TY - JOUR
T1 - Regulation of intracellular pH in proximal tubules of avian loopless reptilian-type nephrons
AU - Martinez, Christina L.
AU - Brokl, Olga H.
AU - Shuprisha, Apichai
AU - Abbott, Diane E.
AU - Dantzler, William H.
PY - 1997
Y1 - 1997
N2 - In proximal tubules isolated from chicken superficial loopless reptilian-type nephrons, intracellular pH (pH(i)), measured with pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, was ~7.1- 7.2 under control conditions (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered medium with pH 7.4 at 37°C), and was reduced to ~6.9 in response to NH4Cl pulse. The rate of recovery of phi (control value ≃ 5 x 10-3 pH U/s) from this acid level was 1) significantly decreased by removal of Na+ or both Na+ and Cl- from the bath or addition of 4,4'- diisothiocyanostilbene-2,2'-disulfonic acid (0.25 mM) to the bath, 2) significantly increased by high bath K+ (75 mM), and 3) unchanged by removal of Cl- alone from the bath or addition of ethylisopropylamiloride (1 mM) or Ba2+ (5 mM) to the bath. Resting pH(i) was 1) significantly decreased by Na+ or simultaneous Na+ and Cl- removal, 2) significantly increased by high K+, and 3) unchanged by Cl- removal alone or addition of Ba2+. The data do not fit the concept of pHi regulation by the most commonly suggested basolateral transporters (Na+/H+ exchanger, Na+ -dependent and Na+- independent Cl-/HCO3/- exchangers, or Na+-HCO3/- -CO3/2- cotransporter).
AB - In proximal tubules isolated from chicken superficial loopless reptilian-type nephrons, intracellular pH (pH(i)), measured with pH-sensitive fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, was ~7.1- 7.2 under control conditions (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid-buffered medium with pH 7.4 at 37°C), and was reduced to ~6.9 in response to NH4Cl pulse. The rate of recovery of phi (control value ≃ 5 x 10-3 pH U/s) from this acid level was 1) significantly decreased by removal of Na+ or both Na+ and Cl- from the bath or addition of 4,4'- diisothiocyanostilbene-2,2'-disulfonic acid (0.25 mM) to the bath, 2) significantly increased by high bath K+ (75 mM), and 3) unchanged by removal of Cl- alone from the bath or addition of ethylisopropylamiloride (1 mM) or Ba2+ (5 mM) to the bath. Resting pH(i) was 1) significantly decreased by Na+ or simultaneous Na+ and Cl- removal, 2) significantly increased by high K+, and 3) unchanged by Cl- removal alone or addition of Ba2+. The data do not fit the concept of pHi regulation by the most commonly suggested basolateral transporters (Na+/H+ exchanger, Na+ -dependent and Na+- independent Cl-/HCO3/- exchangers, or Na+-HCO3/- -CO3/2- cotransporter).
KW - Ammonium chloride pulse
KW - Chickens
KW - Intracellular acidification
KW - Intrinsic buffering capacity
KW - Sodium-coupled basolateral acid-base fluxes
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U2 - 10.1152/ajpregu.1997.273.6.r1845
DO - 10.1152/ajpregu.1997.273.6.r1845
M3 - Article
C2 - 9435636
AN - SCOPUS:0031423061
SN - 0363-6119
VL - 273
SP - R1845-R1854
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 6 42-6
ER -