Biomaterial Database

L5 spinal nerve axotomy induces sensitization of cutaneous L4 Aβ-nociceptive dorsal root ganglion neurons in the rat in vivo. 2016

Laiche Djouhri

Department of Physiology, College of Medicine, King Saud University, P.O. Box 7805, Riyadh 11472, KSA. Electronic address: ldjouhri@ksu.edu.sa.

Partial nerve injury often leads to peripheral neuropathic pain (PNP), a major health problem that lacks effective drug treatment. PNP is characterized by ongoing/spontaneous pain, and hypersensitivity to noxious (hyperalgesia) and innocuous (allodynia) stimuli. Preclinical studies using the L5 spinal nerve ligation/axotomy (SNL/SNA) model of PNP suggest that this type of chronic pain results partly from sensitization of ipsilateral L4C-and Aδ-fiber nociceptive dorsal root ganglion (DRG) neurons, but whether L4 β-nociceptors, which constitute a substantial group of DRG neurons, also become sensitized remains unanswered. To address this issue, intracellular recordings from somata of cutaneous Aβ-nociceptors (classified according to their dorsal root conduction velocities (>6.5m/s), and physiologically based on their responses to noxious (but not innocuous) mechanical stimuli) were made from L4-DRGs in normal (control) rats and in rats seven days after L5 SNA in vivo. Compared with control, cutaneous L4 Aβ-nociceptive DRG neurons in SNA rats (that developed mechanical hypersensitivity) exhibited sensitization indicated by: a) decreased mean mechanical threshold (from 57.8±7.1 to 10.3±1.7mN), b) decreased mean dorsal root electrical threshold (from 11.4±0.7 to 4.3±0.4V), c) increased mean response to a suprathreshold mechanical stimulus (from 18.5±1.8 to 34±3.7spikes/sec) and d) an obvious, but non-significant, increase in the incidence of ongoing/spontaneous activity (from 3% to 18%). These findings suggest that cutaneous L4 Aβ-nociceptors also become sensitized after L5 SNA, and that sensitization of this subclass of A-fiber nociceptors may contribute both directly and indirectly to nerve injury-induced PNP.

UI	MeSH Term	Description	Entries
D008161	Lumbosacral Region	Region of the back including the LUMBAR VERTEBRAE, SACRUM, and nearby structures.	Lumbar Region,Lumbar Regions,Lumbosacral Regions,Region, Lumbar,Region, Lumbosacral,Regions, Lumbar,Regions, Lumbosacral
D009413	Nerve Fibers, Myelinated	A class of nerve fibers as defined by their structure, specifically the nerve sheath arrangement. The AXONS of the myelinated nerve fibers are completely encased in a MYELIN SHEATH. They are fibers of relatively large and varied diameters. Their NEURAL CONDUCTION rates are faster than those of the unmyelinated nerve fibers (NERVE FIBERS, UNMYELINATED). Myelinated nerve fibers are present in somatic and autonomic nerves.	A Fibers,B Fibers,Fiber, Myelinated Nerve,Fibers, Myelinated Nerve,Myelinated Nerve Fiber,Myelinated Nerve Fibers,Nerve Fiber, Myelinated
D009437	Neuralgia	Intense or aching pain that occurs along the course or distribution of a peripheral or cranial nerve.	Nerve Pain,Neurodynia,Paroxysmal Nerve Pain,Neuralgia, Atypical,Neuralgia, Iliohypogastric Nerve,Neuralgia, Ilioinguinal,Neuralgia, Perineal,Neuralgia, Stump,Neuralgia, Supraorbital,Neuralgia, Vidian,Neuropathic Pain,Atypical Neuralgia,Atypical Neuralgias,Iliohypogastric Nerve Neuralgia,Iliohypogastric Nerve Neuralgias,Ilioinguinal Neuralgia,Ilioinguinal Neuralgias,Nerve Neuralgia, Iliohypogastric,Nerve Neuralgias, Iliohypogastric,Nerve Pain, Paroxysmal,Nerve Pains,Nerve Pains, Paroxysmal,Neuralgias,Neuralgias, Atypical,Neuralgias, Iliohypogastric Nerve,Neuralgias, Ilioinguinal,Neuralgias, Perineal,Neuralgias, Stump,Neuralgias, Supraorbital,Neuralgias, Vidian,Neurodynias,Neuropathic Pains,Pain, Nerve,Pain, Neuropathic,Pain, Paroxysmal Nerve,Pains, Nerve,Pains, Neuropathic,Pains, Paroxysmal Nerve,Paroxysmal Nerve Pains,Perineal Neuralgia,Perineal Neuralgias,Stump Neuralgia,Stump Neuralgias,Supraorbital Neuralgia,Supraorbital Neuralgias,Vidian Neuralgia,Vidian Neuralgias
D009619	Nociceptors	Peripheral AFFERENT NEURONS which are sensitive to injuries or pain, usually caused by extreme thermal exposures, mechanical forces, or other noxious stimuli. Their cell bodies reside in the DORSAL ROOT GANGLIA. Their peripheral terminals (NERVE ENDINGS) innervate target tissues and transduce noxious stimuli via axons to the CENTRAL NERVOUS SYSTEM.	Pain Receptors,Receptors, Pain,Nociceptive Neurons,Neuron, Nociceptive,Neurons, Nociceptive,Nociceptive Neuron,Nociceptor,Pain Receptor
D010812	Physical Stimulation	Act of eliciting a response from a person or organism through physical contact.	Stimulation, Physical,Physical Stimulations,Stimulations, Physical
D005260	Female		Females
D005727	Ganglia, Spinal	Sensory ganglia located on the dorsal spinal roots within the vertebral column. The spinal ganglion cells are pseudounipolar. The single primary branch bifurcates sending a peripheral process to carry sensory information from the periphery and a central branch which relays that information to the spinal cord or brain.	Dorsal Root Ganglia,Spinal Ganglia,Dorsal Root Ganglion,Ganglion, Spinal,Ganglia, Dorsal Root,Ganglion, Dorsal Root,Spinal Ganglion
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013127	Spinal Nerves	The 31 paired peripheral nerves formed by the union of the dorsal and ventral spinal roots from each spinal cord segment. The spinal nerve plexuses and the spinal roots are also included.	Nerve, Spinal,Nerves, Spinal,Spinal Nerve