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The studied extract of Rhodiola rosea exhibited significant analgesic activity in all the pain models used--inhibition of thermal pain, mechanical hyperalgesia and formalin-induced pain behavior. Significant anti-inflammatory activity was observed from Rhodiola rosea extract in carrageenan induced paw edema in rats.

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Introduction: The Ginkgo biloba L. tree is considered as one of the oldest species on Earth. It is known as a &ldquo;living fossil&rdquo; dating back approximately 200 million years. Both the leaves and seeds of this tree have been used for millennia in traditional Chinese medicine. Aim: To study the phytochemical profile of Gingko biloba seed extract (GBSE) and its memory enhancing effects. Materials and methods: Liquid chromatography with mass detection (LC-MS) was performed for phytochemical analyses of the extracts. For the in vivo experiments, male Wistar rats were divided randomly into 5 groups (n=8): saline; piracetam; &nbsp;GBSE 50; 100, and 200 mg/kg b.w. Y-maze, T-maze, step-down passive avoidance and novel object recognition test (NORT) were performed. The observed parameters were: percentage of spontaneous alternations (% SA), working memory index, latency of reaction and recognition index, respectively. Statistical analysis was done using SPSS 19. Results: LC-MS analysis showed the presence of the flavonoids quercetin, kaempferol and isorhamnetin (as aglycones), the ginkgolides A, B, C, J, and bilobalide. In Y-maze task, the groups treated with 50 and 100 mg/kg of GBSE significantly increased the % SA during the memory test compared to saline (p<0.05). In T-maze test, the three experimental groups with GBSE significantly increased the working memory index in comparison with that of the control group (p<0.05). In step-down test, the animals receiving 100 mg/kg b.w. GBSE, notably increased the latency during both retention tests (p<0.05 and p<0.01, respectively). In NORT, only the animals with the middle dose of GBSE ameliorated the recognition index when compared to saline (p<0.05). Conclusions: GBSE enhances spatial working memory, recognition memory, and short- and long-term recall in na&iuml;ve rats due to the synergic effects of detected flavonoids and terpene lactones on brain functions. The brain structures involved are probably the hippocampus and prefrontal cortex.

Background. Glutamate N-methyl-D-aspartate (NMDA) receptors are known for their importance in the perseverance of chronic neuropathic pain. Ketamine, an intravenous anesthetic agent, is a non-competitive blocker of NMDA receptors. Applied in anesthetic doses, ketamine has anti-nociceptive effects in various animal pain models. Objectives. The objective of this study was to investigate the anti-nociceptive effect of ketamine in acute and neuropathic pain models in rats. Material and methods. To study the anti-nociceptive effect of ketamine on acute pain, 40 Wistar rats were divided into 5 groups (n = 8): control, positive control group and 3 experimental groups treated intraperitoneally (ip.) with 30 mg/kg bw, 40 mg/kg bw and 50 mg/kg bw ketamine, respectively. The anti-nociceptive effect was evaluated in hot plate, analgesy-meter and formalin tests. The model of neuropathic pain was induced by left sciatic nerve ligation. Twenty-four Wistar rats were divided into 3 groups (n = 8): sham-control group, model group and ketamine-treated group subsequently tested in hot plate and analgesy-meter tests. Results. In the hot plate test, the rats treated with ketamine presented increased reaction latency at the 120 th min and 180 th min compared to the controls. In the analgesy-meter test, ketamine produced an antinociceptive effect at the 60 th min compared to the controls. In the formalin test, the paw licking time across the early phase of testing was reduced in the rats treated with the 2 higher doses of ketamine. In a neuropathic pain model, ketamine increased the reaction latency at the 120 th min and 180 th min compared with the model group in the hot plate test. In the analgesy-meter test, in the ketamine-treated animals the paw withdrawal threshold increased at the 60 th min compared with the model group. Conclusions. Our results suggest that ketamine produces peripheral anti-nociceptive effect in an acute pain model. Also, it relieves thermal and mechanical allodynia after 14 days of treatment in a neuropathic pain model.