Biomaterial Database

Taurocholate depolarizes rat hepatocytes in primary culture by increasing cell membrane Na+ conductance. 1993

F Wehner

Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany.

Rat hepatocytes in primary culture were impaled with conventional microelectrodes. Addition of 5-100 mumol/l taurocholate led to a slowly developing depolarization that was maximal at 50 mumol/l (10.5 +/- 1.5 mV, n = 15) and not reversible. The effect was Na+ dependent and decreased in cells preincubated with 1 mumol/l taurocholate. Increasing external K+ tenfold depolarized the cells by 12.3 +/- 2.3 mV under control conditions and by 6.3 +/- 1.2 mV with 50 mumol/l taurocholate present (n = 7). Depolarization by 1 mmol/l Ba2+ was 7.6 +/- 0.8 mV and 6.0 +/- 0.7 mV (n = 9) before and after addition of taurocholate, respectively. Cable analysis and Na+ substitution experiments reveal that this apparent decrease in K+ conductance reflects an actual increase in Na+ conductance: in the presence of taurocholate, specific cell membrane resistance decreased from 2.8 to 2.3 k omega x cm2 x Na+ substitution by 95% depolarized cell membranes by 8.9 +/- 2.9 mV (n = 9), probably due to indirect effects on K+ conductance via changes in cell pH. With taurocholate present, the same manoeuvre changed membrane voltages by -0.8 +/- 2.6 mV. When Na+ concentration was restored to 100% from solutions containing 5% Na+, cells hyperpolarized by 3.5 +/- 3.6 mV (n = 7) under control conditions and depolarized by 4.4 +/- 2.9 mV in the presence of taurocholate, respectively. In Cl- substitution experiments, there was no evidence for changes in Cl- conductance by taurocholate. These results show that taurocholate-induced membrane depolarization is due to an increase in Na+ conductance probably via uptake of the bile acid.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
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
D002034	Bumetanide	A sulfamyl diuretic.	Bumedyl,Bumethanide,Bumex,Burinex,Drenural,Fordiuran,Miccil,PF-1593,PF 1593,PF1593
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
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
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.
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
D013656	Taurocholic Acid	The product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic.	Cholyltaurine,Taurine Cholate,Taurocholate,Sodium Taurocholate,Taurocholate Sodium,Taurocholic Acid, (5 alpha)-Isomer,Taurocholic Acid, (7 beta)-Isomer,Taurocholic Acid, Monolithium Salt,Taurocholic Acid, Monosodium Salt,Taurocholate, Sodium