A morphometric study of cortisol-induced changes in the development of neuronal process outgrowth in the corticoid zone of the embryonic chick telencephalon.
The development of dendritic arborization was analysed and quantitative data (number of stem dendrites, their segments and total length of dendritic tree) were obtained. Early administration of cortisol (on day 11) inhibited all three dendritic parameters of small stellate neurones situated in the corticoid zone of the telencephalon in 19-day-old chick embryos, but in large stellate neurones the number of dendritic segments and their total length were only impaired. Late administration of this hormone (on day 17) did not influence the development of the dendritic network of large neurones, but it affected the number of segments and total dendritic length of small neurones. These results suggest that the number of stem dendrites is set in first, followed by elongation and ramification of the fibres. The main effect of cortisol on the neuronal differentiation is the inhibition of dendritic outgrowth with a dependence on period when dendrites, their branches and dendritic spines develop most rapidly.
D000818:Animals; D001921:Brain / Q000166:cytology / Q000196:embryology*; D002454:Cell Differentiation / Q000187:drug effects; D002642:Chick Embryo; D003712:Dendrites / Q000648:ultrastructure; D006854:Hydrocortisone / Q000494:pharmacology*
D006854:Hydrocortisone