Effect of Mirtazapine Pre-treatment on Haloperidol, Ergometrine and Fluoxetine Induced Behaviours in Albino Rats

Background: Central 5-HT2A and 5-HT2C serotonergic receptors are mainly involved in the control of nigrostriatal and mesolimbic dopaminergic neuronal activity has been well proved and established. 5-HT has facilitatory effect on stimulated dopamine release by stimulating central 5-HT2A receptors and inhibitory effect by stimulating 5-HT2C receptors. Aim and Objectives: To evaluate 5-HT2A and 5-HT2C receptor blocking activity of Mirtazapine (MIR) and the effect of mirtazapine pre-treatment on Ergometrine (ERG) induced behaviours, Fluoxetine (FLU) induced penile erections and Haloperidol (HAL) induced catalepsy in rats. Material and Methods: Each group was subdivided into different subgroups consisting 6 animals in each. Control group received Dimethyl Sulfoxide (DMSO) and other groups received different doses of mirtazapine one hour before ERG/FLU/HAL. Values obtained from control group were compared with all remaining groups pre-treatment with different doses of MIR. Results: MIR (MIR) at 2.5, 5, 10 and 20 mg/kg intraperitoneally (i.p) did not produce any per se effects. Pre-treatment with 5, 10 and 20 mg/kg i.p. MIR significantly antagonised ERG induced behaviours. 5 mg/kg i.p. MIR significantly antagonised whereas 10 and 20 mg/kg i.p. MIR abolished FLU (10 mg/kg) induced penile erections in rats. MIR 5 and 20 mg/kg i.p. significantly antagonised HAL (1mg/kg) induced catalepsy at 1 hr testing time interval while 10 and 20 mg/kg MIR significantly antagonised HAL (1 mg/kg) induced catalepsy at 2 hr testing time interval. Conclusion: Our results indicate that MIR at 5, 10 and 20 mg/kg possesses 5-HT2A and 5-HT2C receptors blocking activity. At 5, 10 and 20 mg/kg MIR, by blocking central 5-HT2C receptors predominantly, causes release of dopamine from nigrostriatal dopaminergic neurons and therefore antagonizes HAL induced catalepsy

An Evaluation of Analgesic Activity of Leaf and Stem Bark Extracts of Ficus Religiosa in Wistar Rats

Introduction: Pain is an unpleasant sensory and emotional experience associated with actual or potential damage. Non- steroidal anti-inflammatory drug (NSAIDs) & Opioids are wide analgesics, but because of adverse effects, their use is limited. Ficus Religiosa is a traditional medicinal plant, its various parts have been used in treating some conditions. Aims & Objective: To evaluate the analgesic activity of methanolic extract of leaves and stem bark of Ficus Religiosa at different doses. Materials & Methodology: This study was conducted in the Department of Pharmacology. Two doses of methanolic extract of leaves (100 & 200 mg/kg) and stem bark (125 & 250 mg/kg) of ficus religiosa were used. Wistar rats were used to evaluate analgesic activity and it was evaluated by using analgesiometer by tail flick method. Phytochemical screening of both the extracts were also done. Results: Both the extracts at their respective doses showed significant analgesic activity as compared with the control group, whereas it was not comparable with the standard drug ibuprofen (40 mg/kg p.o). Conclusion: Therefore, we conclude that both the extracts of ficus religiosa were showing analgesic activity. But this analgesic activity is not comparable with the standard drug Ibuprofen