Contribution of nociceptin/orphanin FQ receptors to the anti-nociceptive and hypothermic effects of dipyrone
ACTA NEUROPSYCHIATRICA
Authors: Ertin, Ismet Hande; Gunduz, Ozgur; Ulugol, Ahmet
Abstract
Background Dipyrone is one of the most commonly used non-opioid analgesic and antipyretic drug. Its anti-nociceptive and hypothermic effects have long been suspected to be centrally mediated. The involvement of the most recently discovered opioid peptide, nociceptin/orphanin FQ (N/OFQ), and its receptor (NOP) in pain transmission is controversial. It appears to be pro-nociceptive when administered supra-spinally, but exerts anti-nociceptive effects when injected spinally or systemically. Objective Investigation of the role of the N/OFQ system in paracetamol-induced anti-nociception and hypothermia led us to determine its role in the anti-nociceptive and hypothermic effects of dipyrone. Material and Methods Hot-plate and tail-flick tests were used to assess nociception, and a rectal thermometer was used to measure rectal temperature in mice. Results Mice injected with dipyrone (150, 300, 600 mg/kg, i.p.) displayed dose-related anti-nociception and hypothermia. The NOP receptor antagonist JTC-801 (3 mg/kg, i.p.), at a dose that exerted no effect when used alone, alleviated dipyrone-induced anti-nociception but did not reverse dipyrone-induced hypothermia. Conclusion We conclude that NOP receptors participate in the anti-nociceptive, but not in the hypothermic, effects of dipyrone.
Evaluation of the Efficacy of Prolonged Pregabalin Administration Before and After Surgery in Patients Undergoing Arthroscopic Anterior Cruciate Ligament Repair A Prospective, Randomized, Double-blind Study
CLINICAL JOURNAL OF PAIN
Authors: Tobias, Alexandro F.; Moura, Ed C. R.; Honda, Claudio A. D. O.; Pereira, Emanuel C.; de Oliveira, Caio M. B.; Leal, Plinio D. C.; Sakata, Rioko K.
Abstract
Context and Objective: Reconstruction of the knee ligament causes postoperative pain and delayed rehabilitation. Objective: The primary objective of this study was to evaluate the effect of a prolonged preoperative and postoperative pregabalin use for arthroscopic anterior cruciate ligament repair. Materials and Methods: Group 1 (N=25) patients received pregabalin 75 mg/d, and group 2 (N=25) received placebo, 7 days before and 7 days after surgery. Spinal anesthesia was performed using 0.5% hyperbaric bupivacaine (15 mg). The following were evaluated: pain intensity immediately after the surgery, and 12 hours, 24 hours, 1 week, 2 weeks, 1 month, and 2 months after the surgery using a Numerical Rating Scale; dose of postoperative supplementary analgesic for 2 months; time to first analgesic requirement; and side effects during 2 months. For supplementation, the participants received 1 g dipyrone; if there was no pain control, 100 mg ketoprofen was administered; if there was no effect, 100 mg tramadol was administered; and if there was no pain control, 5 mg intravenous morphine was administered until pain control. Results: There was no difference between the groups with regard to pain intensity (P=0.077). In the pregabalin group, morphine consumption was lower at 12 hours (P=0.039) and 24 hours (P=0.044) after surgery, and the consumption of tramadol and ketoprofen was lower 24 hours after surgery. There was no significant difference in the incidence of nausea and vomiting. Dizziness was higher in the pregabalin group (group 1=12 patients; group 2=3 patients;P=0.005). Discussion: A prolonged preoperative and postoperative pregabalin prescription for anterior cruciate ligament repair decreased the need for supplementary analgesics during the first 24 postoperative hours but increased dizziness.