Abhijeet V. Tilak

  To compare the effect of mentat and Donepezil was on working memory in rats. The rats were trained for conditioned avoidance response by using Cook’s pole climbing apparatus. Rats trained for CAR received scopolamine (hydrobromide) in a dose of 0.5mg/kg by intraperitoneal route before administration of study drugs. This is known to produce amnesia which will be used to evaluate the effect on learning and memory of study drugs. Donepezil was given in a dose of 0.32mg/kg by intraperitoneal route and mentat was given in a dose of 200mg/kg by oral route for eight days in the animals after training for conditioned avoidance response. Data was analysed by the chi-square test. Findings show that administration of single dose of scopolamine 20 minutes before the test run on the apparatus causes transient amnesia daily for resulting in disruption of the retention of CAR. Mentat and donepezil significantly increased the retention of condition avoidance response in comparison to scopolamine. However there was no significant statistical difference in the increase in the retention of CAR in mentat or donepezil given alone, but the combination of the two drugs showed statistically significant increase in the retention of CAR than either of these drugs alone. Results from this study provide good platform to conduct clinical studies to assess the benefit of combining mentat with donepezil when given for a longer period of time. Key Words: Working memory, mentat, donepezil, scopolamine, conditioned avoidance response.

  To study antidepressant action of nicotine in animal model of depression. The animal model for depression, used was ‘Isolation induced hyperactivity in rats’. Doses given were vehicle 1ml/kg (intra-peritoneal), imipramine10mg/kg (intra-peritoneal), nicotine0.4mg/kg (subcutaneous), nicotine 0.2mg/kg (inhalational) Nicotine administered by subcutaneous route showed significant reduction in hyperactivity at 10 and 20 minutes when compared with that of vehicle (control) group. When it was compared with imipramine, it showed significant reduction in hyperactivity at 10 minutes. Nicotine administered by inhalation route showed significant reduction in hyperactivity at 10 min and at 30, 40 50 minutes when compared with that of control group. When compared with imipramine, it showed significant reduction in hyperactivity at 10 minutes and it showed comparable effect with that of imipramine at 30, 40, and 50 minutes. Nicotine administered by inhalation route produced significant reduction in hyperactivity at 10, 20, 30, 40,50minutes, when compared with that of nicotine administered by subcutaneous route. Combination with imipramine acute or chronic administration of nicotine by inhalational route showed significant reduction in hyperactivity, when compared with imipramine treated rats. Imipramine treated rats showed significant changes in behavior with persistent sniffing, intense biting and paw licking when it compared with vehicle treated rats. Behavioral changes in nicotine treated rats showed     significant change sat persistent sniffing, intense biting, and paw licking. Effects of nicotine with imipramine were studied on all the above parameters. Nicotine administered by subcutaneous and inhalation route showed significant antidepressantactivity. Key words: Behavioral Changes, Depression, Isolation-Induced Hyperactivity, Nicotine