Effects of Ethacrynic Acid on Frog Gastric Mucosa in Chloride Solutions

1974 ◽  
Vol 52 (2) ◽  
pp. 166-173
Author(s):  
Mumtaz A. Dinno ◽  
Manuel Schwartz ◽  
Axel K. Olson ◽  
Gaspar Carrasquer
Keyword(s):  
Gastric Mucosa ◽  
Nutrient Solution ◽  
Ethacrynic Acid ◽  
Secretory Rate ◽  
High K ◽  
Solution Bathing ◽  
Transmembrane Potential Difference ◽  
Low K ◽  
Nutrient Solutions

The addition of ethacrynic acid to a concentration of 1 mM in the nutrient solution bathing the frog gastric mucosa in vitro produced an immediate decrease in resistance followed by an increase in resistance and a decrease in H+ secretory rate. The latter effect was irreversible and the former reversible. During the initial phase for nutrient solutions of 4 mM K+ and 79 mM K+ containing 1 mM ethacrynic acid, the decrease in resistance was about 30% and the decrease in the transmembrane potential difference (P.D.) was about 1 mV in the low K+ case and 2 mV in the high K+ case. The addition of ethacrynic acid to a 4 mM K+ nutrient solution containing 1 mM Ba2+ produced initially a 19% decrease in resistance and both positive and negative changes in P.D. In the absence of Ba2+, these results suggest strongly a marked increase of K+ permeability with the possibility of some increase of Cl− permeability. In the presence of Ba2+, as a result due to the increased K+ resistance of the nutrient membrane, ethacrynic acid may affect predominantly either K+ or Cl− permeability.

NITRIFICATION IN NUTRIENT SOLUTIONS WITH LOW LEVELS OF POTASSIUM

1959 ◽  
Vol 5 (5) ◽  
pp. 425-430 ◽  
Author(s):  
L. F. Welch ◽  
A. D. Scott
Keyword(s):  
Nutrient Solution ◽  
Room Temperature ◽  
Nitrifying Bacteria ◽  
Garden Soil ◽  
Soil Particles ◽  
High K ◽  
Low Levels ◽  
Low K ◽  
Nutrient Solutions ◽  
As If

An active culture of nitrifying bacteria was established by adding moist garden soil to a high-K nutrient solution and incubating the system at room temperature with adequate aeration. By a succession of transfers into a low-K nutrient solution the soil particles were eliminated and the K level reduced to 0.40 p.p.m. Inoculum from this soil-free, low-K nitrifying culture was then used to study nitrification in buffered nutrient solutions that contained even less K.When the nutrient solutions contained 0.40 p.p.m. K or more, there was no effect of the K level on the nitrification of NH4 added as (NH4)2SO4. Nitrification was impaired, however, when the K level was less than 0.35 p.p.m. In a solution that contained virtually no K there was negligible nitrification after a second transfer was made to eliminate the K added by the original inoculum. Under these conditions, the number of nitrifying bacteria apparently decreased, but some of them persisted for at least 48 days. Upon the addition of K, nitrification occurred to about the same extent as if ample K had always been present.

Secretion of H+ and K+ by bullfrog gastric mucosa: characterization of K+ transport pathway

1980 ◽  
Vol 239 (6) ◽  
pp. G485-G492
Author(s):  
P. C. Sen ◽  
L. L. Tague ◽  
T. K. Ray
Keyword(s):  
Gastric Mucosa ◽  
Nutrient Solution ◽  
Rana Catesbeiana ◽  
Transport Pathway ◽  
Mucosal Side ◽  
Apical Membranes ◽  
K Transport ◽  
Co2 Addition

The transport of K+ and H+ (both expressed as mueq/h) by in vitro chambered bullfrog (Rana catesbeiana) gastric mucosa have been studied under a variety of conditions such as anoxia, addition of p-chloromercuribenzene sulfonic acid (PCMBS) into the secretory solution, inclusion of ouabain in the nutrient solution, addition of thiocyanate (SCN-) into the mucosal solution, and replacement of nutrient chloride (Cl-) with sulfate (SO4(2-)), or gluconate (Gl). Anoxia reversibly reduced the H+ transport close to zero within 15 min and gradually reduces the K+ transport throughout the 2-h period of anoxia. The presence of 2.5 X 10(-4) M mucosal PCMBS in the histamine-stimulated mucosa increases the K+ transport, which is promptly reduced by changing the gas phase to 95% N2-5% CO2. Addition of ouabain to the nutrient solution of the histamine-stimulated mucosa with PCMBS on the mucosal side significantly (P < 0.05) reduces the K+ transport within 60 min. Addition of SCN- to the mucosal solution of a histamine-stimulated mucosa with regular nutrient or O, K+ nutrient and 10, K+ mucosal solution reduces the H+ transport to near zero within 60 min. This SCN- inhibition can be reversed by elevating secretory K+. Substitution of nutrient Cl- with SO4(2-) or Gl in the histamine-stimulated mucosa reversibly inhibits H+ transport and reduces K+ transport to a low level (0.7 +/- 0.05). Our data suggest that the K+ transport across the apical membranes of gastric cells is to a large extent a passive carrier-mediated process, and the transport of both K+ and Cl- are coupled at the apical membrane.

Differentiation of Na(+)-K+ pumps of low-K+ sheep red blood cells is promoted by Lp membrane antigens

1993 ◽  
Vol 265 (1) ◽  
pp. C99-C105 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Rat Kidney ◽  
Striking Increase ◽  
Sheep Red Blood Cells ◽  
High K ◽  
Membrane Antigens ◽  
Low K ◽  
Kinetics Of

Na(+)-K+ pumps of red blood cells from sheep of the low-K+ (LK) phenotype undergo differentiation during circulation, manifested in part by a striking increase in sensitivity to inhibition by intracellular K+ (Ki). Pumps of red blood cells from sheep from the allelic phenotype, high K+ (HK), do not undergo this type of maturation. The hypothesis was tested that the Lp antigen, found on LK but not HK cells, is responsible for the maturation of LK pumps. Lp antigens have been shown to inhibit LK pumps because anti-Lp antibody stimulates the pumps by relieving inhibition by the antigen. Lp antigens were recently shown to be molecular entities separate from Na(+)-K+ pumps [Xu, Z.-C., P. Dunham, J. Munzer, J. Silvius, and R. Blostein. Am. J. Physiol. 263 (Cell Physiol. 32): C1007-C1014, 1992]. The test of the hypothesis was to modify the Lp antigens of immature LK red blood cells with two kinds of treatments, anti-Lp antibody and trypsinization (which cleaves Lp), and to observe the effects of these treatments on maturation of pumps during culture of the cells in vitro. Both of these treatments prevented the maturation of the kinetics of the pumps to the Ki-sensitive pattern, supporting the hypothesis that interaction of the pumps with Lp antigens is responsible for the maturation of the pumps. Strong supportive evidence came from experiments on Na(+)-K+ pumps from rat kidney delivered into immature LK sheep red blood cells by microsome fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Decline in number of Na-K pumps on low-K+ sheep reticulocytes during maturation is modulated by Lp antigen

1994 ◽  
Vol 266 (5) ◽  
pp. C1173-C1181 ◽  
Author(s):  
Z. C. Xu ◽  
P. B. Dunham ◽  
B. Dyer ◽  
R. Blostein
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Group Antigen ◽  
Cell Maturation ◽  
Alpha Subunit ◽  
Ouabain Binding ◽  
High K ◽  
Antigen System ◽  
Low K

The number of the Na-K pumps on sheep red blood cells declines markedly during cell maturation. In addition, in red blood cells of the low-K+ (LK) phenotype, there is an increase during maturation in the affinity of the pumps for intracellular K+. This increase does not occur in cells of the high-K+ (HK) phenotype. This HK/LK polymorphism is associated with the M/L blood group antigen system. The Lp antigen, which is on only LK cells, promotes the increase in affinity for K+ [Am. J. Physiol. 265 (Cell Physiol. 34): C99-C105, 1993]. Mature LK cells have fewer pumps than mature HK cells. The present study shows that the Lp antigen also promotes the loss of pumps in LK cells. The evidence was that modification of the Lp antigen of immature LK red blood cells either with anti-Lp antibody or by trypsinization diminished the loss of pumps during culture in vitro (numbers determined from [3H]ouabain binding). Confirmation came from demonstration of the decline during maturation of the amount of the alpha-subunit of the Na-K pump (measured by immunoblotting), which was also retarded by pretreatment with anti-Lp or trypsin. Comparisons of the relative amounts of Lp antigen on immature and mature LK cells showed that there is little decline in number of antigens during maturation. Therefore there is an increase in the antigen-to-pump ratio during maturation even though an association between pumps and antigens is necessary for the loss of pumps.

Oxygenation of frog gastric mucosa in vitro

1975 ◽  
Vol 229 (6) ◽  
pp. 1510-1513 ◽  
Author(s):  
GW Kidder ◽  
CW Montgomery
Keyword(s):  
Oxygen Consumption ◽  
Gastric Mucosa ◽  
Acid Secretion ◽  
Normal Pressure ◽  
Bathing Solution ◽  
Hyperbaric Chamber ◽  
Secretory Rate ◽  
Co2 Diffusion ◽  
Rate Of Oxygen Consumption

We have recently shown that 5% CO2/95% O2 in the serosal bathing solution, with 100% O2 in the mucosal solution, results in CO2-diffusion limitation of acid secretion in bullfrog gastric mucosa. Changing to 10% CO2/90% 02 on both surfaces doubles the acid secretory rate. We calculate that, were the rate of oxygen consumption to increase significantly as a result of secretory stimulation, the tissue would now be oxygen limited. This prediction is tested by raising the P02 by increasing the total pressure in a hyperbaric chamber. Since no change in acid secretory rate or potential difference was observed upon changing from PO2 = 0.9 to PO2 = 1.9 atm, we conclude that the tissue is not O2 limited at normal pressure. Decreasing PO2 below 0.9 atm, by contrast, decreases the acid secretory rate and raises both PD and resistance. We infer that the rate of oxygen consumption did not rise significantly when acid secretion was increased by supplying sufficient CO2.

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

1975 ◽  
Vol 228 (2) ◽  
pp. 511-517 ◽  
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.

Inhibition of H+ secretion in the frog gastric mucosa by ATP and related compounds

1976 ◽  
Vol 230 (6) ◽  
pp. 1688-1694 ◽  
Author(s):  
SS Sanders ◽  
CF Butler ◽  
J O'Callaghan ◽  
WS Rehm
Keyword(s):  
Gastric Mucosa ◽  
Rana Pipiens ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Threshold Concentration ◽  
Maximal Inhibition ◽  
Secretory Rate ◽  
Free Media ◽  
Related Compounds

Addition of adenosine triphosphate (ATP) to the nutrient (submucosal-facing) solution of the histamine-stimulated in vitro frog (Rana pipiens) gastric mucosa produces a marked reduction in the H+ secretory rate and an increase in transmucosal potential difference (PD) and resistance in both Cl- and Cl-free media. The effects are reversible upon removal of ATP. The threshold concentration is between 1 and 2 mM, and 5 mM produce maximal inhibition. It is shown that the effects of ATP are not due to a change in pH or osmolarity of the nutrient fluid, or to a decrease in the Ca2+ and/or Mg2+ activities of the nutrient fluid. It is also shown that the inhibitory action of ATP is not dependent on a chelation complex between Ca2+ or Mg2+. Adenosine diphosphate also produces effects essentially the same as ATP whereas 5'-adenosine monophosphate and adenosine produce relatively little or no change.

Inhibition of gastric H+ secretion, K+-ATPase and K+-phosphatase by estradiol in vivo and in vitro

1982 ◽  
Vol 60 (5) ◽  
pp. 680-684 ◽  
Author(s):  
L. Limlomwongse ◽  
P. Piyachaturawat
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Enzyme Activities ◽  
Direct Action ◽  
Inhibitory Effect ◽  
Secretory Rate ◽  
Dose Dependent

The effect of estrogen on the gastric acid secretion and H+-transporting enzymes, K+ -ATPase and K+-phosphatase, were investigated in the rat. The maximum H+ secretory rate in response to 1 mM histamine was significantly reduced (P < 0.05) in both the isolated gastric mucosa obtained from the rats treated with estradiol in vivo for 7 days and the mucosa directly incubated in vitro with estradiol. The inhibitory effect on the gastric enzyme activities in vitro showed a dose-dependent pattern of a noncompetitive type. The result suggested that estradiol may have a direct action on the gastric H+ secretion by inhibiting the H+ transport enzyme activities.

Effects of increased O2 and CO2 on acid secretion by dogfish gastric mucosa in vitro

1976 ◽  
Vol 231 (4) ◽  
pp. 1240-1245 ◽  
Author(s):  
Kidder GW
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Squalus Acanthias ◽  
Transepithelial Resistance ◽  
O2 Consumption ◽  
Hyperbaric Chamber ◽  
Secretory Rate ◽  
Co2 Diffusion ◽  
Hyperbaric Conditions

The gastric mucosa of the dogfish (Squalus acanthias), as usually prepared for in vitro chambered experiments, shows a secretory rate (JH) of about 2 mueq/cm2-h, but a potential difference (PD) of zero. Raising PCO2 from 0.05 to 0.1 atm increases JH by 40% and causes the development of a PD of about 2 mV, mucosal surface positive. Increasing PO2 from 0.9 to 1.9 atm in a hyperbaric chamber (at constant PCO2 = 0.1 atm) doubles JH and increases PD to 5 mV. Transepithelial resistance falls by 20% at high PO2. It appears that the dogfish gastric mucosa, like that of the frog, is rate limited by CO2 diffusion into the tissue from the usual 5% mixture and is also rate limited by the usual O2 levels (unlike the frog), presumably due to its thicker structure and higher O2 consumption. The mucosal-positive PD, which is reversed from all other mucosae studied, is readily explained by separate electrogenic H+ and Cl- pumps, but less readily by schemes embodying a neutral HCl pump. It is not yet known whether the hyperbaric conditions are sufficient to ensure O2 sufficiency.

scholarly journals Antidiarrheal and antispasmodic activities of Polygonum bistorta rhizomes are mediated predominantly through K+ channels activation

2015 ◽  
Vol 10 (3) ◽  
pp. 627 ◽  
Author(s):  
Muhammad Zeeshan Ali ◽  
Khalid Hussain Janbaz ◽  
Malik Hassan Mehmood ◽  
Anwar Hassan Gilani
Keyword(s):  
Tetraethylammonium Chloride ◽  
Relaxant Effect ◽  
Complete Relaxation ◽  
High K ◽  
Rabbit Jejunum ◽  
Low K ◽  
Dose Dependent ◽  
Antagonist Effect

<p class="Abstract"><em>Polygonum bistorta</em> is a popular medicinal herb used to treat diarrhea. This study provides pharmacological basis to its folk use in diarrhea using <em>in vivo</em> and <em>in vitro</em> assays. Administration of<em> P. bistorta</em>  rhizomes extract to mice offered protection against castor oil-induced diarrhea at 300-1,000 mg/kg and was found safe up to the dose of 5 g/kg. In isolated rabbit jejunum, the extract caused a dose-dependent relaxation of spontaneous and low K<sup>+</sup> (25 mM)-induced contractions with weak effect against high K<sup>+ </sup>(80 mM). In tissues pretreated with glibenclamide or tetraethylammonium chloride (TEA), the relaxant effect of the extract was markedly inhibited by TEA only. While verapamil showed complete relaxation of spontaneous, low K<sup>+</sup>, low K<sup>+</sup> with TEA and high K<sup>+</sup>-induced contractions. In guinea-pig ileum, mild atropine-sensitive effect was observed. This study indicates that <em>P. bistorta</em> possesses anti-diarrheal and antispasmodic activities mediated predominantly through K<sup>+</sup>-channels activation along with weak Ca<sup>++</sup> antagonist effect.</p><p> </p>

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