The effect of intrahippocampal insulin microinjection on spatial learning and memory

• Published in: Hormones and behavior Vol. 50; no. 5; pp. 748 - 752
• Main Authors: Moosavi, M., Naghdi, N., Maghsoudi, N., Zahedi Asl, S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-12-2006; Elsevier; Elsevier BV
• Subjects: Animal behavior; Animals; Behavioral psychophysiology; Biological and medical sciences; Blood Glucose - drug effects; Brain; Fundamental and applied biological sciences. Psychology; Hippocampus; Hippocampus - drug effects; Hormones and behavior; Injections; Insulin; Insulin - administration & dosage; Insulin - pharmacology; Learning; Male; Maze Learning - drug effects; Memory; Memory - drug effects; Microinjections; Morris water maze; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rodents; Spatial Behavior - drug effects; Learning; Brain; Morris water maze; Insulin; Memory; Hippocampus; Pancreatic hormone; Central nervous system; Cognition; Space perception; Encephalon; Acquisition process; Perceptive learning; Spatial memory
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2006.06.025

Insulin is best known for its action on peripheral target tissues such as the adipocyte, muscle and liver to regulate glucose homeostasis. Insulin and its receptor are found in specific area of CNS with a variety of region-specific functions different from its direct glucose regulation in the periphery. The hippocampus and cerebral cortex distributed insulin/insulin receptor has been shown to be involved in brain cognitive functions. Previous studies about the effect of insulin on memory are controversial. In the present study, the effect of insulin microinjection into CA1 region of rat hippocampus on water maze performance has been investigated. Insulin had a discrepant effect dose dependently. The spatial learning and memory were impaired with lower dose of insulin, had not changed with intermediate doses, while they improved with higher doses. These results suggest that insulin may have a dose-dependent effect on spatial learning and memory.