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

• Published in: Lasers in medical science Vol. 37; no. 2; pp. 821 - 829
• Main Authors: Santos, Gabriela Xavier, Barbosa, Danillo, de-Souza, Giovane Galdino, Kosour, Carolina, Parizotto, Nivaldo Antonio, dos Reis, Luciana Maria
• Format: Journal Article
• Language: English
• Published: London Springer London 01.03.2022; Springer Nature B.V
• Subjects: Albinism; Animal models; Animals; Central nervous system; Dentistry; Disease Models, Animal; Drug dosages; Ethics; Evaluation; Experiments; Filaments; Hyperalgesia; Hyperalgesia - etiology; Hyperalgesia - radiotherapy; I.R. radiation; Infrared lasers; Irradiation; Lasers; Light therapy; Male; Medicine; Medicine & Public Health; Mice; Nervous system; Neuralgia; Neuralgia - radiotherapy; Optical Devices; Optics; Original Article; Pain; Pain perception; Photonics; Physical therapy; Polyethylene; Quantum Optics; Receptor, Serotonin, 5-HT1A; Receptors; Sciatic Nerve; Serotonin S1 receptors; Nociception; Rehabilitation; Serotonin; mice; Laser
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-021-03318-w

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/cm 2 (control group) or 50 J/cm 2 . 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/cm 2 group showed an increase in nociceptive threshold ( p <0.001) in all measurement moments in comparison with groups CCI + SALINE + PBM 0 J/cm 2 , CCI + WAY100635 + PBM 50 J/cm 2 , and CCI + WAY100635 + PBM 0 J/cm 2 . Similarly, in hot plate test, CCI + SALINE + PBM 50 J/cm 2 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.