The evaluation of analgesic effects of milnacipran and sertraline in tail-flick test.

INTRODUCTION: Antidepressant drugs are used in the treatment of pain as an adjuvant or alone. It has been shown that antidepressant drugs have analgesic effects in various diseases (diabetic neuropathy, low back pain, cancer pain etc.) Sertraline is a potent serotonin re-uptake inhibitor. Some antidepressant drugs inhibited both of the reuptake of serotonin and of noradrenaline. These drugs are called serotonin-noradrenaline re-uptake inhibitors (SNRIs). Milnacipran is a serotonin-noradrenaline re-uptake inhibitor. We have studied the analgesic effects of sertraline and milnacipran after acute and chronic application in tail-flick test in mice. METHODS: The analgesic effects of milnacipran (10, 30, 50 mg/kg) and sertraline (10, 20, 50 mg/kg) were measured after acute and chronic application in tail flick test. The analgesic effects of milnacipran (30 mg/kg) or sertraline (50 mg/kg) were evaluated after the application of L-NAME (10 mg/kg), naloxone (5 mg/kg), prazosin (1 mg/kg), ondansetron (0.1 mg/kg) in tail flick test. RESULTS: Milnacipran (30 mg/kg) and sertraline (50 mg/kg) produced statistically significant analgesic effect compared to their control values after acute and chronic application in tail-flick test. The analgesic effects of both milnacipran (30 mg/kg) and sertraline (50 mg/kg) in the presence of L-NAME (10 mg/kg), naloxone (5 mg/kg), ondansetron (0.1 mg/kg) and prazosin (1 mg/kg) were inhibited in tail-flick test. CONCLUSION: These results indicate that the analgesic effects of milnacipran and sertraline are related to nitrergic, opioidergic, serotonergic and adrenergic system (Fig. 8, Ref. 23).

The evaluation of analgesic effects of simvastatin, pravastatin and atorvastatin in hot plate test.

OBJECTIVES: Simvastatin, pravastatin and atorvastatin have been evaluated whether to have analgesic effects in mice in hot plate test. MATERIALS AND METHODS: Simvastatin (5, 10, 30 mg/kg), pravastatin (5, 10, 30 mg/kg) and atorvastatin (5, 10, 30 mg/kg) were administered acute and chronically by oral gavage in mice. Control (pretreatment value) and posttreatment (after drugs application) values in 60th and 120th minutes were measured in hot-plate test. RESULTS: All three drugs at 10, 30 mg/kg doses produced analgesic effects compared with their control values in 60th and 120th minutes on acute and chronic application in mice. The analgesic effects of drugs were evaluated after the application of L-nitro arginine methyl ester (L-NAME) (10 mg/kg) or naloxone (0.5 mg/kg). L-NAME (10 mg/kg) has no effect compared to the control value on both minutes. The analgesic effects of both atorvastatin (30 mg/kg) and simvastatin (30 mg/kg) in the presence of L-NAME (10 mg/kg) were not inhibited. However, the analgesic effect of pravastatin (30 mg/kg) in the presence of L-NAME (10 mg/kg) was inhibited significantly on both minutes (p < 0.05). Naloxone (0.5 mg/kg) has no effect compared to the control value on both minutes. The analgesic effect of atorvastatin (30 mg/kg) in the presence of naloxone (0.5 mg/kg) was partially (43%) but significantly inhibited only on 60th minute (p < 0.05). The analgesic effect of pravastatin (30 mg/kg) in the presence of naloxone (0.5 mg/kg) was partially (48-40%) but significantly inhibited on both minutes (p < 0.05). However, the analgesic effect of simvastatin (30 mg/kg) in the presence of naloxone (0.5 mg/kg) was inhibited significantly on both minutes (p < 0.05). CONCLUSIONS: These finding indicated that the analgesic effect of pravastatin was related to nitrergic systems and partially opioidergic system; analgesic effect of simvastatin was related to opiodergic system in hot plate test. However, the analgesic effect of atorvastatin was not directly related to both system.