Infralimbic medial prefrontal cortex alters electroacupuncture effect in animals with neuropathic chronic pain

• Published in: Behavioural brain research Vol. 424; p. 113803
• Main Authors: Leite Ferreira, Laís, Pereira Generoso, Laura, Medeiros, Ana Carolina, de Medeiros, Priscila, Leonardo de Freitas, Renato, Lourenço da Silva, Marcelo, Resende Torres da Silva, Josie
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 29-04-2022
• Subjects: Animals; Chronic constrictor injury of the ischiadicus nerve; Chronic pain; Chronic Pain - therapy; Electroacupuncture; Hyperalgesia - therapy; Infralimbic region; Medial prefrontal cortex; Neuralgia - therapy; Prefrontal Cortex; Rats; Rats, Wistar; Medial prefrontal cortex; Infralimbic region; Electroacupuncture; Chronic constrictor injury of the ischiadicus nerve; Chronic pain
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2022.113803

Morphological reorganization in the neural networks of the medial prefrontal cortex (mPFC) may be involved in the development of chronic neuropathic pain (NP).
We investigated whether inactivation and neurostimulation of the infralimbic division (IFL) of the mPFC alter electroacupuncture-induced analgesia (EIA) at 2 Hz and 2/100 Hz in animals with chronic NP.
Wistar rats were submitted to chronic constrictor injury of the ischiadicus nerve (CCI). Von Frey and acetone tests were performed to evaluate mechanical or cold allodynia. Animals were submitted to electroacupuncture (EA) at 2 Hz and 2/100 Hz for 20 min. After EA, the IFL cortex synaptic contacts were inactivated by cobalt chloride (200 nL of 1.0 mM CoCl2). Neurostimulation of the IFL cortex was also performed at 20 µA for 15 s, after EA, using a deep brain stimulation device.
EA at 2 Hz and 2/100 Hz attenuated mechanical or cold allodynia in CCI rats. Microinjection of CoCl2 into the IFL division of the mPFC blocked the EA effect. EA at 2 Hz and 2/100 Hz, in association with neurostimulation of the IFL cortex, attenuated mechanical and thermal allodynia.
EA induces antinociception in CCI rats. The analgesia was potentiated in association with neurostimulation in the IFL division of the mPFC.
•Electroacupuncture at 2 Hz or 2/100 Hz produced an antinociceptive effect in animals with chronic neuropathic pain.•Infralimbic medial prefrontal cortex is involved in the electroacupuncture-induced antinociceptive effect.•Stimulation of the infralimbic medial prefrontal cortex improved the antinociception of electroacupuncture at 2 Hz.