Calcium imaging for detection and estimation of spike activities in Aplysia neurons

Ryusuke Yoshida, Akira Iwamoto, Tatsumi Nagahama

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


We explored whether the calcium imaging can be applicable to detection of spike activity of Aplysia wide-spread neurons. Well-used procedures, the membrane permeable acetoxymethyl (AM) types and the retrograde labeling could not be used for loading the calcium sensitive dye into many neurons, however, impalement of each cell body with a microelectrode containing high concentration of the dye solution in turn could load the dye iontophoretically into many large neurons in a relatively short time and into several small neurons in a very short time. Spike activity just induced a fluorescent increase in the cell body while depolarization without spikes induced it in the axon hillock. In the cell body the slope of the fluorescent increase was almost relative to the spike frequency while the period of it almost corresponded to the firing duration. Therefore, the phase relationship of the rhythmic firing responses in plural neurons could be precisely detected. Moreover stable responses could be repeatedly obtained for a long time from small neurons unsuitable for a long time recording with microelectrodes. Removal of the extracellular Ca2+ completely suppressed the spike-induced increase in fluorescence in the cell body and application of nifedipine partly reduced it, suggesting contribution of L-type channels distributing in Aplysia wide-spread neurons.

Original languageEnglish
Pages (from-to)631-643
Number of pages13
JournalZoological science
Issue number5
Publication statusPublished - Jul 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Animal Science and Zoology


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