Expression of Annexin A7 in the adult human isocortex
In the human parietal neocortex of aged individuals without any neuropathological alterations, subpial astrocytes exhibited a staining of Annexin A7 in the cytoplasm. A nuclear presence of Annexin A7 was limited to single astrocytes (Fig. 6B). Pyramidal neurons, predominantly those of layer V exhibited Annexin A7 at the plasma membrane of their perikaryon as well as of the apical dendrite (Fig. 6A,C). The neurons lacked a signal for Annexin A7 in their nuclei. Apical dendrites within the molecular layer also indicated a positive staining for Annexin A7 (Fig. 6B). The staining pattern of Annexin A7 in the human autopsy brain did not change after pre-treatment with trypsin.
Figure 6  Annexin A7 immunostaining in human isocortex. (A) Pyramidal neurons (bold arrow) and apical dendrites (small arrows) were clearly labeled with the antibody against Annexin A7 in the human parietal cortex. (B) A dendritic staining was also seen in the molecular layer (small arrows). In addition the subpial astrocytes were weakly labeled (double headed arrows). The staining was cytoplasmic, only few astrocytes showed a nuclear staining as well (inset). (C) Enlargement of (A): Annexin A7 was seen at the cell membrane of the perikaryon (bold arrow) and the apical dendrite (small arrows). (D) A blank control lacking the primary antibody did not show a specific labeling, but autofluorescent lipofuscin was detectable in the neurons (arrowheads). Bar, (A) 70 μm, (B) 50 μm, (B-inset, C) 17 μm, (D) 20 μm.