The mechanism of PDT-induced electrical blockade: The measurement of intracellular Ca2+ concentration changes in cardiac myocytes

A. Ito, S. Hosokawa, S. Hakomori, S. Miyoshi, K. Soejima, T. Arai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)


We propose the application of early state photodynamic therapy (PDT) to treatment of atrial fibrillation, which is a kind of arrhythmia characterized by irregular rapid beating of heart. We had demonstrated that our PDT can block the propagation of electrical excitation in cardiac myocytes. However, the mechanism of the PDT-induced electrical blockade was not clear. In order to clarify this mechanism, changes in intracellular Ca2+ concentration during the PDT with Talaporfin sodium (water soluble photosensitizer) were measured by fluorescence Ca2+ indicator, fluo-4 AM. The PDT led to the rapid increase of intracellular Ca2+ concentration and the changes in cell shapes. These results indicated that extracellular Ca 2+ flowed into the cells mediated by cell membrane. Moreover, we found bubble generation in the cells after the PDT. In conclusion, the PDT-induced electrical blockade in myocytes can be caused by cell death following the bubble generation, which is accompanied by the increase in intracellular Ca2+ concentration due to the cell membrane malfunction with the PDT.

Original languageEnglish
Title of host publicationOptical Interactions with Tissue and Cells XIX
Publication statusPublished - 2008 Apr 21
EventOptical Interactions with Tissue and Cells XIX - San Jose, CA, United States
Duration: 2008 Jan 212008 Jan 23

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherOptical Interactions with Tissue and Cells XIX
Country/TerritoryUnited States
CitySan Jose, CA


  • Atrial fibrillation (AF)
  • Ca
  • Fluo-4
  • Photodynamic therapy (PDT)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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