[Hydrogen sulfide inhibits Ca(2+)-induced mitochondrial permeability transition pore opening in spontaneously hypertensive rats].

In experiments in vivo and in vitro on the mitochondria isolated from the control and spontaneously hypertensive rats (SHR) hearts, we studied the effects of a donor of hydrogen sulfide (H2S), NaHS, and H2S biosynthesis substrate, L-cysteine, on the sensitivity of the mitochondrial permeability transition pore (mPTP) opening to its natural inductor, Ca2+. We found that NaHS (10(-4), 10(-5) and 5 10(-5) mol/l) influenced the mitochondrial swelling in a concentration-dependent manner in control and spontaneously hypertensive rats. The H2S donor NaHS used in physiological concentrations (10(-6), 10(-5) and 5 10(-5) mol/l) exerted the inhibiting effect on the Ca(2+)-induced mPTP opening in control hearts (corresponding values of such effect were 31, 76, and 100%, respectively), while in spontaneously hypertensive rats hearts the protector effect of NaHS was observed only at its concentration of 10(-5) - 10(-4) mol/l.

[Cardiohemodynamics and efficiency Frank-Starling mechanism in spontaneously hypertensive rats].

We studied cardiohemodynamics and efficiency Frank-Starling mechanism in 6-month-old spontaneously hypertensive rats (SHR) and age-matched Wistar rats, using pressure-volume (PV) conductance catheter system (Millar Instruments, Houston, TX) to evaluate systolic and diastolic function in vivo. Rats were anesthetized with urethane. Cardiohemodynamics analyzed using PVAN 3.

[Increase in the sensitivity of the mitochondrial permeability transition pore opening to Ca2+ in heart of spontaneous hypertensive rat].

In experiments vitro on the mitochondria isolated from adult and spontaneous hypertensive rat hearts, we studied the sensitivity of the mitochondrial permeability transition pore (mPTP) opening to its natural inductor, Ca2+. We observed an increase in the sensitivity of mPTP opening to Ca2+ in the heart of spontaneous hypertensive rats because of a decrease in the threshold concentration of this ion required for organelles swelling by two orders of magnitude. It was shown that the classical inhibitor mPTP cyclosporin A (10(-5) mol/L) partially (54%) inhibited of mPTP opening in the heart of these animals, indicating that the presence in the heart of these animals of cyclosporin A-insensitive component of the mPTP.

[The mitochondrial membrane potential and oxygen consumption in the heart of spontaneously hypertensive rats].

We investigated the mitochondrial membrane potential and processes of respiration and oxidative phosphorylation in suspension of cardiac mitochondria from 6 month old spontaneously hypertensive rats (SHR) and Wistar (as a control) male rats. The mitochondrial membrane potential and the speed of oxygen consumption were measured using the method described by M.Brand (1995).