Biomaterial Database

Pharmacological studies of charge movement in frog skeletal muscle. 1983

C S Hui

Charge movements in frog twitch fibres were studied using the three-microelectrode voltage-clamp technique. In a solution made moderately hypertonic with 350 mM-sucrose, fibre contraction was effectively blocked and a secondary hump appeared in the decay phase of the 'on' part of charge movement. At small depolarizations, the hump (Q gamma) is small and slow. As depolarization is increased, Q gamma becomes larger in magnitude and faster in kinetics until it merges with the main part of charge movement (Q beta). As the fibre is perfused extracellularly with a test solution saturated with dantrolene sodium, Q gamma disappears in about 30 min whereas the kinetics of Q beta are slowed down. After equilibration in the dantrolene sodium solution, the total moveable charge is reduced by about 20%, which could very well be the charge carried by Q gamma. Tetracaine also suppresses Q gamma but does not seem to have any effect on the kinetics of Q beta. The suppression of Q gamma appears to be dose-dependent, with complete abolition occurring at about 4 mM-tetracaine. Dissection of charge movement with tetracaine indicates that Q gamma might be bell-shaped and capacitive in nature. Q beta and Q gamma might be two distinct species of charge and Q gamma would probably be more closely associated with calcium release from the sarcoplasmic reticulum.

UI	MeSH Term	Description	Entries
D006982	Hypertonic Solutions	Solutions that have a greater osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.	Hypertonic Solution,Solution, Hypertonic,Solutions, Hypertonic
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
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
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D011896	Rana temporaria	A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.	European Common Frog,Frog, Common European,Common European Frog,Common Frog, European,European Frog, Common,Frog, European Common
D003620	Dantrolene	Skeletal muscle relaxant that acts by interfering with excitation-contraction coupling in the muscle fiber. It is used in spasticity and other neuromuscular abnormalities. Although the mechanism of action is probably not central, dantrolene is usually grouped with the central muscle relaxants.	Dantrium,Dantrolene Sodium,Sodium, Dantrolene
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
D013748	Tetracaine	A potent local anesthetic of the ester type used for surface and spinal anesthesia.	Tetrakain,Amethocaine,Ametop,Dicaine,Pantocaine,Pontocaine,Tetracaine Monohydrochloride,Tetrracaine Hydrochloride,Hydrochloride, Tetrracaine