Sequential steps underlying neuronal plasticity induced by a transient exposure to gabazine.
Periods of intense electrical activity can initiate neuronal plasticity leading to long lasting changes of network properties. By combining multielectrode extracellular recordings with DNA microarrays, we have investigated in rat hippocampal cultures the temporal sequence of events of neuronal plasticity triggered by a transient exposure to the GABA(A) receptor antagonist gabazine (GabT). GabT induced a synchronous bursting pattern of activity. The analysis of electrical activity identified three main phases during neuronal plasticity induced by GabT: (i) immediately after termination of GabT, an early synchronization (E-Sync) of the spontaneous electrical activity appears that progressively decay after 3-6 h. E-Sync is abolished by inhibitors of the ERK1/2 pathway but not by inhibitors of gene transcription; (ii) the evoked response (induced by a single pulse of extracellular electrical stimulation) was maximally potentiated 3-10 h after GabT (M-LTP); and (iii) at 24 h the spontaneous electrical activity became more synchronous (L-Sync). The genome-wide analysis identified three clusters of genes: (i) an early rise of transcription factors (Cluster 1), primarily composed by members of the EGR and Nr4a families, maximally up-regulated 1.5 h after GabT; (ii) a successive up-regulation of some hundred genes, many of which known to be involved in LTP (Cluster 2), 3 h after GabT likely underlying M-LTP. Moreover, in Cluster 2 several genes coding for K(+) channels are down-regulated at 24 h. (iii) Genes in Cluster 3 are up-regulated at 24 h and are involved in cellular homeostasis. This approach allows relating different steps of neuronal plasticity to specific transcriptional profiles.
Pegoraro
Silvia
S
International School for Advanced Studies, Area Science Park, Trieste, Italy.
Broccard
Frédéric D
FD
Ruaro
Maria Elisabetta
ME
Bianchini
Daniele
D
Avossa
Daniela
D
Pastore
Giada
G
Bisson
Giacomo
G
Altafini
Claudio
C
Torre
Vincent
V
D000200:Action Potentials; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D016000:Cluster Analysis; D004558:Electric Stimulation; D004815:Epidermal Growth Factor / Q000235:genetics; D005071:Evoked Potentials; D018756:GABA Antagonists / Q000494:pharmacology*; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000473:pathology; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects* / Q000235:genetics; D009474:Neurons / Q000187:drug effects* / Q000473:pathology; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D020411:Oligonucleotide Array Sequence Analysis; D057093:Orphan Nuclear Receptors / Q000235:genetics; D015221:Potassium Channels / Q000235:genetics; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
D018756:GABA Antagonists; D019384:Nucleic Acid Synthesis Inhibitors; D057093:Orphan Nuclear Receptors; D015221:Potassium Channels; D047428:Protein Kinase Inhibitors; D011724:Pyridazines; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; C049853:gabazine; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3