Possible role of ghrelin in neuronal conduction in improved memory cognition

Abstract

Background Ghrelin, an appetite stimulator, functions through IP3-DAG signaling. It has been found to increase food related memory retention in rodents. Objective The study aims to investigate the role of Ghrelin signaling in memory cognition and retention using intracerebroventricular streptozotocin (ICV-STZ) model in Wistar rats. Methods Male Wistar rats (250-280 g) were employed into the study with sample size n=6. Streptozotocin (STZ) 3 mg/kg was administered on day one through intra-cerebroventricular route. n-Octanoic acid, a Ghrelin activator was given in two doses 50 and 100uL for 21 daysby dissolving in polyethylene glycol 600whereas Nifedipine, Ca++ channel blocker was given at 10 mg/kg, i.p. to one group underwent to administration of n-octanoic acid high dose.Impairments in cognition, memory consolidation and retention were assessed using Morris water maze, Y maze, balance beam, open field test and photoactometer test. The biochemical estimations for oxidative stress i.e. lipid peroxidation, glutathione, and acetylcholinesterase activity were done in rat brain homogenate. Statistical analysis was carried out using graph pad prism 5. Results ICV-STZ treated animals exhibited memory deficits in Morris water maze, Y maze, balance beam test. Administration of low and high doses of n-Octanoic acid produced significant restoration of memory retention. However, nifedipine abolished the memory improvement produced by n-octanoic acid. The level of oxidative stress and AChE activity observed in rat brain was also reversed. Conclusion The finding may reveal that ghrelin plays pivotal role in improving cognition, retentionand working memory possible through Ca signaling.