Biomaterial Database

Membrane potential drives organic cation transport into teleost renal proximal tubules. 1988

P M Smith, and J B Pritchard, and D S Miller

Laboratory of Pharmacology, National Institute of Environmental Health Sciences, Research Triangle Park 27709.

The relationship between organic cation uptake and basolateral membrane potential was studied in renal tubules from two marine teleost fish, Southern flounder (Paralicthys lethostigma) and killifish (Fundulus heteroclitis). Carrier-mediated uptake of the model organic cation, tetraethylammonium (TEA), increased when K+ was changed from 2.5 to 0.2 mM and decreased when medium K+ was increased to 20 mM. Uptake was also reduced by the K+ channel blocker barium (1 mM). Furthermore, basolateral membrane potential hyperpolarized 15-25 mV in low-K+ medium and depolarized 30-40 mV in high-K+ medium. Barium also depolarized. Finally, basolateral membrane potential was depolarized in a concentration-dependent manner by addition of 100-500 microM TEA or Darstine. Thus treatments that hyperpolarize the basolateral membrane potential increase carrier-mediated TEA uptake, whereas those that depolarize basolateral membrane potential reduce uptake. Furthermore, organic cation transport into tubular cells involves the net influx of positive charge. Together, these findings support the argument that carrier-mediated organic cation uptake at the basolateral membrane is a potential-driven, electrogenic process.

UI	MeSH Term	Description	Entries
D007687	Kidney Tubules, Proximal	The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.	Proximal Kidney Tubule,Proximal Renal Tubule,Kidney Tubule, Proximal,Proximal Kidney Tubules,Proximal Renal Tubules,Renal Tubule, Proximal,Renal Tubules, Proximal,Tubule, Proximal Kidney,Tubule, Proximal Renal,Tubules, Proximal Kidney,Tubules, Proximal Renal
D007700	Kinetics	The rate dynamics in chemical or physical systems.
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
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.
D002412	Cations	Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.	Cation
D005432	Flounder	Common name for two families of FLATFISHES belonging to the order Pleuronectiformes: left-eye flounders (Bothidae) and right-eye flounders (Pleuronectidae). The latter is more commonly used in research.	Plaice,Platichthys,Pleuronectes,Pseudopleuronectes,Halibut,Pleuronectes platessa,Flounders
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
D001692	Biological Transport	The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.	Transport, Biological,Biologic Transport,Transport, Biologic
D013757	Tetraethylammonium Compounds	Quaternary ammonium compounds that consist of an ammonium cation where the central nitrogen atom is bonded to four ethyl groups.	Tetramon,Tetrylammonium,Compounds, Tetraethylammonium
D019789	Tetraethylammonium	A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)	Tetraethylammonium Chloride,Tetraethylammonium Ion,Tetraethylammonium Bromide,Tetraethylammonium Hydroxide,Tetraethylammonium Iodide,Bromide, Tetraethylammonium,Chloride, Tetraethylammonium,Hydroxide, Tetraethylammonium,Iodide, Tetraethylammonium,Ion, Tetraethylammonium