Nitric oxide synthesized from L‐arginine regulates vascular tone in the coronary circulation of the rabbit

• Published in: British journal of pharmacology Vol. 97; no. 4; pp. 1119 - 1124
• Main Authors: Amezcua, J.L., Palmer, R.M.J., Souza, B.M., Moncada, S.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.1989; Nature Publishing
• Subjects: Acetylcholine - pharmacology; Animals; Antianginal agents. Coronary vasodilator agents; Arginine - metabolism; Arginine - pharmacology; Biological and medical sciences; Cardiovascular system; Coronary Circulation - drug effects; heart; Heart - drug effects; In Vitro Techniques; Luminescent Measurements; Male; Medical sciences; Muscle Relaxation - drug effects; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - physiology; nitric oxide; Nitric Oxide - pharmacology; omega-N-Methylarginine; Pharmacology. Drug treatments; Rabbits; smooth muscle; Superoxide Dismutase - pharmacology; Heart; Vasodilator agent; Coronary artery; Contractility; Rabbit; Smooth muscle; Lagomorpha; Metabolism; In vitro; Biological activity; Isolated organ; Vertebrata; Mammalia; Synthesis; Animal; Blood vessel; Nitrogen monoxide; Inhibitor; Blood pressure; Intraarterial administration; Circulatory system; Endothelium derived relaxing factor
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1111/j.1476-5381.1989.tb12569.x

1 The role of nitric oxide (NO) in the regulation of the vascular tone of the coronary circulation of the Langendorff‐perfused rabbit heart was investigated. 2 NG‐monomethyl‐L‐arginine (L‐NMMA; 10–100 μm), a specific inhibitor of NO formation from L‐arginine (L‐Arg), but not its D‐enantiomer (D‐NMMA; 100 μm) produced a dose‐related, sustained increase in the coronary perfusion pressure (CPP). In addition, L‐NMMA inhibited the vasodilator responses of acetylcholine (ACh), unmasking in some instances its direct vasoconstrictor effect. These effects of L‐NMMA were attenuated by L‐Arg. 3 L‐NMMA (10 and 30 μm), but not D‐NMMA (30 μm), caused a long‐lasting inhibition of NO formation which was reversed by L‐Arg (30 and 100 μm), but not by D‐Arg (100 μm). 4 This study indicates that the formation of NO from L‐Arg in the coronary circulation of the rabbit plays a role both as a regulator of vascular tone and as a mediator of the vasodilatation induced by ACh.