Biomaterial Database

Isoproterenol directly stimulates the Na+-K+ pump in isolated cardiac myocytes. 1986

M Désilets, and C M Baumgarten

It has been suggested that catecholamines directly stimulate Na+-K+ pump activity in heart; however, these studies on multicellular preparations are confounded by possible alterations of extracellular K+ concentrations ([K+]o). We reinvestigated this problem by studying the effect of the beta-agonist isoproterenol (Iso) on intracellular Na+ activity (aiNa) in ventricular myocytes enzymatically isolated from rabbit heart. In 5 mM [K+]o, 0.1 microM Iso caused a 24.6 +/- 2.0% decrease of aiNa. Exposure to 1 microM Iso only caused a small additional decrease (27.8 +/- 2.4%), while a diminution of aiNa could already be noticed with only 10 nM Iso (12.8 +/- 1.9% diminution). Myocytes superfused with 15 mM [K+]o also exhibited a significant decrease of aiNa (22.9 +/- 3.6%) when exposed to 0.1 microM Iso. These data argue that accumulation of external K+ does not account for the effect of Iso on steady-state aiNa as postulated by Gadsby (Nature Lond. 306: 691-693, 1983). Furthermore, aiNa in myocytes superfused with 1.5 mM [K+]o decreased by only 8.7% on addition of 0.1 microM Iso. The latter observation suggests that the beta-agonist effect on aiNa regulation is directly or indirectly dependent on membrane potential and/or aiNa. Finally, kinetic analysis of the effect of 1 microM Iso on the decrease in aiNa on changing [K+]o from 1.5 to 5 mM demonstrated that the time course of aiNa recovery was accelerated by a factor of 1.9. This readily suggests that active Na+ transport is directly stimulated by Iso. The much greater relative effect of Iso on the time constant than on steady-state aiNa further indicates that Iso may also increase passive Na+ influx.

UI	MeSH Term	Description	Entries
D007545	Isoproterenol	Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.	Isoprenaline,Isopropylarterenol,4-(1-Hydroxy-2-((1-methylethyl)amino)ethyl)-1,2-benzenediol,Euspiran,Isadrin,Isadrine,Isopropyl Noradrenaline,Isopropylnoradrenaline,Isopropylnorepinephrine,Isoproterenol Hydrochloride,Isoproterenol Sulfate,Isuprel,Izadrin,Norisodrine,Novodrin,Hydrochloride, Isoproterenol,Noradrenaline, Isopropyl,Sulfate, Isoproterenol
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008839	Microelectrodes	Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)	Electrodes, Miniaturized,Electrode, Miniaturized,Microelectrode,Miniaturized Electrode,Miniaturized Electrodes
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
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.
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
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
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump
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
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