Topographical evaluation of the analgesic effect induced by transdural electrical stimulation of the motor cortex of rats: somatotopy of behavioral response and profile of neuronal activation.

Author(s)

Nubia Regina Moreira França

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2012-12-14

Examining board members

Camila Squarzoni Dale; Jackson Cioni Bittencourt; Erich Talamoni Fonoff

• Advisor: Camila Squarzoni Dale

Abstract

Stimulation of the motor cortex (MC) has been used to treat patients with pain syndromes resistant to other treatments. Data from our group demonstrates that electrical stimulation of the motor cortex (MCS) induces opioid-dependent analgesia in rats. This study investigated the topography of the antinociceptive effect induced by MCS and the pattern of neuronal activation in the dorsal horn of the spinal cord (DHSC) and in the PAG through Fos and Egr-1 expression. Rats received implantation of transdural electrodes positioned on distinct areas of the corresponding MC: fore limb, hind limb, whiskers and tail and after 1 week were submitted to 15min. MCS sessions, and were evaluated in behavioral tests: paw pressure test, von Frey microfilaments, electronic von Frey and tail pinch. MCS induced analgesia only in the limb area corresponding to the stimulated MC in each group, involving the inhibition of DHSC, demonstrated by decrease of immunoreactivity in the superficial laminae; and activation of endogenous analgesia systems, by the increase of PAG immunoreactivity. (AU)

• FAPESP's process: 10/13460-1 - Topographical study of transdural motor cortex stimulation-induced analgesia of rats: somatotopy of behavioral response and neuronal activation
• Grantee: Nubia Regina Moreira França
• Support Opportunities: Scholarships in Brazil - Master