Relationship between the Level of Hippocampal Leptin Receptor Gene Expression and Learning Performance in Diabetic Rats

Abstract

Diabetes mellitus may be associated with impaired cognitive function. Decreased peripheral glucose regulation was associated with decreased general cognitive performance, memory impairments, and atrophy of the hippocampus, a brain area that is key for learning and memory. Leptin that is a peptide hormone, acts in the hippocampus where it facilitates the induction of long-term potentiation and enhances NMDA receptor mediated transmission. The aim of the present study is to investigate possible relationship between the hippocampal leptin receptor gene expression and learning performance in streptozotocin (STZ) induced diabetic rats. In this study was conducted on a total of 40 Winstar albino female rats, including a control group consisting of 20 rats and experimental group comprising of 20 rats in which diabetes was induced by means of STZ administration. Leptin receptor gene expression was detected in hippocampal samples by using real time-PCR. According to the evaluation, the learning performance of rats with induced diabetes was found to be same throughout the first 3 days after STZ in comparison to the control group rats. End of the 45 days the learning performance of the control group was found to be better than the diabetic group (p<0.05). Hipocampal leptin receptor expression was found lower in diabetic group than the control group (p<0.05). The results provide evidence that leptin receptor gene may related to learning performance in diabetic rats. Further, detailed studies are needed to address the exact role of leptin and related molecules in learning performance.

Brain Signaling Systems in the Type 2 Diabetes and Metabolic Syndrome: Promising Target to Treat and Prevent These Diseases

“…Such weakening can be provoked by the central leptin deficiency, the altered activity of leptin receptor and IRS-proteins, and the decreased response of hypothalamic neurons to insulin [175,176]. It was shown that the leptin deficiency and the leptin resistance in the CNS were involved in the impairment of cognitive functions in T2DM, MS and also in experimental type 1 DM [171,174,177,178].…”