Apelin-APJ system is responsible for stress-induced increase in atrial natriuretic peptide expression in rat heart

Background: The cardiovascular system is a primary target of stress and stress is the most important etiologic factor in cardiovascular diseases. Stressors increase expressions of atrial natriuretic peptide (ANP) and apelin in cardiac tissue. Aim: The aim of the present study was to investigate whether stress-induced apelin has an effect on the expression of ANP in the right atrium of rat heart. Methods: The rats were divided into the control, stress and F13A + stress groups. In the stress and F13A + stress groups, the rats were subjected to water immersion and restraint stress (WIRS) for 6 h. In the F13A + stress group, apelin receptor antagonist F13A, was injected intravenously immediately before application of WIRS. The plasma samples were obtained for the measurement of corticosterone and atrial natriuretic peptide. The atrial samples were used for immunohistochemistry and western blot analysis. Results: F13A administration prevented the rise of plasma corticosterone and ANP levels induced by WIRS. While WIRS application increased the expressions of apelin, HIF-1 alpha and ANP in atrial tissue, while F13A prevented the stress-induced increase in the expression of HIF-1 alpha and ANP. Conclusion: Stress-induced apelin induces ANP expression in atrial tissue and may play a role in cardiovascular homeostasis by increasing ANP expression under WIRS conditions.