6533b7d2fe1ef96bd125f678
RESEARCH PRODUCT
Secondary tactile hypoesthesia: a novel type of pain-induced somatosensory plasticity in human subjects
Rolf-detlef TreedeWalter Magerlsubject
AdultMaleAdolescentPresynaptic TerminalsPainNeurological disorderSomatosensory systemSynaptic TransmissionHypesthesiachemistry.chemical_compoundmedicineHumansNeurons AfferentSkinAfferent PathwaysNerve Fibers UnmyelinatedNeuronal PlasticityGeneral NeuroscienceNociceptorsPeripheral Nervous System DiseasesNeural InhibitionHypoesthesiaMiddle Agedmedicine.diseaseMechanoreceptorNociceptionmedicine.anatomical_structurechemistryTouchCapsaicinAnesthesiaHyperalgesiaNociceptorFemaleCapsaicinmedicine.symptomPsychologyMechanoreceptorsNeurosciencedescription
Quantitative sensory testing revealed that pain induced by intracutaneous capsaicin injection elicited secondary hyperalgesia coexisting with secondary tactile hypoesthesia. Mapping the areas of altered mechanical sensations adjacent to the capsaicin injection disclosed that the area of secondary hyperalgesia was always nested in a larger area of secondary hypoesthesia easily detected as numbness by most subjects. Psychometric functions revealed a twofold rightward shift of tactile detection (hypoesthesia), which coexisted with a more than fourfold leftward shift of pricking pain detection (hyperalgesia) in the same skin area. As a mechanism we propose a functional switch at the spinal level based on C-fibre-induced primary afferent depolarisation resulting in presynaptic inhibition of low threshold mechanoreceptor input and an ensuing loss of tactile sensitivity.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-05-12 | Neuroscience Letters |