Imaging intercellular calcium waves in the developing nervous system of zebrafish

Abstract

Several critical developmental events in the brain are believed to be regulated by spontaneous calcium waves. Commonly used calcium imaging methodologies have not been successful in exploring calcium waves beyond the embryonic stages of zebrafish, due to their invasivity, high noise, poor spatial resolution and other problems. However, using zebrafish transgenic for Cameleon - a FRET based calcium indicator and SOARS - a statistical optimization technique for data analysis, we were able to overcome these limitations and were able to image spontaneous calcium waves in vivo in a live zebrafish brain. The zebrafish that we imaged stably expressed cameleon in all the neurons. Changes in the cameleon FRET signal were detected using SOARS, which is capable of detecting signals from noisy ratiometric datasets. Our results represent the first successful instance of imaging calcium waves with well preserved spatio-temporal information in a live larval zebrafish brain in vivo.