Effect of ghrelin intrahippocampal injection on spatial memory in intact male rats

Abstract

Objectives: The hippocampus has been implicated in many learning and memory processes including spatial memory. Ghrelin is a peptide hormone secreted by stomach and brain structures. Some studies have suggested that ghrelin may affect learning and memory. The goal of this study was to investigate the effect of intrahippocampal injection of different doses of ghrelin on spatial memory formation in normal rats. Methods: Fifty maleWistar rats were divided into 5 groups including: control, saline and different doses of ghrelin (0.3, 1.5 or 3 nmol). Saline or ghrelin was injected into hippocampus. All groups were trained in Morris water maze for two consecutive days. Learning parameters including escape latency and distance traveled were compared among groups. Results: ghrelin with dose of 0.3 didn't alter Learning parameters compared to saline (p< 0.05) but ghrelin with doses of 1.5 or 3 nmol significantly improved spatial memory compared to saline in normal rats(p< 0.05). Conclusion: The findings indicated that ghrelin has positive effect on memory processes.