Volume 81, April 1999

Pages 1636-1644: H. R. Koerber, K. Mirnics, A. M. Kavookjian, and A. R. Light, "Ultrastructural Analysis of Ectopic Synaptic Boutons Arising From Peripherally Regenerated Primary Afferent Fibers."

The reproduction quality of the micrographs shown in the original printing was unsatisfactory. All of the micrographs are reproduced here displaying a sharper contrast.

View larger version (141K): [in this window] [in a new window]   Fig. 3. Examples of 3 sections through the same bouton (fiber 2). A: noncounterstained section through HRP-labeled profile. Arrow shows asymmetric synaptic specialization. B: section through the same profile counterstained with uranyl acetate and lead citrate. Arrow shows same axo-dendritic contact. C: high-power view of a 3rd section through the same profile showing a 2nd axo-dendritic (long arrow) and an asymmetric axo-axonic (short arrow) contact. Note numerous mitochondria contained in the terminal. Scale bars, 0.5 µm; d, dendrite; at, axon terminal.

View larger version (175K): [in this window] [in a new window]   Fig. 4. Counterstained section through an ectopic bouton from fiber 1. , asymmetric contact with a dendritic (d) profile that contains a few clear round vesicles. Note close apposition between axon terminals (at) containing pleomorphic vesicles and the HRP-stained profile. Scale bar = 0.5 µm.

View larger version (150K): [in this window] [in a new window]   Fig. 5. Additional examples of frequent synaptic contacts of HRP-stained ectopic profiles. A and B: adjacent sections through a bouton from fiber 2. Long arrows denote an asymmetric contact with a dendritic profile (d) and short arrows point to an asymmetric contact with a presynaptic axon terminal (at) containing pleomorphic vesicles. C: section through a different profile also from fiber 2 demonstrating similar ultrastructure. Scale bar = 0.5 µm.

View larger version (149K): [in this window] [in a new window]   Fig. 6. A: light micrograph of 100-µm-thick sagittal section. Asterisk, locations of ectopic boutons (fiber 2) isolated for EM analysis. B: example of a typical ectopic profile forming an asymmetric axo-denritic contact (curved arrow). Profile is filled with numerous clear round vesicles and a few large dense core vesicles (arrows). Different arrows distinguish light and dark dense core vesicles in the ectopic profile and surrounding neuropil. C: example of a stained unmyelinated fiber filled with clear round vesicles. Open arrow denotes an en passant bouton. D: high-power view of same section. Scale bars: A = 100 µm; B and D = 0.5 µm; C = 1.0 µm.

View larger version (160K): [in this window] [in a new window]   Fig. 7. Example of similar ultrastructure seen in Fig. 6, C and D, for a bouton from fiber 1. A: section through a bouton and unmyelinated fiber. , asymmetric axo-dendritic contact. Note numerous clear round vesicles in the fiber. B: enlargement of same section. Scale bars = 0.5 µm.