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Titolo:
Hypertonicity stimulates Cl- transport in the intestine of fresh water acclimated EEL, Anguilla anguilla.
Autore:
Lionetto, MG; Giordano, ME; Nicolardi, G; Schettino, T;
Indirizzi:
Univ Lecce, Dipartimento Biol, Lab Anat Umana, I-73100 Lecce, Italy Univ Lecce Lecce Italy I-73100 iol, Lab Anat Umana, I-73100 Lecce, Italy Univ Lecce, Lab Fisiol Gen & Ambientale, I-73100 Lecce, Italy Univ Lecce Lecce Italy I-73100 ol Gen & Ambientale, I-73100 Lecce, Italy
Titolo Testata:
CELLULAR PHYSIOLOGY AND BIOCHEMISTRY
fascicolo: 1, volume: 11, anno: 2001,
pagine: 41 - 54
SICI:
1015-8987(2001)11:1<41:HSCTIT>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHLORIDE CELL; FUNDULUS-HETEROCLITUS; BASOLATERAL MEMBRANE; LUMINAL MEMBRANE; NA+/H+ EXCHANGE; PH REGULATION; HIGH SALINITY; ADAPTED EEL; K-ATPASE; NA;
Keywords:
short circuit current; Cl- absorption; cell volume regulation; Na+-K+-2Cl(-) cotransport;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Schettino, T Univ Lecce, Dipartimento Biol, Lab Anat Umana, Via Provinciale Lecce Monteroni, I-73100 Lecce, Italy Univ Lecce Via Provinciale Lecce Monteroni Lecce Italy I-73100
Citazione:
M.G. Lionetto et al., "Hypertonicity stimulates Cl- transport in the intestine of fresh water acclimated EEL, Anguilla anguilla.", CELL PHYS B, 11(1), 2001, pp. 41-54

Abstract

Eel intestinal epithelium when bathed symmetrically with normal Ringer solution develops a net Cl- current (short circuit current, Isc) giving rise to a negative transepithelial potential (Vt) at the basolateral side of the epithelium, lower in fresh-water (FW)-acclimated animals with respect to sea-water (SW). The aim of the present work was to study the cell response tohypertonic stress of FW eel intestinal epithelium in relation to Cl- absorption. The hypertonicity of the external bathing solutions produced first atransient increase of Vt and Isc, then followed (after 10-15min) by a gradual and sustained increase which reached the maximum value after 40-60 min. The morphometric analysis of the intestine revealed the shrinkage of the cells after 5 min hypertonicity exposure, and then a regulatory volume increase (RVI) response, which parallels the gradual and sustained increase in the electrophysiological parameters. This last phase is inhibited by drugs known to block Cl- absorption in eel intestine, such as luminal bumetanide (10 muM), specific inhibitor of Na+-K+-2Cl(-) cotransport, or basolateral NPPB (0.5 mM), dichloro-DPC (0.5 mM), inhibitors of basolateral Cl- conductance. Serosal dimethyl-amiloride (100 muM), specific inhibitor of the Na+/H+ antiport, was ineffective on the hyperosmotic response. Bicarbonate revealed a crucial role as a modulator of hypertonicity response, since in bicarbonate-free conditions or in the presence of serosal 0.25mM SITS, blocker of HCO3- transport systems, the Isc response to hypertonicity was lost. In nominally Ca2+-free conditions the Isc response to hypertonicity was abolished. The same results were obtained by bilateral additionof 100 muM verapamil or 50 muM nifedipine or 1 mM lanthanum, known Ca2+ channel blockers, indicating that extracellular Ca2+ plays a key role for theactivation of Cl- current in the response to hypertonic stress. The data show that in the eel intestinal epithelium the hypertonicity of the external medium affects cell volume which in turn might represent the signal to increase the rate of Cl- transport. This response is sustained by the activation of the luminal Na+-K+-2Cl(-) cotransporter and the functionality of basolateral Cl- channels. Copyright (C) 2001 S. Karger AG, Basel.

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Documento generato il 29/02/20 alle ore 14:25:10