Hippocampal neuropeptide Y 2 receptor blockade improves spatial memory retrieval and modulates limbic brain metabolism

• Published in: Neurobiology of learning and memory Vol. 187; p. 107561
• Main Authors: Méndez-Couz, Marta, González-Pardo, Héctor, Arias, Jorge L, Conejo, Nélida M
• Format: Journal Article
• Language: English
• Published: United States 01.01.2022
• Subjects: Animals; Brain - metabolism; Hippocampus - metabolism; Limbic System - metabolism; Male; Mental Recall - physiology; Morris Water Maze Test; Neuronal Plasticity; Neurons - metabolism; Neuropeptide Y - metabolism; Rats; Receptors, Neuropeptide Y - metabolism; Spatial Memory - physiology; Ventral hippocampus; Cytochrome C oxidase; Dentate gyrus; Infralimbic cortex; Mammillary bodies; Synaptic plasticity
• ISSN: 1095-9564
• DOI: 10.1016/j.nlm.2021.107561

The neuropeptide Y (NPY) is broadly distributed in the central nervous system (CNS), and it has been related to neuroprotective functions. NPY seems to be an important component to counteract brain damage and cognitive impairment mediated by drugs of abuse and neurodegenerative diseases, and both NPY and its Y receptor (Y R) are highly expressed in the hippocampus, critical for learning and memory. We have recently demonstrated its influence on cognitive functions; however, the specific mechanism and involved brain regions where NPY modulates spatial memory by acting on Y R remain unclear. Here, we examined the involvement of the hippocampal NPY Y R in spatial memory and associated changes in brain metabolism by bilateral administration of the selective antagonist BIIE0246 into the rat dorsal hippocampus. To further evaluate the relationship between memory functions and neuronal activity, we analysed the regional expression of the mitochondrial enzyme cytochrome c oxidase (CCO) as an index of oxidative metabolic capacity in limbic and non-limbic brain regions. The acute blockade of NPY Y R significantly improved spatial memory recall in rats trained in the Morris water maze that matched metabolic activity changes in spatial memory processing regions. Specifically, CCO activity changes were found in the dentate gyrus of the dorsal hippocampus and CA1 subfield of the ventral hippocampus, the infralimbic region of the PFC and the mammillary bodies. These findings suggest that the NPY hippocampal system, through its Y R receptor, influences spatial memory recall (retrieval) and exerts control over patterns of brain activation that are relevant for associative learning, probably mediated by Y R modulation of long-term potentiation and long-term depression.