Biomaterial Database

Beta-adrenergic stimulation of Na+, K+, Cl- cotransport in fetal nonpigmented ciliary epithelial cells. 1996

R B Crook, and K Riese

Department of Opthalmology, University of California, San Francisco 94143, USA.

OBJECTIVE The effects of adrenergic agonists and antagonists on Na+, K+, Cl- cotransport in fetal human nonpigmented ciliary epithelial (NPE) cells were investigated. METHODS 86Rb+ as a marker for K+ was used to study ouabain-insensitive, bumetanide-sensitive 86Rb+ uptake in cultured NPE monolayers. Cyclic adenosine monophosphate (cAMP) formation in NPE cells was determined by radioimmunoassay. RESULTS 1 microM isoproterenol caused a 1.65-fold stimulation in Na+,K+,Cl cotransport measured as bumetanide-sensitive, ouabain-insensitive 86Rb+ uptake. The half-maximal concentration for this effect was 6.4 nM, with maximal stimulation at 100 nM isoproterenol. Epinephrine stimulated Na+, K+, Cl- cotransport similarly to isoproterenol, whereas norepinephrine stimulated at much higher concentrations (half-maximal effective concentration = 1.4 microM). Stimulation of Na+, K+, Cl- cotransport by 1 microM isoproterenol was inhibited completely by the beta 2-adrenergic antagonist ICI-118,551 at 100 nM, with a half-maximal inhibitory concentration of 5 nM. Neither atenolol, a beta 1-specific adrenergic antagonist, prazosin, an alpha 1-adrenergic antagonist, nor yohimbine, an alpha 2-specific antagonist, was as effective. These four antagonists inhibited isoproterenol-stimulated cAMP formation with potencies similar to those observed against stimulated Na+, K+, Cl- cotransport. The hypotensive adrenergic antagonist timolol, propranolol, and betaxolol also inhibited Na+, K+, Cl- cotransport stimulated by isoproterenol in the order timolol > propranolol > betaxolol. Na+, K+, Cl- cotransport could be maintained in a stimulated state for at least 2 hours in the presence of agonist, but activity returned to basal levels within 20 minutes of isoproterenol removal. Adrenergic stimulation of Na+, K+, Cl- cotransport was blocked 80% to 85% by 70 microM H-89, a protein kinase A inhibitor. CONCLUSIONS These data suggest that beta 2-adrenergic receptor activation results in increased cAMP formation and sustained stimulation of Na+, K+, Cl- cotransport in fetal human NPE cells. Protein kinase A activation is required for maximal stimulation of Na+, K+, Cl- cotransport by adrenergic agonists.

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
D010857	Pigment Epithelium of Eye	The layer of pigment-containing epithelial cells in the RETINA; the CILIARY BODY; and the IRIS in the eye.	Eye Pigment Epithelium
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.
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
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D002924	Ciliary Body	A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.	Corpus Ciliare,Corpus Ciliaris,Bodies, Ciliary,Body, Ciliary,Ciliare, Corpus,Ciliares, Corpus,Ciliari, Corpus,Ciliaris, Corpus,Ciliary Bodies,Corpus Ciliares,Corpus Ciliari
D004848	Epithelium	The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body.	Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D005333	Fetus	The unborn young of a viviparous mammal, in the postembryonic period, after the major structures have been outlined. In humans, the unborn young from the end of the eighth week after CONCEPTION until BIRTH, as distinguished from the earlier EMBRYO, MAMMALIAN.	Fetal Structures,Fetal Tissue,Fetuses,Mummified Fetus,Retained Fetus,Fetal Structure,Fetal Tissues,Fetus, Mummified,Fetus, Retained,Structure, Fetal,Structures, Fetal,Tissue, Fetal,Tissues, Fetal
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic