In the article “Dopamine Neurons Make Glutamatergic SynapsesIn Vitro,” by D. Sulzer, M. P. Joyce. L. Lin, D. Geldwert, S. N. Haber, T. Hattori, and S. Rayport, which appeared on pages 4588–4602 of the June 15, 1998 issue, the resolution Figure 6 (page 4597) was unsatisfactory. The figure and legend are reprinted.
Fig. 6.
Ultrastructure of a DA neuron in single cell microculture. Sections are shown from a single DA neuron grown in microcultures and TH-stained using DAB (inset). To maximize antibody penetration, we used a relatively high detergent concentration. Although this solubilized membranes, resulting in an apparent degradation of the quality of ultrastructural preservation, it enhanced the visualization of synaptic specializations.A, In the cell body, TH staining was distributed in a patchy pattern throughout weakly stained cytoplasm. TH+processes emerged from intensely stained regions (filled arrows); nearby, TH− processes emerged from unstained regions (open arrows). B, Within the neuropil, distinctly stained and unstained processes intermingled with each other; in some cases within a single process, a stained portion (filled arrow) was clearly distinguishable from an unstained portion (open arrow).C, Single TH-immunoreactive neurons formed morphological synapses on themselves (autapses). Those autapses were in close proximity to the cell body (as seen at the light level; Fig. 5). In this cell, a total of eight autapses with clear postsynaptic specializations were identified after serial sectioning; one autapse showed presynaptic TH staining and had symmetric synaptic membrane specializations. D, The other autapses had asymmetric synaptic specializations with no detectable immunostaining of the presynaptic elements. Two of the seven TH− boutons (data not shown) made asymmetric synaptic contacts with TH+dendritic elements. TH+ varicosities at a distance from the cell body had accumulations of synaptic vesicles but lacked presynaptic or postsynaptic densities (data not shown).