ABSTRACT
Serotonin [5-hydroxytryptamine (5-HT)] neurons are widely distributed throughout the mammalian brain. This neuronal system is one of the earliest to develop, and the turnover rate of 5-HT is higher in the immature mammalian brain than at any other time in life. Serotonin plays a key role as a growth factor in the immature brain, directing both proliferation and maturation (1). For these reasons and others, 5-HT has been a target of investigation into the pathophysiology of autistic disorder (autism) for nearly 50 years. This chapter reviews results from studies of peripheral and central neurochemistry, behavioral/neuroendocrine challenges, neuroimaging, and genetics related to 5-HT function in autism. The reader is referred to other excellent reviews of this topic for additional information (2-4). We first recount the historical developments that led, in part, to studies of 5-HT function in autism.
