Functional activity of catecholaminergic system in human fetal midbrain and diencephalon

The development of catecholaminergic system of the midbrain and diencephalon was studied in human embryos and fetuses aged 6, 8, 10, and 12 weeks by specific capture and K⁺-stimulated release of³H-dopaminein vitro. Specific capture of³H-dopamine was first detected in the midbrain of 6-week embryos and in the diencephalon of 8-week fetuses. The time course of the capture points to on-going differentiation of catecholaminergic neurons and fiber growth and the presence of the caudorostral gradient in the development of brain catecholaminergic system. The release of catecholamines was not stimulated in response to membrane depolarization in the midbrain and diencephalon at any of the studied stages of development. The difference in the time of capture and K⁺-stimulated release of catecholamines is related to specific features of differentiation of these neurons in human fetuses. Tranlated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 9, pp. 259–262, September, 1997