Biomaterial Database

Palmitoyl-L-carnitine acts like ouabain on voltage, current, and contraction in guinea pig ventricular cells. 1995

J B Shen, and A J Pappano

Department of Pharmacology, University of Connecticut Health Center, Farmington 06032.

We previously showed that palmitoyl-L-carnitine (L-PC) inhibits the Na/K pump current (INa/K). In the present report, we test the hypothesis that L-PC, like ouabain, should increase myocyte shortening. Membrane potentials or ionic currents were recorded simultaneously with cell shortening in single guinea pig ventricular myocytes at room temperature (22 degrees C). Like ouabain, L-PC (1 microM) reversibly depolarized the resting membrane, decreased action potential duration, and increased the amplitude of myocyte contractions. Neither L-PC nor ouabain had a significant effect on Ca current (ICa). When L-PC increased cell shortening during ramp voltage clamp, membrane current shifted inward at voltages negative to -20 mV and shifted outward at more positive voltages. Similar to toxic concentrations of ouabain, L-PC induced transient inward currents and aftercontractions. At concentrations that inhibit INa/K, L-PC acted like ouabain to produce characteristic effects on membrane potentials, currents, and cell contractions that were unrelated to significant changes in ICa. L-PC reduces surface negative charge of erythrocytes and myocytes (C. Gruver and A. J. Pappano, J. Mol. Cell. Cardiol. 25: 1275-1284, 1993), and we speculate that L-PC inhibits INa/K by this mechanism.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
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
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D010172	Palmitoylcarnitine	A long-chain fatty acid ester of carnitine which facilitates the transfer of long-chain fatty acids from cytoplasm into mitochondria during the oxidation of fatty acids.	Palmitylcarnitine,Hexadecanoylcarnitine
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
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
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.
D005260	Female		Females
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea