Relaxin‐induced increased coronary flow through stimulation of nitric oxide production
T Bani‐Sacchi, M Bigazzi, D Bani… - British journal of …, 1995 - Wiley Online Library
British journal of pharmacology, 1995•Wiley Online Library
1 Relaxin (RLX) is a multifunctional hormone which, besides its role in pregnancy and
parturition, has also been shown to influence the cardiovascular system. In this study, we
investigated the effect of RLX on coronary flow of rat and guinea‐pig hearts, isolated and
perfused in a Langendorff apparatus. RLX was either added to the perfusion fluid at a
concentration of 5× 10− 9 m for a 20‐min perfusion, or given as a bolus into the aortic
cannula at concentrations of 10− 9 m, 5× 10− 9 m and 10− 8 m dissolved in 1 ml of perfusion …
parturition, has also been shown to influence the cardiovascular system. In this study, we
investigated the effect of RLX on coronary flow of rat and guinea‐pig hearts, isolated and
perfused in a Langendorff apparatus. RLX was either added to the perfusion fluid at a
concentration of 5× 10− 9 m for a 20‐min perfusion, or given as a bolus into the aortic
cannula at concentrations of 10− 9 m, 5× 10− 9 m and 10− 8 m dissolved in 1 ml of perfusion …
- 1Relaxin (RLX) is a multifunctional hormone which, besides its role in pregnancy and parturition, has also been shown to influence the cardiovascular system. In this study, we investigated the effect of RLX on coronary flow of rat and guinea‐pig hearts, isolated and perfused in a Langendorff apparatus. RLX was either added to the perfusion fluid at a concentration of 5 × 10−9 M for a 20‐min perfusion, or given as a bolus into the aortic cannula at concentrations of 10−9 M, 5 × 10−9 M and 10−8 M dissolved in 1 ml of perfusion fluid.
- 2RLX, given either for a 20‐min perfusion or as a bolus in the aortic cannula to guinea‐pig and rat isolated hearts, increased the coronary flow and the amount of nitrite, a stable end‐product of nitric oxide (NO) metabolism, that appeared in the perfusates in a concentration‐dependent fashion.
- 3The increase in coronary flow and in nitrite in the perfusates induced by RLX was significantly reduced by pretreatment with the nitric oxide synthase (NOS) inhibitor, NG‐monomethyl‐L‐arginine (L‐NMMA, 10−4 M).
- 4The effects of RLX on coronary flow and nitrite amounts in the perfusates were compared with those induced by the endothelium‐dependent vasodilator agent, acetylcholine (ACh, 10−8 − 10−7 M), and by the endothelium‐independent vasodilator agent, sodium nitroprusside (SNP, 10−7‐10−6M). The results obtained show that RLX is more effective than ACh and SNP in increasing coronary flow.
- 5The results of this study show that RLX increases coronary flow through stimulation of NO production; hence this hormone should be regarded as a novel agent capable of improving myocardial perfusion.
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