• Luiz Fabio Dimov, Elaine Flamia Toniolo, Heloísa Alonso-Matielo, de Andrade Daniel Ciampi DC Department of Neurology, Central Institute, Av. Dr Enéas de Carvalho Aguiar, 255, 5th floor, Room 5084, Cerqueira César, São Paulo, SP, 05403-, Luis Garcia-Larrea, Gerson Ballester, Manoel Jacobsen Teixeira, and Camila Squarzoni Dale.
• Department of Anatomy, Institute of Biomedical Sciences of University of São Paulo - Av. Prof. Lineu Prestes, 2415, ICB-III, Cidade Universitária, São Paulo, SP, 05508-900, Brazil.
• Behav. Brain Res. 2018 Jul 2; 346: 86-95.

AbstractCortical electrical stimulation (CES) has shown to be an effective therapeutic alternative for neuropathic pain refractory to pharmacological treatment. The primary motor cortex(M1) was the main cortical target used in the vast majority of both invasive and non-invasive studies. Despite positive results M1-based approaches still fail to relieve pain in a significant proportion of individuals. It has been advocated that the direct stimulation of cortical areas directly implicated in the central integration of pain could increase the efficacy of analgesic brain stimulation. Here, we evaluated the behavioral effects of electrical stimulation of the insular cortex (ESI) on pain sensitivity in an experimental rat model of peripheral neuropathy, and have described the pathways involved. Animals underwent chronic constriction of the sciatic nerve in the right hind limb and had concentric electrodes implanted in the posterior dysranular insular cortex. Mechanical nociception responses were evaluated before and at the end of a 15-min session of ESI (60Hz, 210μs, 1V). ESI reversed mechanical hypersensitivity in the paw contralateral to the brain hemisphere stimulated, without inducing motor impairment in the open-field test. Pharmacological blockade of μ-opioid (MOR) or type 1-cannabinoid receptors (CB1R) abolished ESI-induced antinociceptive effects. Evaluation of CB1R and MOR spatial expression demonstrated differential modulation of CB1R and MOR in the periaqueductal gray matter (PAG) of ESI-treated rats in sub-areas involved in pain processing/modulation. These results indicate that ESI induces antinociception by functionally modulating opioid and cannabinoid systems in the PAG pain circuitry in rats with experimentally induced neuropathic pain.Copyright © 2017 Elsevier B.V. All rights reserved.

45 keywords...

hide…