptor. The antinociceptive effects of a 5-HT7 receptor agonist have been shown in neuropathic and inflammatory animal models of pain. A recent study demonstrated the functional expression of 5-HT7 receptors in the substantia gelatinosa (SG) of the trigeminal subnucleus caudalis, which receives and processes orofacial nociceptive inputs. Objective To investigate the antinociceptive effects of pharmacological activation of 5-HT7 receptors on orofacial pain in mice. Material and Methods Nociception was evaluated by using an orofacial formalin test in male Balb-C mice. Selective 5-HT7 receptor agonists, LP 44 and LP 211 (1, 5, and 10 mg/kg), were given intraperitoneally 30 min prior to a formalin injection. A bolus of 10 µl of 4% subcutaneous formalin was injected into the upper lip of mice and facial grooming behaviors were monitored. The behavioral responses consisted of two distinct periods, the early phase corresponding to acute pain (Phase I: 0–12 min) and the late phase (Phase II: 12–30 min). Results LP 44 and LP 211 (1, 5, and 10 mg/kg) produced an analgesic effect with reductions in face rubbing time in both Phase I and Phase II of the formalin test. Conclusion Our results suggest that 5-HT7 receptor agonists may be promising analgesic drugs in the treatment of orofacial pain.
Subject(s)
Animals , Male , Mice , Piperazines/therapeutic use , Facial Pain/drug therapy , Receptors, Serotonin , Serotonin Receptor Agonists/therapeutic use , Analgesics/therapeutic use , Substantia Gelatinosa/drug effects , Time Factors , Trigeminal Nerve/drug effects , Facial Pain/chemically induced , Reproducibility of Results , Treatment Outcome , Disease Models, Animal , Dose-Response Relationship, Drug , Formaldehyde , Mice, Inbred BALB CABSTRACT
Trigeminal neuralgia (TN) patients may develop side effects from centrally acting drugs, have contraindications for neurosurgical procedures, or experience relapse during conventional therapies. OnabotulinumtoxinA (BoNT/A) has been reported to be effective for TN, although this finding has been challenged. An overview of the available evidence based on a narrative/qualitative analysis of the literature is presented. About 90% of patients who receive BoNT/A show an improvement, a higher figure than that reported for the placebo effect of BoNT/A for other headaches. Tolerability of BoNT/A is good, and its few side-effects are transient. The articles reviewed were mainly case reports, case series and open-label trials; however, randomized controlled trials have endorsed the efficacy of BoNT/A for TN. This evidence, together with a better understanding of the analgesic mechanisms of BoNT/A and its proven efficacy in treating other pain syndromes, supports the use of this toxin as a therapeutic option for TN.
Pacientes com neuralgia do trigêmeo (NT) podem apresentar efeitos colaterais decorrentes do uso de drogas psicoativas, contra-indicações a procedimentos neurocirúrgicos ou perda da eficácia destas terapias. A neurotoxina botulínica do tipo A (NTB/A) tem demonstrado ser eficaz no alívio da NT, ainda que este achado tenha sido contestado. Uma análise narrativa/qualitativa da literatura disponível é apresentada. Cerca de 90% dos pacientes que receberam NTB/A melhoram, um número superior aos atribuíveis ao efeito placebo da NTB/A em outras cefaléias. Além disso, a NTB/A mostrou uma baixa incidência de efeitos colaterais, transitórios. Embora a maioria dos artigos consistam de relatos de caso, séries de casos e ensaios abertos, ensaios clínicos randomizados controlados recentes reafirmam a eficácia da NTB/A na NT. Estas evidências, associadas ao melhor entendimento dos mecanismos analgésicos da NTB/A e a sua eficácia em outras síndromes dolorosas, ratificam a NTB/A como uma opção terapêutica para a NT.
Subject(s)
Animals , Humans , Acetylcholine Release Inhibitors/therapeutic use , Botulinum Toxins, Type A/therapeutic use , Trigeminal Neuralgia/drug therapy , Placebo Effect , Trigeminal Nerve/drug effects , Trigeminal Neuralgia/physiopathology , Visual Analog ScaleABSTRACT
Classical trigeminal neuralgia (CTN) is treated predominantly by pharmacotherapy but side effects and unsuccessful occurs. The current study was carried out to evaluate the therapeutic effect of combination of pharmacotherapy and lidocaine block. Thirteen patients with CTN managed with pharmacotherapy were recruited and assigned either to no additional treatment (Group I) or to additional analgesic block (Group II). The primary endpoint was the reduction in the frequency of pain episodes in a month assessed at 30 and 90 days. Comparisons of measurements of pain, general health and depression scales were secondary endpoints. The results from the follow-up visits at 30 and 90 days showed the Group II to have larger reduction in the frequency of pain and exhibited a bigger improvement in the scores of the pain, general health and depression scales. The results from this preliminary study suggest a clinical benefit of the combination of pharmacotherapy and lidocaine block.
A neuralgia clássica do trigêmio (NTC) é tratada predominantemente por drogas, porém efeitos colaterais e falhas terapêuticas ocorrem. Avaliamos o efeito terapêutico da combinação entre farmacoterapia e bloqueio analgésico utilizando a lidocaína. Treze pacientes portadores de NTC tratados com farmacoterapia foram divididos em dois grupos: Grupo I pacientes que mantiveram somente tratamento medicamentos e Grupo II pacientes que associaram bloqueio anestésico. O objetivo primário do estudo foi à redução da freqüência da dor 30 e 90 dias após o bloqueio. Secundariamente avaliamos o impacto sobre as escalas de depressão, dor e qualidade de vida. O grupo II teve uma redução significativa na freqüência da dor e uma melhora nos escores de qualidade de vida, dor e escala de depressão. Os resultados sugerem um benefício clinico da combinação de farmacoterapia e bloqueio anestésico no tratamento da NTC.