Biomaterial Database

Effects of (+) and (-) enantiomers of calcium channel agonist, Bay K 8644, on mechanical and electrical responses of frog skeletal muscle. 2000

M Oz, and Y Tchugunova, and M Dinç

Loeb Research Institute, Ottawa Hospital, ON, Canada. moz@lri.ca

The effects of (+) and (-) enantiomers of Bay K 8644, a Ca2+ channel agonist, on the mechanical and electrical properties of frog skeletal muscle fibers were investigated. In the concentration range of 10(-6) to 10(-5) M, both (+) and (-) enantiomers of Bay K 8644 significantly increased the maximum amplitudes of twitch responses. Both (+) and (-) enantiomers of Bay K 8644, at higher concentrations such as 10(-4) M, greatly depressed the amplitudes of twitches. Potentiating and depressing effects of (-) enantiomer of Bay K 8644 on twitch responses were significantly greater than those of the (+) enantiomer. At all concentrations used, both (+) and (-) enantiomers of Bay K 8644 significantly decreased the area under the tetanic force x time curve. In intracellular recordings, it was found that the depressing effects of both (+) and (-)-Bay K 8644 on tetanic contractions and twitch responses were due to the inhibition of action potentials. The inhibitory effect of (-) enantiomer of Bay K 8644 on action potentials also was significantly greater than that of the (+) enantiomer. In conclusion, present results suggest that, in contrast with cardiac muscle fibers, (+) and (-) enantiomers of Bay K 8644 have similar inhibitory effects on the electrical and mechanical properties of frog skeletal muscle fibers.

UI	MeSH Term	Description	Entries
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D011894	Rana pipiens	A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.	Frog, Leopard,Leopard Frog,Lithobates pipiens,Frogs, Leopard,Leopard Frogs
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
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential
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
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D018482	Muscle, Skeletal	A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.	Anterior Tibial Muscle,Gastrocnemius Muscle,Muscle, Voluntary,Plantaris Muscle,Skeletal Muscle,Soleus Muscle,Muscle, Anterior Tibial,Muscle, Gastrocnemius,Muscle, Plantaris,Muscle, Soleus,Muscles, Skeletal,Muscles, Voluntary,Skeletal Muscles,Tibial Muscle, Anterior,Voluntary Muscle,Voluntary Muscles