Sites of resistance changes with inhibition of acid secretion in frog stomach

1986 ◽  
Vol 250 (5) ◽  
pp. G639-G647
Author(s):  
W. S. Rehm ◽  
G. Carrasquer ◽  
M. Schwartz
Keyword(s):  
Acid Secretion ◽  
Proton Pump ◽  
Tubular Cell ◽  
Secretory Rate ◽  
Tubular Cells ◽  
Resistance Increase ◽  
Frog Stomach ◽  
Scn Resistance ◽  
Gastric Proton Pump ◽  
Resistance Decrease

The primary purpose of this study was to determine the sites of resistance changes from thiocyanate inhibition of secretion to better evaluate models of the gastric proton pump. The potential difference, resistance, and H+ secretory rate were measured with various tonicities of the secretory fluid. Thiocyanate (SCN) inhibition generally produces a resistance increase, but with nutrient Ba, the resistance is high and SCN decreases it. The latter effect is also seen with cimetidine. In the secreting fundus a hypotonic secretory solution has a small effect on resistance, but in the inhibited fundus the effect is huge, due to increase of resistance of the lumen-tubular cell pathway. With a hypotonic secretory solution, for inhibited fundus (cimetidine or omeprazole) and antrum, SCN does not decrease the resistance of the surface cells and/or the transintercellular pathways with or without Ba. The SCN resistance decrease with Ba is via the tubular cell pathway. With Ba the resistance of the nutrient membrane of the tubular cells decreases after SCN or cimetidine inhibition. The findings further support the concept that under standard conditions the resistance via the lumina and tubular cells is low and that via the surface cells and transintercellular pathways is high.

scholarly journals Effect of omeprazole--a gastric proton pump inhibitor--on pentagastrin stimulated acid secretion in man.

Gut ◽  
1983 ◽  
Vol 24 (4) ◽  
pp. 270-276 ◽  
Author(s):  
T Lind ◽  
C Cederberg ◽  
G Ekenved ◽  
U Haglund ◽  
L Olbe
Keyword(s):  
Proton Pump Inhibitor ◽  
Acid Secretion ◽  
Proton Pump ◽  
Gastric Proton Pump

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.

Acid secretion by frog gastric mucosa is electroneutral

1985 ◽  
Vol 248 (2) ◽  
pp. G246-G250 ◽  
Author(s):  
S. J. Hersey ◽  
G. Sachs ◽  
D. K. Kasbekar
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Proton Pump ◽  
Short Circuit ◽  
Specific Inhibitor ◽  
Short Circuit Current ◽  
Potential Difference ◽  
Sulfate Solutions ◽  
High K ◽  
Gastric Proton Pump

The action of a newly developed, specific inhibitor of the gastric proton pump, omeprazole, was investigated using intact frog gastric mucosa. Omeprazole was found to inhibit acid secretion, and the inhibition could be reversed with glutathione or 2-mercaptoethanol. Inhibition was not stimulus specific, occurring with histamine, carbachol, and forskolin. With hypertonic solutions bathing the mucosal surface, omeprazole inhibition of acid secretion did not change the tissue conductance, whereas inhibition by thiocyanate or cimetidine resulted in a significant decrease in conductance. With high-K+ (greater than 80 mM) sulfate solutions bathing both surfaces, omeprazole inhibition of acid secretion resulted in no change in transtissue potential difference. In chloride solutions, omeprazole caused an increase in potential difference and short-circuit current. These results provide evidence that the proton pump in frog gastric mucosa is electroneutral.

Acid secretion, potential, and resistance of frog stomach in K+-free solutions

1965 ◽  
Vol 209 (1) ◽  
pp. 146-152 ◽  
Author(s):  
T. L. Davis ◽  
J. R. Rutledge ◽  
D. C. Keesee ◽  
F. J. Bajandas ◽  
W. S. Rehm
Keyword(s):  
Gastric Mucosa ◽  
Acid Secretion ◽  
Electrical Resistance ◽  
Transient Increase ◽  
Potential Difference ◽  
Secretory Rate ◽  
Frog Stomach ◽  
Voltage Clamping

The removal of K+ from the fluids bathing the in vitro frog gastric mucosa results in a decrease of the H+ secretory rate to zero, a marked increase in electrical resistance, a transient increase in potential difference (PD), and relatively little change in the K+ content of the mucosa. The effects of K+ removal are reversed by adding K+ either to the nutrient fluid (4 mm) or to the secretory fluid (104 mm). They are not reversed by voltage clamping (nutrient positive). Following the cessation of H+ secretion, the PD gradually decreases to a level that is low but still greater than zero. The PD under these conditions can be reversibly reduced to about zero by anoxia. It is concluded that the presence of K+ in certain regions of the mucosa is necessary for the functioning of the H+ and Cl– mechanisms.

scholarly journals PP2Acα promotes macrophage accumulation and activation to exacerbate tubular cell death and kidney fibrosis through activating Rap1 and TNFα production

2021 ◽  
Author(s):  
Yan Liang ◽  
Xiaoli Sun ◽  
Mingjie Wang ◽  
Qingmiao Lu ◽  
Mengru Gu ◽  
...  
Keyword(s):  
Cell Death ◽  
Tubular Cell ◽  
Kidney Fibrosis ◽  
Tubular Cells ◽  
Ureter Obstruction ◽  
Underlying Mechanisms ◽  
Factor Α ◽  
Rap1 Activation ◽  
Necrosis Factor ◽  
Macrophage Accumulation

AbstractMacrophage accumulation and activation play an essential role in kidney fibrosis; however, the underlying mechanisms remain to be explored. By analyzing the kidney tissues from patients and animal models with kidney fibrosis, we found a large induction of PP2Acα in macrophages. We then generated a mouse model with inducible macrophage ablation of PP2Acα. The knockouts developed less renal fibrosis, macrophage accumulation, or tubular cell death after unilateral ureter obstruction or ischemic reperfusion injury compared to control littermates. In cultured macrophages, PP2Acα deficiency resulted in decreased cell motility by inhibiting Rap1 activity. Moreover, co-culture of PP2Acα−/− macrophages with tubular cells resulted in less tubular cell death attributed to downregulated Stat6-mediated tumor necrosis factor α (TNFα) production in macrophages. Together, this study demonstrates that PP2Acα promotes macrophage accumulation and activation, hence accelerates tubular cell death and kidney fibrosis through regulating Rap1 activation and TNFα production.

scholarly journals Luminescent Immunoprecipitation System (LIPS) for Detection of Autoantibodies Against ATP4A and ATP4B Subunits of Gastric Proton Pump H+,K+-ATPase in Atrophic Body Gastritis Patients

2017 ◽  
Vol 8 (1) ◽  
pp. e215 ◽  
Author(s):  
Edith Lahner ◽  
Cristina Brigatti ◽  
Ilaria Marzinotto ◽  
Marilia Carabotti ◽  
Giulia Scalese ◽  
...  
Keyword(s):  
Proton Pump ◽  
Gastric Proton Pump

scholarly journals Ionic mechanisms of two types of on-center bipolar cells in the carp retina. I. The responses to central illumination.

1979 ◽  
Vol 73 (1) ◽  
pp. 73-90 ◽  
Author(s):  
T Saito ◽  
H Kondo ◽  
J I Toyoda
Keyword(s):  
Reversal Potential ◽  
Maximum Amplitude ◽  
Bipolar Cells ◽  
Light Spot ◽  
Membrane Properties ◽  
Resistance Increase ◽  
Membrane Conductances ◽  
Electric Interaction ◽  
Ionic Mechanisms ◽  
Resistance Decrease

Properties of the depolarizing response of on-center bipolar cells to a light spot stimulus were studied in the carp retina. On-center bipolar cells were classified into two types, cone-dominant and rod-dominant, according to their major input from cones and rods. Cone-dominant bipolar cells responded to spectral light with the maximum amplitude near 625 nm, suggesting major input from red cones. The response was accompanied by a resistance increase and showed a reversal potential at -63 +/- 21 mV when the membrane was hyperpolarized by current. The results suggest that the photoresponse of cone-dominant cells is due to a decrease of gK and/or gCl, membrane conductances to potassium and chloride, respectively. Rod-dominant bipolar cells responded to spectral light with the maximum amplitude near 525 nm under scotopic conditions and near 625 nm under photopic conditions, providing evidence that they receive input from rods and red cones. In the scoptopic condition their response was accompanied by a resistance decrease and showed a reversal potential at 29 +/- 13 mV, whereas in the photopic condition the response in most of them was accompanied by a resistance increase, at least in their part and showed a reversal at -53 +/- 11 mV. The results suggest that the photoresponse activated by rod input is due to an increase in gNa. In the mesopic condition rod-dominant cells showed complex electrical membrane properties as the result of electric interaction between the above two differnt ionic mechanisms activated by rod and cone inputs.

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