Annals of NeurologyVolume 45, Issue 3 p. 287-295 Original Article Developmental changes in brain serotonin synthesis capacity in autistic and nonautistic children Diane C. Chugani PhD, Diane C. Chugani PhD Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI Department of Radiology, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorOtto Muzik PhD, Otto Muzik PhD Department of Radiology, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorMichael Behen BA, Michael Behen BA Department of Psychiatry, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorRobert Rothermel PhD, Robert Rothermel PhD Department of Psychiatry, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorJames J. Janisse MA, James J. Janisse MA Center for Health Care Effectiveness Research, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorJennifer Lee, Jennifer Lee Department of Pediatrics, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorHarry T. Chugani MD, Corresponding Author Harry T. Chugani MD Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI Department of Radiology, Wayne State University School of Medicine, Detroit, MI Department of Neurology, Wayne State University School of Medicine, Detroit, MIChildren's Hospital of Michigan PET Center, 3901 Beaubien Boulevard, Detroit, MI 48201Search for more papers by this author Diane C. Chugani PhD, Diane C. Chugani PhD Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI Department of Radiology, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorOtto Muzik PhD, Otto Muzik PhD Department of Radiology, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorMichael Behen BA, Michael Behen BA Department of Psychiatry, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorRobert Rothermel PhD, Robert Rothermel PhD Department of Psychiatry, Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorJames J. Janisse MA, James J. Janisse MA Center for Health Care Effectiveness Research, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorJennifer Lee, Jennifer Lee Department of Pediatrics, Wayne State University School of Medicine, Detroit, MISearch for more papers by this authorHarry T. Chugani MD, Corresponding Author Harry T. Chugani MD Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI Department of Radiology, Wayne State University School of Medicine, Detroit, MI Department of Neurology, Wayne State University School of Medicine, Detroit, MIChildren's Hospital of Michigan PET Center, 3901 Beaubien Boulevard, Detroit, MI 48201Search for more papers by this author First published: 31 May 2001 https://doi.org/10.1002/1531-8249(199903)45:3<287::AID-ANA3>3.0.CO;2-9Citations: 408AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Serotonin content, serotonin uptake sites, and serotonin receptor binding measured in animal studies are all higher in the developing brain, compared with adult values, and decline before puberty. Furthermore, a disruption of synaptic connectivity in sensory cortical regions can result from experimental increase or decrease of brain serotonin before puberty. The purpose of the present study was to determine whether brain serotonin synthesis capacity is higher in children than in adults and whether there are differences in serotonin synthesis capacity between autistic and nonautistic children. Serotonin synthesis capacity was measured in autistic and nonautistic children at different ages, using α[11C]methyl-L-tryptophan and positron emission tomography. Global brain values for serotonin synthesis capacity (K complex) were obtained for autistic children (n = 30), their nonautistic siblings (n = 8), and epileptic children without autism (n = 16). K-complex values were plotted according to age and fitted to linear and five-parameter functions, to determine developmental changes and differences in serotonin synthesis between groups. For nonautistic children, serotonin synthesis capacity was more than 200% of adult values until the age of 5 years and then declined toward adult values. Serotonin synthesis capacity values declined at an earlier age in girls than in boys. In autistic children, serotonin synthesis capacity increased gradually between the ages of 2 years and 15 years to values 1.5 times adult normal values and showed no sex difference. Significant differences were detected between the autistic and epileptic groups and between the autistic and sibling groups for the change with age in the serotonin synthesis capacity. 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