Myocardial relaxant effect of exogenous nitric oxide in isolated ejecting hearts

1994 ◽  
Vol 266 (5) ◽  
pp. H1699-H1705 ◽  
Author(s):  
R. Grocott-Mason ◽  
S. Fort ◽  
M. J. Lewis ◽  
A. M. Shah

In isolated myocytes and papillary muscles, both nitric oxide, acting through guanosine 3',5'-cyclic monophosphate (cGMP), and cGMP analogues exert a novel effect on myocardial contraction, influencing mainly the onset of relaxation. We studied the effect of the exogenous nitric oxide donor, sodium nitroprusside (0.1-10 microM), in isolated ejecting guinea pig hearts at constant filling pressure, afterload, and heart rate to identify its direct myocardial effects in the whole heart. Sodium nitroprusside induced concentration-dependent increases in coronary flow as well as premature and faster early left ventricular (LV) pressure decline, but did not change end-diastolic or peak LV pressure or peak rate of rise of LV pressure. There was no correlation between changes in coronary flow and LV pressure decline. Sodium nitroprusside effects were inhibited by hemoglobin, which inactivates nitric oxide. The cGMP-independent vasodilator nicardipine also increased coronary flow but did not influence early LV pressure fall. Thus exogenous nitric oxide exerts novel direct myocardial relaxant effects in the isolated ejecting heart, independent of its known vasodilator activity, and without compromising systolic function.

1998 ◽  
Vol 95 (5) ◽  
pp. 557-564 ◽  
Author(s):  
Oluwole S. FAGBEMI ◽  
Basil J. NORTHOVER

1.This study examined the effects of altering nitric oxide levels with sodium nitroprusside or l-arginine in rat hearts stored hypothermically. 2.Hearts were microperfused at 4 ;°C for 24 ;h with a modified Krebs–Henseleit buffer (KHB) that contained either sodium nitroprusside, l-arginine, l-arginine methyl ester or dexamethasone. 3.After hypothermic storage, hearts were rewarmed to 37 ;°C with KHB alone or KHB containing sodium nitroprusside or l-arginine. Cardiac function was then assessed in either Langendorff mode or working heart mode. 4.Compared with values from fresh unstored hearts, hypothermic stored hearts showed a significant decrease in coronary flow and left ventricular developed pressure when the stored hearts were perfused in Langendorff mode. These hearts also produced less aortic flow and cardiac output when perfused in the working mode. 5.Hearts hypothermically microperfused with buffer containing either l-arginine or sodium nitroprusside and then reperfused in the Langendorff mode with untreated KHB buffer had the highest left ventricular developed pressure and coronary flow values. Aortic flow and cardiac output were also higher in these hearts. 6.In all groups of stored hearts, the concentrations of both ATP and creatine phosphate were significantly low, when compared with values from freshly isolated hearts. Addition of dexamethasone to the buffer either during storage or during reperfusion had no beneficial effect on high-energy phosphate loss or cardiac performance of stored hearts. 7.This study showed that the addition of nitric oxide donors to storage buffer significantly improves cardiac function on normothermic reperfusion. The improved functional recovery is unrelated to the high-energy phosphate content of these hearts.


Circulation ◽  
1997 ◽  
Vol 95 (9) ◽  
pp. 2303-2311 ◽  
Author(s):  
Nobuhiko Ito ◽  
Josef Bartunek ◽  
Kenneth W. Spitzer ◽  
Beverly H. Lorell

Nitric Oxide ◽  
2009 ◽  
Vol 21 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Darren C. Henstridge ◽  
Brian G. Drew ◽  
Melissa F. Formosa ◽  
Alaina K. Natoli ◽  
David Cameron-Smith ◽  
...  

2006 ◽  
Vol 78 (3) ◽  
pp. 171-177 ◽  
Author(s):  
L. F. A. Huitema ◽  
A. B. Vaandrager ◽  
P. R. van Weeren ◽  
A. Barneveld ◽  
J. B. Helms ◽  
...  

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