title: The fine structural demonstration of monoaminergic synapses in immature rat neocortex.
abstract: The radial distribution of monoaminergic (MA) synapses has been studied in lateral neocortex (SI) of infant rats using an electron microscopic histochemical technique. Systemically administered 5-hydroxydopamine crosses the blood-brain barrier and produces small granular vesicles (SGV) in 30% of all synaptic terminals in SI. In the primordium of layer IV, at six days postnatal, 70% of the synaptic terminals contain SGVs. Immature cortex thus contains a high proportion of synapses with a vesicular uptake-storage mechanism for catecholamines. It is proposed that in infant rat there is a major projection from brain stem MA nuclei to the neocortex; this projection may exert a potent influence on the activity of neurons in layer IV.
authors: Department of Anatomy, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors: M E
authors: ME
authors: Molliver
authors: D A
authors: DA
authors: Kristt