Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Nitric oxide inhibits sodium/hydrogen exchange activity in the thick ascending limb
Autore:
Garvin, JL; Hong, NJ;
Indirizzi:
Henry Ford Hosp, Dept Internal Med, Div Hypertens & Vasc Res, Detroit, MI 48202 USA Henry Ford Hosp Detroit MI USA 48202 ns & Vasc Res, Detroit, MI 48202 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY
fascicolo: 3, volume: 46, anno: 1999,
pagine: F377 - F382
SICI:
0363-6127(199909)46:3<F377:NOISEA>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORTICAL COLLECTING DUCT; PROXIMAL TUBULE; RAT-KIDNEY; CGMP; TRANSPORT; CELLS; EXPRESSION; RESPONSES; MEMBRANE; PRESSURE;
Keywords:
acid-base balance; bicarbonate transport; natriuresis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Garvin, JL Henry Ford Hosp, Dept Internal Med, Div Hypertens & Vasc Res, 2799 W GrandBlvd, Detroit, MI 48202 USA Henry Ford Hosp 2799 W Grand Blvd Detroit MI USA 48202 8202 USA
Citazione:
J.L. Garvin e N.J. Hong, "Nitric oxide inhibits sodium/hydrogen exchange activity in the thick ascending limb", AM J P-REN, 46(3), 1999, pp. F377-F382

Abstract

Nitric oxide (NO) inhibits transport in various nephron segments, and the thick ascending limb (TAL) expresses nitric oxide synthase (NOS). However, the effects of NO on TAL transport have not been extensively studied. We tested the hypothesis that NO inhibits apical and basolateral Na+/H+ exchangeby the TAL by measuring intracellular pH (pH(i)) of isolated, perfused ratTALs using the fluorescent dye 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF). The NO donor spermine NONOate (SPM, 10 mu M) decreased steady-state pH(i) in medullary TALs from 7.18 +/- 0.13 to 7.13 +/- 0.14 (P < 0.02), whereas controls did not decrease significantly. We next measured the buffering capacity of medullary TALs and the rate at which they recovered from acid loads to investigate the mechanism whereby NO reduces steady-state pHi. SPM decreased H+ flux (J(H)) from 2.41 +/- 0.66 to 0.97 +/- 0.19 pmol . min(-1) . mm(-1) 55%. To assure that the decrease in J(H) was dueto NO, another donor, nitroglycerin (NTG; 10 mu M), was used. NTG decreased J(H) from 1.65 +/- 0.11 to 1.07 +/- 0.24 pmol . min(-1) . mm-l, 37%. To determine the relative contributions of the apical and basolateral Na+/H+ exchangers, 5-(N,N-dimethyl)-amiloride (DMA; 100 mu M) was added to either bath or lumen. With DMA added to the bath, SPM decreased J(H) from 4.78 +/- 1.08 to 2.74 +/- 0.54 pmol . min(-1) . mm(-1), an inhibition of 41%; and with DMA added to the lumen, SPM decreased J(H) from 2.31 +/- 0.29 to 1.74 +/-0.27 pmol . min(-1) . mm(-1), a reduction of 26%. Addition of DMA alone toboth bath and lumen resulted in an 87% inhibition of J(H). We conclude that NO inhibits both apical and basolateral Na+/H+ exchangers and consequently may play an important role in regulating pH(i) and may alter acid/base balance by directly affecting bicarbonate absorption in the TAL.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 12:56:42