Biomaterial Database

Activation of the Na pump current by external K and Cs ions in cardioballs from sheep Purkinje fibres. 1989

H G Glitsch, and T Krahn, and F Verdonck

Department of Cell Physiology, Ruhr-University Bochum, Federal Republic of Germany.

The Na pump current (Ip) was measured at 30-33 degrees C as a function of the extracellular K+ or Cs+ concentrations ([K]o; [Cs]o) by means of whole cell recording from cardioballs isolated from sheep Purkinje fibres. The results show that the magnitude of Ip is an s-shaped, saturating function of [K]o or [Cs]o, respectively. Half maximal Ip activation occurs at 1.2 mM Ko or 3.2 mM Cso (clamp potential: -20 mV). These values are appreciably lower than earlier measurements on sheep Purkinje fibres indicated. The Hill coefficients for Ip activation by external K+ or Cs+ were calculated to be 1.94 and 1.73, respectively. The numbers suggest that Ip activation requires at least two external activator cations.

UI	MeSH Term	Description	Entries
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011690	Purkinje Fibers	Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.	Purkinje Fiber,Fiber, Purkinje,Fibers, Purkinje
D002478	Cells, Cultured	Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.	Cultured Cells,Cell, Cultured,Cultured Cell
D002586	Cesium	A member of the alkali metals. It has an atomic symbol Cs, atomic number 55, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.	Caesium,Caesium-133,Cesium-133,Caesium 133,Cesium 133
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D006329	Heart Conduction System	An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.	Conduction System, Heart,Conduction Systems, Heart,Heart Conduction Systems,System, Heart Conduction,Systems, Heart Conduction
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
D012756	Sheep	Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.	Ovis,Sheep, Dall,Dall Sheep,Ovis dalli
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23