Oxytocin in Cardiovascular Homeostasis

Oxytocin (OT) historically known for its actions on the reproductive system may also contribute to the regulation of cardiovascular and water-electrolyte homeostasis. OT is produced in the supraoptic and paraventricular nuclei of the hypothalamus and released into plasma from neural terminals of the posterior pituitary however many studies have identified extra-cerebral sites of OT production including the heart and vascular endothelium. Activation of its receptors on endothelial cells as well as in hypothalamic/hypophyseal and cardiac systems may result in nitric oxide (NO) production. We aimed to verify the role of NO in the regulation of OT-stimulated atrial natriuretic peptide (ANP) secretion in primary culture of mouse embryonic cardiomyocytes. For this we used hearts from Balb C mouse embryos 19 to 21 days old intrauterine were isolated and cultured for assays with OT and other interfering substances in the synthesis of NO and cGMP its second messenger.