Nicotine-induced phosphorylation of phosphorylated cyclic AMP response element-binding protein (pCREB) in hippocampal neurons is potentiated by agrin.
The scope of this study was to test whether increased levels of the extracellular matrix molecule (ECM) agrin might enhance nicotine effects on those molecular mechanisms that initiate neuroadaptative processes in the hippocampus, a key brain area for learning and memory. We studied the effects of repetitive applications of neuronal agrin to primary hippocampal cell culture on nicotine-induced phosphorylated cyclic AMP response element-binding protein (pCREB) expression, a marker of neuroadaptation, by using immunofluorescence-based assessment of pCREB-positive neurons. We also tested agrin effects on nicotine-induced expression of a marker of metabolic activation, the immediate early gene c-fos. Agrin was shown to significantly enhance nicotine-induced pCREB, but not c-fos, expression. By using Western blotting analysis, cumulative agrin has been shown to increase nicotine-induced pCREB phosphorylation. These analyses, however, showed that inhibition of the CaMKII pathway blocked general pCREB phosphorylation, whereas inhibition of the MAPK pathway potentiated the synergistic effect of cumulative agrin and nicotine. These findings suggest that increasing the concentration of an ECM molecule, i.e. agrin, may enhance nicotine effects on pCREB and that both MAPK and CaMKII signalling may play a regulatory role.
Chiamulera
Christian
C
Section of Pharmacology, Department of Medicine and Public Health, University of Verona, P.le Scuro, 10, 37134 Verona, Italy. cristiano.chiamulera@univr.it
Di Chio
Marzia
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Tedesco
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V
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D018171:Agrin / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000187:drug effects* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D018171:Agrin; D017362:Cyclic AMP Response Element-Binding Protein; D018722:Nicotinic Agonists; D009538:Nicotine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D048049:Extracellular Signal-Regulated MAP Kinases