The analgesic effect of crotoxin on neuropathic pain is mediated by central muscarinic receptors and 5-lipoxygenase-derived mediators

Crotoxin (CTX). a neurotoxin isolated from the venom of the South American rattlesnake Crotalus durissus terrificus. induces analgesia. In this study, we evaluated the antinociceptive effect of CTX in a model of neuropathic pain induced by rat sciatic nerve transection. Hyperalgesia was detected 2 h after nerve transection and persisted for 64 days. Immersion of proximal and distal nerve stumps in CTX solution (0.01 mM for 10 s), immediately after nerve transection, blocked hyperalgesia. The antinociceptive effect of CTX was long-lasting, since it was detected 2 h after treatment and persisted for 64 days. CTX also delayed, but did not block, neurectomy-induced neuroma formation. The effect of CTX was blocked by zileuton (100 mg/kg, p.o.) and atropine (10 mg/kg. i.p.), and reduced by yohimbine (2 mg/kg, i.p.) and methysergide (5 mg/kg, i.p.). on the other hand. indomethacin (4 mg/kg, i.v.). naloxone (1 mg/kg, i.p.). and N-methyl atropine (30 mg/kg, i.p.) did not interfere with the effect of CTX. These results indicate that CTX induces a long-lasting antinociceptive effect in neuropathic pain, which is mediated by activation of central muscarinic receptors and partially, by activation of alpha-adrenoceptors and 5-HT receptors. Eicosanoids derived from the lipoxygenase pathway modulate the action of crotoxin. (C) 2008 Elsevier B.V. All rights reserved.

Plant derived alkaloid (-)-cassine induces anti-inflammatory and anti-hyperalgesics effects in both acute and chronic inflammatory and neuropathic pain models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Association between neuropathic pain and A-Waves in Leprosy patients with type 1 and 2 reactions

Summary: Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. Of the 27 ulnar nerves of leprosy patients, 18 with type 1 reaction (T1R) and 9 with type 2 reaction (T2R) were followed-up for 6 months before and after steroid treatment. Clinical characteristics of pain complaints and clinical function were assessed, as well as the presence of F- and A-waves of the ulnar nerve using nerve conduction studies. The clinical and the neurophysiologic findings were compared to note positive concordances (presence of NP and A-waves together) and negative concordances (absence of NP and A-waves together) before and after treatment. Both reactions presented a high frequency of A-waves (61.1% in T1R and 66.7% in T2R, P < 0.05) and prolonged F-waves (69.4% in T1R and 65.8% in T2R, P = 0.4). No concordances were seen between pain complaints and F-waves. However, significant concordances between NP and A-waves were observed, although restricted to the T2R group ([chi]2 = 5.65, P = 0.04). After treatment, there was a significant reduction in pain complaints, as well as the presence of F- and A-waves in both groups (P < 0.05 for all comparisons). In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.

Fos-like immunoreactivity in central nervous system of mice simultaneously exposed to the elevated plus-maze and nociception

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Harmful effects of carbamazepine on the postnatal development of the rat ventral prostate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação dos efeitos da crotoxina isolada do veneno de serpente Crotalus durissus terrificus sobre a transecção do nervo ciático de ratos: avaliação histológica da formação do neuroma e capacidade de interferir com a condutividade nervosa (dor)

Pós-graduação em Medicina Veterinária - FMVZ

Citral: A monoterpene with prophylactic and therapeutic anti-nociceptive effects in experimental models of acute and chronic pain

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Intercostal nerve mononeuropathy: study of 14 cases

Este trabalho apresenta estudo retrospectivo de 14 pacientes com mononeuropatia de nervo intercostal (MNI), obtidos dentre 5.560 exames eletromiográficos, realizados de janeiro de 1991 até junho de 2004, em nosso Hospital Universitário. MNI foi encontrada em 14 pacientes, tendo como causas prováveis intervenções cirúrgicas torácicas em 6 (43%), neuropatia por herpes-zoster em 4 (28%), provável neurite de nervo intercostal em 2 (14%), neoplasia pulmonar em 1 (7%) e radiculopatia em 1 (7%). As principais causas de MNI de nosso Serviço são similares às da literatura. Os antidepressivos tricíclicos e anticonvulsivantes foram os fármacos mais utilizados no controle da dor.

The Effects of Subarachnoid Administration of Preservative-Free S(+)-Ketamine on Spinal Cord and Meninges in Dogs

BACKGROUND: The N-methyl-D-aspartate receptor antagonist ketamine and its active enantiomer, S(+)-ketamine, have been injected in the epidural and subarachnoid spaces to treat acute postoperative pain and relieve neuropathic pain syndrome. In this study we evaluated the effects of a single dose of preservative-free S(+)-ketamine, in doses usually used in clinical practice, in the spinal cord and meninges of dogs.METHODS: Under anesthesia (IV etomidate (2 mg/kg) and fentanyl (0.005 mg/kg), 16 dogs (6 to 15 kg) were randomized to receive a lumbar intrathecal injection (L5/6) of saline solution of 0.9% (control group) or S(+)-ketamine 1 mg/kg(-1) (ketamine group). All doses were administered in a volume of 1 mL over a 10-second interval. Accordingly, injection solution ranged from 0.6% to 1.5%. After 21 days of clinical observation, the animals were killed; spinal cord, cauda equine root, and meninges were removed for histological examination with light microscopy. Tissues were examined for demyelination (Masson trichrome), neuronal death (hematoxylin and eosin) and astrocyte activation (glial fibrillary acidic protein).RESULTS: No clinical or histological alterations of spinal tissue or meninges were found in animals from either control or ketamine groups.CONCLUSION: A single intrathecal injection of preservative-free S(+)-ketamine, at 1 mg/kg-1 dosage, over a concentration range of 6 to 15 mg/mL injected in the subarachnoid space in a single puncture, did not produce histological alterations in this experimental model. (Anesth Analg 2012;114:450-55)

The Neuraxial Effects of Intraspinal Amitriptyline at Low Concentrations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Manejo da dor inguinal crônica pós-hernioplastia (inguinodinia)

A dor inguinal crônica pós-herniorrafia é uma situação preocupante, pois aproximadamente 10% dos pacientes submetidos à hernioplastia inguinal apresenta os sintomas, que com frequência limita a capacidade física. A etiopatogênese está relacionada a uma periostite do púbis (dor somática) e mais frequentemente à lesão nervosa (dor neuropática). É importante distinguir clinicamente entre os dois tipos de dor, pois o tratamento pode ser diferente. O médico deve estabelecer uma rotina diagnóstica e de tratamento, sendo que a maior parte dos pacientes necessitarão de terapêutica cirúrgica. A prevenção desta condição é de grande importância e pode levar a uma menor incidência da síndrome. Algumas medidas são fundamentais, como evitar pontos ou clipes no periósteo do púbis, usar criteriosamente as próteses e identificar os nervos da região inguinal. Esta última medida é certamente a mais importante na prevenção da dor crônica e implica em conhecimento profundo da anatomia e o uso de uma técnica aprimorada.

Efeito analgésico de longa duração da dipirona sobre a hiperalgesia persistente induzida pela constrição do nervo ciático em ratos: participação do óxido nítrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Abscesso do músculo psoas em paciente submetida à analgesia por via peridural. Relato de caso

BACKGROUND AND OBJECTIVES: Psoas muscle abscess is a rare complication of epidural analgesia. The adequate approach to this complication is fundamental for a good resolution. The objective of this report was to discuss the diagnosis and treatment of psoas muscle abscess. CASE REPORT: A female patient, 65 years old, with neuropathic pain in the lower limbs, difficult to control with systemic drugs. The patient was treated with epidural opioid and local anesthetic as an alternate treatment. Twenty days after the continuous epidural administration, the patient complained of lumbar pain, headache, and fever. A CT scan of the pelvis showed an abscess of the psoas muscle, thus, closed drainage and antibiotics were indicated. CONCLUSIONS: An adequate, continuous supervision of the patient is necessary when an epidural catheter is placed, and it should continue after its removal. © Sociedade Brasileira de Anestesiologia, 2007.

Métodos de avaliação da eficácia dos tratamentos para a dor.

Pain is a subjective condition and, thus, difficult to measure. The best tools to assess pain are the pain evaluation questionnaires, which provide either diagnostic, pain evolution or pain intensity information. To provide information which could help differentiate between nociceptive pain and neuropathic pain is one of the most important functions of these questionnaires. The questionnaires can measure pain intensity, quality of life, or sleep quality. Quality of life and sleep are two really important characteristics to assess the pain impact on patients' life. Pain intensity assessing questionnaires combine physical evaluations with questions, providing information either from the patient sensations or clinical assessment of pain manifestations as well as the underlying biological mechanisms (such as hyperalgesia or allodynia). For example, the Pain Detect questionnaire has two parts: the patient form (intuitive, with pictures and easy understandable) and the physician form. Thus, in this questionnaire, subjective information is provided by the patient and the objective one is provided by the physician. Other pain intensity questionnaires are NPSI, DN4, LANSS or StEP. Quality of life questionnaires are versatile (can be used in different pathologies). These questionnaires include functional self-evaluation questions, and other ones associated to physical and mental health. Two of such quality of life questionnaires are SF-36 and NHP. Sleep evaluation questionnaires include quantitative features such as the number of sleep interruptions, sleep latency or sleep duration as well as qualitative characteristics such as rest sensation, mood and dreams. One of the most used sleep evaluation questionnaires is PSQI, which includes patient questions and bed-partner questions, providing information from two points of view. Copyright 2009 Prous Science, S.A.U. or its licensors. All rights reserved.