Gennadi M. Kravtsov

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Certain manifestations of alterations of membrane cytoskeleton, protein kinase C activity, and ion transport were revealed in erythrocytes of patients with essential hypertension: 1) the average volume of erythrocytes is reduced by 4%; 2) about 7% of the total number of erythrocytes is represented by cup-shaped forms compared with 1.5 to 3.0% in the control(More)
This study examined Ca(2+) handling mechanisms involved in cardioprotection induced by chronic intermittent hypoxia (CIH) against ischemia-reperfusion (I/R) injury. Adult male Sprague-Dawley rats were exposed to 10% inspired O(2) continuously for 6 h daily from 3, 7, and 14 days. In isolated perfused hearts subjected to I/R, CIH-induced cardioprotection was(More)
We hypothesized that testosterone at physiological levels enhances cardiac contractile responses to stimulation of both alpha(1)- and beta(1)-adrenoceptors by increasing Ca(2+) release from the sarcoplasmic reticulum (SR) and speedier removal of Ca(2+) from cytosol via Ca(2+)-regulatory proteins. We first determined the left ventricular developed pressure,(More)
Our previous study has demonstrated that ovariectomy (Ovx) significantly increased the left ventricular developed pressure (LVDP) and the maximal rate of developed pressure over time (+/-dP/dt(max)) in the isolated perfused rat heart and the effects were reversed by female sex hormone replacement. In the present investigation, we studied the effects of Ovx(More)
We previously showed that oestrogen confers cardioprotection by downregulating the cardiac beta1-adrenoceptor (beta1-AR). The present study examined the effect of oestrogen on the post beta1-AR signalling cascade, with particular emphasis on the activity of protein kinase A (PKA) and its influence on the L-type Ca2+ channel. Three groups of adult female(More)
Aortic rings of Sprague-Dawley rats developed reproducible contractions in Ca-free, nominally Mg-free (2 microM), Na-free, K solution, but not in Ca-free, nominally Mg-free, K-free, Na solution. Further reduction of the residual Mg by 0.5 mM EDTA in the above solutions potentiated this K-induced contraction and allowed the development of a relatively small(More)
Strong, K+-induced contractions of rat aorta in Ca-free, Mg-free media were not accompanied by increased intracellular calcium concentration, [Ca2+]i, whereas such contractions in the presence of the divalent cations were correlated with rising [Ca2+]i as assessed by fura-2. At the same time, calcium channel blockers, a modulator of Ca2+-binding proteins,(More)
In the absence of depolarizing agents, 45Ca uptake by synaptosomes of the brain tissue of spontaneously hypertensive rats (SHR) was 40% greater than in normotensive controls. This difference disappeared after membrane treatment with depolarizing agents or with the addition of the Ca channel blocker verapamil. Increased 45Ca uptake was also observed in(More)
Platelet aggregation, plasmatic membrane potential and sodium and calcium uptake were investigated in spontaneously hypertensive rats (SHR). The sensitivity of SHR's platelets to effects of all aggregational agents examined (ADP, collagen, ADP + noradrenaline) was enhanced. Ca-ionophore A 23187 caused complete SHR platelet aggregation when Ca2+(More)
In contrast to vascular muscles, the contribution of a hypotensive peptide adrenomedullin (AM) to the regulation of visceral smooth muscles is obscure. The content, synthesis, and effects of AM on the muscular tone in rat ileum were explored. It was found that there was immunoreactive AM (301 pg/mg of protein) and AM mRNA expression (162 fg/pg actin mRNA)(More)