Potassium intracellular

Patients with acute hyperkalemia usually require other therapies to manage hyperkalemia until dialysis can be initiated. Patients who present with cardiac abnormalities caused by hyperkalemia should receive calcium gluconate or chloride (1 g intravenously) to reverse the cardiac effects. Temporary measures can be employed to shift extracellular potassium into the intracellular compartment to stabilize cellular membrane effects of excessive serum potassium levels. Such measures include the use of regular insulin (5 to 10 units intravenously) and dextrose (5% to 50% intravenously), or nebulized albuterol (10 to 20 mg). Sodium bicarbonate should not be used to shift extracellular potassium intracellularly in patients with CKD unless severe metabolic acidosis (pH less than 7.2) is present. These measures will decrease serum potassium levels within 30 to 60 minutes after treatment, but potassium must still be removed from the body. Shifting potassium to the intracellular compartment, however, decreases potassium removal by dialysis. Often, multiple dialysis sessions are required to remove potassium that is redistributed from the intracellular space back into the serum. 

Rapid correction of hyperkalemia requires administration of drugs that shift potassium intracellularly (e.g., insulin and dextrose, sodium bicarbonate, or albuterol). 

Sodium and Potassium. Whereas sodium ion is the most abundant cation in the extracellular fluid, potassium ion is the most abundant in the intracellular fluid. Small amounts of K" are requited in the extracellular fluid to maintain normal muscle activity. Some sodium ion is also present in intracellular fluid (see Fig. 5). Common food sources rich in potassium may be found in Table 7. Those rich in sodium are Hsted in Table 8. 

Additional cellular events linked to the activity of blood pressure regulating substances involve membrane sodium transport mechanisms Na+/K.+ ATPase Na+fLi countertransport Na+ -H exchange Na+-Ca2+ exchange Na+-K+ 2C1 transport passive Na+ transport potassium channels cell volume and intracellular pH changes and calcium channels. 

Inhibition of the Na+/K+-ATPase leads to a loss of potassium and an increase of sodium within the cell. Secondary intracellular calcium is increased via the Na VCa -exchanger. This results in a positive inotropic effect in the myocardium, with an increase of peak force and a decrease in time to peak tension. Besides this, cardiac glycosides increase vagal activity by effects on the central vagal nuclei, the nodose ganglion and increase in sensitivity of the sinus node to acetylcholine. 

Potassium homeostasis refers to the maintaining and regulating of a relatively stable and mostly internal (intracellular) potassium balance (concentration), although more generally it refers to the maintenance of potassium balance in any compartment (e.g. in the blood). 

The main endogenous mineralocorticoid is aldosterone, which is mainly produced by the outer layer of the adrenal medulla, the zonaglomerulosa. Aldostorone, like other steroids, binds to a specific intracellular (nuclear) receptor, the mineralocorticoid receptor (MR). Its main action is to increase sodium reabsotption by an action on the distal tubules in the kidney, which is accompanied by an increased excretion of potassium and hydrogen ions. 

YI BA, Minor Jr., Lin Y-F et al (2001) Controlling potassium channel activities interplay between the membrane and intracellular factors. Proc Natl Acad Sci USA 98 11016-11023... 

Lubin, M. Ennis, H.L. (1964). On the role of intracellular potassium in protein synthesis. Biochimica et Biophysica Acta, 80, 614-31. 

Involved in membrane function principal cations of extracellular-and intracellular fluids, respectively Sodium, potassium... 

The P2X receptor subunits are unusual in having only two transmembrane domains with both the amino terminal and carboxy terminal located intracellularly. The ion channel is proposed by analogy with the structure of some potassium channels to be formed by a short loop which enters the membrane from the extracellular side (North and Surprenant 2000). 

In the family of cation pumps, only the Na,K-ATPase and H,K-ATPase possess a p subunit glycoprotein (Table II), while the Ca-ATPase and H-ATPase only consist of an a subunit with close to 1 000 amino acid residues. It is tempting to propose that the p subunit should be involved in binding and transport of potassium, but the functional domains related to catalysis in Na,K-ATPase seem to be contributed exclusively by the a subunit. The functional role of the P subunit is related to biosynthesis, intracellular transport and cell-cell contacts. The P subunit is required for assembly of the aj8 unit in the endoplasmic reticulum [20]. Association with a j8 subunit is required for maturation of the a subunit and for intracellular transport of the xP unit to the plasma membrane. In the jSl-subunit isoform, three disulphide... 

As with the effects of oxidant stress on the calcium channel, part of the change in the steady-state background current could also be attributed to an indirect effect secondary to the elevation of intracellular calcium (Matsuura and Shattock, 1991b). However, oxidant stress also exerted a direct effect on the inward rectifying potassium current (7ki). The combination of an inhibition of 7ki and the activation of a calcium-dependent current are likely to contribute to the prolongation of the action potential duration and the increased susceptibility... 

ANSWER That is Lacey et al., Allan North s group. It was published in the Journal of Physiology last year. It was also an abstract in the Society 2 years ago. It is the consequence of that application of the agonists, recording intracellularly in the slice of the dopamine neuron. He gets the same thing by virtue of application of norepinephrine agonists to noradrene-gic slice preparation. That is a conventional way to create a hyperpolarization of the cell, to increase the potassium conductance, and so forth. 

To prevent insulin-mediated intracellular shift of potassium during the infusion... 

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