Natriuretic peptide receptors and the heart

The synthesis of ANP and BNP by the heart has emerged as a sensor of cardiac strain, with increased synthesis the hallmark of myocyte hypertrophy in cell culture, and raised plasma concentrations a biomarker of ventricle dysfunction in vivo. It is 20 years since de Bold reported that homogenates of normal atria stimulated a natriuresis and diuresis when administered intravenously to rats.1 This observation led to the isolation of atrial natriuretic peptide (ANP) from cardiac tissue. Subsequently other peptides with a similar ring structure and biological properties have been recognised, named in alphabetical order—BNP, CNP, and DNP—and termed the natriuretic peptide family. Initial studies of the biology of natriuretic peptides focused on their endocrine role—measuring circulating levels in response to different stimuli and looking at the effects of administering exogenous peptide to isolated tissues and whole animals. Most attention has been given to ANP and BNP. Both are synthesised by cardiac myocytes and their production is increased by factors that increase cardiac work—pressure and volume overload. Indeed, the cardiac synthesis of ANP and BNP has emerged as a sensor of cardiac strain, with increased synthesis the hallmark of myocyte hypertrophy in cell culture and raised plasma concentrations a biomarker of ventricle dysfunction in vivo. Both peptides relax isolated resistance vessels. Pharmacological infusions of either peptide reduce renin and aldosterone concentrations, promote renal sodium and water excretion, and lower blood pressure …