We observed endocytosis of glutamate receptors around the post-synaptic membrane using total internal reflection fluorescence microscopy. Cultured rat neurons were transfected with GluA-SEP, glutamate receptor tagged by pH-sensitive green fluorescent protein, super ecliptic pHluorin (SEP), and PSD95-TagRFPt (a post-synaptic marker). SEP shows fluorescence signals under neutral pH conditions such as extracellular solutions and the lumen of newly formed endocytic vesicles