Serotonin and nialamide differentially regulate survival and growth of cultured serotonin and catecholamine neurons.
In this morphometric analysis of immunoreactive serotonin (5-HT) and tyrosine hydroxylase (TH) neurons in culture, 5-HT and the MAO inhibitor nialamide influenced the survival, cell body size and neurite outgrowth of embryonic day 14 (E14) 5-HT neurons after treatment from 1-3 days in vitro (DIV), but did not significantly affect E14 or E15 TH neurons of either the noradrenergic or dopaminergic phenotype. These treatments had minimal effects on 5-HT neurons derived from E15 embryos. The stimulatory effects of 5-HT on survival and somal growth of E14 5-HT neurons was in contrast to its inhibitory effects on neurite outgrowth, suggesting trophic and inhibitory autoregulation of different cellular compartments of developing 5-HT neurons. The decreased sensitivity of E15 5-HT neurons to these treatments, despite similar viability and growth of these neurons in control cultures, suggests the existence of a critical period for this regulation during the initial period of serotonergic neurogenesis when these neurons are forming the bilateral B4-9 raphe complex. The lack of significant effects of 5-HT on TH neurons suggests differential sensitivities of 5-HT and TH neurons to developmental regulation by this neurotransmitter.
Department of Cell Biology and Anatomy, University of North Carolina School of Medicine, Chapel Hill 27599-7090.
J P
JP
Liu
J M
JM
Lauder
D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D016501:Neurites / Q000648:ultrastructure; D009457:Neuroglia / Q000166:cytology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009526:Nialamide / Q000494:pharmacology*; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002395:Catecholamines; D012701:Serotonin; D014446:Tyrosine 3-Monooxygenase; D009526:Nialamide