Potassium is quantitatively the main cation of the intracellular fluid compartment and, therefore, plays major roles in the maintenance and regulation of cell volume. In addition, potassium is thought to participate in the regulation of a number of functions common to most or all cells, including differentiation and growth. Finally, transport of potassium ions across the cell membranes influences not only the intracellular content (and chemically activity) of the cation but also the extracellular concentration, particularly in the case of tissues possessing extracellular compartments in which ionic diffusion and blood-flow mediated extraction are restricted. This is of paramount importance in excitable tissues, in which the potassium concentration gradient across the cell membrane is the main determinant of the membrane voltage and, hence, of automatism and/or excitability. (JES).On a longer time scale, magnesium regulates the activity of the Na, K, Cl and K, Cl cotransport systems which become more active ... of cell magnesium also cause loss of cell potassium and reduce the ability of cells and the body to accumulate and retain potassium. ... Magnesium enters the mouth of the channel, as does potassium, but gets stuck deep in the channel preventing further movement of ions.
|Title||:||Regulation of potassium transport across biological membranes|
|Author||:||Luis Reuss, John M. Russell, Gábor Szabó|
|Publisher||:||Univ of Texas Pr - 1990-07|