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Titolo:
INTRACELLULAR PH REGULATION OF HUMAN COLONIC CRYPT CELLS
Autore:
TELEKY B; HAMILTON G; COSENTINI E; BISCHOF G; RIEGLER M; KOPERNA T; FEIL W; SCHIESSEL R; WENZL E;
Indirizzi:
UNIV VIENNA,SCH MED,DEPT SURG 1,ALSERSTR 4 A-1090 VIENNA AUSTRIA
Titolo Testata:
Pflugers Archiv
fascicolo: 3-4, volume: 426, anno: 1994,
pagine: 267 - 275
SICI:
0031-6768(1994)426:3-4<267:IPROHC>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTESTINAL ELECTROLYTE TRANSPORT; GLOMERULAR MESANGIAL CELLS; BASOLATERAL MEMBRANE; EPITHELIAL-CELLS; CYTOPLASMIC PH; DIARRHEAL DISEASE; CL-HCO3 EXCHANGE; PROXIMAL TUBULE; GROWTH-FACTORS; OXYNTIC CELLS;
Keywords:
HUMAN ISOLATED COLONOCYTES; PH REGULATION; MICROSPECTROFLUOROMETRY 2',7'-BIS(CARBOXYETHYL)-5(6)-CARBOXYFLUORESCEIN; SODIUM/HYDROGEN EXCHANGER; AMILORIDE; CHLORIDE/BICARBONATE EXCHANGE; SODIUM/BICARBONATE COTRANSPORT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
B. Teleky et al., "INTRACELLULAR PH REGULATION OF HUMAN COLONIC CRYPT CELLS", Pflugers Archiv, 426(3-4), 1994, pp. 267-275

Abstract

In order to investigate the regulation of intracellular pH (pH(i)) infreshly isolated human colonocytes, we have used a newly developed technique for the rapid isolation and covalent attachment of these cellsto glass surfaces and microspectrofluorimetric measurement of the pH-sensitive fluorescence of 2',7'-bis(carboxyethyl)5(6)-carboxyfluorescein (BCECF)-loaded specimens in a perfusion chamber (37 degrees C). In N-2-hydroxyethylpiperazine- N'-2- ethanesulphonic- acid- (HEPES)-buffered Ringer solution (KBS) a baseline pH(i) of 7.35 +/- 0.03 (mean +/- SD; n = 42) was found for human colonocytes and in HBS, NH4Cl-prepulse-induced intracellular acidification in colonocytes is reversed rapidly by the ubiquitous amiloride-sensitive (1 mmol/l) Na+/H+ exchanger. Switching from HBS to HCO,-buffered solution (BBS) led to a transient intracellular acidification (7.29 +/- 0.09), followed by a recovery to a final resting pH(i) of 7.43 +/- 0.03. One-third of the acid extrusion in BBS is amiloridesensitive; the remaining two-thirds are caused bythe dihydroderivative of 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (H,DIDS)-sensitive HCO3--dependent mechanisms. The functional activity of an acid-extruding Na+/HCO3- cotransporter in human colonocytes was observed in response to the reintroduction of Na+ into amiloride-containing Na+/Cl--free BBS. In addition, the mechanism leading toalkalinization (7.56 +/- 0.05) in Cl(-)free BBS was identified as Na+-dependent Cl-/HCO3- exchange, by its H2DIDS sensitivity and the specific requirement for Cl- and Na+. The intrinsic buffering capacity (beta(i)) of the human colonocytes was calculated from pH changes induced by sequential NH4Cl-loading steps during blockage of acid/ base transporters. With beta(i) = 80 mmol.l(-1) pH unit(-1) for the pH interval ranging from 6.9 to 7.1 (n = 8) the colonocytes exhibited a relatively high intrinsic buffering in comparison with other cell types. In conclusion, the freshly isolated human colonocytes express a Na+/ H+ exchanger, a Na+/HCO3- cotransporter and a Na+-dependent CI-M[CO; exchanger,all of them likely to be involved in the regulation of pH homeostasisin vivo in the presence of widely varying extracellular conditions. Maintenance of a stable pH, of human colonocytes seems to be facilitated by a comparatively high Pi at physiological pH values.

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Documento generato il 30/09/20 alle ore 07:29:44