Особенности функционального состояния сердца при острой гемодинамической перегрузке левого желудочка в эксперименте

On animal model of an acute hemodynamic overload of the left ventricle (LV) caused by the artificial aortic stenosis, some characteristics of left and right ventricular contractive activity and diastolic function were studied. It was found that a sudden increase in afterload leads to a significant reduction of contractive activity and potential working capacity of both ventricles. LV also suffers from diastolic dysfunction.В эксперименте на модели острой гемодинамической перегрузки левого желудочка сердца, вызванной искусственным стенозом восходящей аорты, изучали особенности сократительной активности и диастолической функции левого и правого желудочков. Установлено, что внезапное увеличение постнагрузки приводит к значительному снижению сократительной активности и потенциальной работоспособности обоих желудочков. В левом желудочке также развивается диастолическая дисфункция

Активность каспазы 3 и каспазы 8 в клетках миокарда правого желудочка при экспериментальной артериальной гипертензии

Caspase-3 and caspase-8 activity in right ventricular myocardial cells of rabbits with experimental arterial hypertension (AH) was investigated. Caspase-3 activity significantly increased at 2 and 4 weeks after modeling of AH. Obtained data demonstrated increased apoptosis in right ventricular myocardial cells in experimental arterial hypertension. Absence of significant increasing of caspase-8 activity indicates the predominance of intrinsic apoptogenic signals.Исследована активность каспазы 3 и каспазы 8 в клетках миокарда правого желудочка сердца кроликов с экспериментальной артериальной гипертензией (АГ). Обнаружено достоверное повышение активности каспазы 3 через 2 и 4 недели после моделирования АГ. Полученные результаты свидетельствуют об усилении апоптотической гибели клеток миокарда правого желудочка при экспериментальной артериальной гипертензии. Статистически незначимое повышение активности каспазы 8 указывает на преобладание внутриклеточного апоптогенного сигнала

Особенности изменения сократительной функции сердца при сочетании экспериментальной артериальной гипертензии с острой коронарной недостаточностью на фоне применения антагонистов кальция

The functional state of cardiovascular system was studied in a rabbit model of acute coronary insufficiency and arterial hypertension treated with Calcium channel blocker verapamil. It was established that the potential working capacity of cardiac left ventricle decreases more significantly in case of 6-week experimental model of arterial hypertension in comparison with acute coronary insufficiency, which affect more considerably the working capacity of the right ventricle. We also assume that the favorable effect of verapamil on the parameters of heart contractile function in case of arterial hypertension with consequent development of acute coronary insufficiency is linked to the preservation of right ventricle's functional reserve.Изучали функциональное состояние сердечно-сосудистой системы кроликов после моделирования острой коронарной недостаточности и артериальной гипертензии и лечения ее верапамилом. Было установлено, что потенциальная работоспособность левого желудочка сердца снижается более значительно при развитии 6-недельной экспериментальной артериальной гипертензии по сравнению с острой коронарной недостаточностью, которая влияет более выражено на работоспособность правого желудочка. Также можно предположить, что положительное влияние верапамила на показатели сократительной функции сердца при артериальной гипертензии и последующим развитием острой коронарной недостаточности связанно с сохранением на фоне приема верапамила функционального резерва правого желудочка

О типовых реакциях поврежденного сердца

On the basis of experimental research we described nine typical (nonspecific) responses of the damaged heart which are initially protective and adaptive but are able to have a pathogenetic character under some certain conditions. These typical responses are as follows: shortening of the effective refractory period of the myocardium, cardiomyocyte mitochondrion swelling, activation of lysosomal apparatus, initial intensification of lipolysis, hypertrophy of cardiac muscle, formation of collagen muffs around blood vessels due to intoxication, functional deafferentation of the heart, changes in the intensity of cardiomyocyte apoptosis, rearrangement of cardiac chronostructure. The represented results can be used as a basis to elaborate some new effective methods of prophilaxis and treatment of heart diseases caused by different etiological factors.На основании экспериментальных исследований выделено девять типовых (неспецифических) реакций поврежденного сердца, первично являющихся защитно-приспособительными, но могущих при определенных обстоятельствах играть и патогенетическую роль: укорочение эффективного рефрактерного периода миокарда, набухание митохондрий кардиомиоцита, активация лизосомного аппарата, инициальное усиление липолиза, гипертрофия сердечной мышцы, образование вокруг миокардиальных сосудов коллагеновых муфт при интоксикациях, функциональная деафферентация сердца, изменение интенсивности апоптоза кардиомиоцитов, перестройка хроноструктуры сердца. Представленные результаты дают основания для разработки новых эффективных методов профилактики и лечения заболеваний сердца различной этиологии

Daytime Exposure to Blue Light Alters Cardiovascular Circadian Rhythms, Electrolyte Excretion and Melatonin Production

Artificial light is characterized by certain features of its impact on the body in terms of its spectral distribution of power, duration of exposure and intensity. Short waves, perceived as blue light, are the strongest synchronizing agent for the circadian system. In the present work, we investigated the features of the circadian rhythms of blood pressure (BP), heart rate (HR), the excretion of electrolytes and the secretion of melatonin in normotensive (Wistar–Kyoto) and hypertensive (SHR) rats under the action of monochromatic blue light in the daytime period. It was found that the exposure of Wistar–Kyoto rats to monochromatic blue light was accompanied by a significant decrease in nighttime and 24 h systolic BP. The most remarkable changes are characteristic of the HR in SHR rats under monochromatic light. A significant decrease in HR in each time period was found, but the predominance of nighttime over daytime values remained in SHR animals. There was also a significant increase in the mesor of the HR in SHR rats. Additionally, the amplitude of diastolic BP and HR, as well as the range of oscillations in HR, were significantly increased compared with the standard light pattern. In contrast to SHR rats, the regulation of the circadian rhythms in Wistar–Kyoto rats was more flexible and presented more changes, which may be aimed at the adaptation of the body to environmental conditions. For Wistar–Kyoto rats, an increase in the level of excreted electrolytes was observed under the action of monochromatic light, but no similar changes were found in SHR rats. For Wistar–Kyoto rats, a significant decrease in the urine concentration of aMT6s in the daytime and nighttime periods is characteristic, which results in the loss of the circadian rhythm. In SHR rats, there was a significant decrease in the nighttime content of aMT6s in the urine, while the daytime concentration, on the contrary, increased. The obtained data demonstrate that prolonged exposure to monochromatic blue light in the daytime period affects the circadian structure of the rhythms of the cardiovascular system, the rhythm of electrolyte excretion and the production of epiphyseal melatonin in wild-type and hypertensive animals. In SHR rats, the rhythms of BP and HR exhibit a more rigid pattern

Specific function and morphology of the right ventricle of the heart during ischemic injury of the left ventricle

Focal ischemia of the left ventricular myocardium was modeled by surgical ligation of the descending branch of the left coronary artery at the junction of the lower and middle thirds of this artery in anesthetized rabbits. Contractility and morphological characteristics of the right ventricular myocardium were evaluated 24, 72, and 120 h after treatment. Significant morphofunctional changes in the right ventricle manifested in the development of severe extracellular edema and increase in the area of damaged and destroyed myofibrils. However, the actual and maximum intraventricular pressure remained unchanged under these conditions. The degree of cardiomyocyte apoptosis increased on day 1, but returned to normal in the follow-up period. Our study demonstrated high sensitivity of the right ventricle to left ventricular dysfunction and early activation of compensatory mechanisms. © Springer Science+Business Media, Inc. 2008

Induction of caspase cascade as a nonspecific response to myocardial damage

In three experimental series, acute hemodynamic overload of the left ventricle, focal ischemia of the left ventricle, and diphtheritic intoxication were modeled in rabbits. On days 1, 3, and 5 of the experiments, activity of myocardial caspase-3 and caspase-8 were measured separately in the left and right ventricles. In the left ventricle, caspase-3 activity increased in all 3 modeled pathological processes, while in the right ventricle this parameter increased during acute overload and ischemic injury to the left ventricle. Caspase-8 activity increased only in the left ventricle during its hemodynamic overload and remained unchanged in other cases. It was concluded that induction of the caspase cascade can be considered as a nonspecific response to myocardial damage. In this case, specific mechanisms responsible for generation and transmission of apoptotic stimuli in cardiomyocytes have unique features. © 2011 Springer Science+Business Media, Inc

Induction of caspase cascade as a nonspecific response to myocardial damage

In three experimental series, acute hemodynamic overload of the left ventricle, focal ischemia of the left ventricle, and diphtheritic intoxication were modeled in rabbits. On days 1, 3, and 5 of the experiments, activity of myocardial caspase-3 and caspase-8 were measured separately in the left and right ventricles. In the left ventricle, caspase-3 activity increased in all 3 modeled pathological processes, while in the right ventricle this parameter increased during acute overload and ischemic injury to the left ventricle. Caspase-8 activity increased only in the left ventricle during its hemodynamic overload and remained unchanged in other cases. It was concluded that induction of the caspase cascade can be considered as a nonspecific response to myocardial damage. In this case, specific mechanisms responsible for generation and transmission of apoptotic stimuli in cardiomyocytes have unique features. © 2011 Springer Science+Business Media, Inc

Specific function and morphology of the right ventricle of the heart during ischemic injury of the left ventricle

Focal ischemia of the left ventricular myocardium was modeled by surgical ligation of the descending branch of the left coronary artery at the junction of the lower and middle thirds of this artery in anesthetized rabbits. Contractility and morphological characteristics of the right ventricular myocardium were evaluated 24, 72, and 120 h after treatment. Significant morphofunctional changes in the right ventricle manifested in the development of severe extracellular edema and increase in the area of damaged and destroyed myofibrils. However, the actual and maximum intraventricular pressure remained unchanged under these conditions. The degree of cardiomyocyte apoptosis increased on day 1, but returned to normal in the follow-up period. Our study demonstrated high sensitivity of the right ventricle to left ventricular dysfunction and early activation of compensatory mechanisms. © Springer Science+Business Media, Inc. 2008

Analysis of central blood pressure during diphtheria intoxication in rabbits

Diphtheria intoxication was induced in rabbits by a single intravenous injection of native diphtheria toxin in dose of 0.3 MLD/kg, preliminary titrated on guinea pigs. Significant decrease in diastolic and systolic blood pressure and in intraventricular pressure in the left ventricle was established to take place during intoxication. Pulse wave propagation time was prolonged, likely due to prolongation of pressure wave, while the reflection wave appeared at the same time. Reduction of central blood pressure was concluded to result from changes in biomechanical characteristics of the left ventricle, and not to be associated with changes in elastic properties of the arterial wall. © 2009 Springer Science+Business Media, Inc