Pain
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The loss of GABAergic inhibition is a mechanism that underlies neuropathic pain. Therefore, rescuing the GABAergic inhibitory tone through the activation of GABA A receptors is a strategy to reduce neuropathic pain. This study was designed to elucidate the function of the spinal α 6 -containing GABA A receptor in physiological conditions and neuropathic pain in female and male rats. ⋯ Finally, α 6 subunit is expressed in humans. This receptor is found in CGRP + and P2X3 + primary afferent fibers but not astrocytes in the human spinal dorsal horn. Our results suggest that the spinal α 6 -containing GABA A receptor has a sex-specific antinociceptive role in neuropathic pain, suggesting that this receptor may represent an interesting target to develop a novel treatment for neuropathic pain.
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Randomized Controlled Trial
Sleep Disruption and Activation of Cellular Inflammation Mediate Heightened Pain Sensitivity: A Randomized Clinical Trial.
Sleep loss heightens pain sensitivity, but the pathways underlying this association are not known. Given that experimental sleep disruption induces increases in cellular inflammation as well as selective loss of slow wave, N3 sleep, this study examined whether these mechanisms contribute to pain sensitivity following sleep loss in healthy adults. This assessor-blinded, cross-over sleep condition, single-site, randomized clinical trial enrolled 95 healthy adults (mean [SD] age, 27.8 [6.4]; female, 44 [53.7%]). ⋯ A comprehensive causal mediation analysis found that FA had an indirect effect on hPTH by decreases in N3 sleep and subsequent increases in inflammation (estimate=-0.15; 95% confidence interval, -0.30 to -0.03; P < 0.05) with the proportion mediated 34.9%. Differential loss of slow wave, N3 sleep, and increases in cellular inflammation are important drivers of pain sensitivity after sleep disruption. Clinical Trials Registration: NCT01794689.
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Randomized Controlled Trial
Adenosine causes short-lasting vasodilation and headache, but not migraine attacks in migraine patients: A randomized clinical trial.
Migraine is a common disabling disease with a complex pathophysiology. Headache is a frequent side effect after intravenous adenosine administration, although adenosine receptor antagonist, caffeine, relieves migraine headache. These observations suggest a possible involvement of adenosine signaling in headache and migraine pathophysiology. ⋯ Adenosine increased heart rate ( P < 0.001), facial skin blood flow ( P < 0.05), and STA diameter (AUC T0-20min , P = 0.01) and decreased V MCA (AUC T0-20min , P < 0.001) compared with placebo. Adenosine induced headache accompanied by a short-lasting (<30 minutes) dilation of intracerebral and extracerebral arteries. The nonsignificant migraine induction might be because of the presence of several adenosine receptors with counteracting signaling, highlighting the need of more selective modulators to dissect the implication of adenosine in migraine.
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Randomized Controlled Trial
Randomized controlled trial of intrathecal oxytocin on speed of recovery after hip arthroplasty.
Recovery from surgery is quicker in the postpartum period, and this may reflect oxytocin action in the spinal cord. We hypothesized that intrathecal injection of oxytocin would speed recovery from pain and disability after major surgery. Ninety-eight individuals undergoing elective total hip arthroplasty were randomized to receive either intrathecal oxytocin (100 μg) or saline. ⋯ In planned secondary analyses, postoperative opioid use ended earlier in the oxytocin group and oxytocin-treated patients walked nearly 1000 more steps daily at 8 weeks ( P < 0.001) and exhibited a clinically meaningful reduction in disability for the first 21 postoperative days ( P = 0.007) compared with saline placebo. Intrathecal oxytocin before hip replacement surgery does not speed recovery from worst daily pain. Secondary analyses suggest that further study of intrathecal oxytocin to speed functional recovery without worsening pain after surgery is warranted.