Membrane chloride

Abam Engineers, Final Report on Process Engineering andEconomic Evaluations of Diaphragm and Membrane Chloride Cell Technologies, ANL/OEPM-80-9, Argonne National Laboratories, Argonne, lU., Dec. 1980. 

C1C-6 and C1C-7 define the third branch of the CLC family. These proteins are only about 45% identical to each other. Whereas CLC-7 is very broadly expressed, the CLC-6 protein seems to be restricted to the nervous system. It proved impossible to obtain plasma membrane chloride currents with either C1C-6 or C1C-7. This is due to the fact that both channels reside in intracellular organelles under most circumstances. Based on structural features, it appeals likely that they also mediate CF/H + exchange. 

Olsen JC, Johnson LG, Stutts MJ, Sarkadi B, Yankaskas JR, Swanstrom R, Boucher RC (1992) Correction of the apical membrane chloride permeability defect in polarized cystic fibrosis airway epithelia following retroviral-mediated gene transfer. Hum Gene Ther 3(3) 253-266. 

Chloral hydrate, clomethiazole and barbiturates also enhance GABA function but at high doses have the additional capacity directly to open the membrane chloride channel (see Figure 19.4) this may lead to potentially lethal respiratory depression and explains their low therapeutic ratio. These drugs also have a propensity for abuse/misuse and are very much second-line treatments. 

The hypothesis that Pgp regulates volume-activated chloride channels was developed by the observation that Pgp was highly related to the cystic fibrosis transmembrane regulator protein (CFTR). CFTR belongs, like Pgp, to the ABC superfamily of transporters and is a plasma membrane chloride channel that is dysfunctional in cystic fibrosis (50). However, the role of Pgp in volume-regulatory processes has been controversial, and a current hypothesis is that Pgp does not have channel activity itself, but it may regulate swelling-induced anion channels (57). 

The paralysing action of ivermectin on the nematodes is due to its ability to activate a membrane chloride conductance in neurons of the nerve cord either directly or by enhancing the presynaptic release of GABA [180, 189] which eventually results in opening of chloride channels. 

The B subunit of cholera toxin, which is made up of five identical subunits (Figure 5A), attaches to the membranes of intestinal cells. The A subunit is then inserted into these cells, where it activates an enzyme that increases the concentration of a nucleotide called cyclic AMP (cAMP). High sustained concentrations of cAMP, a molecule that opens membrane chloride channels, causes severe diarrhea. (Loss of chloride results in water loss because of osmotic pressure. Several gallons of fluid per day may be lost.) If left untreated, severe dehydration may cause death within 48 hours, by circulatory shock brought on by low blood volume. 

Z. Gao and M. Lu, Flow Injection Analysis by Ion-Selective Electrodes. Use of a Solid Membrane Chloride Ion-Selective Electrode for Determination of Chloride in Soil-Water Extracts [in Chinese]. Huanjing Kexue, 2 (1981) 376. 

Membrane chloride transport (e.g. sodium-dependent transport. Renal brush-border, GABAa receptor),... 

Convection and diffusion determine the flow of uncharged compounds and ions through the membrane. Chloride anions in the catholyte are excluded by the cation-exchange membrane and repelled by the electric field, so that the transfer rate of chloride anions from the anolyte is extremly low. As a result, a caustic soda solution of... 

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