Biomaterial Database

Calcium-sensitivity modulation of cardiac myofibrillar proteins. 1989

J C Rüegg, and I Morano

II. Physiologisches Institut, Universität Heidelberg, F.R.G.

Myocardial contractile force may be altered not only by changing intracellular free Ca2+ but also by increasing or decreasing the calcium responsiveness of the myofilaments. The latter effect may be due to interventions that decrease the calcium affinity of troponin C, such as intracellular acidosis or factors that act "downstream" of the calcium-troponin-C interaction in the process of muscle activation. These include inorganic phosphate, which accumulates under hypoxic conditions. Conversely, calcium responsiveness may be increased by drugs that probably increase the calcium affinity of troponin C, such as sulmazole, adibendan, pimobendan, and isomazole. These and related drugs also increase the force development of skinned trabeculae that are submaximally activated by Ca2+ stimulation in ATP salt solution. Thus, we confirmed earlier studies showing that adibendan increased submaximal Ca2+-activated force of pig-heart trabecula skinned by 0.5% lubrol-WX. Qualitatively similar results were obtained with pimobendan. However, calcium responsiveness may not only be modulated by factors influencing troponin, but also by modulation of crossbridge rate constants as well as by other factors that act downstream of troponin C. These include peptides derived from thin-filament proteins and subfragment S1 of myosin.

UI	MeSH Term	Description	Entries
D007093	Imidazoles	Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
D009124	Muscle Proteins	The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.	Muscle Protein,Protein, Muscle,Proteins, Muscle
D009186	Myelin Sheath	The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.	Myelin,Myelin Sheaths,Sheath, Myelin,Sheaths, Myelin
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
D009210	Myofibrils	The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .	Myofilaments,Myofibril,Myofilament
D011724	Pyridazines	Six-membered rings with two adjacent nitrogen atoms also called 1,2-diazine.
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
D002316	Cardiotonic Agents	Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).	Cardiac Stimulant,Cardiac Stimulants,Cardioprotective Agent,Cardioprotective Agents,Cardiotonic,Cardiotonic Agent,Cardiotonic Drug,Inotropic Agents, Positive Cardiac,Myocardial Stimulant,Myocardial Stimulants,Cardiotonic Drugs,Cardiotonics,Agent, Cardioprotective,Agent, Cardiotonic,Drug, Cardiotonic,Stimulant, Cardiac,Stimulant, Myocardial
D002335	Carnivora	An order of MAMMALS, usually flesh eaters with appropriate dentition. Suborders include the terrestrial carnivores Fissipedia, and the aquatic carnivores CANIFORMIA.
D005289	Ferrets	Semidomesticated variety of European polecat much used for hunting RODENTS and/or RABBITS and as a laboratory animal. It is in the subfamily Mustelinae, family MUSTELIDAE.	Domestic Polecat,Domestic Polecats,European Polecat,European Polecats,Ferret,Mustela putorius,Mustela putorius furo,Polecat, Domestic,Polecat, European,Polecats, Domestic,Polecats, European