PSA-NCAM expression in the piriform cortex of the adult rat. Modulation by NMDA receptor antagonist administration.
Administration of NMDA receptor antagonists upregulates the expression of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) in the adult hippocampus. Since the piriform cortex is also populated by PSA-NCAM immunoreactive neurons during adulthood, we sought to characterize them in detail and to test whether NMDA receptor antagonists also modulate PSA-NCAM in this cortical region. PSA-NCAM immunoreactivity is located mainly in layer II, where many neurogliaform and some pyramidal-semilunar transitional neurons are labeled. Many large neurons in layer III and endopiriform nucleus also express PSA-NCAM. Interestingly, some small labeled cells resembling migratory neuroblasts appear in these layers and in the ventral end of the corpus callosum subjacent to the piriform cortex. These putative migratory cells and some neurogliaform neurons in layer II do not express NeuN, a marker of differentiated neurons. Many of these PSA-NCAM immunoreactive cells also express doublecortin, a molecule involved in neuronal migration. The number of PSA-NCAM immunoreactive neurogliaform neurons increases significantly 7 days after the administration of an NMDA receptor antagonist. Moreover, 21 days after the treatment we observe a significant increase in the number of doublecortin expressing cells in the deep layers of the piriform cortex. These results expand the current knowledge of the neuronal populations expressing PSA-NCAM in the piriform cortex, suggesting that some of these cells could be involved in structural plastic events such as axonal outgrowth, synaptogenesis or even neuronal migration. Similar to the hippocampus, NMDA receptors appear to play a critical role in these processes in the adult piriform cortex.
Nacher
Juan
J
Laboratory of Neuroendocrinology, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA. nacher@uv.es
Alonso-Llosa
Gregori
G
Rosell
Daniel
D
McEwen
Bruce
B
D000818:Animals; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D000089662:Doublecortin Protein; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage* / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D008297:Male; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules / Q000096:biosynthesis*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009833:Olfactory Pathways / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000502:physiology; D012794:Sialic Acids / Q000096:biosynthesis*
C000714848:Dcx protein, rat; D000089662:Doublecortin Protein; D018691:Excitatory Amino Acid Antagonists; D039842:Neural Cell Adhesion Molecule L1; D019006:Neural Cell Adhesion Molecules; D016194:Receptors, N-Methyl-D-Aspartate; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule