Regulation of natriuretic peptide secretion by the heart

Secreted by the heart, more specifically by atrial cardiomyocytes under nor mal conditions but also by ventricular myocytes during cardiac hypertrophy, natriuretic peptides are now considered important hormones in the control of blood pressure and salt and water excretion. Studies on natriuretic pept ide secretagogues and their mechanisms of action have been complicated by h emodynamic changes and contractions to which the atria are constantly subje cted. It now appears that atrial stretch through mechano-sensitive ion chan nels, adrenergic stimulation via alpha(1A)-adrenergic receptors, and endoth elin via its ETA receptor subtype are major triggering agents of natriureti c peptide release. With several other stimuli, such as angiotensin II and b eta-adrenergic agents, modulation of natriuretic peptide release appears to be Linked to local generation of prostaglandins. In all cases, intracellul ar calcium homeostasis, controlled by several ion channels, is considered a key element in the regulation of natriuretic peptide secretion.