Calcium-binding of cardiac sarcoplasmic reticulum and diastolic hemodynamics in volume overloaded canine hearts. 1985

T Maeba

The relationship between the active Ca2+-binding function of the cardiac sarcoplasmic reticulum (SR) and left ventricular (LV) relaxation was studied in various stages of chronically volume overloading canine hearts induced by complete atrio-ventricular (A-V) block. Rapid kinetic measurement of the Ca2+-binding activity of SR was made using a dual-beam spectrophotometric assay procedure. LV hemodynamics, especially diastolic indexes, were evaluated by the pressure-volume relationship using a trans-epicardial echo-cardiographic technique. In this study the maximum Ca2+-binding capacity and the initial Ca2+-binding rate of SR were impaired in eccentric hypertrophied hearts and failing hearts induced by volume overload. However, there was no significant difference of SR functional defect between the hypertrophied and the failing hearts. LV systolic properties were not influenced even by chronic volume overload. Its diastolic properties, however, were reduced with the progress of eccentric hypertrophy, and were estimated to respond more sensitively to the abnormalities of cardiac function compared with systolic properties. There was a close interrelation between the Ca2+-binding activity of SR on the molecular level and diastolic parameters, especially the time constant T, on the ventricular chamber level. In conclusion, the impairment of the Ca2+-binding activity of SR is a cause of depression of LV diastole. However, the role of SR in the occurrence of heart failure could not be clarified in this study.

UI MeSH Term Description Entries
D009200 Myocardial Contraction Contractile activity of the MYOCARDIUM. Heart Contractility,Inotropism, Cardiac,Cardiac Inotropism,Cardiac Inotropisms,Contractilities, Heart,Contractility, Heart,Contraction, Myocardial,Contractions, Myocardial,Heart Contractilities,Inotropisms, Cardiac,Myocardial Contractions
D009206 Myocardium The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow. Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002306 Cardiac Volume The volume of the HEART, usually relating to the volume of BLOOD contained within it at various periods of the cardiac cycle. The amount of blood ejected from a ventricle at each beat is STROKE VOLUME. Heart Volume,Cardiac Volumes,Heart Volumes,Volume, Cardiac,Volume, Heart,Volumes, Cardiac,Volumes, Heart
D003971 Diastole Post-systolic relaxation of the HEART, especially the HEART VENTRICLES. Diastoles
D004285 Dogs The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065) Canis familiaris,Dog
D006327 Heart Block Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects. Auriculo-Ventricular Dissociation,A-V Dissociation,Atrioventricular Dissociation,A V Dissociation,A-V Dissociations,Atrioventricular Dissociations,Auriculo Ventricular Dissociation,Auriculo-Ventricular Dissociations,Block, Heart,Blocks, Heart,Dissociation, A-V,Dissociation, Atrioventricular,Dissociation, Auriculo-Ventricular,Dissociations, A-V,Dissociations, Atrioventricular,Dissociations, Auriculo-Ventricular,Heart Blocks
D006333 Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION. Cardiac Failure,Heart Decompensation,Congestive Heart Failure,Heart Failure, Congestive,Heart Failure, Left-Sided,Heart Failure, Right-Sided,Left-Sided Heart Failure,Myocardial Failure,Right-Sided Heart Failure,Decompensation, Heart,Heart Failure, Left Sided,Heart Failure, Right Sided,Left Sided Heart Failure,Right Sided Heart Failure
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012519 Sarcoplasmic Reticulum A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions. Reticulum, Sarcoplasmic,Reticulums, Sarcoplasmic,Sarcoplasmic Reticulums

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