The role of calcium in modulating the reactivity of the smooth muscle cells during ischemia/reperfusion. Part 2.

Background: Damage of transplanted organs during reperfusion is still a problem that prompts the search for new drugs able to diminish the risk of graft rejection. The aim of this study was to examine the influence of antioxidant system on the contraction of arteries induced by angiotensin II during ischemia/reperfusion and to determine the role of intracellular and extracellular calcium ions under these conditions.

Material/methods: The experiments were performed on male Wistar rats' tail arteries. The effects of angiotensin II on vascular tone were examined after ischemia/reperfusion in the presence of catalase or aminotriazole. To determine the role of intracellular and extracellular Ca(2+), the experiments were performed in Ca(2+)-free PSS and PSS.

Results: Angiotensin II increased perfusion pressure in both Ca(2+)-free PSS and PSS. After ischemia, the reactions induced by angiotensin II were lower, while after reperfusion they were higher. In the presence of catalase the effects induced by angiotensin II were lower and in the presence of aminotriazole higher.

Conclusions: Ischemia inhibits and reperfusion augments the perfusion pressure induced by angiotensin II. The results confirm the vasoprotective effect of catalase and the destructive influence of aminotriazole in modulating the reactions of vascular smooth muscle cells to ANG II after ischemia/reperfusion. These results suggest that the antioxidant system plays a role in modulating the reactions induced by angiotensin II after ischemia/reperfusion and that reperfusion disturbs the balance between antioxidants and the production of reactive oxygen species.