Comparison of two Chinese medical herbs, Huangbai and Qianniuzi, on influence of short circuit current across the rat intestinal epithelia

2004 ◽  
Vol 93 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Jong-Chang Tsai ◽  
Shuli Tsai ◽  
Weng-Cheng Chang
2004 ◽  
Vol 280 (6) ◽  
pp. 4048-4057 ◽  
Author(s):  
Vasantha Kolachala ◽  
Vivian Asamoah ◽  
Lixin Wang ◽  
Shanthi Srinivasan ◽  
Didier Merlin ◽  
...  

2019 ◽  
Author(s):  
Yoshio Takei ◽  
Marty K.S. Wong ◽  
Masaaki Ando

AbstractThe intestine of marine teleosts secretes HCO3- into the lumen and precipitates Ca2+ and Mg2+ in the imbibed seawater as carbonates to decrease luminal fluid osmolality and facilitate water absorption. However, reports on studies on the hormonal regulation of HCO3- secretion are just emerging. Here, we showed that guanylin (GN) applied to the mucosal side of intestinal epithelia increased HCO3- secretion in seawater-acclimated eels. The effect of GN on HCO3- secretion was slower than that on the short-circuit current, and the time-course of the GN effect was similar to that of bumetanide. Mucosal bumetanide and serosal 4,4’-dinitrostilbene-2,2’-disulfonic acid (DNDS) inhibited the GN effect, suggesting an involvement of apical Na+-K+-2Cl- cotransporter (NKCC2) and basolateral Cl-/HCO3- exchanger (AE)/Na+-HCO3- cotransporter (NBC) in the GN effect. However, mucosal DNDS and diphenylamine-2-carboxylic acid (DPC) failed to inhibit the GN effect, showing that apical AE and Cl- channel are not involved. To identify molecular species of possible transporters involved in the GN effect, we performed RNA-seq analyses followed by quantitative real-time PCR after transfer of eels to seawater. Among the genes upregulated after seawater transfer, those of Slc26a3a, b (DRAa, b) and Slc26a6a, c (Pat-1a, c) on the apical membrane of the intestinal epithelial cells, and those of Sls4a4a (NBCe1a), Slc4a7 (NBCn1), Slc4a10a (NBCn2a) and Slc26a1 (Sat-1) on the basolateral membrane were candidate transporters involved in HCO3- secretion. Judging from the slow effect of GN, we suggest that GN inhibits NKCC2b on the apical membrane and decreases cytosolic Cl- and Na+, which then activates apical DNDS-insensitive DRAa, b and basolateral DNDS-sensitive NBCela, n1, n2a to enhance transcellular HCO3- flux across the intestinal epithelia of seawater-acclimated eels.


2000 ◽  
Vol 279 (5) ◽  
pp. G866-G874 ◽  
Author(s):  
Pamela J. Gunter-Smith ◽  
Oluwakemi Abdulkadir ◽  
Latanya Hammonds-Odie ◽  
Mary Scanlon ◽  
Raquel Terrell

We have developed a cell culture of guinea pig gallbladder epithelial cells with which to study ion transport. When grown on permeable supports, the cultured epithelia developed a transepithelial resistance ( R t) of ∼500 Ω · cm2. The epithelial cell origin of the cell culture was further confirmed by immunocytochemical localization of cytokeratin. Ionomycin and forskolin increased transepithelial voltage and short-circuit current ( I sc) and decreased R t. The response to ionomycin was transient, whereas that to forskolin was sustained. Both were attenuated by replacement of Cl− and/or HCO3 −. Mucosal addition of the anion transport inhibitors DIDS or diphenylamine-2-carboxylic acid (DPC) blocked the response to ionomycin. The response to forskolin was blocked by DPC but not by DIDS. Ionomycin, but not forskolin, increased intracellular Ca2+ concentration in fura 2-loaded cells. PGE2, histamine, vasoactive intestinal polypeptide, and secretin elicited a sustained increase in I sc. Responses to ATP and CCK were transient. Thus cultured guinea pig gallbladder epithelia display the range of responses observed in the native tissue and are an appropriate model for studies of ion transport in gallbladder and intestinal epithelia.


2000 ◽  
Vol 279 (4) ◽  
pp. G707-G718 ◽  
Author(s):  
B. R. Grubb ◽  
E. Lee ◽  
A. J. Pace ◽  
B. H. Koller ◽  
R. C. Boucher

The Na+-K+-2Cl− cotransporter (NKCC1) located on the basolateral membrane of intestinal epithelia has been postulated to be the major basolateral Cl− entry pathway. With targeted mutagenesis, mice deficient in the NKCC1 protein were generated. The basal short-circuit current did not differ between normal and NKCC1 −/− jejuna. In the −/− jejuna, the forskolin response (22 μA/cm2; bumetanide insensitive) was significantly attenuated compared with the bumetanide-sensitive response (52 μA/cm2) in normal tissue. Ion-replacement studies demonstrated that the forskolin response in the NKCC1 −/− jejuna was HCO3 − dependent, whereas in the normal jejuna it was independent of the HCO3 − concentration in the buffer. NKCC1 −/− ceca exhibited a forskolin response that did not differ significantly from that of normal ceca, but unlike that of normal ceca, was bumetanide insensitive. Ion-substitution studies suggested that basolateral HCO3 − as well as Cl− entry (via non-NKCC1) paths played a role in the NKCC1 −/− secretory response. In contrast to cystic fibrosis mice, which lack both basal and stimulated Cl− secretion and exhibit severe intestinal pathology, the absence of intestinal pathology in NKCC1 −/− mice likely reflects the ability of the intestine to secrete HCO3 − and Cl− by basolateral entry mechanisms independent of NKCC1.


1985 ◽  
Vol 248 (5) ◽  
pp. R573-R577 ◽  
Author(s):  
K. A. Thompson ◽  
A. Kleinzeller

D-Glucose (Glc) transport was studied in stripped intestinal epithelial sheets of the winter flounder Pseudopleuronectes americanus. At 1 mM Glc and 15 degrees C, Glc uptake did not occur against a concentration gradient (free cell Glc 0.78 +/- 0.06 mM) but was inhibited by 0.5 mM phlorizin or ouabain. [U-14C]-Glc oxidation to 14CO2 was also depressed by these agents or the absence of Na+ and was saturable (Km 3.3 +/- 1.2 mM Glc; maximal velocity at saturating substrate concentration (Vmax) 4.0 +/- 2.0 mumol X g wet wt-1 X h-1]. No electrical transcellular manifestations of the Na-Glc cotransport system were seen in regular media. In the absence of Cl-, Glc and nonmetabolizable Glc analogs (alpha-methyl-D-glucopyranoside or 3-O-methyl-D-glucose) added mucosally elicited an increase in a serosally directed short-circuit current that was inhibitable by 0.5 mM mucosal phlorizin or 0.1 mM serosal ouabain and dependent on the external sugar concentration [Km 2.3 +/- 1.8 mM (range 0.6 to 6.1); Vmax 2.4 +/- 1.1 microA X cm-2 (range 0.8-4.2)]. Vmax for L-leucine transport was fivefold greater [13.4 +/- 7.3 microA X cm-2 (range 4.6-20.7)]. These results indicate the presence of a mucosal Na+-linked Glc absorptive system and reflect the paucity of transport sites for Glc relative to leucine.


2013 ◽  
Vol 133 (1) ◽  
pp. 37-44
Author(s):  
Suresh Chand Verma ◽  
Yoshiki Nakachi ◽  
Yoshihiko Wazawa ◽  
Yoko Kosaka ◽  
Takenori Kobayashi ◽  
...  

2017 ◽  
pp. 34-41
Author(s):  
Andrei V. MAIOROV ◽  
◽  
Kirill A. OSINTSEV ◽  
Andrei V. SHUNTOV ◽  
◽  
...  

2020 ◽  
Vol 16 (4) ◽  
pp. 556-567
Author(s):  
Asma Khalil ◽  
Zubair Ahmad ◽  
Farid Touati ◽  
Mohamed Masmoudi

Background: The photo-absorption and light trapping through the different layers of the organic solar cell structures are a growing concern now-a-days as it affects dramatically the overall efficiency of the cells. In fact, selecting the right material combination is a key factor in increasing the efficiency in the layers. In addition to good absorption properties, insertion of nanostructures has been proved in recent researches to affect significantly the light trapping inside the organic solar cell. All these factors are determined to expand the absorption spectrum and tailor it to a wider spectrum. Objective: The purpose of this investigation is to explore the consequence of the incorporation of the Ag nanostructures, with different sizes and structures, on the photo absorption of the organic BHJ thin films. Methods: Through a three-dimensional Maxwell solver software, Lumerical FDTD, a simulation and comparison of the optical absorption of the three famous organic materials blends poly(3- hexylthiophene): phenyl C71 butyric acid methyl ester (P3HT:PCBM), poly[N-9″-heptadecanyl-2,7- carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDTBT:PCBM) and poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt- 4,7-(2,1,3-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDPDTBT:PCBM) has been conducted. Furthermore, FDTD simulation study of the incorporation of nanoparticles structures with different sizes, in different locations and concentrations through a bulk heterojunction organic solar cell structure has also been performed. Results: It has been demonstrated that embedding nanostructures in different locations of the cell, specifically in the active layer and the hole transporting layer had a considerable effect of widening the absorption spectrum and increasing the short circuit current. The effect of incorporation the nanostructures in the active layer has been proved to be greater than in the HTL. Furthermore, the comparison results showed that, PCDTBT:PCBM is no more advantageous over P3HT:PCBM and PCPDTBT:PCBM, and P3HT:PCBM took the lead and showed better performance in terms of absorption spectrum and short circuit current value. Conclusion: This work revealed the significant effect of size, location and concentration of the Ag nanostructures while incorporated in the organic solar cell. In fact, embedding nanostructures in the solar cell widen the absorption spectrum and increases the short circuit current, this result has been proven to be significant only when the nanostructures are inserted in the active layer following specific dimensions and structures.


2020 ◽  
Vol 89 (3) ◽  
pp. 30201 ◽  
Author(s):  
Xi Guan ◽  
Shiyu Wang ◽  
Wenxing Liu ◽  
Dashan Qin ◽  
Dayan Ban

Organic solar cells based on planar copper phthalocyanine (CuPc)/C60 heterojunction have been characterized, in which a 2 nm-thick layer of bathocuproine (BCP) is inserted into the CuPc layer. The thin layer of BCP allows hole current to tunnel it through but blocks the exciton diffusion, thereby altering the steady-state exciton profile in the CuPc zone (zone 1) sandwiched between BCP and C60. The short-circuit current density (JSC) of device is limited by the hole-exciton scattering effect at the BCP/CuPc (zone 1) interface. Based on the variation of JSC with the width of zone 1, the exciton diffusion length of CuPc is deduced to be 12.5–15 nm. The current research provides an easy and helpful method to determine the exciton diffusion lengths of organic electron donors.


Sign in / Sign up

Export Citation Format

Share Document