Potassium, Sodium, and Chloride

Macklon, A.E.S. (1975). Cortical cell fluxes and transport to the stele in excised root segments of Allium cepa L. I. Potassium, sodium and chloride. Planta, 122, 109-30. 

Tazawa, M., Kishimoto, U. Kikuyama, M. (1974). Potassium, sodium and chloride in the protoplasm of Characea. Plant and Cell Physiology, 15, 103-10. 

Loop diuretics work by increasing the excretion of electrolytes (sodium, chloride, potassium) which the body normally uses to maintain intra cellular and extracellular water. Monitoring of the re-absorption of potassium, sodium, and chloride ions during use should have been a must, but few did so. Lasix can and has caused death. 

Several of the monatomic cations play important roles in our bodies. For example, we need calcium ions in our diet for making bones and teeth. Iron(ll) ions are found in hemoglobin molecules in red blood cells that carry oxygen from our lungs to the tissues of our bodies. Potassium, sodium, and chloride ions play a crucial role in the transfer of information between nerve cells. Enzymes (chemicals in the body that increase the speed of chemical reactions) ofren contain metallic cations, such as manganese(II) ions, iron(III) ions, copper(II) ions, and zinc ions. For example, Zn " " ions are in the center of the enzyme alcohol dehydrogenase, which is the enzyme in our livers that accelerates the breakdown of the ethanol consumed in alcoholic beverages. 

Diffusion potentials for the primary biological ions (potassium, sodium, and chloride) represent the primary source of the resting membrane potential. The diffusion potential for a given ionic species can be calculated from the modified Nernst equation developed by Hodgkin and Huxley. The equation is ordinarily written as... 

As the current density through the membrane is the sum of the contributions of potassium, sodium and chloride, if the equilibrium is disturbed by applying small current d/ then the potential will change by dV. Since,... 

PREVENTION AND TREATMENT OF MINERAL DEFICIENCIES AND/OR TOXICITIES. The prevention and treatment of the various mineral deficiencies require the cautious use of mineral-rich foods or special supplements because (1) there is a narrow range between the safe levels and the toxic levels of such trace elements as iron, copper, fluorine, and selenium (2) excesses of certain minerals are likely to reduce the absorption and utilization of others and (3) large excesses of most minerals—except for potassium, sodium, and chloride—are not well absorbed, but are excreted in the stool. Therefore, lay persons should not dose themselves with shotgun amounts of mineral supplements rather, they should limit themselves to more prudent measures, such as those which follow ... 

Sodium chloride is relatively inexpensive and is provided either free or incorporated directly into animal feed to prevent sodium and chloride deficiencies. Potassium is usually not deficient because most forages have adequate quantities. Therefore, it should be supplemented only when animals consume poor quaHty roughages or a high concentrate diet, or when they are under stress, dehydrated, or suffering from diarrhea (5). Potassium deficiency usually is alleviated by changing the diet or by supplementing with potassium sulfate. 

Potassium Carbonate. Except for small amounts produced by obsolete processes, eg, the leaching of wood ashes and the Engel-Precht process, potassium carbonate is produced by the carbonation, ie, via reaction with carbon dioxide, of potassium hydroxide. Potassium carbonate is available commercially as a concentrated solution containing ca 47 wt % K CO or in granular crystalline form containing 99.5 wt % K CO. Impurities are small amounts of sodium and chloride plus trace amounts (<2 ppm) of heavy metals such as lead. Heavy metals are a concern because potassium carbonate is used in the production of chocolate intended for human consumption. 

Methybcanthine Diuretics. The mild diuretic effect of drinking coffee, from caffeine, and tea, mainly from theophylline, has been recogni2ed for along time. But the methylxanthines (Table 5) are of very limited efficacy when used as diuretics. The excretion of sodium and chloride ions are increased, but the potassium excretion is normal. Methylxanthines do not alter the urinary pH. Even though the methylxanthines have been demonstrated to have minor direct effects in the renal tubules, it is beUeved that they exert their diuretic effects through increased renal blood flow and GER (71). 

Potassium chloride is crystallized from sea bitterns containing chlorides of potassium, sodium and calcium by ammoniation (Jagadesh etai, 1992). This process is less energy intensive and more efficient than by fractional crystallization by evaporation, as the ammonia used is recovered by distillation. Crystallization produces a better quality product in terms of both size and purity than by other methods. 

Woods contain from 0-2 to 4% of mineral ash. This consists largely of calcium, potassium and magnesium as carbonate, phosphate, silicate and sulphate. Aluminium, iron, sodium and chloride are also present. Sulphate contributes 1 to 10% by weight, usually 2 to 4%, and chloride 01 to 5%. 

The most common imbalances are a loss of potassium and water. Other electrolytes, namely magnesium, sodium, and chlorides, are also lost. When too much potassium is lost, hypokalemia (low blood potassium) occurs (see Home Care Checklist Preventing Potassium Imbalances). In certain patients, such as those also receiving a digitalis glycoside or those who currently have a cardiac arrhythmia, hypokalemia has the potential to create a mo re serious arrhythmia Hypokalemia is... 

Several recent determinations of the alkali and alkaline earth metals in serum or urine have been reported. Barrett 29) determined potassium, sodium, and calcium in semm by diluting the samples with lanthanum chloride solution. Suttle and Field 3°) used atomic absorption spectroscopy to determine potassium and magnesium in sheep plasma. 

Physically, ion channels are tiny pores that stud the surface of all cells. The ion channels are important for, among other things, the function of muscles and the nervous system. These channels allow the passage of potassium, calcium, sodium, and chloride ions. Through a balance of electrical forces and chemical bonds, ion channels are specific for one ion for instance, a potassium ion channel will reject a sodium ion trying to enter its channel. An excellent visualization of the overall process is found at the website http //www. rockefeller.edu/pubinfo/howkion.html. It will be helpful to look at this website before going any further in the discussion. 

Another important diuretic contains both triamterene and hydrochlorothiazide. Triamterene is a diuretic and is known to increase sodium and chloride ion excretion but not potassium ion. It is used in conjunction with a hydrothiazide, which is an excellent diuretic but also gives significant loss of potassium and bicarbonate ions. If the triamterene were not included potassium chloride would have to be added to the diet. Hydrochlorothiazide is an antihypertensive agent as well but, unlike other antihypertensives, it lowers blood pressure only when it is too high, and not in normotensive individuals. These two drugs are made by a number of different manufacturers and do not appear in our top 35 list, but they would rank high if all brands were combined. 

The nephronic parts of the kidney are the principal diuretic active sites for secreting ede-matic fluid from the organism. Diuretics basically increase secretion of water and salts from the kidneys by suppressing reabsorption of a few main ions (primarily sodium and chloride ions) however, secretion of calcium, potassium, magnesium, and hydrocarbonate ions also increases to some degree. 

Pharmacology Thiazide diuretics increase the urinary excretion of sodium and chloride in approximately equivalent amounts. They inhibit reabsorption of sodium and chloride in the cortical thick ascending limb of the loop of Henie and the early distal tubules. Other common actions include Increased potassium and bicarbonate excretion, decreased calcium excretion and uric acid retention. At maximal therapeutic dosages all thiazides are approximately equal in diuretic efficacy. 

The most remarkable observation is that all 22 minerals considered to be essential to the human diet are present in milk. Some of these are sodium (Na), potassium (K), and chloride (Cl). The electroneutrality of milk is maintained by free ions (negatively charged to lactose). 

Figure 4.13 — (A) Serially arranged ISEs for the simultaneous determination of sodium, potassium, calcium and chloride ions. (B) Serially and parallelly arranged ISEs for the simultaneous determination of T, Br", Cl and F . WE working electrode PC personal computer Ej-E r, Cr, Br" and F ISEs, respectively C C3 amalgamated-lead columns (1.5 and 2.5 cm long, respectively) AgCl column RE reference electrode PHM pH/mV-meter S sample injection CS carrier stream P pump R chart recorder W waste. (Reproduced from [126] and [127] with permission of Elsevier Science Publishers and Pergamon Press, respectively).

Adrenocorticoid hormones are produced in the adrenal glands. They regulate a variety of metaholic processes. The most important mineralo-corticoid is aldosterone, an aldehyde as well as a ketone, which regulates the reahsorption of sodium and chloride ions in the kidney, and increases the loss of potassium ions. Aldosterone is secreted when hlood sodium ion levels are too low to cause the kidney to retain sodium ions. If sodium levels are elevated, aldosterone is not secreted, so some sodium will he lost in the urine and water. Aldosterone also controls swelling in the tissues. 

Figure 5.5 Correlations between the concentration of sodium and potassium (a) and sodium and chloride (b) in bovine milk.

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