|
|
Synapse Web | |||||
| About | Anatomy | Links | Publications | Search | Tools | |
Polyribosomes are present beneath the various types of synapses on dendrite shafts (symmetric, asymmetric - Fig. 3 a,b,c), axonal initial segments (inhibitory), and especially beneath the synapses present on dendritic spines. They are found in spine heads (Fig. 4 a,b) and necks ( Fig. 5), but most of them (80%) form clusters beneath spines, in the "mounds" of the spine bases (Figs. 6 a,b, 7).
| Fig. 3 a,b,c: A cluster of polyribosomes (arrow) in the subsynaptic region of synapses formed on the dendrite (D). Mitochondrion (M) and multivesicular body (mvb) are associated with the subsynaptic region in c. (Rat, hippocampus, CA1) | b  |
a  |
c  |
a  |
b  |
| Fig. 4 a,b: Polyribosomes (arrows) in the heads of dendritic spines. a. Thin spine (mouse, neocortex) b. Mushroom spine (rat, hippocampus, CA1). D - dendrite. | |
| Fig. 5: A cluster of polyribosomes (arrow) in a neck of a thin spine (S). D - dendrite. (Rat, hippocampus, CA1) |  |
 |
Fig. 6: Polyribosomes (arrow) at the base of a short, sessile spine. D - dendrite, ser - smooth endoplasmic reticulum. (Rat, hippocampus, CA1) |
 |
| Fig. 7: Three-dimensional reconstruction of thin spines emerging from a dendrite (made transparent). Polyribosomes (black) are most frequent at the bases of spines. Areas of synaptic contact are shown in red. (Rat, hippocampus, CA1) |