Detection of cardiac signaling in the injured and hypertrophied heart.

Cardiac hypertrophy is a compensatory response to a variety of physiological or pathological stimuli. However, prolonged hypertrophic responses may eventually lead to heart failure, arrhythmia, and sudden death. A number of intracellular signaling pathways have been implicated to play a critical role in the regulation of cardiac hypertrophy. In this chapter, the mitogen-activated protein kinase signaling pathway is used to illustrate conventional assays to detect the expression, phosphorylation, and activation of signaling proteins during cardiac hypertrophy, including Western blot, immunohistochemical staining, and immune complex kinase assays. Newly emerging techniques for analyzing cell signaling are also discussed in this chapter. Identifying and characterizing the expression and activation of these signaling proteins will provide important insights into the mechanisms that regulate hypertrophic cell growth and assist in development of new therapeutic approaches to limit cardiac hypertrophy.