Pain
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Migraine is a common disabling neurological condition that is associated with several premonitory symptoms that can occur days before the headache onset. The most commonly reported premonitory symptom is marked fatigue that has been shown to be highly predictive of an ensuing migraine attack. The locus coeruleus (LC) is a key nucleus involved in arousal that has also been shown to impact pain processing. ⋯ In addition, we explored the susceptibility to cortical spreading depression initiation, the presumed underlying phenomenon of migraine aura. Our experiments reveal a potent role for LC disruption in the differential modulation of migraine-related phenotypes, inhibiting dural-evoked activation of wide dynamic neurons in the trigeminocervical complex while increasing cortical spreading depression susceptibility. This highlights the potential divergent impact of LC disruption in migraine physiology, which may help explain the complex interactions between dysfunctional arousal mechanisms and migraine.
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This study investigated the moderating role of parental pain-related attention-set shifting and heart rate variability (HRV) for parental distress and pain control behaviour when faced with their child's pain. Participants were 54 schoolchildren and one of their parents. Parental HRV was assessed at study commencement followed by a cued-switching task indexing parental ability to flexibly shift attention between pain-related and neutral attentional sets. ⋯ Parental ability to shift attention away (ie, disengage) from a pain-related set to a neutral set did not impact findings. Results further indicated that although high levels of parental HRV buffer the impact of child facial pain display on parental emotional distress and pain control behaviour, low levels of HRV constitute a risk factor for higher levels of parental distress and pain control behaviour when faced with increased child facial pain display. Theoretical/clinical implications and further research directions are discussed.
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Pain is ubiquitous, but effective pain relief eludes many. Research has shown that some pain behaviours are perceived as gendered, and this may influence the way men and women express and cope with pain, but such enquiries have not extended to specific methods of pain relief. Our aim was to explore perceptions of the most socially acceptable ways for men and women to relieve pain. ⋯ The overarching male stereotype suggested it is most acceptable for men to use pain relief aligned with stereotypical masculinity; however, a second stereotype also emerged, characterised by conventional and effective responses to pain, much like the overarching stereotype for women. These differing viewpoints seem to depend on whether gender norm conformity or perceived analgesic efficacy is believed to determine social acceptability. These studies provide initial evidence of both a gendered and ungendered lens through which pain relief can be viewed, which may influence how men and women use pain relief.
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Excitatory interneurons account for the majority of neurons in the superficial dorsal horn, but despite their presumed contribution to pain and itch, there is still limited information about their organisation and function. We recently identified 2 populations of excitatory interneuron defined by expression of gastrin-releasing peptide (GRP) or substance P (SP). Here, we demonstrate that these cells show major differences in their morphological, electrophysiological, and pharmacological properties. ⋯ The 2 populations also differed in responses to neuromodulators, with most SP cells, but few GRP cells, responding to noradrenaline and 5-HT; the converse was true for responses to the μ-opioid agonist DAMGO. Although a recent study suggested that GRP cells are innervated by nociceptors and are strongly activated by noxious stimuli, we found that very few GRP cells receive direct synaptic input from TRPV1-expressing afferents, and that they seldom phosphorylate extracellular signal-regulated kinases in response to noxious stimuli. These findings indicate that the SP and GRP cells differentially process somatosensory information.
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Sickle cell disease (SCD) pain associates with cold temperature and touch. Patients and murine models with SCD have baseline thermal and mechanical pain. In SCD mice, the baseline hypersensitivity is exacerbated by experimental vaso-occlusive crises. ⋯ There were no differences in heat pain sensitivity. The increased cold (P = 0.02) and mechanical (P = 0.0016) pain sensitivity during hospitalization persisted after adjusting for age, sex, hydroxyurea use, opioid consumption, and numeric pain score. Thus, cold and mechanical pain is significantly worse during an acute SCD painful event as compared to baseline health in patients with SCD.