Serotonergic Neurotransmission in Autism Spectrum Disorders

Abstract

Serotonin (5-hydroxytryptamine, 5-HT) was isolated and characterized during the late 1930s through the 1950s. Since then, serotonin has been shown to play a key role in a range of behaviors and processes, including sensory gating and processing, behavioral inhibition, appetite, aggression, sleep, mood, and neuroendocrine secretion (Anderson, 2005). The serotonin neuron system stretches abundant branches from a limited number of cells in the brain stem and widely and densely projects the brain (Takeuchi, 1988). Therefore, the serotonin neuron system is considered to be “the total control system”. During development of the brain, the serotonin neuron system is not only essential for formation and maintenance of synapses (Lauder, 1990), but also is affected by a variety of environmental factors. These findings are crucial for understanding the pathogenesis of many developmental disorders. This paper reviews the involvement of the serotonin neuron system in neurotransmission in autism spectrum disorders.