scholarly journals OEsophageal Ion Transport Mechanisms and Significance Under Pathological Conditions

2020 ◽  
Vol 11 ◽  
Author(s):  
Eszter Becskeházi ◽  
Marietta Margaréta Korsós ◽  
Bálint Erőss ◽  
Péter Hegyi ◽  
Viktória Venglovecz
Keyword(s):  
Ion Transport ◽  
Transport Mechanisms ◽  
Pathological Conditions

The anterior and posterior ‘stomach’ regions of larval Aedes aegypti midgut: regional specialization of ion transport and stimulation by 5-hydroxytryptamine

1999 ◽  
Vol 202 (3) ◽  
pp. 247-252 ◽  
Author(s):  
T.M. Clark ◽  
A. Koch ◽  
D.F. Moffett
Keyword(s):  
Steady State ◽  
Aedes Aegypti ◽  
Ion Transport ◽  
Malpighian Tubules ◽  
Transport Mechanisms ◽  
Regional Specialization ◽  
Negative Deflection ◽  
Electrical Polarity

The ‘stomach’ region of the larval mosquito midgut is divided into histologically distinct anterior and posterior regions. Anterior stomach perfused symmetrically with saline in vitro had an initial transepithelial potential (TEP) of −66 mV (lumen negative) that decayed within 10–15 min to a steady-state TEP near −10 mV that was maintained for at least 1 h. Lumen-positive TEPs were never observed in the anterior stomach. The initial TEP of the perfused posterior stomach was opposite in polarity, but similar in magnitude, to that of the anterior stomach, measuring +75 mV (lumen positive). This initial TEP of the posterior stomach decayed rapidly at first, then more slowly, eventually reversing the electrical polarity of the epithelium as lumen-negative TEPs were recorded in all preparations within 70 min. Nanomolar concentrations of the biogenic amine 5-hydroxytryptamine (5-HT, serotonin) stimulated both regions, causing a negative deflection of the TEP of the anterior stomach and a positive deflection of the TEP of the posterior stomach. Phorbol 12,13-diacetate also caused a negative deflection of the TEP of the anterior stomach, but had no effect on the TEP of the posterior stomach. These data demonstrate that 5-HT stimulates region-specific ion-transport mechanisms in the stomach of Aedes aegypti and suggest that 5-HT coordinates the actions of the Malpighian tubules and midgut in the maintenance of an appropriate hemolymph composition in vivo.

scholarly journals Molecular Dynamics Study of Ion Transport in Polymer Electrolytes of All-Solid-State Li-Ion Batteries

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1012
Author(s):  
Takuya Mabuchi ◽  
Koki Nakajima ◽  
Takashi Tokumasu
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Ion Transport ◽  
Polyethylene Oxide ◽  
Polymer Electrolytes ◽  
Li Ion Batteries ◽  
Transport Mechanisms ◽  
Li Ion ◽  
Dynamics Simulations ◽  
The Relationship

Atomistic analysis of the ion transport in polymer electrolytes for all-solid-state Li-ion batteries was performed using molecular dynamics simulations to investigate the relationship between Li-ion transport and polymer morphology. Polyethylene oxide (PEO) and poly(diethylene oxide-alt-oxymethylene), P(2EO-MO), were used as the electrolyte materials, and the effects of salt concentrations and polymer types on the ion transport properties were explored. The size and number of LiTFSI clusters were found to increase with increasing salt concentrations, leading to a decrease in ion diffusivity at high salt concentrations. The Li-ion transport mechanisms were further analyzed by calculating the inter/intra-hopping rate and distance at various ion concentrations in PEO and P(2EO-MO) polymers. While the balance between the rate and distance of inter-hopping was comparable for both PEO and P(2EO-MO), the intra-hopping rate and distance were found to be higher in PEO than in P(2EO-MO), leading to a higher diffusivity in PEO. The results of this study provide insights into the correlation between the nanoscopic structures of ion solvation and the dynamics of Li-ion transport in polymer electrolytes.

scholarly journals Pharmacological analysis of ion transport mechanisms in heart mitochondria.

1996 ◽  
Vol 71 ◽  
pp. 314
Author(s):  
Kazumi Takeya ◽  
Yoshihiro Hotta ◽  
Michiko Fujita ◽  
Junichi Nakagawa ◽  
Masataka Itoigawa
Keyword(s):  
Ion Transport ◽  
Heart Mitochondria ◽  
Transport Mechanisms ◽  
Pharmacological Analysis

scholarly journals Understanding Multi-Ion Transport Mechanisms in Bipolar Membranes

2020 ◽  
Vol 12 (47) ◽  
pp. 52509-52526
Author(s):  
Justin C. Bui ◽  
Ibadillah Digdaya ◽  
Chengxiang Xiang ◽  
Alexis T. Bell ◽  
Adam Z. Weber
Keyword(s):  
Ion Transport ◽  
Transport Mechanisms ◽  
Bipolar Membranes

scholarly journals Ion transport mechanisms in salt‐doped polymerized zwitterionic electrolytes

2020 ◽  
Vol 58 (4) ◽  
pp. 578-588 ◽  
Author(s):  
Jordan R. Keith ◽  
Venkat Ganesan
Keyword(s):  
Ion Transport ◽  
Transport Mechanisms

Ion transport mechanisms in rat parotid intralobular striated ducts

1994 ◽  
Vol 266 (6) ◽  
pp. C1594-C1602 ◽  
Author(s):  
M. Paulais ◽  
E. J. Cragoe ◽  
R. J. Turner
Keyword(s):  
Ion Transport ◽  
Channel Blocker ◽  
K Channel ◽  
Muscarinic Agonist ◽  
Transport Mechanisms ◽  
Adrenergic Agonist ◽  
Acid Load ◽  
Rat Parotid ◽  
H Channels ◽  
Beta Adrenergic Agonist

The intracellular pH (pHi) indicator 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein and microfluorimetry were used to characterize several ion transport mechanisms in rat parotid striated ducts. The recovery of ductal pHi from an acute acid load was Na+ dependent and inhibited by the amiloride analogue ethylisopropylamiloride with 50% inhibitory concentration 4.7 +/- 0.8 microM, indicating the presence of a Na(+)-H+ exchanger of the amiloride-insensitive type. The rate of this recovery was stimulated approximately 20% in ducts pretreated with the muscarinic agonist carbachol (10(-5) M) and inhibited approximately 20% in ducts pretreated with the beta-adrenergic agonist isoproterenol (10(-6) M). Upon removal of extracellular K+, ductal pHi rapidly decreased (0.19 +/- 0.02 pH units/min), consistent with a coupling between K+ and H+ (or OH-) fluxes in this tissue. In HCO(3-)-containing medium, the acidification due to K+ removal was blunted, arguing against ductal K(+)-HCO3- cotransport. However, the effect of K+ removal was inhibited by the K+ channel blocker Ba2+ (1 mM) and by the H+ channel blocker Zn2+ (25 microM), consistent with the involvement of electrically coupled K+ and H+ channels. The effect of K+ removal was unaffected by pretreatment of ducts with isoproterenol (10(-6) M) but markedly inhibited (approximately 50%) by pretreatment with carbachol (10(-5) M). No evidence for a significant component of Cl(-)-HCO3- exchange was found in striated ducts. The properties of the Na(+)-H+ exchanger and K(+)-H+ exchange mechanism identified here are consistent with their involvement in ductal salt reabsorption and secretion.

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