Kisspeptin-13 Improves Spatial Memory Consolidation and Retrieval against Amyloid-β Pathology

It has been shown that brain glucose metabolism impairment, obesity, and diabetes could lead to cognitive decline and Alzheimer's disease (AD) pathogenesis. Kisspeptin (KP) a G-protein coupled receptor neuropeptide, has been suggested as a link between energy balance and reproduction. Some studies have shown that the attenuation of KP signaling decreases metabolism and energy expenditure. KP mRNAs and receptors are detected in the hippocampus and cause the promotion of excitatory synaptic responses through modulation of postsynaptic signaling. The purpose of this study was to investigate the effect of KP on spatial learning and memory and its possible neuroprotective effect on Amyloid-Beta induced cognitive impairment using the Morris Water Maze (MWM) task in rats. The reference and reversal spatial learning and memory have been measured in this study. Rats were injected bilaterally by Aβ1-42 (2 μg/μL) or saline as a vehicle into the hippocampal CA1 area. One week later, KP-13 (1.5 or 2 µg/µL) was injected i.c.v before or after each training session for 3 days and memory was tested 24 h later. The results showed KP-13 by itself could significantly enhance spatial memory consolidation and retrieval, and Aβ induced reversal and reference memory impairment was significantly ameliorated by KP-13. In Conclusion, it seems that KP-13 as a neuropeptide has to enhance spatial memory properties and could be a possible neuroprotective peptide on amyloid-beta induced pathology.