1Firat University Faculty of Medicine Department of Physiology, Elazig, Turkey
2Firat University Faculty of Medicine Department of Cardiovascular Surgery Elazig, Turkey
3Firat University Faculty of Medicine Department of Biophysics, Elazig, Turkey
Aim: Apelin has important effects on the circulatory system and heart. The main aim of this study was to investigate the effects of apelin-13 on the contraction induced by norepinephrine (NE), and the endothelium-independent relaxation induced by sodium nitroprusside (SNP) in human internal mammary artery (IMA) obtained from patients undergoing coronary artery bypass grafting (CABG) surgery.
Material and Methods: IMA rings, obtained from patients undergoing CABG surgery, were suspended in isolated tissue baths containing Krebs-Henseleit solution, which were continuously gassed with 95% O2 and 5% CO2 at 37°C.
Results: The IMA rings were pre-contracted with increasing concentrations of norepinephrine (NE 10-9–10-4 mol/l) and the endothelium-independent relaxation responses to sodium nitroprusside (SNP) were studied. Apelin-13 (10 μM) caused a dose-dependent relaxation in NE pre-contracted IMA rings. Apelin also facilitated the endothelium-independent relaxation induced by SNP.
Conclusion: According to the results, apelin facilitated the endothelium-independent relaxation and inhibited the contractile activity of IMA. These results suggest that apelin may be a physiological agent against the deterioration of vascular elasticity caused by endothelial damage especially in atherosclerotic cardiac patients and hypertensive patients.