NMDA receptor-dependent CREB activation in survival of cerebellar granule cells during in vivo and in vitro development.
During both in vivo and in vitro development, cerebellar granule cells depend on the activity of the NMDA glutamate receptor subtype for survival and full differentiation. With the present results, we demonstrate that CREB activation, downstream of the NMDA receptor, is a necessary step to ensure survival of these neurons. The levels of CREB expression and activity increase progressively during the second week of postnatal cerebellar development and the phosphorylated form of CREB is localized selectively to cerebellar granule cells during the critical developmental stages examined. Chronically blocking the NMDA receptor through systemic administration of the competitive antagonist, CGP 39551, during the in vivo critical developmental period, between 7-11 postnatal days, results in increased apoptotic elimination of differentiating granule neurons in the cerebellum [Monti & Contestabile, Eur. J. Neurosci., 12, 3117-3123 (2000)]. We report here that this event is accompanied by a significant decrease of CREB phosphorylation in the cerebellum of treated rat pups. When cerebellar granule neurons are explanted and maintained in dissociated cultures, the levels of CREB phosphorylation increase with differentiation, similar to that which happens during in vivo development. When granule cells are kept in non-trophic conditions, their viability is affected and both CREB phosphorylation and transcriptional activity are decreased significantly. The neuronal viability and the deficiency of CREB activity, are both rescued by the pharmacological activation of the NMDA receptor. These results provide good circumstantial evidence for a functional link between the NMDA receptor and CREB activity in promoting neuronal survival during development.
Monti
Barbara
B
Department of Biology, University of Bologna, Via Selmi 3, 40126 Bologna, Italy.
Marri
Lucia
L
Contestabile
Antonio
A
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002525:Cerebellar Cortex / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007150:Immunohistochemistry; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D017362:Cyclic AMP Response Element-Binding Protein; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; C064540:CGP 39551; D005576:Colforsin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D015763:2-Amino-5-phosphonovalerate