Hypothalamic monoaminergic systems in ontogenesis: development and functional significance.
This paper summarizes recent data on the development of hypothalamic monoaminergic (MArgic) systems which play a key role in neuroendocrine regulation in adult mammals. Hypothalamic catecholaminergic (CArgic) and 5-hydroxytryptamine (=serotonin, 5-HT) systems undergo synchronous development that begins from the origin of dopaminergic neurons in the hypothalamus and 5-HT neurons in the raphe nucleus long before birth. Moreover, some hypothalamic neurons of fetuses and young rats partly express the 5-HT phenotype patterns: the 5-HT specific uptake and synthesis from 5-hydroxytryptophan. Differentiation of MArgic neurons is manifested in expression of specific enzymes and MA synthesis as well as in the onset of the MA specific uptake and potassium-stimulated release. In the course of differentiation, MArgic neurons send their axons to target neurons, hypophysial portal circulation, the third ventricle and adenohypophysis, followed by the establishment of specialized contacts: synapses, axo-vascular, axo-ventricular and axo-glandular. The hypothalamic CAs and 5-HT firstly appeared in embryogenesis control phenotype expression of target neurons: gene expression, specific synthesis, uptake and release, axonal growing, etc. In turn, the development of the hypothalamic MArgic systems is under control of MAs (autoregulation) and hormones of the peripheral endocrine glands (androgens). Conversely, there is a minor role, if any, of the maternal and placental neurohumoral factors in differentiation of MArgic neurons.
Ugrumov
M V
MV
Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow. MUgrumov@ibrran.msk.su
D000818:Animals; D015306:Biogenic Monoamines / Q000502:physiology*; D002454:Cell Differentiation; D006801:Humans; D007031:Hypothalamus / Q000166:cytology / Q000254:growth & development*; D009474:Neurons / Q000166:cytology; D012701:Serotonin / Q000502:physiology
D015306:Biogenic Monoamines; D012701:Serotonin