Biomaterial Database

Conductive pathways for HCO3- in basolateral membrane of salamander intestinal cells. 1989

J F White

Department of Physiology, Emory University, Atlanta, Georgia 30322.

To understand the route of HCO3- exit across the basolateral membrane of Amphiuma small intestinal cells during active H+ secretion the influence of bath HCO3- on serosal membrane potential (Vs) was measured using conventional microelectrodes. The villus sheet preparation was used, which allowed direct access to the basal membrane for microelectrode impalement. When tissues were incubated in Cl(-)-free (SO2-4 based) medium, Vs averaged -85.8 mV. Elevation of serosal bath [HCO3-] at constant CO2 increased Vs; reduction of the [HCO3-] reduced Vs and increased the fractional resistance of the serosal membrane. When serosal bath HCO3- and CO2 were completely replaced, Vs was -44.8 mV. The serosal membrane was also depolarized on complete replacement of medium HCO3- and CO2 when bath pH was buffered with phosphate. 4,4'-Dinitro-2,2'-stilbene disulfonate (DNDS) and acetazolamide blocked the decline in Vs produced by lowering serosal medium [HCO3-]. Replacement of serosal Na+ reduced Vs 32.7 mV. DNDS blocked this response. It is concluded that a Na+-dependent, stilbene-sensitive HCO3- exit pathway resides in the basolateral membrane of the intestinal cells. Possibly there is also a parallel, conductive pathway for HCO3-.

UI	MeSH Term	Description	Entries
D007413	Intestinal Mucosa	Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.	Intestinal Epithelium,Intestinal Glands,Epithelium, Intestinal,Gland, Intestinal,Glands, Intestinal,Intestinal Gland,Mucosa, Intestinal
D007421	Intestine, Small	The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.	Small Intestine,Intestines, Small,Small Intestines
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
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
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
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D000086	Acetazolamide	One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)	Acetadiazol,Acetazolam,Acetazolamide Sodium, (Sterile),Acetazolamide, Monosodium Salt,Ak-Zol,Apo-Acetazolamide,Diacarb,Diamox,Diuramide,Défiltran,Edemox,Glauconox,Glaupax,Huma-Zolamide,Ak Zol,AkZol,Apo Acetazolamide,ApoAcetazolamide,Huma Zolamide,HumaZolamide
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