European journal of pain : EJP
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Comparative Study
Social comparison performance standards, threat, and tolerance for experimentally-induced pain.
Social modelling experiments have illustrated how upward social comparisons (i.e., observing pain tolerant role models) can facilitate tolerance relative to downward social comparison (i.e., observing pain intolerant alternatives). However, because clinical studies suggest that people prefer to make downward social comparisons with less fortunate others when they are threatened or overwhelmed with pain or illness, it seems plausible that upward social comparisons confer fewer benefits when pain is appraised as threatening. ⋯ Conversely, the average tolerance time for participants presented with the higher threat orienting prime and upward comparison standard did not differ from that of either downward comparison group. The research highlighted powerful situational influences on tolerance for experimental pain and identified conditions under which verbally-presented upward social comparison standards may facilitate and hinder the capacity to bear pain.
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Comparative Study
Estrogen receptors localization in the spinal trigeminal nucleus: an immunohistochemical study in humans.
There is increasing evidence for estrogenic modulation of neurotransmission within the trigeminal pain pathway. It is also likely that the effects of estrogens may be influenced by the presence and localization of estrogen receptors (ERs) in a given brain area. To date, human data on the localization of ERs in the spinal trigeminal nucleus (STN), a key brain region in craniofacial nociception, are lacking. ⋯ This study is the first to provide evidence in humans that ER immunoreactivity is detectable on neuronal and glial cells of the STN. The two ER subtypes exhibited different expression patterns, with higher expression levels of ERα than ERβ. The presence of ER-containing cells in the STN suggests that estrogens may directly affect trigeminal neuron excitability in humans.
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Under-treatment of pain is a worldwide problem. We examine how often pain was addressed and the factors that influence how much time was spent on treating pain. We analyzed 385 videotapes of routine office visits in several primary care practices in the Southwest and Midwest regions of the United States. ⋯ Time constraints and racial concordance significantly influenced the length of discussion. We conclude that despite repeated calls for addressing under-treatment for pain, only a limited amount of time is used to address pain among elderly patients. This phenomenon could contribute to the under-treatment of pain.
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Clinical Trial
Transcutaneous spinal direct current stimulation inhibits nociceptive spinal pathway conduction and increases pain tolerance in humans.
Despite concerted efforts from pharmacologic research into neuropathic pain, many patients fail to achieve sufficient pain relief with medication alone. For this reason, increasing interest centres on neurostimulation techniques. We assessed whether transcutaneous spinal direct current stimulation (tsDCS) modulates conduction in ascending nociceptive spinal pathways. ⋯ Pain tolerance to the cold pressor test was significantly higher after anodal than after cathodal tsDCS (P<0.05). Conversely, no difference was found in the pain threshold or pain ratings to the cold pressor test between the two polarity conditions. Our data suggest that anodal tsDCS over the thoracic spinal cord might impair conduction in the ascending nociceptive spinal pathways, thus modulating LEPs and increasing pain tolerance in healthy subjects.
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Shakuyakukanzoto (SKT) has been shown to modulate nociception in streptozotocin-induced diabetic mice via selective activation of the descending noradrenergic systems. However, the active components of SKT that exert the analgesic effect remain unknown. Here, we administered Glycyrrhizae radix (G. radix), Paeoniae radix (P. radix), and the two active constituents of P. radix, paeoniflorin and albiflorin, to determine the components that stimulate spinal α₂-adrenoceptors by promoting noradrenaline release. ⋯ Our findings suggest that paeoniflorin is the key antinociceptive component in SKT that increases noradrenaline release and activates α₂-adrenoceptors to modulate spinal nociceptive transmission in diabetic neuropathy.