IMAGING OF CA2(+) CALMODULIN-DEPENDENT PROTEIN-KINASE-II ACTIVITY IN HIPPOCAMPAL-NEURONS/

OUR aim was to visualize the dynamic features of Ca2+/calmodulin-depen dent protein kinase II (CaMKII) activity. In order to do so, we synthe sized a new reagent by conjugating a fluoroprobe, 6-acryloyl-2-dimethy laminonaphthalene (acrylodan), to syntide 2, a specific peptide substr ate for CaMKII. In cell-free conditions, the conjugate was found to be an effective indicator of calmodulin activation by Ca2+ and the subse quent activation of CaMKII. The reagent is cell-permeable and can stai n living cells when bath-applied. Using this technique we were able to obtain fluorescence images of stained cells and analyse the dynamic f eatures of CaMKII inside the cells by means of image processing. Regio nal heterogeneity of CaMKII activation in cultured hippocampal neurone s was seen following L-glutamate administration.