Remodelling and functional alterations of the rabbit coronary artery in volume overloaded heart.

Objective: The aim was to study the contractility of the conduit coronary artery to vasoactive agents in developing and established volume overload cardiac hypertrophy and to compare it with structural alterations in the artery.

Methods: Aortic valve insufficiency in rabbits was used to produce a volume overloaded heart. One month (developing hypertrophy), and four months (stabilised hypertrophy) after inducing aortic insufficiency, the isometric contraction of the coronary artery to acetylcholine, serotonin, and potassium chloride was recorded.

[Modification of the composition of the hypertrophic myocardium by beta adrenergic blockade].

Adaptation of the rabbit heart to volume load of the left ventricle is characterized by hypertrophic growth. This process involves an increase in the mass and changes in the composition of the myocardium. In the fifth week after perforation of the aortic valve an increase in phospholipid content and in mitochondria and a decrease in protein content was observed in the myocardium.

[The effect of long-term administration of metipranolol on passive diastolic properties of the hypertrophic ventricle].

In the course of adaptation of the rabbit heart to volume load passive diastolic properties of the hypertrophic ventricle and myocardium were changing significantly. On day 30 following perforation of the aortic valve stiffness of the ventricle was reduced, yet normalized ventricular stiffness and myocardial stiffness were increased. These changes were prevented by beta adrenergic blockade during development of adaptation of the heart to volume load.

[Strategies in the use of isolated cardiomyocytes in relation to other models in experimental cardiology].

Selection of the optimal model for a specific experiment considerably determines the results and their correct interpretation. The model of the isolated cardiomyocyte is increasingly being used in experimental cardiology as it provides several advantages in comparison to models in which the heart tissue remains relatively complete. Similarly as in other models, the factors limiting its use have to be known also in the case of the isolated cardiomyocyte.

[Quantitative ultrastructural characteristics of mitochondria and myofibrils in the myocardium in chronic hemodynamic overload].

Stereological morphometry was used to determine ultrastructural changes of the myocardium in the course of well defined chronic hemodynamic overload. Overload was induced in the hearts of rabbits by perforation of aortic valves. Relative volumes of mitochondria, myofibrils were measured in tissue samples taken from subendocardial and subepicardial region of the left ventricle.