C-type natriuretic peptide (CNP) is a natriuretic peptide (NP) that binds NP-B receptors. This peptide exhibits cardioprotective and anti-inflammatory activities. In animal models, CNP increases conduction velocity in the sinoatrial node and decreases infarct size in models of ischemia/reperfusion. In vitro, CNP decreases basal ATP-sensitive K+ channel openings and currents. Animal models of mutant CNP display arthritis, cartilage damage, and growth delay, highlighting roles for CNP in the regulation of skeletal growth and inflammation. CNP binding NP receptors increases cGMP levels and opens cystic fibrosis transmembrane receptor (CTFR) Cl- channels in a PDE3/cAMP/PKA-dependent manner.