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Descending mechanisms activated by the anterior pretectal nucleus initiate but do not maintain neuropathic pain in rats.
Rossaneis, A C; Genaro, K; Dias, Q M; Guethe, L M; Fais, R S; Del Bel, E A; Prado, W A.
Afiliación
  • Rossaneis AC; Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
  • Genaro K; Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
  • Dias QM; Oswaldo Cruz Foundation, Fiocruz Rondônia, Brazil.
  • Guethe LM; Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
  • Fais RS; Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
  • Del Bel EA; Department of Morphology, Estomatology and Physiology, Faculty of Odontology of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.
  • Prado WA; Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
Eur J Pain ; 19(8): 1148-57, 2015 Sep.
Article en En | MEDLINE | ID: mdl-25487357
BACKGROUND: The anterior pretectal nucleus (APtN) activates descending mechanisms of pain control. This study evaluated whether the APtN also controls neuropathic pain in rats. METHODS: The hypersensitivity to mechanical stimulation with an electronic von Frey apparatus and the number of Fos-immunoreactive (Fos-ir) neurons in the APtN were evaluated in rats before and after chronic constriction injury of the sciatic nerve. RESULTS: The tactile hypersensitivity was characterized by an initial phase (the 2 days following the injury) and a maintenance phase (the subsequent 7 days). The injection of 2% lidocaine (0.25 µL) or N-methyl-D-aspartate (2.5 µg/0.25 µL) into the APtN intensified the tactile hypersensitivity observed 2 days after injury but did not alter the tactile hypersensitivity observed 7 and 14 days after injury. The injection of naloxone (10 ng/0.25 µL) or methysergide (40 pg/0.25 µL) but not atropine (100 ng/0.25 µL) into the APtN also intensified the tactile hypersensitivity observed 2 days after the injury. A significant increase in the number of Fos-ir cells was found in the contralateral APtN 2 days but not 7 or 14 days after the injury. Electrical stimulation of the APtN reduced the tactile hypersensitivity at 2, 7 and 14 days after the nerve ligation. CONCLUSION: APtN exerts a tonic inhibitory influence on persistent pain. The results point out to an important role of opioid and serotonergic mediation into the APtN to inhibit hyperalgesia during the initial phase of neuropathic pain.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Área Pretectal / Vías Nerviosas / Neuralgia Límite: Animals Idioma: En Revista: Eur J Pain Asunto de la revista: NEUROLOGIA / PSICOFISIOLOGIA Año: 2015 Tipo del documento: Article País de afiliación: Brasil Pais de publicación: Reino Unido
Texto completo
Añadir a Mi BVS
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XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Área Pretectal / Vías Nerviosas / Neuralgia Límite: Animals Idioma: En Revista: Eur J Pain Asunto de la revista: NEUROLOGIA / PSICOFISIOLOGIA Año: 2015 Tipo del documento: Article País de afiliación: Brasil Pais de publicación: Reino Unido