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Basolateral Na-H exchange in the rabbit cortical collecting tubule

We used the intracellular absorbance spectrum of the dye 4',5'-dimethyl- 5- (and -6-) carboxyfluorescein (Me2CF) to measure intracellular pH (pHi) in the isolated, perfused cortical collecting tubule (CCT) of the rabbit nephron. The incident spot of light was generally 10 micron in diamete...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1985
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228792/
https://www.ncbi.nlm.nih.gov/pubmed/3001217
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description We used the intracellular absorbance spectrum of the dye 4',5'-dimethyl- 5- (and -6-) carboxyfluorescein (Me2CF) to measure intracellular pH (pHi) in the isolated, perfused cortical collecting tubule (CCT) of the rabbit nephron. The incident spot of light was generally 10 micron in diameter, large enough to illuminate from two to six cells. No attempt was made to distinguish principal from intercalated cells. All experiments were carried out in HCO3- -free Ringer to minimize HCO3- transport. When cells were acid-loaded by briefly exposing them to Ringer containing NH+4 and then withdrawing the NH+4, pHi spontaneously recovered from the acid load. The pHi recovery was best fit by the sum of two exponentials. When the acid loading was performed in the absence of Na+, the more rapid of the two phases of pHi recovery was absent. The remaining slow phase never returned pHi to normal and was sometimes absent. Returning Na+ to the lumen had only a slight effect on the pHi recovery. However, when Na+ was returned to the basolateral (i.e., blood-side) solution, pHi recovered rapidly and completely. The apparent Km for basolateral Na+ was 27.3 +/- 4.5 mM. The basolateral Na- dependent pHi recovery was reversibly inhibited by amiloride. We conclude that the mechanism responsible for the rapid phase of pHi recovery is an Na-H exchanger confined primarily, if not exclusively, to the basolateral membrane of the CCT.
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spelling pubmed-22287922008-04-23 Basolateral Na-H exchange in the rabbit cortical collecting tubule J Gen Physiol Articles We used the intracellular absorbance spectrum of the dye 4',5'-dimethyl- 5- (and -6-) carboxyfluorescein (Me2CF) to measure intracellular pH (pHi) in the isolated, perfused cortical collecting tubule (CCT) of the rabbit nephron. The incident spot of light was generally 10 micron in diameter, large enough to illuminate from two to six cells. No attempt was made to distinguish principal from intercalated cells. All experiments were carried out in HCO3- -free Ringer to minimize HCO3- transport. When cells were acid-loaded by briefly exposing them to Ringer containing NH+4 and then withdrawing the NH+4, pHi spontaneously recovered from the acid load. The pHi recovery was best fit by the sum of two exponentials. When the acid loading was performed in the absence of Na+, the more rapid of the two phases of pHi recovery was absent. The remaining slow phase never returned pHi to normal and was sometimes absent. Returning Na+ to the lumen had only a slight effect on the pHi recovery. However, when Na+ was returned to the basolateral (i.e., blood-side) solution, pHi recovered rapidly and completely. The apparent Km for basolateral Na+ was 27.3 +/- 4.5 mM. The basolateral Na- dependent pHi recovery was reversibly inhibited by amiloride. We conclude that the mechanism responsible for the rapid phase of pHi recovery is an Na-H exchanger confined primarily, if not exclusively, to the basolateral membrane of the CCT. The Rockefeller University Press 1985-12-01 /pmc/articles/PMC2228792/ /pubmed/3001217 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Basolateral Na-H exchange in the rabbit cortical collecting tubule
title Basolateral Na-H exchange in the rabbit cortical collecting tubule
title_full Basolateral Na-H exchange in the rabbit cortical collecting tubule
title_fullStr Basolateral Na-H exchange in the rabbit cortical collecting tubule
title_full_unstemmed Basolateral Na-H exchange in the rabbit cortical collecting tubule
title_short Basolateral Na-H exchange in the rabbit cortical collecting tubule
title_sort basolateral na-h exchange in the rabbit cortical collecting tubule
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2228792/
https://www.ncbi.nlm.nih.gov/pubmed/3001217