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Titolo:
Spontaneous water secretion in T84 cells: effects of STa enterotoxin, bumetanide, VIP, forskolin, and A-23187
Autore:
Toriano, R; Kierbel, A; Ramirez, MA; Malnic, G; Parisi, M;
Indirizzi:
Univ Buenos Aires, Fac Med, Dept Fisiol, Lab Biomembranes, RA-1453 Buenos Aires, DF, Argentina Univ Buenos Aires Buenos Aires DF Argentina RA-1453 Aires, DF, Argentina Univ Sao Paulo, Inst Ciencias Biomed, Dept Fisiol & Biofis, BR-05508 Sao Paulo, Brazil Univ Sao Paulo Sao Paulo Brazil BR-05508 fis, BR-05508 Sao Paulo, Brazil
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
fascicolo: 3, volume: 281, anno: 2001,
pagine: G816 - G822
SICI:
0193-1857(200109)281:3<G816:SWSITC>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHLORIDE SECRETION; EPITHELIAL-CELLS; PROTEIN-KINASE; LINE; CL; EXPRESSION; CHANNELS; COTRANSPORTER; MECHANISM; CAMP;
Keywords:
water-ion permeability; chloride secretion; aquaporins; water-solute cotransport; heat-stable enterotoxin; vasoactive intestinal peptide;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Parisi, M Univ Buenos Aires, Fac Med, Dept Fisiol, Lab Biomembranes, CC 128,Suc 53B,RA-1453 Buenos Aires, DF, Argentina Univ Buenos Aires CC 128,Suc 53B Buenos Aires DF Argentina RA-1453
Citazione:
R. Toriano et al., "Spontaneous water secretion in T84 cells: effects of STa enterotoxin, bumetanide, VIP, forskolin, and A-23187", AM J P-GAST, 281(3), 2001, pp. G816-G822

Abstract

The regulated Cl- secretory apparatus of T84 cells responds to several pharmacological agents via different second messengers (Ca2+, cAMP, cGMP). However, information about water movements in T84 cells has not been available. In the absence of osmotic or chemical gradient, we observed a net secretory transepithelial volume flux (J(w), = -0.16 +/-0.02 mu1.min(-1).cm(-2)) in parallel with moderate short-circuit current values (I-sc = 1.55 +/-0.23 muA/cm(2)). The secretory J(w) reversibly reverted to an absorptive value when A-23187 was added to the serosal bath. Vasoactive intestinal polypeptide increased I-sc, but, unexpectedly, J(w) was not affected. Bumetanide, an inhibitor of basolateral Na+-K+-2Cl(-) cotransporter, completely blocked secretory J(w) with no change in I-sc. Conversely, serosal forskolin increased I-sc, but J(w) switched from secretory to absorptive values. Escherichia coli heat-stable enterotoxin increased secretory J(w) and I-sc. No difference between the absorptive and secretory unidirectional Cl- fluxes was observed in basal conditions, but after STa stimulation, a significant net secretory Cl- flux developed. We conclude that, under these conditions, the presence of secretory or absorptive J(w) values cannot be shown by I-sc and ionflux studies. Furthermore, RT-PCR experiments indicate that aquaporins were not expressed in T84 cells. The molecular pathway for water secretion appears to be transcellular, moving through the lipid bilayer or, as recently proposed, through water-solute cotransporters.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/04/20 alle ore 09:45:00