Joint manipulation reduces hyperalgesia by activation of monoamine receptors but not opioid or GABA receptors in the spinal cord

摘要: Joint manipulation has long been used for pain relief. However, the underlying mechanisms manipulation-related relief remain largely unexplored. The purpose of current study was to determine which spinal neurotransmitter receptors mediate manipulation-induced antihyperalgesia. Rats were injected with capsaicin (50 μl, 0.2%) into one ankle joint and mechanical withdrawal threshold measured before after injection. decreases 2 h Two hours injection, following drugs administered intrathecally: bicuculline, blocks γ-aminobutyric acid (GABAA) receptors; naloxone, opioid yohimbine blocks, α2-adrenergic methysergide, 5-HT1/2 receptors. In addition, NAN-190, ketanserin, MDL-72222 selectively block 5-HT1A, 5-HT2A, 5-HT3 receptors, respectively. Knee performed 15 min administration drug. knee flexed extended end range extension while tibia simultaneously translated in an anterior posterior direction. treatment group received three applications manipulation, each 3 duration separated by 1 rest. injection significantly increases 45 treatment. Spinal blockade methysergide prevented, attenuated, NAN-190 also blocked antihyperalgesia suggesting that effects are mediated 5-HT1A receptor blockade. or GABAA had no effect on induced-antihyperalgesia. Thus, produced appears involve descending inhibitory utilize serotonin noradrenaline.