A comparative study of Central Analgesic activity of potential Antidepressants

Pain is an ill-defined, disabling accompaniment of many medical conditions. It is often evoked by an external and internal noxious stimulus. It affects millions of people suffering with depression and other psychiatric disorders. Most of the antidepressants are having analgesic capacity to treat the pain by inhibiting nociceptive stimuli by increasing the seratonergic and noradrenergic transmission in CNS. Objectives: The Present study carried out to investigate the central analgesic activity of potential antidepressants like Fluoxetine, Imipramine, Amitriptyline and to compare the analgesic activity with standard central analgesic Pentazocine. Methods: Analgesic activity was evaluated by using hot plate and tail immersion models in mice. Fluoxetine (10 mg/kg), Imipramine (20 mg/kg), Amitriptyline(20 mg/kg) were used as test drugs and Pentazocine (10 mg/kg) was used as standard drug. Results: In tail immersion model of analgesic activity Fluoxetine possess significant analgesic activity (*p<0.05 at 60 min interval, ***p<0.001 at 90 and 120 min interval) Amitriptyline also showed significant analgesic activity (**p<0.01) at 90 min interval and ***p<0.001 at 120 min interval. Imipramine is the least effective analgesic in this study showed mild analgesic activity (*p<0.05 at 90 min interval and **p <0.01 at 120 min interval). In hot plate analgesic model Fluoxetine and Amitriptyline possess significant analgesic activity (***p<0.001 at 120 min interval), Imipramine same like above said model less effective, doesn’t shown significant analgesic activity. Conclusion: All the test drugs significantly reduce the painful stimuli when compared to the control group in both the models. These results suggest that the antidepressants which increase the monoamine transmission in the brain posse’s significant antidepressant activity and might be useful as potent analgesics.