Expanded ontogeny of neurotransmitters and their metabolites in the brains of fetal and newborn lambs.
To evaluate the ontogeny of the brain neurotransmitters norepinephrine, dopamine, serotonin and the metabolites hydroxyindoleacetic acid and homovanillic acid, we measured these neurotransmitters in 10 brain areas at three ages in fetal sheep and two ages in newborn lambs. Norepinephrine exhibited an increase only at 25-30 days after birth in the midbrain, lateral hypothalamus, dorsal medial hypothalamus and ventral medial hypothalamus. Dopamine concentration was very low and did not change over the ages examined. Homovanillic acid decreased after 125 days in the cerebellum, but this change is probably not biologically meaningful, since there were no statistically significant changes in homovanillic acid in other brain areas. Serotonin increased at 25-30 days after birth in the ventral medial hypothalamus, but changes in other brain areas were not significant. Hydroxyindoleacetic acid reached its greatest concentration at 1-5 days after birth in nine of the ten brain areas examined. Thus we conclude that the serotonin system is undergoing more change in the last third of gestation and first month of extrauterine life than the norepinephrine or dopamine systems.
Richards
G E
GE
Department of Pediatrics, University of Texas Medical Branch, Galveston.
Gluckman
P D
PD
Ball
K
K
Mannelli
S C
SC
Kalamaras
J A
JA
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000196:embryology / Q000254:growth & development; D001923:Brain Chemistry; D004298:Dopamine / Q000032:analysis*; D005314:Embryonic and Fetal Development; D005260:Female; D005865:Gestational Age; D006719:Homovanillic Acid / Q000032:analysis*; D006897:Hydroxyindoleacetic Acid / Q000032:analysis*; D009638:Norepinephrine / Q000032:analysis*; D011247:Pregnancy; D012701:Serotonin / Q000032:analysis*; D012756:Sheep
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D004298:Dopamine; D009638:Norepinephrine; D006719:Homovanillic Acid