Anesthesiology
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Morphine can desensitize mu-opioid receptor (MOR), but it does not cause internalization of the receptor after binding. Acute desensitization of MOR impairs the efficiency of signaling, whereas the receptor internalization restores the cell responsiveness to the agonists. Thereby, the property of morphine may limit the analgesic effects of this opiate drug. It has been shown that [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAMGO), a potent MOR agonist inducing the internalization, facilitates morphine to internalize MOR, suggesting that MOR agonists with low relative activity versus endocytosis (RAVE) values such as DAMGO can potentiate analgesic effects of morphine through stimulating MOR internalization. The authors examined whether the acute analgesic effect of morphine can be potentiated by low relative activity versus endocytosis agonists DAMGO and fentanyl. ⋯ The results suggest that the coadministration of morphine with MOR-internalizing agonist is clinically applicable to develop successful pain-management regimens to achieve satisfactory analgesia using less morphine.
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Randomized Controlled Trial Multicenter Study
Effect of patient-controlled perineural analgesia on rehabilitation and pain after ambulatory orthopedic surgery: a multicenter randomized trial.
Efficacy of continuous perineural and patient-controlled ropivacaine infusion at home after orthopedic surgery was compared with patient-controlled intravenous morphine for functional recovery and postoperative analgesia in a multicenter randomized trial. ⋯ After ambulatory orthopedic surgery, 0.2% ropivacaine delivered as a perineural infusion using a disposable elastomeric pump with patient-controlled anesthesia bolus doses optimizes functional recovery and pain relief while decreasing the consumption of rescue analgesics and ropivacaine, and the number of adverse events.
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Randomized Controlled Trial
Postoperative left prefrontal repetitive transcranial magnetic stimulation reduces patient-controlled analgesia use.
Several recent studies suggest that repetitive transcranial magnetic stimulation can temporarily reduce pain perception in neuropathic pain patients and in healthy adults using laboratory pain models. No studies have investigated the effects of prefrontal cortex stimulation using transcranial magnetic stimulation on postoperative pain. ⋯ A single session of postoperative prefrontal repetitive transcranial magnetic stimulation was associated with a reduction in patient-controlled analgesia pump use in gastric bypass surgery patients. This is important because the risks associated with postoperative morphine use are high, especially among obese patients who frequently have obstructive sleep apnea, right ventricular dysfunction, and pulmonary hypertension. These preliminary findings suggest a potential new noninvasive method for managing postoperative morphine use.