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Developmental changes in brain serotonin synthesis capacity in autistic and nonautistic children
Author(s) -
Chugani Diane C.,
Muzik Otto,
Behen Michael,
Rothermel Robert,
Janisse James J.,
Lee Jennifer,
Chugani Harry T.
Publication year - 1999
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/1531-8249(199903)45:3<287::aid-ana3>3.0.co;2-9
Subject(s) - serotonin , psychology , 5 ht receptor , medicine , endocrinology , tryptophan , developmental psychology , receptor , chemistry , biochemistry , amino acid
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[ 11 C]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. These data suggest that humans undergo a period of high brain serotonin synthesis capacity during childhood, and that this developmental process is disrupted in autistic children. Ann Neurol 1999;45:287–295