Dorsal Horn Neurons In Pain Transmission is an important cell type in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
The dorsal horn of the spinal cord is the first central processing station for nociceptive (pain) information. It receives input from peripheral sensory neurons and modulates pain signals before they ascend to the brain. Dysfunction in dorsal horn circuitry contributes to chronic pain conditions and neurodegenerative pain disorders.
| Property |
Value |
| Category |
Pain |
| Location |
Spinal cord dorsal horn (laminae I-VI) |
| Cell Type |
Nociceptive projection neurons, interneurons, glial cells |
| Function |
Pain signal processing, modulation, and transmission |
The dorsal horn is organized into Rexed laminae (I-VI), each with distinct neuronal populations:
- Neurons: Projection neurons (输出), interneurons
- Function: Receives Aδ and C fiber input, pain temperature
- Pathways: Spinothalamic, spinoreticular tracts
- Neurons: Interneurons ( excitatory and inhibitory)
- Function: Pain gating, local modulation
- Key cells: Islet cells, central cells, stalked cells
- Neurons: Projection neurons, interneurons
- Function: Mechanoreception, proprioception
- Input: Aβ fibers (non-nociceptive)
- Neurons: Wide dynamic range (WDR) neurons
- Function: Visceral pain, multimodal input
- Role: Central sensitization
- Respond to: Noxious thermal, mechanical, chemical stimuli
- Fire: Only at noxious intensities
- Axons: Cross in anterior commissure, ascend contralaterally
- Respond to: Both innocuous and noxious stimuli
- Fire: Proportionally to stimulus intensity
- Function: Encode pain intensity, sensitize in chronic pain
- Neurotransmitter: Glutamate
- Receptors: AMPA, NMDA, kainite
- Function: Transmit pain signals, facilitate wind-up
- Neurotransmitter: GABA, glycine
- Function: Gate pain transmission, modulate sensitivity
- Loss: Contributes to chronic pain
- Function: Maintain extracellular glutamate homeostasis
- Activation: By pain signals, release cytokines
- Role: Contribute to central sensitization
- Function: Immune surveillance
- Activation: By nerve injury, release pro-inflammatory factors
- Role: Neuropathic pain development
- Conduction: 5-30 m/s
- Stimuli: Sharp, well-localized pain
- Neurotransmitter: Glutamate
- Conduction: 0.5-2 m/s
- Stimuli: Burning, aching pain
- Neurotransmitters: Glutamate, substance P, CGRP
- Nociceptor activation: Peripheral injury/disease
- Release: Glutamate, substance P from central terminals
- Postsynaptic activation: AMPA/NMKDA receptors on dorsal horn neurons
- Signal propagation: Via ascending tracts to brain
Activity-dependent plasticity in dorsal horn:
- Mechanism: Progressive increase in neuronal firing
- Cause: Repeated C fiber activation
- NMDA role: Calcium influx enhances excitability
- Mechanism: Strengthening of synaptic connections
- Result: Enhanced pain transmission
- Duration: Persistent, contributes to chronic pain
- Rostral ventromedial medulla (RVM): Modulates dorsal horn
- Periaqueductal gray (PAG): Activates RVM
- Serotonin/NE: Can facilitate or inhibit pain
- Aβ fiber input: Activates inhibitory interneurons
- Inhibition: Closes "gate" to pain transmission
- Basis: TENS, rubbing reduces pain
¶ Chronic Pain and Neurodegeneration
- Cause: Nerve injury, disease
- Mechanisms: Ectopic firing, central sensitization
- Dorsal horn changes: Glial activation, LTP
¶ Alzheimer's Disease and Pain
- Altered perception: Pain threshold changes
- Recognition deficits: May not report pain
- Cholinergic impact: Descending inhibition affected
- Undertreatment: Pain often unrecognized
- Assessment challenges: Communication difficulties
¶ Parkinson's Disease and Pain
- Prevalence: Up to 85% of PD patients experience pain
- Types: Musculoskeletal, neuropathic, visceral
- Mechanisms: Dopaminergic dysfunction, altered processing
- Dopaminergic modulation: Lost in PD
- Sensitization: Enhanced in chronic pain
- Treatment: Dopaminergic agents may help
- Early: Muscle cramps, spasticity
- Late: Impaired mobility pain
- Dorsal horn: May show degeneration
- NSAIDs: Reduce peripheral inflammation
- Opioids: Activate descending inhibition
- Antidepressants: Enhance descending inhibition
- Gabapentinoids: Reduce calcium currents
- TCAs: Block serotonin/norepinephrine reuptake
- Anticonvulsants: Stabilize neuronal membranes
- Dorsal column stimulation: Activates Aβ fibers, gates pain
- Dorsal root ganglion stimulation: Targets peripheral input
- Intrathecal delivery: Direct spinal drug delivery
- Gene therapy: Target pain pathways
- Cell therapy: Transplanted analgesic neurons
- Optogenetics: Control pain circuits
The study of Dorsal Horn Neurons In Pain Transmission has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- Todd AJ. Neuronal circuitry for pain processing in the dorsal horn. Nat Rev Neurosci. 2010
- Woolf CJ, Mann GE, Aldskogius H. Nociceptor function in normal and pathological states: introducing the concept of "pain phenotypes". Pain. 2019
- Woolf CJ, Costigan M. Transcriptional and posttranslational plasticity and the generation of inflammatory pain. Proc Natl Acad Sci U S A. 1999
- Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965
- Kuner R. Central mechanisms of pathological pain. Nat Med. 2010
- Scholz J, Woolf CJ. The neuropathic pain triad: neurons, immune cells and glia. Nat Neurosci. 2007
- Basbaum AI, et al. Cellular and molecular mechanisms of pain. Cell. 2009
- Latremoliere A, Woolf CJ. Central sensitization: a generator of pain hypersensitivity by central neural plasticity. J Pain. 2009