Mechanical Antiallodynic Effect of Intrathecal Nefopam in a Rat Neuropathic Pain Model

Nefopam has a pharmacologic profile distinct from that of opioids or other anti-inflammatory drugs. Several recent studies demonstrate that nefopam has a mechanism of action similar to those of anti-depressants and anticonvulsants for treating neuropathic pain. The present study investigates the mechanical antiallodynic effect of nefopam using immunohistochemical study and western blot analysis in a rat neuropathic pain model. Twenty-eight male Sprague-Dawley rats were subjected to left fifth lumbar (L5) spinal nerve ligation and intrathecal catheter implantation, procedures which were not performed on the 7 male Sprague-Dawley rats in the sham surgery group (group S). Nefopam, either 10 or 100 microg/kg (group N10 or N100, respectively), and normal saline (group C) were intrathecally administered into the catheter every day for 14 days. The mechanical allodynic threshold of intrathecal nefopam was measured using a dynamic plantar aesthesiometer. Immunohistochemistry targeting cluster of differentiation molecule 11b (CD11b) and glial fibrillary acidic protein (GFAP) was performed on the harvested spinal cord at the level of L5. Extracellular signal-regulated kinase 1/2 (ERK 1/2) and cyclic adenosine monophosphate response element binding protein (CREB) were measured using western blot analysis. The N10 and N100 groups showed improved mechanical allodynic threshold, reduced CD11b and GFAP expression, and attenuated ERK 1/2 and CREB in the affected L5 spinal cord. In conclusion, intrathecal nefopam reduced mechanical allodynia in a rat neuropathic pain model. Its mechanical antiallodynic effect is associated with inhibition of glial activation and suppression of the transcription factors' mitogen-activated protein kinases in the spinal cord.

Analgesia preemptiva com nepafenaco 0, 1% na fotocoagulação da retina / Preemptive analgesia of nepafenac 0. 1% in retinal photocoagulation

Objetivo: Avaliar o efeito preemptivo com nepafenaco 0,1% em pacientes submetidos à fotocoagulação da retina para tratamento da retinopatia diabética proliferativa. Métodos: Trinta pacientes foram submetidos à fotocoagulação com laser de argônio em ambos os olhos. O olho contralateral de cada paciente foi o controle. O nepafenaco e o placebo foram utilizados 30 minutos antes da aplicação do laser. Ambos os olhos foram fotocoagulados no mesmo dia. A intensidade da dor foi avaliada por meio da escala analógica visual e da escala descritiva de dor. Resultados: A análise da interação instilação versus nepafenaco mostrou que os pacientes do grupo placebo apresentaram níveis de dor semelhantes em ambos os olhos, e os do grupo nepafenaco apresentaram redução importante do nível de dor no olho em que foi instilado a suspensão de 0,1% quando comparado ao olho contralateral que recebeu placebo (p=0,023). Conclusão: Este estudo sugere que a suspensão de 0,1% de nepafenaco foi útil na analgesia preemptiva de pacientes submetidos à fotocoagulação de retina quando comparada ao placebo. .

Objective: To evaluate the preemptive effect of nepafenac 0,1% in patients undergoing retinal photocoagulation for the treatment of proliferative diabetic retinopathy Methods: Thirty patients underwent argon laser photocoagulation in both eyes. The contralateral eye of each patient was the control. The nepafenac and placebo were used 30 minutes before the application of the laser. Both eyes were photocoagulated in the same day. Pain intensity was assessed by visual analog scale and descriptive pain scale Results: The analysis of the interaction instillation versus nepafenac showed that patients in the placebo group had similar levels of pain in both eyes, and the nepafenac group had significant reduction in pain in the eye that was instilled suspension of 0,1% when compared to the contralateral eye which received placebo (p = 0.023). Conclusion: This study suggests that a suspension of 0,1% nepafenac helpful for preemptive analgesia in patients undergoing retinal photocoagulation compared to placebo. .

[ effects of testosterone and gonadectomy conditions on nociception and their effect on morphine-induced analgesia in male mice, using the formalin test]

There are too many disagreements about the effects of gender and sex hormones on the behavioral responses to noxious stimuli and morphine analgesia. The purpose of this study was to determine the different effects of testosterone and gonadectomy conditions on pain and morphine-induced analgesia, using the formalin test. The present study was conducted at Razi University, in Kermanshah. Sixty three male NMRI mice were divided into nine groups [n=7]. The effects of gonadectomy and testosterone on responses to noxious stimuli were evaluated in five groups [G1 to G5]. The effects of these factors on morphine-induced analgesia were investigated in other groups [G6 to G9]. According to grouping, each group received normal saline, testosterone, testosterone solvent or morphine and some groups were also gonadectomized and separately received these agents. Finally, the formalin test was taken from all groups. Data were statistically analyzed by one-way ANOVA. The results showed that the response to the painful stimuli had no significant difference in 5 minutes [acute pain] in all groups. Testosterone increased the response to the noxious stimuli in sub acute pain [10-30 minutes] and chronic phase [15-60 minutes] stages. This increase was significant in the group receiving testosterone compared with the gonadectomized group in both stages. In the presence of morphine, there were no significant differences in response to painful stimulus in 5 minutes [acute pain] in all groups. But testosterone in the presence of morphine caused an increased in pain score in sub acute pain [10-30 minutes] and chronic phase [15-60 minutes] stages. Testosterone increased the response to the painful stimuli in sub acute and chronic pain stages. Testosterone also reduced morphine-induced analgesia in peripheral and chronic pain stages in mice