Glutamate-induced deporalization in earthworm ventral nerve cord

We investigated glutamate-induced neuron response in the ventral nerve cord of the earthworm (Eisenia foetida) using a voltage-sensitive dye-imaging technique. Isolated earthworm ganglia were stained by fluorescence voltage-sensitive dye, RH414, and voltage image was acquired by a conventional charge-coupled device (CCD) technique or a confocal laser scanning microscope. The fluorescence images before and during the glutamate stimulation was acquired and the relative fluorescence change was imaged as pseudo-color. Bath-applied glutamate (1 mM) depolarized many neurons on the ventral side, and in the three giant fibers on the dorsal side.