H. Tomimoto et al., ULTRASTRUCTURAL-LOCALIZATION OF AMYLOID PROTEIN-PRECURSOR IN THE NORMAL AND POSTISCHEMIC GERBIL BRAIN, Brain research, 672(1-2), 1995, pp. 187-195
Intracellular localization of amyloid protein precursor (APP) in the n
ormal and postischemic gerbil brain was examined by immunoelectron mic
roscopy. In the normal brain, APP immunoreactivity was localized to th
e multivesicular body, the nuclear membrane, Golgi apparatus and rough
endoplasmic reticulum. After ischemia for 5 min and reperfusion for 2
4 h, some neurons became intensely immunoreactive for APP in the subic
ulum and CA3 region of the hippocampus and layers III and V/VI of the
cerebral cortex. No intense labeling occurred in glial cells. Intensel
y labeled neurons were characterized by eccentric nuclei and accumulat
ion of cellular organelles in the center of the neuronal perikarya, as
well as a strongly immunoreactive nuclear membrane and cisternal stru
ctures, which were presumed to be dispersed Golgi apparatus and/or fra
gmented rough ER. APP immunoreactivity in the multivesicular body sugg
ests re-internalization of APP and its degradation in the endosomal-ly
sosomal pathway. The ultrastructural features of neurons with intense
APP immunoreactivity suggested mild neuronal damage, similar to those
found in central chromatolysis. This indicates that accumulation of AP
P in these neurons is caused by disturbance of axonal transport, altho
ugh the information does not allow us to exclude the possibility of an
increase in APP production.