CONICET | Buscador de Institutos y Recursos Humanos

Age is the main risk factor for a number of pathologies, including neurodegenerative diseases like Alzheimer, which is characterized by a loss of cholinergic neurons and impairment of the cognitive function. The physiological aging of the brain is encompassed by changes in different memory abilities. It is accepted that these alterations are related to deficient neuronal communication in absence of cell death. Therefore, alterations in the expression of the neurotransmitter receptors might be one of the causes leading to memory impairment with age.The most abundant nicotinic receptors in the brain are the α7 and α4/β2 pentamers, which are expressed in the hippocampus, cortex, limbic regions, thalamus and basal ganglia. These receptors have been shown to modulate the hippocampus-dependent learning and memory.We quantified the expression of the α7, α4 and β2 nicotinic subunits in the hippocampus of aging mice, using quantitative RT-PCR. We observed a significant reduction in the messenger RNA levels of the α7 and α4 subunits in 24-month old mice, compared to 3- and 12-month old mice. We did not detect significant variations in the messenger RNA amount of the β2 subunit in the aging animals. Immunohistochemical studies are needed to identify in which area and neuronal population of the hippocampus these receptor changes are taking place, in order to understand their relevance for the age-related memory loss.