[Expression of iNOS and activities of iNOS and cNOS in right and left ventricles of the isolated heart during ischemia and reperfusion]. / Ekspresiia iNOS i aktyvnist' iNOS i cNOS u pravomu i livomu shlunochkakh isol'ovanoho sertsia shchura pry ishemiï-reperfuziï.

Isolated using Langendorff technique hearts of male Wistar rats were ischemized for 30 min and reperfused for 40 min. Both iNOS expression determined by immunoblotting, and its activity shown by a modified Griess method have been found to predominate in the right ventricle over the left one, as compared to cNOS activity which prevailed in the left ventricle. The latter significantly diminished after an ischemic injury in the left ventricle. On the contrary, an expression of iNOS and the total NOS activities increased progressively after ischemia and postischemic reperfusion; all the values in the right ventricle were higher than in the left one. The high level of iNOS expression in the right ventricle in a postischemic period decreased during reperfusion, although an activity of the enzyme went on elevating. These data can give an evidence for different regulation of NO synthesis in right or left ventricles of the heart, including normal conditions or ischemia.

[Effects of nitric oxide donor SIN-1 on calcium transport in rat cardiac sarcoplasmic reticulum]. / Vplyv donora oksydu azotu SIN-1 na kal'tsiitransportnu funktsiiu sarkoplazmatychnoho retykuluma sertsia shchura.

The effects of non-enzymatic disintegration of SIN-1 products (nitric oxide, superoxide anion and peroxynitrite) on Ca(2+)-transport of sarcoplasmic reticulum were studied on homogenates of rats myocardium. It was shown that SIN-1 (30 microM) exerts a significant activating effect on ryanodine-sensitive calcium channels resulted in three-fold increase of Ca2+ release rate via these channels. Such effect of SIN-1 realized mainly by nitric oxide effect and, partially, superoxide radical. SIN-1 did not effect the Ca(2+)-ATPase activity of sarcoplasmic reticulum.