Posttranslational modifications in proteins play critical roles in synaptic plasticity and memory. In addition, the enduring form of long-term potentiation (LTP) and long-term memory require synthesis of proteins. Some of the mRNAs are present in the dendrites and are locally translated into proteins. Microtubules play critical roles in neuronal transport including the transport of mRNAs from the cell body to the dendrites. Here, we show that KCl depolarization increases acetylation of α-tubulin, a constituent of microtubules, in the CA1 region of the hippocampal slices. Furthermore, activation of N-methyl-D: -aspartate receptor, a type of glutamate receptor that plays critical roles in LTP and memory, also enhances α-tubulin acetylation. These results show that acetylation of α-tubulin is modulated in an activity-dependent manner.