Ultrastructural identification of synapses between mitral/tufted cell dendrites.
Asymmetrical, type 1 synapses between mitral and/or tufted (M/T) cell dendrites were observed in the glomerular layer (GL) and juxtaglomerular external plexiform layer (EPL) of salamander olfactory bulb sections. The dendrites had electron-lucent cytoplasm containing regularly-arrayed microtubules and spherical translucent vesicles. The vesicles were clustered against a thin pre-synaptic density that was aligned with a 17-20 nm-wide synaptic cleft and a thicker post-synaptic density. These dendrodendritic synapses could be a source of the delayed, prolonged excitation that originates from the GL/EPL. During spatiotemporal encoding of odor stimuli, they could amplify or synchronize M/T cell responses.
Allen
D M
DM
Department of Cellular Biology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, USA. dallen@lsumc.edu
Hamilton
K A
KA
D000557:Ambystoma; D000818:Animals; D003712:Dendrites / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure; D009830:Olfactory Bulb / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure*