GHRL and obesity due to melanocortin 4 receptor deficiency: In the MSG-generated rat model of obesity and cognitive decline, the administration of the ghrelin analog GHRP-6 normalized the plasma concentrations of various hormones, decreased the abnormally elevated hippocampal pools of Aβ and acetylcholine and enhanced the spatial memory of these rodents (Kutty and Subramanian, 2014).