About this Research Topic
Somatosensory nerve fibers are classified based on their conduction velocity and degree of myelin thickness. The nociceptive/pain pathway comprises myelinated (Aβ and Aδ) and unmyelinated (C) nerve fibers that are believed to mediate fast and slow pain, respectively. Much is known about the C-fiber involvement in nociception and pain; however, the myelinated A-fiber nociceptors, particularly the fast-conducting A-beta fibers which constitute a substantial group of the A-fiber afferent neurons and have unique physiological and molecular properties, have received less attention. Classically, acute pain is thought to result from chemo-, mechano- and/or thermal-activation of nociceptors (high-threshold peripheral sensory neurons with slow [C] and fast [A] conducting fibers), and hypersensitivity is thought to be, at least in part, due to the increased sensitivity of nociceptors (peripheral sensitization) that innervate the damaged area. Although C nociceptors undoubtedly contribute to both acute and persistent pain, there is a clear discrepancy with the stimulus-response latency of pain in humans, which is much shorter than possible from C-nociceptor activation to noxious mechanical or heat stimulation. This discrepancy indicates a potential underestimation of the role of fast-conducting afferents (tactile and nociceptive) in fast-pain perception, and the contribution of these fibers to central sensitization and pain persistence. The current research topic is focused on this potential oversight, addressing current updated knowledge on these fibers' unique physiological and molecular properties.
Studies that focus on the structure (peripheral and central architecture), molecular markers, and function (transductional, biophysical, and physiological) of the fast-pain system and quantitative methods of assessment are welcome. A question of particular interest is the effect of injury/inflammation/trauma on the A-fiber system. This is not limited to the high-threshold receptors/nociceptors but may include evidence on the role (or lack thereof) of low-threshold/touch receptors in the context of pain-hypersensitivity (allodynia/hyperalgesia).
Areas to be covered in this research topic may include, but are not limited to: • Physiology of myelinated nociceptive fibers (transduction, biophysics, physiology) • Contribution or lack thereof of non-nociceptive fibers to pain hypersensitivity • Comparison of A- and C-fiber pain signaling (response dynamics, sensitization, modality-specific stimulation) • Peripheral anatomy and central projections of myelinated inputs • Molecular markers for fast nociceptive afferents • Techniques to study fast-pain signaling
All article types will be considered for publication in the special issue. Details can be found here: https://www.frontiersin.org/journals/pain-research/sections/pain-mechanisms#about
Keywords: “fast-pain system”
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.