title: Modulation of NaCl absorption by [HCO(3)(-)] in the marine teleost intestine is mediated by soluble adenylyl cyclase.
abstract: Intestinal HCO(3)(-) secretion and NaCl absorption are essential for counteracting dehydration in marine teleost fish. We investigated how these two processes are coordinated in toadfish. HCO(3)(-) stimulated a luminal positive short-circuit current (I(sc)) in intestine mounted in Ussing chamber, bathed with the same saline solution on the external and internal sides of the epithelium. The I(sc) increased proportionally to the [HCO(3)(-)] in the bath up to 80 mM NaHCO(3), and it did not occur when NaHCO(3) was replaced with Na(+)-gluconate or with NaHCO(3) in Cl(-)-free saline. HCO(3)(-) (20 mM) induced a approximately 2.5-fold stimulation of I(sc), and this [HCO(3)(-)] was used in all subsequent experiments. The HCO(3)(-)-stimulated I(sc) was prevented or abolished by apical application of 10 muM bumetanide (a specific inhibitor of NKCC) and by 30 microM 4-catechol estrogen [CE; an inhibitor of soluble adenylyl cyclase (sAC)]. The inhibitory effects of bumetanide and CE were not additive. The HCO(3)(-)-stimulated I(sc) was prevented by apical bafilomycin (1 microM) and etoxolamide (1 mM), indicating involvement of V-H(+)-ATPase and carbonic anhydrases, respectively. Immunohistochemistry and Western blot analysis confirmed the presence of an NKCC2-like protein in the apical membrane and subapical area of epithelial intestinal cells, of Na(+)/K(+)-ATPase in basolateral membranes, and of an sAC-like protein in the cytoplasm. We propose that sAC regulates NKCC activity in response to luminal HCO(3)(-), and that V-H(+)-ATPase and intracellular carbonic anhydrase are essential for transducing luminal HCO(3)(-) into the cell by CO(2)/HCO(3)(-) hydration/dehydration. This mechanism putatively coordinates HCO(3)(-) secretion with NaCl and water absorption in toadfish intestine.
authors.affiliation: Department of Pharmacology, Weill Cornell Medical College, New York, New York 10065, USA. mat2031@med.cornell.edu
authors.forename: Martin
authors.initials: M
authors.lastname: Tresguerres
authors.forename: Lonny R
authors.initials: LR
authors.lastname: Levin
authors.forename: Jochen
authors.initials: J
authors.lastname: Buck
authors.forename: Martin
authors.initials: M
authors.lastname: Grosell
mesh_terms: D000042:Absorption; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D024541:Batrachoidiformes / Q000502:physiology*; D002034:Bumetanide / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000502:physiology*; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D002034:Bumetanide; D012965:Sodium Chloride; D002256:Carbonic Anhydrases; D000262:Adenylyl Cyclases
references.citation: Am J Physiol. 1984 Jan;246(1 Pt 1):C167-71
references.pmid: 6320655
references.citation: J Exp Biol. 2009 Jun;212(Pt 11):1684-96
references.pmid: 19448078
references.citation: Nature. 1970 Aug 15;227(5259):680-5
references.pmid: 5432063
references.citation: J Exp Biol. 2002 Mar;205(Pt 6):745-58
references.pmid: 11914383
references.citation: Am J Physiol Renal Physiol. 2003 Jun;284(6):F1145-54
references.pmid: 12604467
references.citation: Pflugers Arch. 2009 May;458(1):61-76
references.pmid: 18982348
references.citation: Trends Endocrinol Metab. 2001 Oct;12(8):366-70
references.pmid: 11551811
references.citation: J Biol Chem. 2003 Dec 5;278(49):49523-9
references.pmid: 14512417
references.citation: J Biol Chem. 2009 Feb 27;284(9):5774-83
references.pmid: 19126549
references.citation: Am J Physiol. 1985 Nov;249(5 Pt 1):C531-4
references.pmid: 2998198
references.citation: J Exp Biol. 2010 Feb 1;213(3):459-68
references.pmid: 20086131
references.citation: Dev Cell. 2005 Aug;9(2):249-59
references.pmid: 16054031
references.citation: Science. 2000 Jul 28;289(5479):625-8
references.pmid: 10915626
references.citation: Am J Physiol. 1982 Jul;243(1):G60-8
references.pmid: 6979941
references.citation: PLoS One. 2008 Sep 22;3(9):e3251
references.pmid: 18806876
references.citation: Am J Physiol Regul Integr Comp Physiol. 2008 Nov;295(5):R1660-70
references.pmid: 18799636
references.citation: J Exp Biol. 2007 Mar;210(Pt 6):1015-24
references.pmid: 17337714
references.citation: Nature. 1982 Nov 25;300(5890):351-3
references.pmid: 7144890
references.citation: J Exp Biol. 2005 Jan;208(Pt 2):345-54
references.pmid: 15634853
references.citation: Scand J Gastroenterol. 1989 Jan;24(1):1-8
references.pmid: 2928719
references.citation: J Membr Biol. 1980 Aug 7;55(3):157-63
references.pmid: 6251225
references.citation: Am J Physiol Regul Integr Comp Physiol. 2008 Mar;294(3):R1033-43
references.pmid: 18184765
references.citation: Proc Natl Acad Sci U S A. 1999 Jan 5;96(1):79-84
references.pmid: 9874775
references.citation: Comp Biochem Physiol A Comp Physiol. 1973 Dec 1;46(4):639-45
references.pmid: 4148159
references.citation: Proc Natl Acad Sci U S A. 1994 Mar 15;91(6):2201-5
references.pmid: 8134373
references.citation: Science. 2009 Jan 16;323(5912):359-62
references.pmid: 19150840
references.citation: Am J Physiol. 1998 Dec;275(6):F885-93
references.pmid: 9843905
references.citation: Methods Enzymol. 1990;192:746-53
references.pmid: 2074816
references.citation: Physiol Rev. 1985 Jul;65(3):760-97
references.pmid: 2409564
references.citation: Kidney Int. 1996 Jan;49(1):40-7
references.pmid: 8770947
references.citation: Comp Biochem Physiol B Biochem Mol Biol. 2008 Jan;149(1):63-73
references.pmid: 17950642
references.citation: Am J Physiol Renal Physiol. 2008 Oct;295(4):F877-87
references.pmid: 18684888
references.citation: Am J Physiol. 1993 Mar;264(3 Pt 1):G569-75
references.pmid: 8384799
references.citation: J Biol Chem. 2003 Jul 18;278(29):26946-51
references.pmid: 12732642
references.citation: Comp Biochem Physiol A Mol Integr Physiol. 2007 Sep;148(1):14-22
references.pmid: 17142078
references.citation: J Membr Biol. 1978 Jul 5;41(3):265-93
references.pmid: 671526
references.citation: Nature. 1968 Apr 20;218(5138):267-8
references.pmid: 5648223
references.citation: Proc Natl Acad Sci U S A. 1994 May 10;91(10):4544-8
references.pmid: 7514306
references.citation: J Biol Chem. 2005 Sep 9;280(36):31754-9
references.pmid: 16002394
references.citation: J Gen Physiol. 2008 Sep;132(3):329-38
references.pmid: 18695009
references.citation: Comp Biochem Physiol A Comp Physiol. 1975 Sep 1;52(1):229-33
references.pmid: 240556
references.citation: Gen Comp Endocrinol. 2007 Jun-Jul;152(2-3):339-51
references.pmid: 17561018
references.citation: Am J Physiol. 1988 Aug;255(2 Pt 1):G247-52
references.pmid: 3407779
references.citation: Nat Struct Mol Biol. 2005 Jan;12(1):32-7
references.pmid: 15619637
references.citation: Am J Physiol. 1996 Sep;271(3 Pt 2):F619-28
references.pmid: 8853424
references.citation: Biochim Biophys Acta. 2002 Nov 13;1566(1-2):182-93
references.pmid: 12421549
references.citation: Am J Physiol Cell Physiol. 2005 Jun;288(6):C1305-16
references.pmid: 15659711
references.citation: Am J Physiol. 1989 Jan;256(1 Pt 1):C142-6
references.pmid: 2536226
references.citation: Am J Physiol. 1995 Dec;269(6 Pt 1):C1496-505
references.pmid: 8572179
references.citation: J Membr Biol. 2006 Apr;210(3):161-72
references.pmid: 16909338
references.citation: J Cell Biol. 2004 Feb 16;164(4):527-34
references.pmid: 14769862
references.citation: J Membr Biol. 1987;96(1):11-8
references.pmid: 3585983
references.citation: J Membr Biol. 1979 Apr 12;46(1):27-39
references.pmid: 221659
references.citation: J Exp Biol. 2009 Jun;212(Pt 12):1940-8
references.pmid: 19483012
references.citation: Comp Biochem Physiol A Mol Integr Physiol. 2006 Nov;145(3):312-21
references.pmid: 16945564
references.citation: Biochem Cell Biol. 2002;80(5):483-97
references.pmid: 12440690
references.citation: J Biol Chem. 1995 Jul 28;270(30):17977-85
references.pmid: 7629105
references.citation: Proc Natl Acad Sci U S A. 2010 Jan 5;107(1):442-7
references.pmid: 20018667
references.citation: Am J Physiol Renal Physiol. 2006 Mar;290(3):F608-16
references.pmid: 16144963
references.citation: J Exp Biol. 2006 Dec;209(Pt 24):4908-22
references.pmid: 17142680
references.citation: J Exp Biol. 2006 Aug;209(Pt 15):2813-27
references.pmid: 16857865
references.citation: Comp Biochem Physiol A Mol Integr Physiol. 2003 Apr;134(4):763-76
references.pmid: 12814785
references.citation: Am J Physiol. 1984 Jun;246(6 Pt 2):F946-51
references.pmid: 6742138
references.citation: J Biol Chem. 2009 Sep 11;284(37):24965-71
references.pmid: 19592485
references.citation: Am J Physiol Regul Integr Comp Physiol. 2008 Apr;294(4):R1402-12
references.pmid: 18216137