Histochemically demonstrable catecholamines in the sympathetic nervous system of trisomic 16 and normal fetal mice.

The formaldehyde-induced fluorescence (FIF) and micro-spectrofluorometric techniques were used to study catecholamines in the sympathetic nervous system of normal and trisomy 16 fetal mice with a gestation age of 15 days, an animal model for human trisomy 21 (Down's syndrome). FIF intensity in the stellate sympathetic ganglion of trisomic embryos did not differ from that of controls, whereas in the adrenal medulla the FIF intensity was 38% less in trisomic than in control embryos. When adrenal medullary cells from embryos with a gestational age of 15 days were maintained in culture for 7-10 days, a difference in FIF intensity between groups was still evident. The rate of noradrenaline uptake in cultured adrenal medullary cells also was significantly less in trisomic than in control fetal mice. The results suggest that the development of adrenal medulla is slowed in trisomic 16 mice and that uptake of noradrenaline by trisomic adrenal medullary cells is impaired.