Pharmacology
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The present study evaluated the role of ventrolateral periaqueductal gray (vlPAG)-located orphanin-FQ (OFQ) in the opioid tolerance induced by repeated microinjections of morphine (MOR) into vlPAG. Microinjection of MOR (5 microg/0.5 microl) into vlPAG caused antinociception as quantified with the tail flick and the hot plate tests. When MOR microinjection was repeated twice daily, the antinociceptive effect disappeared within 2 days (tolerance). ⋯ Furthermore, if OFQ (1 ng/0.5 microl) was microinjected into vlPAG, then a MOR microinjection administered 15 min later into vlPAG did not elicit antinociception. Finally, opioid tolerance induced by repeated systemic MOR injections (5 mg/kg, i.p.) was reversed by a single microinjection of NST into vlPAG. This emphasizes the central importance of vlPAG-located OFQ in the MOR tolerance.
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To evaluate the protective effect of alpha-lipoic acid in reducing oxidative damage after severe hepatic ischemia/reperfusion (IR) injury. ⋯ Since lipoic acid administration alleviated the I/R-induced liver injury and improved the hepatic structure and function, it seems likely that lipoic acid with its antioxidant and oxidant-scavenging properties may be of potential therapeutic value in protecting the liver against oxidative injury due to ischemia-reperfusion.