Articles: hyperalgesia.
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Individual differences in interoceptive sensitivity are associated with differences in reported intensity of emotional experience, vulnerability to anxiety and mood disorder and capacity for emotional self-regulation. Enhanced sensitivity to autonomic state is often accompanied by increased autonomic reactivity. Here we tested the hypothesis that healthy people classified as more interoceptively sensitive, by their performance of a heartbeat monitoring task, will demonstrate enhanced perception of pain. ⋯ We observed significant relationships between heightened interoceptive sensitivity and both enhanced sensitivity and decreased tolerance to pain. These effects were accompanied by a more pronounced parasympathetic decrease and a change in sympathovagal balance during pain assessment in the high, compared to the low, interoceptively sensitive group. Our study provides novel evidence that interoceptive sensitivity is associated with the experience and tolerability of pain in conjunction with reactive changes in autonomic balance.
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Lysophosphatidic acid (LPA), an initiator of neuropathic pain, causes allodynia. However, few studies have evaluated the pharmacological profile of LPA-induced pain. In this study, a LPA-induced pain model was developed and pharmacologically characterized with clinically relevant drugs used for neuropathic pain, including antiepileptics, non-steroidal anti-inflammatory agents, analgesics, local anaesthetics/antiarrhythmics and antidepressants. ⋯ In LPA-injected mice, expression of the α2δ1 subunit of the voltage-gated calcium channel (VGCC) was increased in the dorsal root ganglion (DRG) and spinal dorsal horn. Furthermore, the VGCC current was potentiated in both the DRG from LPA-injected mice and LPA (1 μM)-treated DRG from saline-injected mice, and the potentiated VGCC current was amended by treatment with gabapentin (100 μM). The LPA-induced pain model described here mimics aspects of the neuropathic pain state, including the sensitization of VGCC, and may be useful for the early assessment of drug candidates to treat neuropathic pain.
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Although acupuncture analgesia is well documented, its mechanisms have not been thoroughly clarified. We previously showed that electroacupuncture (EA) activates supraspinal serotonin- and norepinephrine-containing neurones that project to the spinal cord. This study investigates the involvement of spinal alpha(2)-adrenoceptors (α2-ARs) and 5-hydroxytryptamine (serotonin) receptors (5-HTRs) in EA effects on an inflammatory pain rat model. ⋯ The data show that α2a-ARs and 5-HT1ARs are involved in the EA inhibition of inflammatory pain and that the NMDA receptors are involved in EA action.