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Titolo:
Free-flow potential profile along rat kidney proximal tubule - Comments (Reprinted from Pflugers. Arch. vol 351,pg 69-83, 1974)
Autore:
Fromter, E; Boulpaep, EL;
Indirizzi:
Max Planck Inst Biophys, D-6000 Frankfurt, Germany Max Planck Inst Biophys Frankfurt Germany D-6000 6000 Frankfurt, Germany
Titolo Testata:
JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY
fascicolo: 10, volume: 12, anno: 2001,
pagine: 2197 - 2206
SICI:
1046-6673(200110)12:10<2197:FPPARK>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Keywords:
renal proximal tubule; transepithelial electrical potential difference microelectrode technique;
Tipo documento:
Reprint
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Citazione:
E. Fromter e E.L. Boulpaep, "Free-flow potential profile along rat kidney proximal tubule - Comments (Reprinted from Pflugers. Arch. vol 351,pg 69-83, 1974)", J AM S NEPH, 12(10), 2001, pp. 2197-2206

Abstract

The transepithelial electrical potential difference across rat renal proximal tubule was reinvestigated, using improved techniques. To diminish tip potential artefacts the microelectrodes were filled with HCO3- Ringer's solution instead of 3 molar KCI. The error of the potential measurements with HCO3- Ringer's microelectrodes was tested and was found to be less than or equal to0.5 mV A significant electrical potential profile was detected alongthe proximal tubular lumen under free flow. From near zero at the glomerulum the potential difference rose to -1.5 mV, lumen negative, in the first tubular loop at approximately 0.1 to 0.3 mm of tubular length. It decreased then rapidly, changed sign and attained a maximum of ca.2.0 mV, lumen positive, at I mm of tubular length, after which it declined gradually to +1.6 mV in the last accessible loop. The mean of 85 punctures in intermediate andlate loops was +1.8, S.D. +/-0.33 mV range +1.0 to +3.2 mV, On the basis of perfusion experiments described in the subsequent paper, the lumen-negative potential difference across early loops can be explained as an active transport potential. It is caused by the presence of glucose and amino acids in the glomerular filtrate, which increase the rate of active Na absorptionover that of active HCO3- absorption, The lumen-positive potential difference in intermediate and late loops is explained as the sum of a membrane diffusion potential arising from the shift in intratubular Cl- and HCO3- concentrations and a small lumen-positive active transport potential from H+ secretion/HCO3- absorption.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 13/07/20 alle ore 10:07:00