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Titolo:
Intracellular pH regulation in colonocytes of rat proximal colon
Autore:
Vaneckova, I; Vylitova-Pletichova, M; Beskid, S; Zicha, J; Pacha, J;
Indirizzi:
Acad Sci Czech Republ, Inst Physiol, CR-14220 Prague 4KRC, Czech Republic Acad Sci Czech Republ Prague Czech Republic 4KRC ue 4KRC, Czech Republic Charles Univ, Fac Med 2, Dept Physiol, Prague, Czech Republic Charles Univ Prague Czech Republic Dept Physiol, Prague, Czech Republic
Titolo Testata:
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
fascicolo: 2-3, volume: 1536, anno: 2001,
pagine: 103 - 115
SICI:
0925-4439(20010531)1536:2-3<103:IPRICO>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHAIN FATTY-ACIDS; DISTAL COLON; NA+/H+ EXCHANGE; CRYPT CELLS; TRANSPORT; COTRANSPORTER; ALDOSTERONE; PROPIONATE; ATPASE; CHICK;
Keywords:
colon; sodium/hydrogen exchange; potassium-dependent intracellular pH regulation; chlorine/bicarbonate exchange; butyrate;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Pacha, J Acad Sci Czech Republ, Inst Physiol, Videnska 1083, CR-14220 Prague 4KRC, Czech Republic Acad Sci Czech Republ Videnska 1083 Prague Czech Republic 4KRC c
Citazione:
I. Vaneckova et al., "Intracellular pH regulation in colonocytes of rat proximal colon", BBA-MOL BAS, 1536(2-3), 2001, pp. 103-115

Abstract

The regulation of intracellular pH (pH(i)) in colonocytes of the rat proximal colon has been investigated using the pH-sensitive dye BCECF and compared with the regulation of pH(i) in the colonocytes of the distal colon. Theproximal colonocytes in a HEPES-buffered solution had pH(i) = 7.24 +/- 0.04 and removal of extracellular Na+ lowered pH(i) by 0.24 pH units. Acid-loaded colonocytes by an NH3/NH4+ prepulse exhibited a spontaneous recovery that was partially Na+- dependent and could be inhibited by ethylisopropylamiloride (EIPA). The Na+-dependent recovery rate was enhanced by increasing the extracellular Na+ concentration and was further stimulated by aldosterone. In an Na+- and K+-free HEPES-buffered solution, the recovery rate from the acid load was significantly stimulated by addition of K+ and this K+-dependent recovery was partially blocked by ouabain. The intrinsic buffer capacity of proximal colonocytes at physiological pH(i) exhibited a nearly 2-fold higher value than in distal colonocytes. Butyrate induced immediate colonocyte acidification that was smaller in proximal than in distal colonocytes. This acidification was followed by a recovery phase that was both EIPA-sensitive and -insensitive and was similar in both groups of colonocytes. Ina HCO3-/CO2-containing solution, pHi of the proximal colonocytes was 7.20 /- 0.04. Removal of external Cl- caused alkalinization that was inhibited by DIDS. The recovery from an alkaline load induced by removal of HCO3-/CO2from the medium was Cl--dependent, Na+-independent and blocked by DIDS. Recovery from an acid load in EIPA-containing Na+-free HCO3-/CO2-containing solution was accelerated by addition of Na+. Removal of Cl- inhibited the effect of Na+. In summary, the freshly isolated proximal colonocytes of rats express Na+/H+ exchanger, H+/K+ exchanger (H+-K+)-ATPase) and Na+-dependentCl-/HCO3- exchanger that contribute to acid extrusion and Na+-independent Cl-/HCO3- exchanger contributing to alkali extrusion. All of these are likely involved in the regulation of pH(i) in vivo. Proximal colonocytes are able to maintain a more stable pH(i) than distal cells, which seems to be facilitated by their higher intrinsic buffer capacity. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/01/20 alle ore 15:28:46