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1.
Intracellular pH (pHi) was measured during the circadian cycle of Neurospora. Internal pH of Neurospora cultures in liquid medium was assayed by the 5,5-dimethyl-2,4-oxazolidinedione method and gave values for pHi which were similar to those previously obtained by other workers using pH-microelectrodes with agar-grown cultures. Cytoplasmic pH changed in liquid medium cultures, but these changes were not related to the circadian clock. Furthermore, treatments which raise or lower pHi do not phase-shift the circadian rhythm. These results indicate that pHi plays no specific role in regulating the circadian clock of Neurospora.  相似文献   

2.
Intracellular pH (pHi) affects smooth muscle function, yet little is known concerning its regulation. I have therefore investigated pH regulation in rat uterus, using 31P-NMR spectroscopy. A change in extracellular pH(pHe) of 1 pH unit (7.4 to 6.4) elicited a 0.29 change in pHi; smaller changes in pHo were accompanied by proportionately smaller changes in pHi. The pH changes were reversible. There was no fall of uterine ATP or phosphocreatine during the pH changes.  相似文献   

3.
As an in vitro model for the low extracellular pH (pHe) which has frequently been observed in tumors, cell lines have been grown in a low-pH medium in order to allow cell adaptation to that milieu. Two Chinese hamster cell lines [Chinese hamster ovary (CHO) and Chinese hamster ovarian carcinoma (OvCa)] were compared, both of which acquired thermotolerance during 42°C heating in pHe = 7.3 buffer, but not in pHe = 6.7 medium unless grown at that pH long enough to become adapted. CHO cells, even when acutely acidified, showed higher intracellular pH (pHi) values in a suspension assay than OvCa cells, which confirmed the danger of comparing absolute values of pHi between cell lines. Despite this fundamental difference, relative changes in pHi were similar in that both lines showed a higher pHi in adapted than in unadapted cells, over the range of pHe values tested. The upregulation of pHi was statistically significant, but the two lines differed in the time frame over which adaptation occurred. OvCa cells acquired an enhanced ability to develop tolerance to 42° heat at pHe = 6.7 in 4 days, but the CHO cells acquired this ability more progressively, achieving a maximum ability at approximately 100 days. In contrast, both lines were able to upregulate their pHi within 4 hours of being exposed to pH 6.7 medium. A further indication of different biochemical mechanisms at work was the opposite effects seen on pHi in the two cell lines upon the removal of extracellular CO2/HCO3. The differential between adapted and unadapted OvCa cells was enhanced by removal of bicarbonate, whereas CHO cells seemed less stable and the data with greater scatter failed to show any difference between adapted and unadapted cells. © 1996 Wiley-Liss, Inc.  相似文献   

4.
Intracellular pH (pHi) affects smooth muscle function, yet little is known concerning its regulation. I have therefore investigated pH regulation in rat uterus, using 31P-NMR spectroscopy. A change in extracellular pH(pHe) of 1 pH unit (7.4 to 6.4) elicited a 0.29 change in pHi; smaller changes in pHo were accompanied by proportionately smaller changes in pHi. The pH changes were reversible. There was no fall of uterine ATP or phosphocreatine during the pH changes.  相似文献   

5.
Full-grown Xenopus oocytes undergo meiotic maturation in response to progesterone stimulation. Using [14C]dimethyloxazolidine dione (DMO), we have measured a cytoplasmic alkalization in these oocytes starting at pH 7.14 ± 0.17 during the germinal vesicle (GV) stage, and increasing to 7.56 ± 0.14 at the time of germinal vesicle breakdown (GVBD). During this period, the rate of protein synthesis increases 2-fold from 18.9 ± 3.1 to 37.7 ± 8.8 ng/hr/oocyte. Artificial alkalization of GV stage oocytes to pHi 7.68 ± 0.16, by exposure to the weak bases trimethylamine, methylamine, procaine, or imidazole, led to a 1.8-fold increase in the synthetic rate. Intracellular acidification from 7.5 back to 7.0 had no apparent effect on the elevated rate of protein synthesis following GVBD. Therefore, a cytoplasmic alkalization in the range of 7.5 to 7.6 seems to be one of the events that is necessary for initiating the increase in protein synthesis in maturing Xenopus oocytes; however, it does not appear that an elevated pHi is necessary to maintain the increased synthetic rate following GVBD.  相似文献   

6.
Preferential intracellular pH (pHi) regulation, where pHi is tightly regulated in the face of a blood acidosis, has been observed in a few species of fish, but only during elevated blood PCO2. To determine whether preferential pHi regulation may represent a general pattern for acid–base regulation during other pH disturbances we challenged the armoured catfish, Pterygoplichthys pardalis, with anoxia and exhaustive exercise, to induce a metabolic acidosis, and bicarbonate injections to induce a metabolic alkalosis. Fish were terminally sampled 2–3 h following the respective treatments and extracellular blood pH, pHi of red blood cells (RBC), brain, heart, liver and white muscle, and plasma lactate and total CO2 were measured. All treatments resulted in significant changes in extracellular pH and RBC pHi that likely cover a large portion of the pH tolerance limits of this species (pH 7.15–7.86). In all tissues other than RBC, pHi remained tightly regulated and did not differ significantly from control values, with the exception of a decrease in white muscle pHi after anoxia and an increase in liver pHi following a metabolic alkalosis. Thus preferential pHi regulation appears to be a general pattern for acid–base homeostasis in the armoured catfish and may be a common response in Amazonian fishes.  相似文献   

7.
The distribution of bromophenol blue between the cell and the medium was used to calculate the intracellular pH of yeast. In buffered media the intracellular pH exhibited a plateau at pH i =5.8 for low external pH values and another at pH i =7.6 for high external pH values. The production of H ions by the yeast during utilization of glucose is not accompanied by an alkalinization of the cell interior. The pH i even decreases somewhat in the presence of glucose and K ions.
  1. (1)
    Внутриклеточный pH дрожжей вычисляли на основании распределения бромфеноловой сини между клетками и средой.  相似文献   

8.
Intracellular pH (pHi) of Listeria monocytogenes was determined after exposure to NaCl or sorbitol in liquid and solid media (agar). Both compounds decreased pHi, and recovery on solid medium was impaired compared to that in liquid medium. N,N′-dicyclohexylcarbodiimide abolished pHi recovery, and lowering aw with glycerol showed no effect on pHi.  相似文献   

9.
The effects of jasmonic acid (JA) on elongation growth of coleoptile segments from etiolated maize (Zea mays L.) were investigated in the presence and absence of auxin. When supplied alone, at physiological concentrations (10−9, 10−8, and 10−5 m), JA (or methyl-JA) inhibited growth. JA at a similar range of concentrations also inhibited auxin-induced elongation growth. To determine whether this effect on growth depended on endogenous abscisic acid (ABA), we grew maize coleoptiles in the presence of norflurazon (an inhibitor of carotenoid biosynthesis) that results in reduced endogenous ABA levels. Growth of etiolated coleoptile segments from these plants was inhibited by JA (or methyl-JA) in both the absence and presence of auxin. Previously, we have observed a correlation between elongation growth and cytosolic pH (pHi), in which auxin lowers pHi, and growth inhibitors such as ABA raise pHi. We examined the effect of low concentrations of methyl-JA on pHi with dual emission dye, carboxy seminaphthorhodafluor-1, and confocal microscopy. To confirm these studies, we also used in vivo 31P NMR spectrometry to ascertain the changes in pHi after addition of jasmonate to maize coleoptiles. Coleoptiles grown in either the absence or presence of norflurazon responded to methyl-JA or JA by increases in pHi of approximately 0.2 pH unit. This response occurs over a period of 15–20 min and appears to be independent of endogenous ABA. This alkalization induced by JA is likely to form a permissive environment for JA signal transduction pathway(s). Received February 5, 1999; accepted August 25, 1999  相似文献   

10.
Intracellular pH (pHi) was assayed during the hormonally induced maturation of oocytes of the starfish Pisaster ochraceus. Cytoplasmic pH was measured by the DMO method, and concurrently, the initiation of maturation was determined by germinal vesicle breakdown (GVBD) and the increase in protein synthesis (percentage incorporation of amino acids). Our results indicate that (1) oocyte pHi rises slightly after initiation of maturation; (2) GVBD is not inhibited by acidifying pHi; and (3) amino acid incorporation can be affected by large changes in pHi, but not by the small pHi change promoted by maturation. Therefore, activation of GVBD and amino acid incorporation must proceed by mechanisms which do not include changing pHi. These conclusions appear to be true of oocyte activation by fertilization as well, for the pHi change following insemination is even smaller than during maturation. These results are discussed in terms of mechanisms by which dormancy is controlled.  相似文献   

11.
The functional significance of the apical vacuolar-type proton pump (V-ATPase) in Drosophila Malpighian tubules was studied by measuring the intracellular pH (pHi) and luminal pH (pHlu) with double-barrelled pH-microelectrodes in proximal segments of the larval anterior tubule immersed in nominally bicarbonate-free solutions (pHo 6.9). In proximal segments both pHi (7.43±0.20) and pHlu (7.10±0.24) were significantly lower than in distal segments (pHi 7.70±0.29, pHlu 8.09±0.15). Steady-state pHi of proximal segments was much less sensitive to changes in pHo than pH of the luminal fluid (pHlu/pHo was 0.49 while pHi/pHo was 0.18; pHo 6.50–7.20). Re-alkaliniziation from an NH4Cl-induced intracellular acid load (initial pHi recovery rate 0.55±0.34 pH·min-1) was nearly totally inhibited by 1 mmol·l-1 KCN (96% inhibition) and to a large degree (79%) by 1 mol·l-1 bafilomycin A1. In contrast, both vanadate (1 mmol·l-1) and amiloride (1 mmol·l-1) inhibited pHi recovery by 38% and 33%, respectively. Unlike amiloride, removal of Na+ from the bathing saline had no effect on pHi recovery, indicating that a Na+/H+ exchange is not significantly involved in pHi regulation. Instead pHi regulation apparently depended largely on the availability of ATP and on the activity of the bafilomycin-sensitive proton pump.Abbreviations DMSO dimethylsulphoxide - DNP 2,4-dinitrophenol - NMDG N-methyl-D-glucamine - pHi intracellular pH - pHlu pH of the luminal fluid - pHo pH of the superfusion medium - I intrinsic intracellular buffer capacity  相似文献   

12.
We previously demonstrated that the progesterone‐ (P) initiated human sperm acrosome reaction (AR) was dependent on the presence of extracellular Na+ (Na+o). Moreover, Na+o depletion resulted in a decreased cytosolic pH (pHi), suggesting involvement of a Na+‐dependent pHi regulatory mechanism during the P‐initiated AR. We now report that the decreased pHi resulting from Na+o depletion is reversible and mediated by a Na+/H+ exchange (NHE) mechanism. To determine the role of an NHE in the regulation of pHi, capacitated spermatozoa were incubated in Na+‐deficient, bicarbonate/CO2‐buffered (0NaB) medium for 15–30 min, which resulted in an intracellular acidification as previously reported. These spermatozoa were then transferred to Na+‐containing, bicarbonate/CO2‐buffered (NaB) medium; Na+‐containing, Hepes‐buffered (NaH) medium; or maintained in the 0NaB medium. Included in the NaH medium was the NHE inhibitor 5‐(N‐ethyl‐N‐isopropyl) amiloride (EIPA). The steady‐state pHi was then determined by spectrofluorometric measurement of bis(carboxyethyl)‐5(6)‐carboxyfluoroscein (BCECF) fluorescence. EIPA (0.1 μM) significantly (P < 0.05) inhibited the pHi recovery produced by NaH medium. Moreover, the pHi in NaH medium was not significantly (P < 0.05) different than NaB medium. These results indicate that a Na+‐dependent, bicarbonate‐independent pHi regulatory mechanism, with a pharmacological characteristic consistent with an NHE, is present in capacitated spermatozoa. In support of the involvement of a sperm NHE, we also demonstrated specific immunoreactivity for a 100 kDa porcine sperm protein using an NHE‐1 specific monoclonal antibody. Interestingly, no significant (P = 0.79) effect was seen on the P‐initiated AR when EIPA was included in either the NaH or NaB medium. While these findings suggest that inhibition of NHE‐dependent pHi regulation in capacitated spermatozoa is not sufficient to block initiation of the AR by P, they do not preclude the possibility that an NHE mediates the regulation of capacitation or sperm motility. Mol. Reprod. Dev. 52:189–195, 1999. © 1999 Wiley‐Liss, Inc.  相似文献   

13.
Fluorescence ratio imaging microscopy and microelectrode ion flux estimation techniques were combined to study mechanisms of pH homeostasis in Listeria monocytogenes subjected to acid stress at different levels of glucose availability. This novel combination provided a unique opportunity to measure changes in H+ at either side of the bacterial membrane in real time and therefore to evaluate the rate of H+ flux across the bacterial plasma membrane and its contribution to bacterial pH homeostasis. Responses were assessed at external pHs (pHo) between 3.0 and 6.0 for three levels of glucose (0, 1, and 10 mM) in the medium. Both the intracellular pH (pHi) and net H+ fluxes were affected by the glucose concentration in the medium, with the highest absolute values corresponding to the highest glucose concentration. In the presence of glucose, the pHi remained above 7.0 within a pHo range of 4 to 6 and decreased below pHo 4. Above pHo 4, H+ extrusion increased correspondingly, with the maximum value at pHo 5.5, and below pHo 4, a net H+ influx was observed. Without glucose in the medium, the pHi decreased, and a net H+ influx was observed below pHo 5.5. A high correlation (R = 0.75 to 0.92) between the pHi and net H+ flux changes is reported, indicating that the two processes are complementary. The results obtained support other reports indicating that membrane transport processes are the main contributors to the process of pHi homeostasis in L. monocytogenes subjected to acid stress.  相似文献   

14.
Pyranine is shown to be a convenient and sensitive probe for reporting pH values, pHi, at the interior of anionic and at the outer surface of cationic liposomes. It is well shielded from the phospholipid headgroups by water molecules in the interior of anionic liposomes, but it is bound to the surface of cationic liposomes. Hydrogen ion concentrations outside the liposomes, ‘bulk pH values’, pHo, were measured by a combination electrode. While pHi = pHo for neutral, pHi < pHo for anionic and pHi > pHo for cationic liposomes prepared in 5.0 · 10?3 M phosphate buffers. pKa values for the ionization of pyranine were 7.22 ± 0.04 and 6.00 ± 0.05 in water and at the external surface of cationic liposomes. The surface potential for cationic liposomes containing dipalmitoyl-d-α-phosphatidylcholine, cholesterol and octadecylamine in the molar ratio of 1.00 : 0.634 : 1.01, were calculated to be +72.2 mV. Proton permeabilities were measured for single and multicompartment anionic liposomes. Transfer of anionic liposomes prepared at a given pH to a solution of different pH resulted in a pH gradient if sodium phosphate or borate were used as buffers. In the presence of sodium acetate proton equilibration is promptly established.  相似文献   

15.
In the sea urchin, some other marine invertebrates, and the frog, Xenopus, egg activation at fertilization is accompanied by an increase in intracellular pH (pHi). We measured pHi, in germinal vesicle (GV)-intact mouse oocytes, ovulated eggs, and in vivo fertilized zygotes using the pH indicator dye, SNARF-1. The mean pHi was 6.96 ± 0.004 (± SEM) in GV-intact oocytes, 7.00 ± 0.01 in ovulated, unfertilized eggs, and 7.02 ± 0.01 in fertilized zygotes, indicating no sustained changes in pHi after germinal vesicle breakdown (GVBD) or fertilization. To examine whether transient changes in pHi occur shortly after egg activation, mouse eggs were parthenogenetically activated by 7% ethanol in phosphate buffered saline (PBS); no significant change in pHi followed ethanol activation. Since increased Na+/H+ antiporter activity is responsible for pHi increase in the sea urchin, pHi was measured in the absence of added bicarbonate or CO2 la condition under which the antiporter would be the only major pHi regulatory mechanism able to operate, since the others were bicarbonate- dependent) in GV-intact oocytes, ovulated eggs, and in vivo fertilized zygotes to determine whether a Na+/H+ antiporter was activated. There was no physiologically significant difference in pHi after GVBD or fertilization, when pHi was measured in bicarbonate-free medium, nor any change upon parthenogenetic activation. Thus, a change in pHi is not a feature of egg activation in the mouse. © 1996 Wiley-Liss, Inc.  相似文献   

16.
The effect of heparin-induced capacitation on the intracellular pH (pHi) of individual bovine sperm was determined with image analysis. Sperm were loaded with the acetoxymethyl ester of the pH sensitive fluorescent indicator, 2′,7′-bis(carboxyethyl)-5(6)-carboxy-fluorescein (BCECF). The pHi of 5303 sperm was evaluated from a total of five bulls at .5, 2, 3, 4, and 5 h of incubation. The pHi did not differ between the sperm head and mid-piece (P > 0.05). An increase in sperm head pHi was seen in heparin-treated sperm at 3, 4, and 5 h of incubation relative to sperm incubated without heparin (control, P < 0.05). At 5 h of incubation, the pHi in heparin-treated sperm was 6.92 ± 0.07, while control-treated sperm pHi was 6.70 ± 0.03. Initially a normal frequency distribution was seen for sperm pHi in both heparin- and control-treated sperm. As the incubation progressed, the frequency distribution began to skew towards higher pHi in both samples but was more dispersed for the heparin-treated sperm. Following an NH4Cl-induced alkaline load, the pHi of both control- and heparin-treated sperm recovered toward the resting pHi with a half-time of recovery of 1.5–1.7 min. The recovery of sperm pHi was not due to leakage of NH4+ into sperm because recovery also occurred with trimethylamine. The instantaneous velocity of the pHi recovery (vi) was dependent on pHi and decreased as pHi decreased. Capacitation by heparin was associated with an 81% decrease in vi at a pHi of 7.00, but there was no effect of capacitation on the proton buffering power of the sperm, which was 87 ± 8 mM/pH unit. Results demonstrate that both the regulation of pHi and resting pHi were altered during capacitation of bovine sperm by heparin. © 1995 Wiley-Liss, Inc.  相似文献   

17.
N. Iijima  A. Amagai  Y. Maeda 《Protoplasma》1991,160(2-3):72-76
Summary Dictyostelium mucoroides-7 (Dm 7) and a mutant MF 1 derived from it exhibit two developmental pathways: sorocarp formation occurs during the asexual process, and macrocyst formation during the sexual cycle. The two developmental pathways are mainly regulated by two chemical substances: 3,5-cyclic adenosine monophosphate (cAMP) and ethylene. Recently, we have demonstrated that cytoplasmic pH (pHi) has a critical role for the choice of developmental pathways, higher pHi being favourable to macrocyst formation. Thereupon, attention was riveted to the relation of pHi to biosynthesis of cAMP and ethylene. Effect of pHi on the production and release of ethylene, a potent inducer of macrocyst formation, was examined, using the two facing culture method. The result showed that lowered pHi inhibits ethylene production, thus resulting in a failure of cells to form macrocysts. The accumulation of cAMP, an inhibitor of macrocyst formation, was found to vary depending on extracellular pH (pHo), but diethylstilbestrol (DES) that is a proton pump inhibitor and also an inhibitor of macrocyst formation had no significant effect on the accumulation. Taken together these results indicate that higher pHi may induce macrocyst formation through enhancement of ethylene production rather than inhibition of cAMP synthesis.Abbreviations cAMP 3,5-cyclic adenosine monophosphate - pHi cytoplasmic pH - pHo extracellular pH - ACC 1-1-aminocyclopropane-1-carboxylic acid  相似文献   

18.
The food pathogen Bacillus cereus is likely to encounter acidic environments (i) in food when organic acids are added for preservation purposes, and (ii) during the stomachal transit of aliments. In order to characterise the acid stress response of B. cereus ATCC14579, cells were grown in chemostat at different pH values (pHo from 9.0 to 5.5) and different growth rates (μ from 0.1 to 0.8 h−1), and were submitted to acid shock at pH 4.0. Cells grown at low pHo were adapted to acid media and induced a significant acid tolerance response (ATR). The ATR induced was modulated by both pHo and μ, and the μ effect was more marked at pHo 5.5. Intracellular pH (pHi) was affected by both pHo and μ. At a pHo above 6, the pHi decreased with the decrease of pHo and the increase of μ. At pHo 5.5, pHi was higher compared to pHo 6.0, suggesting that mechanisms of pHi homeostasis were induced. The acid survival of B. cereus required protein neo-synthesis and the capacity of cells to maintain their pHi and ΔpH (pHi - pHo). Haemolysin BL and non-haemolytic enterotoxin production were both influenced by pHo and μ.  相似文献   

19.
Abstract: The role of transmembrane processes that are dependent on external anions in the regulation of cerebral intracellular pH (pHi), high-energy metabolites, and lactate was investigated using 31P and 1H NMR spectroscopy in an ex vivo brain slice preparation. During oxygenated superfusion, removal of external HCO3?/CO2 in the presence of Na+ led to a sustained split of the inorganic phosphate (Pi) peak so that the pHi indicated by one part of the peak was 0.38 pH units more alkaline and by the other part 0.10 pH units more acidic at 5 min than in the presence of HCO3?. The pH in the compartment with a higher pHi value returned to 7.29 ± 0.04 by 10.5 min of superfusion in a HCO3?-free medium, whereas the pHi in an acidic compartment was reduced to 7.02. In the presence of 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid or the absence of external Cl?, removal of HCO3? caused alkalinization without split of the Pi peak. Both treatments reduced the rate of pHi normalization following alkalinization. Simultaneous omission of external HCO3? and Na+ did not inhibit alkalinization of the pHi following CO2 exit. All these data show that the acid loading mechanism at neutral pHi is mediated by an Na+-independent anion transport. During severe hypoxia, pHi dropped from 7.29 ± 0.05 to 6.13 ± 0.16 and from 7.33 ± 0.03 to 6.67 ± 0.05 in the absence and presence of HCO3?, respectively, in Na+-containing medium. Lactate accumulated to 18.7 ± 2.8 and 19.6 ± 1.5 mmol/kg under the respective conditions. In the HCO3?-free medium supplemented with 1 mM amiloride, the pHi fell only to 6.94 ± 0.08 despite the lactate concentration of 18.9 ± 2.4 mmol/kg. Acidification caused by hypoxia was also small in the slice preparations superfused in the absence of both HCO3? and Cl?, as the pHi was 7.01 ± 0.12 at a lactate concentration of 24.5 ± 2.4 mmol/kg. These data indicate that apart from anaerobic glucose metabolism, separate acidifying mechanisms are functioning during hypoxia under these conditions. Recovery of phosphocreatine levels following reoxygenation was >75% relative to the prehypoxic level in the slice preparations superfused in the absence of HCO3? but <47% in those preparations superfused without HCO3? and Cl?. This indicates that either neutral pHi or absence of Cl? during hypoxia was deleterious to the energy metabolism. The present data indicate that Cl?/HCO3? exchange mechanisms have distinct roles in cerebral H+ homeostasis depending on the level of pHi and energy state.  相似文献   

20.
Summary The present study was designed to investigate the apical and basolateral transport processes responsible for intracellular pH regulation in the thin descending limb of Henle. Rabbit thin descending limbs of long-loop nephrons were perfused in vitro and intracellular pH (pH i ) was measured using BCECF. Steady-state pH i in HEPES buffered solutions (pH 7.4) was 7.18±0.03. Following the removal of luminal Na+, pH i decreased at a rate of 1.96±0.37 pH/min. In the presence of luminal amiloride (1mm), the rate of decrease of pH i was significantly less, 0.73±0.18 pH/min. Steady-state pH i decreased 0.18 pH units following the addition of amiloride (1mm) to the lumen (Na+ 140mm lumen and bath). When Na+ was removed from the basolateral side of the tubule, pH i decreased at a rate of 0.49±0.05 pH/min. The rate of decrease of pH i was significantly less in the presence of 1mm basolateral amiloride, 0.29±0.04 pH/min. Addition of 1mm amiloride to the basolateral side (Na+ 140mm lumen and bath) caused steady-state pH i to decrease significantly by 0.06 pH units. When pH i was acutely decreased to 5.87±0.02 following NH4Cl removal (lumen, bath), pH i failed to recover in the absence of Na+ (lumen, bath). Addition of 140mm Na+ to the lumen caused pH i to recover at a rate of 2.17±0.59 pH/min. The rate of pH i recovery was inhibited 93% by 1mm luminal amiloride. When 140mm Na+ was added to the basolateral side, pH i recovered only partially at 0.38±0.07 pH/min. Addition of 1mm basolateral amiloride inhibited the recovery of pH i , by 97%. The results demonstrate that the rabbit thin descending limb of long-loop nephrons possesses apical and basolateral Na+/N+ antiporters. In the steady state, the rate of Na+-dependent H+ flux across the apical antiporter exceeds the rate of Na+-dependent H+ flux via the basolateral antiporter. Recovery of pH i following acute intracellular acidification is Na+ dependent and mediated primarily by the luminal antiporter.  相似文献   

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