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Titolo:
EFFECT OF NOREPINEPHRINE ON INTRACELLULAR PH IN KIDNEY PROXIMAL TUBULE - ROLE OF NA-(HCO3-)(N) COTRANSPORT()
Autore:
ABDULNOURNAKHOUL S; KHURI RN; NAKHOUL NL;
Indirizzi:
TULANE UNIV,MED CTR,SCH MED,DEPT MED,NEPHROL SECT,SL-45,1430 TULANE AVE NEW ORLEANS LA 70112 TULANE UNIV,MED CTR,SCH MED,DEPT MED,NEPHROL SECT NEW ORLEANS LA 70112 TULANE UNIV,SCH MED,DEPT PHYSIOL NEW ORLEANS LA 70112 E CAROLINA UNIV GREENVILLE NC 27858
Titolo Testata:
American journal of physiology. Renal, fluid and electrolyte physiology
fascicolo: 1, volume: 44, anno: 1998,
pagine: 33 - 45
SICI:
0363-6127(1998)44:1<33:EONOIP>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
ADRENERGIC AGONISTS; BASOLATERAL MEMBRANES; NEUROGENIC REGULATION; CONVOLUTED TUBULE; SALAMANDER; TRANSPORT; REABSORPTION; RAT; STIMULATION; BICARBONATE;
Keywords:
ADRENERGIC AGONISTS; ELECTROGENIC SODIUM-BICARBONATE COTRANSPORT; INTRACELLULAR PH; SODIUM/PROTON EXCHANGE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
30
Recensione:
Indirizzi per estratti:
Citazione:
S. Abdulnournakhoul et al., "EFFECT OF NOREPINEPHRINE ON INTRACELLULAR PH IN KIDNEY PROXIMAL TUBULE - ROLE OF NA-(HCO3-)(N) COTRANSPORT()", American journal of physiology. Renal, fluid and electrolyte physiology, 44(1), 1998, pp. 33-45

Abstract

We examined the effect of norepinephrine (NE) on intracellular pH (pH(i)) and activity of Na+ (a(i)(Na)) in the isolated perfused kidney proximal tubule of Ambystoma, using single-barreled voltage and ion-selective microelectrodes. In control HCO, Ringer, addition of 10(-6) M NEto the bath reversibly depolarized the basolateral membrane potential(V-1), the luminal membrane potential (V-2), and the transepithelial potential difference (V-3) and increased pH(i) by 0.14 +/- 0.02. Theseeffects were mimicked by isoproterenol but were abolished after pretreatment with SITS or in the absence of CO2/HCO3-. Removal of bath Na+ depolarized V-1 and V-2, hyperpolarized V-3, and decreased pH(i). These effects are largely mediated by the electrogenic Na+-(HCO3-)(n) cotransporter. In the presence of NE, the effects of Na+ removal on membrane potential differences and the rate of change of pH(i) were significantly smaller. Reducing bath HCO3- concentration from 10 to 2 mM at constant CO2 (pH 6.8) depolarized V-1 and V-2, decreased pH(i), and lowered a(i)(Na). These changes are also due to Na+-(HCO3-)(n). In the presence of NE, reducing bath [HCO3-] caused a smaller depolarizations ofV-1 and V-2 and the rate of pH(i) decrease was significantly reduced. Our results indicate: 1) NE causes an increase in pH(i); 2) the NE-induced alkalinization is mediated by a SITS-sensitive and HCO3--dependent transporter on the basolateral membrane; and 3) in the presence of NE, the reduced effects caused by basolateral HCO3- changes or Na+ removal are indicative of an inhibitory effect of NE on Na+-(HCO3-)(n) cotransport.

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Documento generato il 01/10/20 alle ore 01:31:05