Fig. 1.
EMs obtained from the monkey prefrontal cortex immunolabeled using the α2A-AR antiserum and HRP-DAB as the immunolabel. (A) The receptor occurs directly over the presynaptic plasma membrane of a labeled terminal (small arrow in LT) forming a synaptic junction (open arrow) with a spine emanating from a dendritic shaft (arrow and D; sa = spine apparatus). (B) The receptor also occurs away from the synaptic region of a terminal, T, and instead at an intervaricose portion (large arrow and in between the two small arrows). The arrowhead points to a patch of plasma membrane undergoing endocytosis. (C) A terminal, T, forming a synaptic junction Simultaneously with two dendrites, one of which exhibits immunoreactivity over the postsynaptic membrane (LD, arrowhead) and another that is unlabeled (UD). The tissue was fixed by transcardial perfusion with a mixture of acrolein and paraformaldehyde, and then postfixed following the ICC procedure with osmium tetroxide. Calibration bar = 500 nm for all panels (from ref. 6, reproduced with permission from Oxford University Press).