Rapid expression and transport of embryonic N-CAM in dentate gyrus following entorhinal cortex lesion: ultrastructural analysis.
Neural cell adhesion molecules are known to be important in axon guidance and synapse formation in the developing brain. The embryonic form of neural cell adhesion molecule (eN-CAM) is reexpressed in the outer molecular layer (OML) of the dentate gyrus following entorhinal cortex (ERC) lesion. Ultrastructural analysis revealed localization of eN-CAM to the membrane of granule-cell dendritic membranes and occasionally axons within the denervated zone. Because eN-CAM is expressed rapidly (within 2 days) after ERC lesion, we were interested in the temporal sequence of expression. Denervated hippocampi (12, 15, 24, and 48 hours post-ERC lesion) were stained with anti-eN-CAM and processed for immunoelectron microscopy. At 12 hours, there was no evidence of staining for eN-CAM. By 15 hours after lesion, membranes of both dendrites and axons throughout the molecular layer exhibited moderate eN-CAM staining, and dendritic cytoplasm was heavily labeled. Twenty-four hours following lesion, plasma membrane staining of eN-CAM on both axons and dendrites had increased in intensity within the OML, whereas membrane eN-CAM staining was diminished in the inner molecular layer (IML), and the intradendritic cytoplasmic staining disappeared. By 48 hours after lesion, eN-CAM staining had disappeared from the IML but remained intense and widely distributed in the OML. These findings suggest a rapid transport of de novo synthesized protein. A generalized reaction appears to occur immediately following denervation, and eN-CAM is up-regulated in the complete expanse of the dendritic membrane, despite the fact that only the OML is denervated.(ABSTRACT TRUNCATED AT 250 WORDS)
Styren
S D
SD
Department of Psychiatry, Western Psychiatric Institute and Clinic, Pittsburgh, Pennsylvania 15213.
Lagenaur
C F
CF
Miller
P D
PD
DeKosky
S T
ST
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism; D018728:Entorhinal Cortex / Q000196:embryology / Q000502:physiology* / Q000648:ultrastructure; D006624:Hippocampus / Q000196:embryology / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D008297:Male; D000090204:Mesothelin; D016253:Microscopy, Immunoelectron; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D015816:Cell Adhesion Molecules, Neuronal; C000715529:Msln protein, rat; D000090204:Mesothelin