Effects of peripheral nerve injury on functional spinal VR1 receptors.
VR1 receptors, present on Adelta- and C-fibres and post-synaptic sites within the spinal cord dorsal horn, is an integrator of noxious stimuli. Here, the contribution of spinal VR1 receptors to spinal nociceptive processing in nerve injured (selective spinal nerve ligated SNL) and sham anaesthetised rats was studied. Spinal capsazepine (0.5-30 microM), a competitive VR1 antagonist, reduced noxious evoked responses of spinal neurones to a greater extent in sham operated rats, compared to SNL rats. Significant differences between the effect of spinal capsazepine on the non-potentiated component of the C-fibre evoked response of SNL and sham operated rats are reported (p< 0.01, two-way ANOVA). Our data suggest there is a functional plasticity of the spinal VR1 receptor following nerve injury.
Kelly
Sara
S
School of Biomedical Sciences, University of Nottingham Medical School, E Floor, Queen's Medical Centre, UK.
Chapman
Victoria
V
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002211:Capsaicin / Q000031:analogs & derivatives* / Q000494:pharmacology; D003714:Denervation; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000502:physiology; D006930:Hyperalgesia / Q000378:metabolism / Q000503:physiopathology; D008026:Ligation; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism*; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000378:metabolism*; D009437:Neuralgia / Q000378:metabolism / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009619:Nociceptors / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000187:drug effects / Q000503:physiopathology*; D010523:Peripheral Nervous System Diseases / Q000378:metabolism / Q000503:physiopathology*; D010812:Physical Stimulation; D020671:Posterior Horn Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011955:Receptors, Drug / Q000037:antagonists & inhibitors / Q000378:metabolism*
D011955:Receptors, Drug; C071423:capsazepine; D002211:Capsaicin