Amantadine prevented hypersensitivity and decreased oxidative stress by NMDA receptor antagonism after spinal cord injury in rats

Abstract

Background: Neuropathic pain (NP) after spinal cord injury (SCI) is a disabling condition, without an effective treatment. Hyperexcitability of N-methyl-D-aspartate (NMDA) receptors and oxidative stress have been reported to be associated with pain development. Amantadine, an NMDA receptor antagonist, has been proposed as a potential therapy for NP. However, its use has not been tested for NP after SCI. Methods: To produce SCI, 120 female Wistar rats were used, a contusion injury to the T10 and T12 thoracic vertebrae was performed from heights of 6.25 mm and 12.5 mm. Nociceptive behaviour, was evaluated with the use of von Frey filaments for 31 days. The final products of lipid peroxidation (LP) and concentration of reduced glutathione (GSH) in the injured tissue were quantified by fluorescence spectrophotometry. The antinociceptive effect of the acute (15 days after the injury) and chronic (once daily for three days immediately after the injury) with amantadine (6.25-50 mg/Kg. I.p.) was determined. Finally, the LP and GSH were quantified in the injured tissue. Results: Acute treatment with amantadine reduced nociceptive behaviour.Concomitantly, LP was decreased by Amantadine treatment while GSH increased in the injured tissue. Similar effects were observed with chronic treatment with amantadine. Conclusions: Data from this study suggested that the antinociceptive effects of amantadine treatment are modulated through oxidative stress and excitotoxicity reduction associated with N-methyl-D-aspartate receptors activation. Significance: This study suggests that acute treatment with amantadine decreases hypersensitivity threshold and frequency of hypersensitivity response in a dosedependent manner, in rats with SCI, by decreasing oxidative stress. Since amantadine is an easily accessible drug and has fewer adverse effects than current treatments for hypersensitivity threshold and frequency of hypersensitivity response, amantadine could represent a safe and effective therapy for the treatment of neuropathic pain.However, further research is required to provide evidence of the effectiveness and feasibility.How to cite this article: Mata-Bermudez A, Ríos C, Burelo M, et al. Amantadine prevented hypersensitivity and decreased oxidative stress by NMDA receptor antagonism after spinal cord injury in rats.

Research progress on the mechanism of chronic neuropathic pain

“…For instance, damage to the central nervous system and the resulting increase in extracellular levels of glutamate causes excessive activation of N-methyl- D -aspartate (NMDA) receptors. This, in turn, leads to an influx of calcium ions which eventually produces large amounts of ROS ( Yang et al, 2021 , Mata-Bermudez et al, 2021 ). Altogether, these processes damage cells irreversibly and may even lead to apoptosis.…”

Therapeutic potential of progesterone in spinal cord injury‐induced neuropathic pain: At the crossroads between neuroinflammation and N‐methyl‐D‐aspartate receptor

“…75 In addition, NMDARs are present in dorsal root ganglion neurons and afferent terminals in the superficial dorsal horn. 76 Studies revealed the contribution of altered expression and/or phosphorylation of NMDAR subunits to abnormal pain processing in different conditions such as peripheral nerve injury, 77 diabetes, 78 morphine exposure 79 and excitotoxic 80 or traumatic spinal cord injuries, 30,81,82 indicating the central role of NMDAR-associated signaling pathways in the development of several types of chronic pain. In addition, studies using either antagonists or knockdown of NMDAR demonstrated reduced nociceptive behaviors and pain sensitivity caused by central or peripheral injury.…”