Comparative anatomical assessment of the piglet as a model for the developing human medullary serotonergic system.
Because the piglet is frequently used as a model for developmental disorders of the medullary serotonergic (5-HT) system in the human infant, this review compares the topography and developmental profile of selected 5-HT markers between humans in the first year of life and piglets in the first 60 days of life. The distribution of tryptophan hydroxylase-immunoreactive 5-HT neurons in the human infant medulla is very similar, but not identical, to that in the piglet. One notable difference is the presence of compact clusters of 5-HT neurons at the ventral surface of the piglet medulla. While it lacks these distinctive clusters, the human infant medulla contains potentially homologous 5-HT neurons scattered along the ventral surface embedded in the arcuate nucleus. Each species shows evidence of age-related changes in the 5-HT system, but the changes are different in nature; in the human infant, statistically significant age-related changes are observed in the proportional distribution of medullary 5-HT cells, while in the piglet, statistically significant age-related changes are observed in the levels of 5-HT receptor binding in certain medullary nuclei. Analyses of 5-HT receptor binding profiles in selected nuclei in the two species suggest that the equivalent postnatal ages for 5-HT development in piglets and human infants are, respectively, 4 days and 1 month, 12 days and 4 months, 30 days and 6 months, and 60 days and 12 months. Collectively, when certain species differences are considered, these data support the use of the piglet as a model for the human infant medullary 5-HT system.
Niblock
Mary M
MM
Department of Physiology, Dartmouth Medical School, 1 Medical Center Drive, Lebanon, NH 03756, USA. mary.niblock@dartmouth.edu
Luce
Catherine J
CJ
Belliveau
Richard A
RA
Paterson
David S
DS
Kelly
Michelle L
ML
Sleeper
Lynn A
LA
Filiano
James J
JJ
Kinney
Hannah C
HC
D000818:Animals; D000831:Animals, Newborn; D002648:Child; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D006801:Humans; D008526:Medulla Oblongata / Q000254:growth & development / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D012701:Serotonin / Q000378:metabolism*; D013552:Swine
D012701:Serotonin