Pharmacol Rep
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In clinical practice, using the lowest doses of drugs for anesthesia or analgesia is the main goal. Opioid combinations with local anesthetics can be preferable for achieving adequate anesthesia or analgesia. The primary purpose of this study was to examine possible thermal antinociceptive effects of the opioid -fentanyl and the amide local anesthetics levobupivacaine and lidocaine when locally administered alone or in combination. ⋯ However, in the presence of fentanyl, the effects of levobupivacaine and lidocaine were different. Although co-injection of levobupivacaine with fentanyl both enhanced and prolonged antinociceptive action, the lidocaine-fentanyl combination did not significantly change the paw withdrawal latency. These results suggest that intraplantar co-administration of fentanyl with levobupivacaine, but not lidocaine, may provide more effective antinociception without increasing the dose requirements.
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Resveratrol (RSV), a polyphenolic phytoestrogen, has been shown to activate the serine/threonine kinase 5'-adenosine monophosphate-activated protein kinase (AMPK) and to stimulate insulin signaling and glucose uptake in skeletal muscle cells. A direct effect of RSV on neuronal insulin signaling, however, has not been demonstrated. ⋯ Compound C abrogates RSV-induced Akt and GSK-3β phosphorylation and glucose uptake. Thus, we demonstrate that RSV potentiates insulin signaling and glucose uptake via AMPK activation in neuronal cells.
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A conditioned place preference paradigm was used to assess potential rewarding properties of melatonin. The conditioning with melatonin was carried out at two periods of the 12-h light/dark cycle: in the morning (08.30-10.00) and in the evening (18.30-20.00). Morning administration of melatonin (2.5, 5 and 10 mg/kg) did not support conditioned place preference. ⋯ In chronic experiment, melatonin (10 mg/kg) caused similar increase of the time spent on conditioned side both in animals administered vehicle for 7 days and in rats receiving 10 mg/kg of melatonin for the same period of time. Potent activity in the conditioned preference model suggests that melatonin may have rewarding properties, which moreover, is not tolerated following repeated pre-exposure to the drug. These findings may indicate potential abuse liability of melatonin, and therefore, its use by humans should require a careful monitoring for abuse and/or dependency.
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The results of recent studies suggest that metformin, in addition to its efficacy in treating type 2 diabetes, may also have therapeutic potential for the treatment of neuroinflammatory diseases in which reactive microglia play an essential role. However, the molecular mechanisms by which metformin exerts its anti-inflammatory effects remain largely unknown. Adenosine-monophosphate-activated protein kinase (AMPK) activation is the most well-known mechanism of metformin action; however, some of the biological responses to metformin are not limited to AMPK activation but are mediated by AMPK-independent mechanisms. ⋯ The presented evidence supports the conclusion that metformin-activated AMPK participates in regulating the release of TNF-α. Furthermore, the effects of metformin on the release of IL-1β, IL-6, IL-10, TGF-β, NO, and ROS as well as on the expression of arginase I, iNOS, NF-κB p65 and PGC-1α were not AMPK-dependent, because pretreatment of LPS-activated microglia with compound C, a pharmacological inhibitor of AMPK, did not reverse the effect of metformin. Based on the present findings, we propose that the shift of microglia toward alternative activation may underlie the beneficial effects of metformin observed in animal models of neurological disorders.
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The aim of this study was to determine the analgesic effects of pregabalin (a third-generation antiepileptic drug) using the acute thermal pain model (hot-plate test) in mice. Linear regression analysis was used to evaluate a dose-response relationship between logarithms of pregabalin doses and their resultant maximum possible antinociceptive effects (MPAE) using the hot-plate test in mice. From the linear equation of the dose-response relationship, doses of pregabalin that increased antinociceptive effects by 20%, 30%, 40%, and 50% were calculated and amounted to 9.33, 24.80, 65.93, and 175.26 mg/kg, respectively. In conclusion, pregabalin produces analgesic effects in a dose-dependent manner, as demonstrated using the hot-plate test in mice.