Chloride , efflux

Zonia, L., Cordeiro, S., Tupy, J. and Feijo, J.A., 2002, Oscillatory chloride efflux at the pollen tube apex has a role in growth and cell volume regulation and is targeted by inositol 3,4,5,6-tetrakisphosphate. Plant Cell 14 2233-2249. 

When the only cation present is Na" the illumination results in volume decrease [97,388,402], a consequence of active sodium extrusion and passive chloride efflux due to the membrane potential created. When is also added, in order to create conditions similar to those which the cells face during growth, the volume decrease is less because potassium is taken up [402], In envelope vesicles the permeabihty of... 

When the resting parietal cell is stimulated by acid secretagogues, the tubulovesicles are transformed into the secretory canaliculus. The parietal cell has the largest mitochondrial content of any mammalian cell (—34% of cell volume) and the ATP generated by this is mainly used for acid secretion. Hydrolysis of ATP results in a conformational change in the protein that mediates the electroneutral exchange of intracellular and extracellular K+. The pump is activated only when it is associated with a potassium chloride pathway in the canalicular membrane (Fig. 3.6). This allows potassium chloride efflux into the extra-cytoplasmic space and thus results in the secretion of HCl at the expense of ATP... 

The last mediator of gastric secretion in the parietal cell is an H+,K+-ATPase (proton or acid pump) which is a member of the phosphorylating class of ion transport ATPases. Hydrolysis of ATP results in ion transport. This chemical reaction induces a conformational change in the protein that allows an electroneutral exchange of cytoplasmic H+ for K+. The pump is activated when associated with a potassium chloride pathway in the canalicular membrane which allows potassium chloride efflux into the extracytoplasmic space, and thus results in secretion of hydrochloric acid at the expense of ATP breakdown. The activity of the pump is determined by the access of K+ on this surface on the pump. In the absence of K+, the cycle stops at the level of the phosphoenzyme [137]. 

Schwartz, R. D., Jackson, J. A., Weigert, D, Skolmck, P, and Paul, S M (1985) GABA- and barbiturate-stimulated chloride efflux from rat brain synaptoneurosomes J, Neurosci 5,2963-2970. 

Artificial phospholipid vesicles (liposomes) are used to transport vaccines, drugs, enzymes or other substances to target cells or organs. They also make excellent model systems for studying biological ion transport across cell membranes. The vesicles, which are several hundred nanometres in diameter, do not suffer from interference from residual natural ion-channel peptides or ionophores, unlike purified natural cells. For example, the synthetic heptapeptide 5.23 forms pores that promote chloride efflux in vesicle models. Similarly, the ion-pair receptor 2.108 can ferry NaCl from vesicles as an ion-pair ionophore (see Chapter 2, Section 2.6.2), while the hydraphile 5.24 has been shown to transport Na using Na NMR spectroscopy through the bilayer walls of a vesicle model system. 

Andersson, C. Roomans, G. M. Determination of chloride efflux by X-ray microanalysis versus MQAE-fluorescence. Microsc. Res. Tech. 2002, 59, 531-535. 

Fromm and Spanswick [79] found that electrical stimulation of a plant is followed by ion shifts which are most striking in the phloem cells. While their content of potassium and chloride was diminished after stimulation, the amount of cytoplasmic calcium increased slightly (Table 1). These displacements lead to the conclusion that Ca + influx as well as and CP efflux are involved in the propagation of action potentials. The main difference between propagation of action potentials in animals and plants is that in an axon there is the K /Na transmembrane transport but in phloem cells the K /Ca channels are involved in this process [Fig. 22(b)]. 

Mercuric chloride may induce catecholamine release from adrenals. The initial phase may be due to amine displacement by the mercury ion but the secondary phase probably involves alteration of membrane structures [95]. Mercury compounds have also been shown to increase the efflux of monoamines from mouse striated slices [96] and from adrenergic nerve fibre terminals [97], the effect being attributed to inhibition of Na /K+-ATPase activity and(or) disruption of intracellular Ca2+ regulatory mechanisms [96]. 

The proton which is generated is secreted from the osteoclasts by an ATP-dependent pump and chloride follows via a specific ion channel. Cytosolic concentration of chloride is maintained by an anion exchanger that mediates influx of chloride and efflux of bicarbonate (see Section 8.2.2 for comparison). 

Romanova, N. A., Wolffs, P. P. G., Brovko, L. Y., and Griffiths, M. W. (2006). Role of efflux pump in adaptation and resistance of Listeria monocytogenes to Benzalkonium chloride. Appl. Environ. Microbiol. 72(5), 3498-3503. 

Ca2+-gated chloride channels open. Efflux of Cl- depolarizes the cell, triggering an electrical signal to the brain. 

NaPi-1 (SLC17A1), alternatively referred to as NPT1, was originally cloned as a transporter involved in the reabsorption of phosphate in the body. Expression of NaPi-1 in X. laevis oocytes induced saturable uptake of benzylpenicillin (189). This uptake does not depend on Na+ and H+, but on Cl- (190), and increasing extracellular concentration of chloride reduced the uptake of benzyl-penicillin (190). The substrates include faropenem, foscamet, and mevalonate, as well as benzylpenicillin (190). In contrast to the kidney, the expression is localized to the sinusoidal membrane of the liver (190). When the direction of the concentration gradient of Cl- is taken into consideration, the transport direction mediated by NaPi-1 is efflux from inside the cells to the blood and urine in the liver and kidney, respectively. 

Stimulation of inhibitory neurons causes movement of ions that results in a hyperpolarization of the postsynaptic membrane. These inhibitory postsynaptic potentials (IPSP) are generated by the following (1) Stimulation of inhibitory neurons releases neurotransmitter molecules, such as Y-aminobutyric acid (GABA) or glycine, which bind to receptors on the postsynaptic cell membrane. This causes a transient increase in the permeability of specific ions, such as, potassium and chloride ions. (2) The influx of chloride (Cl ) and efflux of potassium (K+) cause a weak hyperpolarization or inhibitory post-... 

Anthocyanins isolated from plants were studied for their possible inhibitory action on the MDR1 efflux pump. Among anthocyanins tested in this study, only cyanidin chloride showed a slight inhibition on P-gp function (Table 9). The chlorides of callistephin, pelargonin, ideanin, cyanin and pellargonidin slightly enhanced the activity of the efflux pumps. 

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