Hypotensive effect and vascular relaxation in different arteries induced by the nitric oxide donor RuBPY

- The NO donor (RuBPY) induces a dose-dependent and long-lasting hypotensive effect only in renal hypertensive rats.
- RuBPY does not induce tachycardia.
- RuBPY induces vasodilation of coronary artery and mesenteric resistance artery so it may be useful in hypertension and angina.
- RuBPY does not induce dilatation of cerebral basilar artery, which could imply in no headache as a side effect.
- Therefore, RuBPY presents several advantages over the well known NO donor SNP.

NO donors are compounds that release NO that can be used when the endogenous NO bioavailability is impaired. The compound cis-[Ru(bpy)2(py)(NO2)](PF6) (RuBPY) is a nitrite-ruthenium, since it has a NO2 in its molecule. The aim of the present study was to evaluate the effect of RuBPY on arterial pressure, as well as on the vascular relaxation of different vascular arteries in renal hypertensive (2K-1C) and normotensive (2K) rats. We have evaluated the arterial pressure and heart rate changes as well as the RuBPY and SNP-induced relaxation (thoracic aorta, mesenteric resistance, coronary and basilar arteries). The administration of RuBPY in awake rats evoked a smaller but long lasting hypotensive effect when compared to SNP, with no increase in heart rate. The relaxation induced by RuBPY was similar between 2K-1C and 2K rats in thoracic aorta, mesenteric resistance and coronary arteries. However, the relaxation induced by RuBPY was smaller in basilar arteries from 2K-1C than in 2K. Taken together, our results show that RuBPY presents several advantages over SNP, since it does not induce hypotensive effect in normotensive animals, the hypotensive effect is slower, with no reflex tachycardia, and it is long lasting. In addition, RuBPY induces coronary artery relaxation (useful for angina) and presented only a small effect on basilar artery (may not induce headache).

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