Understanding of Spinal Wide Dynamic Range Neurons and Their Modulation on Pathological Pain

Abstract

The spinal dorsal horn (SDH) transmits sensory information from the periphery to the brain. Wide dynamic range (WDR) neurons within this relay site play a critical role in modulating and integrating peripheral sensory inputs, as well as the process of central sensitization during pathological pain. This group of spinal multi-receptive neurons has attracted considerable attention in pain research due to their capabilities for encoding the location and intensity of nociception. Meanwhile, transmission, processing, and modulation of incoming afferent information in WDR neurons also establish the underlying basis for investigating the integration of acupuncture and pain signals. This review aims to provide a comprehensive examination of the distinctive features of WDR neurons and their involvement in pain. Specifically, we will examine the regulation of diverse supraspinal nuclei on these neurons and analyze their potential in elucidating the mechanisms of acupuncture analgesia.

Keywords:

• WDR neurons
• spinal dorsal horn
• pain
• central sensitization
• receptive fields
• DNIC
• acupuncture analgesia

Abbreviations

SDH, spinal dorsal horn; WDR, wide dynamic range; LTM, low-threshold mechanoreceptor; HT, high-threshold; SRD, subnucleus reticularis dorsalis; CeA, central nucleus; PVN, paraventricular nucleus; PB, parabrachial nucleus; PAG, periaqueductal gray; LC, locus coeruleus; RVM, rostral ventromedial medulla; CV, conduction velocities; CFA, complete Freund’s adjuvant; RF, receptive fields; LTP, long-term potentiation; SNL, spinal nerve ligation; CRF, corticotrophin-releasing factor; MORs, mu opioid receptors; COX, cyclooxygenase; PFC, prefrontal cortex; NRM, nucleus raphe magnus; DRt, dorsal reticular nucleus; TEAS, transcutaneous electrical acupoints stimulation; EA, electro-acupuncture; GABA, gamma-aminobutyric acid; VGLUT2, vesicular glutamate transporter 2; KOR, kappa opioid receptors; NS, nociceptive specific.

Acknowledgments

This review was supported by grants from the National Natural Science Foundation of China (82204796, 82130122).

Disclosure

The authors report no conflicts of interest in this work.