Figure 2

Chronic activity alterations regulate genes involved in hippocampal synaptic and intrinsic membrane properties. (A) Pie chart showing the relative proportion of neurons and glia in rat dissociated hippocampal neuronal culture. Immunostaining studies revealed that 2.3 ± 2.1% of cells expressed glial marker, glial fibrillary acid protein (GFAP) whereas 97.3 ± 2.9% were positive for the neuronal marker NeuN. Of the NeuN-positive cells, 86.2 ± 5.0% were immunoreactive for vesicular glutamate transporter 1 (VGLUT1) indicative of glutamatergic neurons. (B) Venn diagram showing 901 transcripts identified by microarray analysis whose expression were significantly changed by 48 h TTX and BC treatment compared to CTL-H₂O treatment at 48 h using an FDR < 0.05 and a fold change < 0.667 (repressed) or > 1.5 (induced) (black circle). The genes whose protein products have previously been implicated in homeostatic plasticity are also indicated (gray circle). (C) The colormetric representation shows select genes, indicated by HUGO Gene Nomenclature gene symbols, whose transcripts were repressed (green) and induced (red). The *denotes genes that further tested for activity-dependent changes in their mRNA levels using QPCR analysis. Using Gene Ontology analysis, select activity-regulated genes were grouped by cellular components, molecular function, and biological processes.