Calcium-dependent activation of mitochondrial metabolism in mammalian cells.

Endogenous fluorophores provide a simple, but elegant means to investigate the relationship between agonist-evoked Ca2+ signals and the activation of mitochondrial metabolism. In this article, we discuss the methods and strategies to measure cellular pyridine nucleotide and flavoprotein fluorescence alone or in combination with Ca2+-sensitive indicators. These methods were developed using primary cultured hepatocytes and neurons, which contain relatively high levels of endogenous fluorophores and robust metabolic responses. Nevertheless, these methods are amendable to a wide variety of primary cell types and cell lines that maintain active mitochondrial metabolism.