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Light and electron microscopic study of corticorubral synapses in adult cat: Evidence for extensive synaptic remodeling during postnatal development
Author(s) -
Saito Yasuhiko,
Katsumaru Hironobu,
Wilson Charles J.,
Murakami Fujio
Publication year - 2001
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.1382
Subject(s) - synaptogenesis , dendritic spine , soma , biology , cats , neuroscience , synapse , dendrite (mathematics) , anatomy , geometry , mathematics , hippocampal formation , computer science , embedded system
Spine‐like dendritic protrusions (SLDPs) emanating from developing dendrites have been proposed to play an important role in early synaptogenesis. We previously analyzed synaptic termination sites on soma‐dendritic membrane of newborn cats and found that corticorubral (CR) axons form synapses preferentially on SLDPs (Saito et al., 1997). In the present study, we examined CR synapses in adult cats to elucidate the maturation process of CR synapses in relation to SLDPs. Electron microscopic observation of serial thin sections of Phaseolus vulgaris ‐leucoagglutinin–labeled axons revealed that approximately 60% of CR terminals in adult cats formed synapses on dendritic spines. We also found that CR axons terminate on dendritic spines originating from the intermediate or distal dendrites of rubrospinal cells (more than 200 μm apart from the soma), in contrast to kittens in which CR fibers terminate on SLDPs originating from the proximal dendrites (less than 100 μm apart from the soma) of rubrospinal cells (Saito et al. [1997] J. Neurosci. 17:8792–8803). These results suggest that CR synapses undergo remarkable remodeling after initial termination on SLDP during postnatal development. J. Comp. Neurol. 440:236–244, 2001. © 2001 Wiley‐Liss, Inc.