From the Guidelines
The proposed mechanism by which Spinal Cord Stimulation (SCS) operates to treat neuropathic pain is through increased release of GABA in the dorsal horn of the spinal cord.
Mechanism of Action
SCS works by modulating pain transmission at the spinal level through the placement of electrodes in the epidural space that deliver electrical pulses to the dorsal columns. This stimulation activates inhibitory interneurons in the dorsal horn, which then release the inhibitory neurotransmitter GABA 1.
Key Points
- The increased GABA release suppresses the hyperexcitability of wide dynamic range (WDR) neurons that typically occurs in neuropathic pain conditions.
- By enhancing inhibitory neurotransmission, SCS effectively closes the "gate" for pain signals traveling from the periphery to the brain, as described in the Gate Control Theory of pain.
- This mechanism explains why SCS can provide significant pain relief for patients with conditions like failed back surgery syndrome, complex regional pain syndrome, and other neuropathic pain disorders without requiring continuous medication.
Clinical Evidence
While studies such as those published in the Annals of Oncology 1 and the Journal of the National Comprehensive Cancer Network 1 discuss the use of SCS for refractory pain, the most relevant information regarding the mechanism of action is found in the British Journal of Pharmacology 1.
Conclusion Not Needed, only the above information is required to answer the question.
From the Research
Proposed Mechanism of SCS in Treating Neuropathic Pain
The proposed mechanism by which Spinal Cord Stimulation (SCS) operates to treat neuropathic pain involves several key processes:
- Inhibition of the ascending nociceptive transmission by the release of analgesic neurotransmitters such as GABA and endocannabinoids at the spinal dorsal horn 2, 3, 4
- Facilitation of the descending inhibition by release of noradrenalin, dopamine, and serotonin acting on their receptors in the spinal cord 2, 4
- Activation of a variety of supraspinal brain areas related to pain perception and emotion 4
- Activation of dorsal column Aβ fibers, resulting in variable effects on sensory and pain thresholds, and measurable alterations in higher order cortical processing 5
Release of Neurotransmitters
The release of specific neurotransmitters plays a crucial role in the mechanism of SCS:
- Increased release of GABA in the dorsal horn of the spinal cord, which may be linked to a decrease in the release of glutamate and other excitatory amino acids, resulting in a decrease of neuropathic pain 2, 3, 4
- Release of substance P, serotonin, and noradrenaline in the dorsal horns 2
- No evidence suggests that SCS operates through increased release of glutamate from primary afferent neurons or WDR cells, or increased release of GABA from primary afferent neurons 2, 3, 5, 6, 4