Impairment of Ca release from mammalian ventricular sarcoplasmic reticulum by the calcium channel agonist Bay K 8644. 1988

L V Hryshko, and D Bose
Department of Pharmacology & Therapeutics, University of Manitoba, Faculty of Medicine, Winnipeg, Canada.

Positive inotropic concentration of the Ca-channel agonist, Bay K 8644, depressed contraction of canine right ventricular trabecula immediately after a rest period of 8 min, without decreasing action potential plateau amplitude. In contrast, high external Ca and ouabagenin caused only a slight decrease in post-rest contraction. Bay K 8644-induced post-rest depression was inversely related to the extracellular Ca concentration. Hence it could not be due to cellular Ca overload. Since post-rest potentiation is due to increased contribution of Ca from the sarcoplasmic reticulum, these results suggest that Bay K 8644 decrease the amount of releasable Ca from this structure during rest.

UI MeSH Term Description Entries
D008297 Male Males
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
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
D002120 Calcium Channel Agonists Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in VASCULAR SMOOTH MUSCLE and/or CARDIAC MUSCLE cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture. Calcium Channel Activators,Calcium Channel Agonists, Exogenous,Calcium Channel Agonist,Exogenous Calcium Channel Agonists,Activators, Calcium Channel,Agonist, Calcium Channel,Agonists, Calcium Channel,Channel Activators, Calcium,Channel Agonist, Calcium,Channel Agonists, Calcium
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
D005260 Female Females
D006352 Heart Ventricles The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation. Cardiac Ventricle,Cardiac Ventricles,Heart Ventricle,Left Ventricle,Right Ventricle,Left Ventricles,Right Ventricles,Ventricle, Cardiac,Ventricle, Heart,Ventricle, Left,Ventricle, Right,Ventricles, Cardiac,Ventricles, Heart,Ventricles, Left,Ventricles, Right
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
D001498 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester A dihydropyridine derivative, which, in contrast to NIFEDIPINE, functions as a calcium channel agonist. The compound facilitates Ca2+ influx through partially activated voltage-dependent Ca2+ channels, thereby causing vasoconstrictor and positive inotropic effects. It is used primarily as a research tool. BK-8644,Bay R5417,Bay-K-8644,Bay-K-8644, (+)-Isomer,Bay-K-8644, (+-)-Isomer,Bay-K-8644, (-)-Isomer,Bay-K8644,Bay-R-5417,BK 8644,BK8644,Bay K 8644,Bay K8644,Bay R 5417,BayK8644,BayR5417,R5417, Bay
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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