Histone Deacytylase Inhibitor Enhances Long-Term Synaptic Potentiation in Neurons of a Grape Snail

Recently, substantial amount of data has been accumulated in the literature, suggesting an important role of epigenetics in the formation of long-term synaptic plasticity as the main cellular mechanism of learning and memory. In this work, we studied the effect of inhibition of histone deacetylases, one of the types of epigenetic modifications, on the formation of long-term potentiation (LTP) of synaptic responses in premotor (command) neurons responsible for avoidance behavior in grape snails. Potentiation of synaptic inputs in these neurons underlies aversive memory in this animal. We showed that the histone deacetylase inhibitor sodium butyrate increases the amplitude of LTP caused by five tetanizations of the sensory nerve, combined with applications of serotonin. We also found that application of sodium butyrate per se causes an increase in the excitatory postsynaptic potential amplitude 4 h after application, although this increase cannot underlie the effect of LTP observed throughout the experiment. Thus, we demonstrated the role of histone modifications in the mechanisms of synaptic plasticity.