Postnatal synaptic development of the rat.
Presynaptic boutons of the dorsomedial region of the nucleus tractus solitarius (NTS) were studied during the first 30 days of postnatal development of the rat. Electron micrographs were analyzed by conventional and stereological techniques to determine the area and volumetric density and fraction, and the number per linear length on both the dendrites and cell bodies. The numerical density and volumetric fraction of boutons in the NTS increased rapidly within the first 10 postnatal days. The number of boutons per area and volume remained stable between 10 and 30 days. Twice as many boutons synapsed on the larger dendrites than the cell bodies during the first 10 days, and then increased to 4 times the number of synapses per linear length on the cell body after the tenth postnatal day. The rapid synaptic development and shift in shift in sites of synaptic contact on neurons of the NTS suggest synaptic contacts rapidly change during early postnatal development.
D000818:Animals; D002454:Cell Differentiation; D008526:Medulla Oblongata / Q000166:cytology*; D008854:Microscopy, Electron; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D051381:Rats; D011919:Rats, Inbred Strains; D013569:Synapses / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000648:ultrastructure