title: Developmental differences in infant salivary alpha-amylase and cortisol responses to stress.
abstract: This study examined developmental differences in infants' salivary alpha-amylase (sAA) and cortisol levels and responses to the well-baby exam/inoculation stress protocol at 2, 6, 12, and 24 months of age. Mother-infant pairs (n=85; 45 girls) were assessed during well-baby visits and saliva was sampled before the well-baby exam/inoculation procedure (pre-test) and at 5, 10, and 20 min post-inoculation stress. Older infants (24 months) had higher levels of sAA than younger infants (2, 6 and 12 months). Stress-related sAA increases were evident at 6 and 12 months, but not at 2 or 24 months of age. Stress-related cortisol increases were present at 2 and 6 months, but not at older ages. Mothers had higher sAA levels than their infants, but did not show sAA or cortisol increases to their infants' inoculation. Pre-test, maternal and infant sAA levels were positively correlated (rs .47 to .65) at 6, 12, and 24 months of age, but not at 2 months. These findings suggest that the association between the sympathetic branch of the autonomic nervous system and the secretion of sAA develops between 2 and 6 months of age, when levels of sAA are responsive to exposure to a painful stressor.
authors.affiliation: Department of Psychiatry and Human Behavior, University of California, Irvine, USA. edavis@uci.edu
authors.forename: Elysia Poggi
authors.initials: EP
authors.lastname: Davis
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Granger
mesh_terms: D000328:Adult; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis* / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology; D007223:Infant; D008297:Male; D010913:Pituitary-Adrenal System / Q000502:physiology; D012463:Saliva / Q000737:chemistry*; D055291:Salivary alpha-Amylases / Q000032:analysis* / Q000378:metabolism; D013315:Stress, Psychological / Q000378:metabolism*; D013564:Sympathetic Nervous System / Q000502:physiology; D055815:Young Adult
chemical_list: D055291:Salivary alpha-Amylases; D006854:Hydrocortisone