Acid-base balance in amphibian gastric mucosa

It has been established that H+ secretion can be maintained in frog stomach in the absence of exogenous CO2 by using a nutrient bathing fluid containing 25 mM H2PO4 (pH approximately equal to 4.5) or by lowering the pH of a nonbuffered nutrient solution to about 3.0-3.6. Exogenous CO2 in the presence of these nutrient solutions uniformly caused a marked decrease in H+ secretion, PD, adn short-circuit current (Isc) and an increase in transmucosal resistance (R). Elevation of nutrient [k+] to 83 mM reduced R significantly but transiently without change in H+ when nutrient pH less than 5.0, whereas R returned to base line and H+ increased when nutrient pH greater than 5.0. Acidification of the nutrient medium in the presence of exogenous CO2 results in inhibition of the secretory pump, probably by decreasing intracellular pH, and also interferes with conductance at the nutrient membrane. Removal of exogenous CO2 from standard bicarbonate nutrient solution reduced by 50% the H+, PD, and Isc without change in R; K+-free nutrient solutions reverse these changes in Isc and PD but not in H+. The dropping PD and rising R induced by K+-free nutrient solutions in 5% CO2 - 95% O2 are returned toward normal by 100% O2. Our findings support an important role for exogenous CO2 in maintaining normal acid-base balance in frog mucosa by acting as an acidifying agent.

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Role of citrate excretion in acid-base balance in diuretic-induced alkalosis in the rat

AJP Renal Physiology ◽

10.1152/ajprenal.1985.248.6.f796 ◽

1985 ◽

Vol 248 (6) ◽

pp. F796-F803 ◽

Cited By ~ 1

Author(s):

A. M. Kaufman ◽

C. Brod-Miller ◽

T. Kahn

Keyword(s):

Base Line ◽

Acid Excretion ◽

Acid Base Balance ◽

Bicarbonate Concentration ◽

Acid Base ◽

Plasma Bicarbonate ◽

Base Balance ◽

Furosemide Administration ◽

Net Acid Excretion

Studies were performed to assess the role of changes in the excretion of citrate, a metabolic precursor of bicarbonate, in acid-base balance in diuretic-induced metabolic alkalosis. Rats on a low-chloride diet with sodium sulfate added were studied during a base-line period, 3 days of furosemide administration, and 4 days post-furosemide. During the period of furosemide administration, net acid excretion and plasma bicarbonate concentration increased. In the post-furosemide period, net acid excretion remained higher than base line but plasma bicarbonate concentration did not increase further. Citrate excretion was significantly higher in the post-furosemide period than in base line. Studies substituting sodium neutral phosphate or sodium bicarbonate for dietary sodium sulfate demonstrated greater increases in net acid excretion post-furosemide and, again, no increase in plasma bicarbonate concentration during this period. Citrate excretion was greater than in the sulfate group. The increment in citrate excretion was proportional to the base “load,” defined with respect to changes in net acid excretion and/or dietary bicarbonate. Thus, in these studies alterations of base excretion in the form of citrate play an important role in acid-base balance during diuretic-induced metabolic alkalosis.

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Ba++ on the resting frog stomach: effects on electrical and secretory parameters

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.2.511 ◽

1975 ◽

Vol 228 (2) ◽

pp. 511-517 ◽

Cited By ~ 9

Author(s):

PK Rangachari

Keyword(s):

Acid Secretion ◽

Nutrient Solution ◽

Short Circuit ◽

Short Circuit Current ◽

Secretory Rate ◽

Frog Stomach ◽

Solution Bathing ◽

Per Se

Ba++ added to the nutrient solution bathing the resting frog stomach increased resistance, decreased the PD, and stimulated acid secretion. Under short-circuit conditions, the increase in H+-secretory rate was accompanied by a decrease in short-circuit current (I-sc). These changes were reversed by NaSCN (10 mM), suggesting that Ba++ had not impaired the current-generating mechanism per se. Histamine-induced acid secretion was associated with an increase in net Cl- flux, particularly in the N yields S flux (JNS). Ba++ increased acid secretion with no increase in JNS and a decrease in net Cl- flux. The effects of Ba++ were amplified by low-Cl- solutions. Histamine, in the presence of Ba++ and low-Cl- solutions, increased acid secretion and transmucosal resistance, suggesting the operation of a neutral pump in the secretion of HCl. It is concluded that Ba++ limits Cl- entry and also acts as a secretagogue.

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Furosemide and cerebrospinal fluid ions during acute respiratory acidosis

Journal of Applied Physiology ◽

10.1152/jappl.1989.67.2.563 ◽

1989 ◽

Vol 67 (2) ◽

pp. 563-569 ◽

Cited By ~ 4

Author(s):

S. Javaheri ◽

J. F. Freidel ◽

P. J. Davis

Keyword(s):

Cerebrospinal Fluid ◽

Ionic Composition ◽

Respiratory Acidosis ◽

Base Line ◽

Acid Base Balance ◽

Acid Base ◽

Mechanically Ventilated ◽

Group I ◽

Base Balance ◽

Group Ii

The purpose of this study was to investigate the effects of furosemide, an inhibitor of NaCl cotransport, on cisternal cerebrospinal fluid (CSF) acid-base balance during acute respiratory acidosis (ARA). We measured blood and CSF acid-base variables in two groups (n = 7 in each) of anesthetized, paralyzed, and mechanically ventilated dogs with bilateral ligation of renal pedicles (to eliminate saluresis). After base-line samples were obtained (-1 h), furosemide (50 mg/kg) was administered intravenously within 15 min (group II); group I received an equal volume of half-normal saline. ARA was induced 1 h later (0 h) and arterial CO2 tension was maintained between 55 and 60 Torr for 5 h. Mean cisternal CSF PCO2 was 42.8 +/- 2.6 and 39.5 +/- 1.7 Torr, respectively in groups I and II and rose approximately 20 Torr during ARA. In group I, CSF [HCO3-] was 22.0 +/- 1.0, 24.8 +/- 0.6, and 25.4 +/- 1.6 meq/l, respectively at 0, 2.5, and 5 h. Respective values for group II were 22.2 +/- 1.3, 24.3 +/- 1.8, and 24.6 +/- 1.0 meq/l. These values were not significantly different from each other. In each group, CSF [Na+-Cl-] increased significantly during ARA, but the changes were not significantly different when the two groups were compared. We conclude that furosemide at the dose used in the present study does not change ionic composition and acid-base balance of cisternal CSF compared with control. Because changes in CSF [Na+-Cl-] during ARA were similar in both groups, any inhibition of Cl- influx into CSF by furosemide should have been proportional to that of Na+.

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Canola meal and diet acid-base balance for broilers

Canadian Journal of Animal Science ◽

10.4141/cjas94-045 ◽

1994 ◽

Vol 74 (2) ◽

pp. 335-339 ◽

Cited By ~ 4

Author(s):

J. D. Summers ◽

M. Bedford

Keyword(s):

Weight Gain ◽

Soybean Meal ◽

Marked Decrease ◽

Calcium Supplementation ◽

Canola Meal ◽

Acid Base Balance ◽

Acid Base ◽

Growth Depression ◽

Sodium Calcium ◽

Base Balance

Experiments were undertaken to investigate the influence of dietary sulphur, calcium and altered anion-cation balance on the response of chicks fed soybean or canola meal diets.The addition of supplemental sulphur to a semi-purified soybean meal diet resulted in a marked decrease in feed intake and weight gain. Additional dietary calcium helped to alleviate the depression caused by excess dietary sulphur. Plotting dietary meq (ranging from −3.7 to +13.4) against weight gain suggested that anion–cation balance was responsible, in part, for the responses noted. Supplementing a canola meal semi-purified diet with sulphur, calcium and a mixture of potassium and sodium carbonate to alter diet anion–cation balance by 0, 10 and 20 meq confirmed that the interaction noted with dietary sulphur and calcium supplementation of soybean and canola meals diets is caused in large part by changes in anion–cation balance of the diet. Thus the present data confirm previous suggestions that part of the growth depression noted with canola meal supplemented diets is due to its high sulphur content and thus an altering of anion–cation balance. Key words: Broilers, canola meal, acid base balance, sulphur, sodium, calcium, potassium

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The Acid-Base Balance of the Outer Mantle Epithelium of Anodonta Cygnea

Journal of Experimental Biology ◽

10.1242/jeb.150.1.159 ◽

1990 ◽

Vol 150 (1) ◽

pp. 159-169 ◽

Cited By ~ 1

Author(s):

J. MACHADO ◽

K. G. FERREIRA ◽

H. G. FERREIRA ◽

P. L. FERNANDES

Keyword(s):

Short Circuit ◽

Basolateral Membrane ◽

Short Circuit Current ◽

Acid Base Balance ◽

Shell Side ◽

Anodonta Cygnea ◽

Acid And Base ◽

Base Balance ◽

Solution Bathing ◽

Outer Mantle Epithelium

1. Under short-circuit conditions the outer mantle epithelium of Anodonta cygnea is known to produce an acidification of the solution bathing the shell side and an alkalinization of the solution bathing the haemolymph side. 2. At steady state, the rates of secretion of acid and base were numerically equal to the simultaneously measured short-circuit current, expressed in the same units. 3. The rates of acid and base secretion, and the short-circuit current, showed close similarity in the reductions caused by anoxia, diamox, DIDS (from haemolymph side), DNP and iodoacetamide. 4. The short-circuit current (Isc) was sensitive to the concentration of CO2, bicarbonate or protons in the solution on the shell side. 5. The short-circuit current was insensitive to vanadate or oligomycin, was slowly inhibited by DCCD added under anoxia to the shell side, and was almost completely inhibited within seconds by TBTO (shell side) which also caused a 40% reduction in transepithelial conductance. 6. It is suggested that Isc is due to a Cl−/HCO−exchange shunted by a Cl− recirculation across the basolateral membrane and to the operation of an electrogenic proton pump located in the apical membrane.

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Higher Dietary Acidity is Associated with Lower Bone Mineral Density in Postmenopausal Iranian Women, Independent of Dietary Calcium Intake

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000207 ◽

2014 ◽

Vol 84 (3-4) ◽

pp. 0206-0217 ◽

Cited By ~ 8

Author(s):

Seyedeh-Elaheh Shariati-Bafghi ◽

Elaheh Nosrat-Mirshekarlou ◽

Mohsen Karamati ◽

Bahram Rashidkhani

Keyword(s):

Calcium Intake ◽

Dietary Calcium ◽

Dietary Calcium Intake ◽

Dietary Intakes ◽

Iranian Women ◽

Acid Base Balance ◽

Mineral Density ◽

Acid Base ◽

Base Balance ◽

Dietary Acid

Findings of studies on the link between dietary acid-base balance and bone mass are relatively mixed. We examined the association between dietary acid-base balance and bone mineral density (BMD) in a sample of Iranian women, hypothesizing that a higher dietary acidity would be inversely associated with BMD, even when dietary calcium intake is adequate. In this cross-sectional study, lumbar spine and femoral neck BMDs of 151 postmenopausal women aged 50 - 85 years were measured using dual-energy x-ray absorptiometry. Dietary intakes were assessed using a validated food frequency questionnaire. Renal net acid excretion (RNAE), an estimate of acid-base balance, was then calculated indirectly from the diet using the formulae of Remer (based on dietary intakes of protein, phosphorus, potassium, and magnesium; RNAERemer) and Frassetto (based on dietary intakes of protein and potassium; RNAEFrassetto), and was energy adjusted by the residual method. After adjusting for potential confounders, multivariable adjusted means of the lumbar spine BMD of women in the highest tertiles of RNAERemer and RNAEFrassetto were significantly lower than those in the lowest tertiles (for RNAERemer: mean difference -0.084 g/cm2; P=0.007 and for RNAEFrassetto: mean difference - 0.088 g/cm2; P=0.004). Similar results were observed in a subgroup analysis of subjects with dietary calcium intake of >800 mg/day. In conclusion, a higher RNAE (i. e. more dietary acidity), which is associated with greater intake of acid-generating foods and lower intake of alkali-generating foods, may be involved in deteriorating the bone health of postmenopausal Iranian women, even in the context of adequate dietary calcium intake.

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