BackgroundSpinal cord stimulation (SCS) has been shown to be effective in the management of certain neuropathic pain conditions, however, the underlying mechanisms are incompletely understood. In this study, we investigated repetitive SCS in a rodent neuropathic pain model, revealing long-lasting and incremental attenuation of hyperalgesia and a mechanism of action involving endocannabinoids.
MethodAnimals were implanted with monopolar electrodes at the time of partial sciatic nerve injury. Dorsal columns at spinal segments T12/13 were stimulated 3days later (early SCS), and again at day 7 (late SCS) using low-frequency parameters. Hypersensitivity to cutaneous mechanical stimuli was assessed using von Frey filaments. Pharmacological agents, selected to identify endocannabinoid and opioid involvement, were administered intraperitoneally, 10min before SCS.
ResultsEarly SCS caused partial reversal of mechanical hypersensitivity with corresponding changes in the biomarker of central sensitization, [phospho-Tyr(1472)]-GluN2B. The partial reversal of hyperalgesia by early SCS was amplified by co-administration of LY 2183240, an inhibitor of endocannabinoid reuptake/breakdown. This amplification was inhibited by a CB1R antagonist, AM251, but not by a CB2R antagonist, AM630. Early SCS-induced reversal of hyperalgesia was attenuated by naloxone, indicating a role for opioids. Late SCS resulted in an incremental level of reversal of hyperalgesia, which was inhibited by AM251, but not by CB2 or opioid receptor antagonists.
ConclusionThe endocannabinoid system, and in particular the CB1R, plays a pivotal role in the long-lasting and incremental reversal of hyperalgesia induced by repetitive SCS in a neuropathic pain model.
SignificanceAlternative parameters for repetitive spinal cord stimulation (SCS) at 25/10Hz elicit particularly long-lasting and incremental reversal of hyperalgesia in a neuropathic pain model through a mechanism involving endocannabinoids.
|Number of pages||11|
|Journal||European Journal of Pain|
|Publication status||Published - May 2017|
- RANDOMIZED CONTROLLED-TRIAL
- CANNABINOID RECEPTOR
- MECHANICAL HYPERSENSITIVITY
- RAT MODEL
- CENTRAL SENSITIZATION
- ENDOGENOUS OPIOIDS
- THERAPEUTIC TARGET
- NERVE INJURY