Abstract
Oxytocin is a neuropeptide that is released into the general circulation from the nerve endings of the posterior pituitary and into the brain from dendrites. The half-life of oxytocin in the brain is longer than that in the blood (about 20 min vs. 2 min, respectively) . Oxytocin is involved in social recognition, pair bonding, and maternal behavior. The transmembrane glycoprotein CD38 regulates oxytocin release, and CD38-knockout mice show insufficient oxytocin release. We have found a single nucleotide polymorphism (SNP) in the exon region of the CD38 gene in a subpopulation of individuals with autism spectrum disorder (ASD) . Oxytocin signaling, including CD38 and oxytocin receptor, is suggested to play an important role in the pathophysiology of ASD, although we did not demonstrate an association between the CD38 gene SNP and ASD. Oxytocin administered using a nasal spray penetrates directly into the brain and not via the general circulation. Four studies have suggested the effectiveness of a single shot of oxytocin in the treatment of ASD. We observed marked improvement in severe irritability shown by two ASD patients using oxytocin nasal spray. The effectiveness of oxytocin in the long-term treatment of patients with ASD should be rigorously investigated in a randomized controlled crossover trial.
