title: Synaptogenesis and Myelination in the Nucleus/Tractus Solitarius: Potential Role in Apnea of Prematurity, Congenital Central Hypoventilation, and Sudden Infant Death Syndrome.
abstract: Fetuses as early as 15 weeks' gestation exhibit rhythmical respiratory movements shown by real-time ultrasonography. The nucleus/tractus solitarius is the principal brainstem respiratory center; other medullary nuclei also participate. The purpose was to determine temporal maturation of synaptogenesis. Delayed synaptic maturation may explain neurogenic apnea or hypoventilation of prematurity and some cases of sudden infant death syndrome. Sections of medulla oblongata were studied from 30 human fetal and neonatal brains 9 to 41 weeks' gestation. Synaptophysin demonstrated the immunocytochemical sequence of synaptogenesis. Other neuronal markers and myelin stain also were applied. The nucleus/tractus solitarius was similarly studied in fetuses with chromosomopathies, metabolic encephalopathies, and brain malformations. Synapse formation in the nucleus solitarius begins at about 12 weeks' gestation and matures by 15 weeks; myelination initiated at 33 weeks. Synaptogenesis was delayed in 3 fetuses with different conditions, but was not specific for only nucleus solitarius. Delayed synaptogenesis or myelination in the nucleus solitarius may play a role in neonatal hypoventilation, especially in preterm infants and in some sudden infant death syndrome cases.
authors.affiliation: Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary and Alberta Children's Hospital Research Institute, Calgary Alberta, Canada harvey.sarnat@albertahealthservices.ca.
authors.forename: Harvey B
authors.initials: HB
authors.lastname: Sarnat
authors.affiliation: Departments of Paediatrics, Pathology (Neuropathology) and Clinical Neurosciences, University of Calgary and Alberta Children's Hospital Research Institute, Calgary Alberta, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Flores-Sarnat
mesh_terms: D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000473:pathology; D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007040:Hypoventilation / Q000151:congenital* / Q000473:pathology / Q000503:physiopathology; D007223:Infant; D007234:Infant, Premature; D008297:Male; D009186:Myelin Sheath / Q000473:pathology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D020182:Sleep Apnea, Central / Q000473:pathology* / Q000503:physiopathology; D017552:Solitary Nucleus / Q000473:pathology*; D013398:Sudden Infant Death / Q000473:pathology*; D013569:Synapses / Q000473:pathology*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D009419:Nerve Tissue Proteins; D016708:Synaptophysin
keywords: apnea of prematurity; hypoventilation; maturational delay; myelination; nucleus solitarius; pneumotaxic center; sudden infant death syndrome (SIDS); synaptogenesis; synaptophysin; tractus/fasciculus solitarius