The Selective Absorption of Potassium by Animal Cells

Abstract

1. Frog muscles perfused with Ringer solution in which potassium chloride has been replaced by an equivalent amount of rubidium or cesium chloride take up rubidium or cesium and incorporate them into the tissue substance in such form as to be retained during a subsequent perfusion with potassium-free Ringer solution, provided the muscles contract during the first perfusion. Retention of rubidium or cesium by a resting muscle does not occur. 2. Rats on synthetic diets, adequate in all respects except that potassium was replaced by an equivalent amount of rubidium or cesium, died after a period varying from 10 to 17 days with characteristic symptoms including tetanic spasms. Muscle, heart, liver, kidney, spleen, and lung tissues were then found to contain significant amounts of rubidium or cesium. The concentration of these metals in the muscle amounted, in some cases, as shown by a spectroscopic estimation, to about half the concentration of potassium normally found in mammallian muscle. 3. The results are regarded as tending to confirm the theory that the peculiarities in the physiological effects of potassium, including the facility with which it is "selected" by living cells in preference to sodium, are related to the electronic structure of the potassium ion as compared with that of similar ions. The possible relationship of the comparative migration velocity, a function of the electronic structure, to physiological effects is suggested.

Cation Accumulation by Muscle Tissue: The Displacement of Potassium by Rubidium and Cesium in the Living Animal12

“…The foregoing observations confirm and extend the earlier data which had indicated that rubidium and cesium could be taken up in large quantities by muscle cells (6)(7)(8)(9). They also confirm the previously reported fact that rubidium chloride lowers the blood CO2 content in alkalotic potassium-deficient rats (9) and extend the observations to demonstrate a similar, but less marked, acidifying effect of cesium chloride.…”

“…2Presented in part at the Annual Meeting of the American Federation for Clinical Research, May, 1956. studies (6)(7)(8)(9) have already established in a general way that animal tissues are capable of accumulating significant quantities of rubidium or cesium, but there have been no determinations of the tissue-plasma concentration gradients when organisms are fed non-tracer amounts of these substances and no quantitative measurements of the extent to which these ions are taken up by tissues relative to potassium. The results of the present work indicate a distinctly greater affinity of rat muscle tissue for rubidium and cesium than for potassium, and the data therefore suggest that processes more complex than simple diffusion are involved in the normal accumulation of potassium.…”

The Acidifying Effect of Rubidium in Normal and Potassium-Deficient Alkalotic Rats 1

“…Since there is evidence that animal tissues can also accumulate large quantities of administered rubidium ions (9,16), it is reasonable to assume that the acidifying effects of rubidium in the present experiments were accomplished, at least in part, by a similar displacement of cellular hydrogen.…”

Essential and non-essential trace metals in scalp hair of men chronically exposed to volcanogenic metals in the Azores, Portugal

“…Although Rb is not considered extremely toxic it can exert toxic effects when in high concentrations, mainly because it competes with K for enzymes, such as the Na + /K + -ATPase (Meltzer, 1991;Mitchell et al, 1921). Accumulation of Rb has been observed in several organs of rats, and reported effects of this accumulation include spasms and tissue disorganization (Mitchell et al, 1921;Salaün and Truchet, 1996).…”

“…Although Rb is not considered extremely toxic it can exert toxic effects when in high concentrations, mainly because it competes with K for enzymes, such as the Na + /K + -ATPase (Meltzer, 1991;Mitchell et al, 1921). Accumulation of Rb has been observed in several organs of rats, and reported effects of this accumulation include spasms and tissue disorganization (Mitchell et al, 1921;Salaün and Truchet, 1996). Strong and significant correlations found in donors from Furnas between Rb-Cd and Rb-Pb show that Rb hair concentrations may be used as biomarker of exposure to volcanic emissions, composed of more harmful gases and aerosols, as previously suggested by Durand et al (2004).…”