The increase of radical forms of mitochondrial respiratory chain compounds (MRCC) is an indicator of an increased risk of the formation of oxygen radicals. Using electron paramagnetic resonance (EPR), we found an increase of signals corresponding to ubisemichinone radical (·QH) and ironsulfur proteins radical forms (·FeS) of these respiratory chain compounds during ischemia in the isolated perfused rat heart (·QH increased from 1.51 to 3.08, ·FeS1 from 1.14 to 2.65 arbitrary units). During the 5-min reperfusion, the signals returned to normoxic levels. In isolated mitochondria exposed to anoxia and reoxygenation the radical forms of ·QH and ·FeS2 changed in a similar manner as in the intact heart. A combination of in vivo captopril treatment and in vitro L-arginine administration significantly decreased the levels of MRCC radicals in the isolated myocardium (·QH from 2.61 to 1.72 and ·FeS1 from 1.82 to 0.46 under normoxia; ·QH from 4.35 to 2.66 and ·FeS1 from 1.93 to 1.35 during ischemia). This decrease in MRCC radical forms was associated with increased NO levels in the perfusate, determined as NO2-/ NO3-, as well as tissue NO levels determined using EPR as the dinitrosyl iron complex (DNIC). These results provide new information about the cardioprotective effects of ACE inhibitors and L-arginine., H. Vavřínková, M. Tutterová, P. Stopka, J. Divišová, L. Kazdová, Z. Drahota., and Obsahuje bibliografii
Spontaneously hypertensive rats (SHR/NIH strain) harbor a deletion variant in the Cd36 fatty acid transporter and display defective fatty acid metabolism, insulin resistance and hypertension. Transgenic rescue of Cd36 in SHR ameliorates insulin resistance and improves dyslipidemia. However, the role of Cd36 in blood pressure regulation remains controversial due to inconsistent blood pressure effects that were observed with transgenic expression of Cd36 on the SHR background. In the current studies, we developed two new SHR transgenic lines, which express wild type Cd36 under the control of the universal Ef-1 promoter, and examined the effects of transgenic expression of wild type Cd36 on selected metabolic and cardiovascular phenotypes. Transgenic expression of Cd36 in the new lines was associated with significantly decreased serum fatty acids, amelioration of insulin resistance and glucose intolerance but failed to induce any consistent changes in blood pressure as measured by radiotelemetry. The current findings confirm the genetic association of defective Cd36 with disordered insulin action and fatty acid metabolism in the SHR/NIH strain and suggest that Cd36 is linked to other gene(s) on rat chromosome 4 that regulate blood pressure., M. Pravenec, V. Landa, V. Zídek, A. Musilová, L. Kazdová, N. Qi, J. Wang, E. St.Lezin, T. W. Kurtz., and Obsahuje bibliografii