The serotonergic system in ageing and Alzheimer's disease

Alzheimer's disease (AD) is one of the major neurodegenerative diseases that deteriorates cognitive functions and primarily affects associated brain regions involved in learning and memory, such as the neocortex and the hippocampus. Following the discovery and establishment of its role as a neurotransmitter, serotonin (5-HT), was found to be involved in a multitude of neurophysiological processes including mnesic function, through its dedicated pathways and interaction with cholinergic, glutamatergic, GABAergic and dopaminergic transmission systems. Abnormal 5-HT neurotransmission contributes to the deterioration of cognitive processes in ageing, AD and other neuropathologies, including schizophrenia, stress, mood disorders and depression. Numerous studies have confirmed the pathophysiological role of the 5-HT system in AD and that several drugs enhancing 5-HT neurotransmission are effective in treating the AD-related cognitive and behavioural deficits. Here we present a comprehensive overview of the role of serotonergic neurotransmission in brain development, maturation and ageing, discuss its role in higher brain function and provide an in depth account of pathological modifications of serotonergic transmission in neurological diseases and AD.

► Comprehensive overview the role of serotonin from development aging, including Alzheimer's disease (AD).
► In depth analysis of serotonergic neurons, projections, receptors, and their physiological and pathophysiological roles.
► Serotonergic neurotransmission plays an important role in memory, both directly and via other transmitter systems modulation.
► Dysfunctional serotonergic system is implicated in the pathophysiology of ageing and AD.
► Deficits in serotonergic neurotransmission directly correlate with AD memory impairments, which can be reversed by serotonomimetic drug treatments.