PRESYNAPTIC ORGANELLES AND JUNCTIONAL INTEGRITY
David Bodian · The Journal of Cell Biology · 1971
The identification of synaptic bulbs at the electron accompanied by attempts to study their fate after microscope level and the description of their major the interruption of parent fibers (1). The degeneracytological characteristics (mitochondria, synap- tive changes in organelles of synaptic bulbs were tic vesicles, and junctional densities) were soon well described by De Robertis, but several years THE JOURNAL OF CELL BIOLOGY • VOLUME 48, 1971 • pages 70 7-711 707FIGURES 1-3. From the same animal (166). Fixation was by perfusion with 2.5 % glutaraldehyde in sodium cacodylate buffer, followed by hardening in osmium tetroxide. Scale markers indicate 0.5 µ. The macaque had a hemisection of the spinal cord at T10 on the left side, seven days before perfusion. Changes shown at L6 were found only on the left side below the lesion. FIGURE 1 Synaptic bulb (S) on motoneuron soma (M), and in early stage of degeneration after interruption of parent axon. X marks zone of severe local depletion of synaptic vesicles. Those remaining in this area are ghostlike. Interface membranes in this region (arrow) are less dense than elsewhere, and possibly deteriorating. X 51,000. FIGURE 2 Synaptic bulb (S) in more advanced stage of degeneration of junctional structures. Interface deterioration at right and left margins (arrows) accompanied by invagination into postsynaptic