Aberrant intercellular calcium waves in the CA1 region of the mouse hippocampus injected with GCaMP-expressing virus

• Main Author: Koh, Charmay Pearl Lin
• Other Authors: Ayumu Tashiro
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Science::Biological sciences
• Online Access: https://hdl.handle.net/10356/165153
• Institution: Nanyang Technological University

The advent of genetically engineered calcium indicators (GECIs) like GCaMP have paved the way for the use of calcium imaging to monitor neuronal activity in neuroscience research. However, accumulating evidence have highlighted undesired phenotypes associated with GCaMP expression. In this study, an adeno-associated virus was used to express GCaMP6f in the CA1 region of C57BL6/J mice. Here, we reveal another unprecedented side effect resulting from elevated GCaMP levels – intercellular Ca2+ waves. These waves were characterised, and were also found to be reduced by diazepam and carbenoxolone, but not CPP, and were completely but reversibly blocked by isoflurane anaesthesia. No waves were observed when the original virus used was diluted, suggesting that high GCaMP levels contributed to the appearance of the intercellular Ca2+ waves. Although GCaMP is a very useful genetic tool, researchers should take note of its faults, to ensure the validity of their experimental results.