Figure 6.

In mature neurons, HDAC2 but not HDAC1 deletion affects spontaneous excitatory neurotransmission. A, Schematic of the experimental timeline showing that floxed HDAC1 or HDAC2 neurons were infected with lentivirus expressing either GFP or CRE on 7 DIV then at 15 DIV cultures were treated with either DMSO vehicle or TSA (1 μm) and then recorded at 16 DIV. B, Representative recordings of miniature excitatory events in GFP- and CRE-infected neurons treated with either DMSO or TSA. Recordings were made in Tyrode's solution containing 1 μm tetrodotoxin and 50 μm picrotoxin. C, Bar graph depicting the significant decrease in mEPSC frequency observed by TSA treatment. In HDAC1 knockdown mature neurons, there was no change in mEPSC treatment, however treatment with TSA did significantly decrease mEPSC frequency. In mature neurons, knockdown of HDAC2 resulted in a significant decrease in mEPSC frequency revealing its importance in mediating synaptic transmission in mature neurons. TSA treatment of neurons with HDAC2 knockdown did not produce a further significant decrease in mEPSC frequency. D, A bar graph of mEPSC amplitude did not reveal a significant change in amplitude in any of the conditions examined in mature neurons. E, F, H, I, Representative images of immunostaining of mature hippocampal culture (15 DIV). Immunostaining was performed using PSD-95 and synapsin antibodies. G, J, Bar graphs depicting the number of PSD-95 and synapsin colocalized puncta/20 μm length of the dendrite.