Mechanisms governing the differentiation of a serotonergic phenotype in culture.
In this study, we explored whether a serotonergic (5-HT) phenotype could be novelly induced in the phenotypically plastic neurons of the developing striatum. We found that the 5-HT biosynthetic enzyme tryptophan hydroxylase (TPH) was expressed in nearly 10% of neurons following treatment with an extract derived from adult raphe tissue. This effect was mimicked by co-treatment with a growth factor (aFGF, bFGF or BDNF; but not GDNF, IGF-1, EGF or TGF) and the neurotransmitter 5-HT (but not GABA, dopamine, glutamate) and/or a protein kinase activator (IBMX, forskolin, TPA). Treatment with combined factors (aFGF+5-HT+IBMX+forskolin+TPA) yielded the greatest level of TPH induction (15.6%). Moreover, TPH was enzymatically active (112.8+/-36 pmol/mg per h) and produced detectable levels of 5-HT (2.12+/-0.30 ng) and its metabolite 5-HIAA (4.24+/-0.11 ng) in maximally stimulated cultures. These findings demonstrate that it is possible to promote the differentiation of serotonergic phenotypic traits in developing brain neurons in culture.
Zhou
J
J
Department of Neurobiology and Anatomy, Medical College of Pennsylvania and Hahnemann University, Philadelphia, PA, USA.
Iacovitti
L
L
D000818:Animals; D002478:Cells, Cultured; D003342:Corpus Striatum; D016895:Culture Media, Serum-Free; D004622:Embryo, Mammalian; D005260:Female; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D006133:Growth Substances / Q000494:pharmacology; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014365:Tryptophan Hydroxylase / Q000187:drug effects / Q000378:metabolism*
D016895:Culture Media, Serum-Free; D006133:Growth Substances; D017366:Serotonin Receptor Agonists; D012701:Serotonin; D014365:Tryptophan Hydroxylase