Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation

Uta, Daisuke; Ishibashi, Naoya; Konno, Takahiro; Okada, Yuki; Kawase, Yuki; Tao, Shinichi; Kume, Toshiaki

doi:10.3390/ijms24032352

Open AccessArticle

Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation

by

Daisuke Uta

^1,*,†

,

Naoya Ishibashi

^2,3,†

,

Takahiro Konno

³

,

Yuki Okada

⁴,

Yuki Kawase

³,

Shinichi Tao

³ and

Toshiaki Kume

¹

Department of Applied Pharmacology, Faculty of Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan

²

Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan

³

Biomedical Engineering Laboratories, Teijin Institute for Bio-Medical Research, Teijin Pharma Ltd., Tokyo 191-8512, Japan

⁴

Toxicology & DMPK Research Department, Teijin Institute for Bio-Medical Research, Teijin Pharma Ltd., Tokyo 191-8512, Japan

^*

Author to whom correspondence should be addressed.

^†

These authors contributed equally to this work.

Int. J. Mol. Sci. 2023, 24(3), 2352; https://doi.org/10.3390/ijms24032352

Submission received: 18 November 2022 / Revised: 16 January 2023 / Accepted: 22 January 2023 / Published: 25 January 2023

(This article belongs to the Special Issue State-of-the-Art Molecular Neurobiology in Japan)

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Abstract

Photobiomodulation has analgesic effects via inhibition of nerve activity, but few reports have examined the effects on the spinal dorsal horn, the entry point for nociceptive information in the central nervous system. In this study, we evaluated the effects of laser irradiation of peripheral nerve axons, which are conduction pathways for nociceptive stimuli, on the neuronal firing in lamina II of the spinal dorsal horn of a rat evoked by mechanical stimulation with von Frey filaments (vFF). In order to record neuronal firing, electrodes were inserted into lamina II of the exposed rat spinal dorsal horn. The exposed sciatic nerve axons were irradiated with an 808 nm laser. The 26.0 g vFF-evoked firing frequency was inhibited from 5 min after laser irradiation and persisted for 3 h. Sham irradiation did not alter the firing frequency. Laser irradiation selectively inhibited 15.0 and 26.0 g vFF-evoked firing, which corresponded to nociceptive stimuli. Histopathological evaluation revealed no damage to the sciatic nerve due to laser irradiation. These results indicate that neuronal firing is inhibited in lamina II of the spinal dorsal horn, suggesting that laser irradiation inhibits Aδ and/or C fibers that conduct nociceptive stimuli.

Keywords: in vivo extracellular recording; spinal dorsal horn; lamina II; pain; peripheral nerve; photobiomodulation; low-level laser therapy

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MDPI and ACS Style

Uta, D.; Ishibashi, N.; Konno, T.; Okada, Y.; Kawase, Y.; Tao, S.; Kume, T. Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation. Int. J. Mol. Sci. 2023, 24, 2352. https://doi.org/10.3390/ijms24032352

AMA Style

Uta D, Ishibashi N, Konno T, Okada Y, Kawase Y, Tao S, Kume T. Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation. International Journal of Molecular Sciences. 2023; 24(3):2352. https://doi.org/10.3390/ijms24032352

Chicago/Turabian Style

Uta, Daisuke, Naoya Ishibashi, Takahiro Konno, Yuki Okada, Yuki Kawase, Shinichi Tao, and Toshiaki Kume. 2023. "Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation" International Journal of Molecular Sciences 24, no. 3: 2352. https://doi.org/10.3390/ijms24032352

APA Style

Uta, D., Ishibashi, N., Konno, T., Okada, Y., Kawase, Y., Tao, S., & Kume, T. (2023). Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation. International Journal of Molecular Sciences, 24(3), 2352. https://doi.org/10.3390/ijms24032352

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Near-Infrared Photobiomodulation of the Peripheral Nerve Inhibits the Neuronal Firing in a Rat Spinal Dorsal Horn Evoked by Mechanical Stimulation

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