ABSTRACT
Major depressive disorder [MDD] is the leading cause of memory impairment in general population. The serotonin hypothesis provides a target model for the treatment of depression and depression-associated memory loss. 5- HT-1B receptor is suggested as a potential candidate in the pathophysiology of depressive illness. Dysfunction of 5-HT- 1B receptors has been observed previously in depressive patients. Zolmitriptan, 5-HT-1B agonist is clinically recommended for the treatment of migraine. However, in present study this drug was tested as a potential treatment for depression and associated memory loss by altering the serotonergic function at receptor level. Rats [n=24] were equally divided into unstressed and stressed groups. Depression was induced by 19 days of restraint stress for 4 h which was followed by forced swim test and pattern separation test to assess depressive symptoms and memory impairment, respectively. The initial sign of depression-associated memory loss involves impaired pattern separation which is regarded as pseudodementia. In this study stressed rats showed depression- and pseudodementia-like symptoms. After the induction of depression, rats were treated with zolmitriptan at a dose of 0.3 mg/kg which resulted in a significant attenuation of depression and depression-associated memory impairment. Results are discussed with reference to the modulation of function of 5-HT-1B receptor following the administration of exogenous agonist
ABSTRACT
This study was designed to investigate the role of enriched environment in preventing and/or reducing the neurobehavioral deficits produced after nicotine administration in albino Wistar rats. Equal numbers of rat in two groups were either placed in social environment [control group] or social along with physically enriched environment for four weeks before the administration of nicotine. Exposure to different environmental conditions was followed by the intraperitoneal injection of nicotine at the dose of 0.6 mg/kg for seven consecutive days during which addictive behavior was monitored using conditioned placed preference paradigm. Behavioral responses to locomotor activity, anxiety and retention of short term memory were investigated in control and nicotine injected groups exposed to different environments. Results of this study showed that the rats pre-exposed to physical along with social enrichment exhibited a decrease in drug seeking behavior, hyper locomotion, anxiogenic effects along with improvement of working memory as compared to control and nicotine injected groups that were kept in social environment alone. This behavioral study suggests that the exposure to physical enrichment along with socialization in young age can later reduce the chances of compulsive dependence on nicotine and related neurobehavioral deficits