Central involvement of 5-HT1A receptors in antinociception induced by photobiomodulation in animal model of neuropathic pain

Lasers Med Sci. 2022 Mar;37(2):821-829. doi: 10.1007/s10103-021-03318-w. Epub 2021 Apr 22.


This study aimed to investigate the central involvement of 5-HT1A receptors in the nociceptive behavior of mice submitted to the chronic constriction injury (CCI) of sciatic nerve and the subsequent application of photobiomodulation (PBM). Male mice (Swiss-albino) were submitted to CCI and subsequently received an infusion of WAY100635 (5-HT1A receptor antagonist) or intracerebroventricular saline (ICV), followed by infrared laser irradiation (808 nm), in continuous mode, with the power of 100 mW and a dose of 0 J/cm2 (control group) or 50 J/cm2. The thermal hyperalgesia was evaluated by hot plate test, while mechanical allodynia was evaluated by von Frey filaments. After CCI, animals showed a reduction in the nociceptive threshold (p<0.001) when compared to the sham group. In von Frey test, the CCI + saline + PBM 50 J/cm2 group showed an increase in nociceptive threshold (p<0.001) in all measurement moments in comparison with groups CCI + SALINE + PBM 0 J/cm2, CCI + WAY100635 + PBM 50 J/cm2, and CCI + WAY100635 + PBM 0 J/cm2. Similarly, in hot plate test, CCI + SALINE + PBM 50 J/cm2 group showed an increase in nociceptive threshold after application of PBM at 120 and 180 min. Because of the results found, it can be suggested the involvement of 5-HT1A receptors in the central nervous system, since WAY100635 was able to reverse the antinociceptive effect provided by PBM in animals submitted to CCI.

Keywords: Laser; Nociception; Rehabilitation; Serotonin; mice.

MeSH terms

  • Animals
  • Disease Models, Animal
  • Hyperalgesia / etiology
  • Hyperalgesia / radiotherapy
  • Male
  • Mice
  • Neuralgia* / radiotherapy
  • Receptor, Serotonin, 5-HT1A*
  • Sciatic Nerve


  • Receptor, Serotonin, 5-HT1A