Preferential localized uptake of K+ and Cs+ over Na+ in the A-band of freeze-dried embedded muscle section: detection by x-ray microanalysis and laser microprobe mass analysis.
Sections of freeze-dried embedded frog muscle were exposed to aqueous solutions containing various combinations of the salts LiCl, NaCl, KCl, and CsCl. Energy dispersive X-ray microanalysis and laser microprobe mass analysis of these sections showed selective and preferential accumulation of K+ (and Cs+) over Na+ on specific protein sites in the A-bands. The selectivity coefficient exceeded 10 and involved a total K+ accumulation of about 40 mmoles/kg (in comparison with a value of about 80 mmoles/kg in normal living frog muscle). These findings support the view that selective K+ adsorption on intracellular proteins is the primary cause of selective accumulation of K+ in living cells.
D000818:Animals; D001692:Biological Transport; D002586:Cesium / Q000378:metabolism*; D004577:Electron Probe Microanalysis; D005612:Freeze Drying; D066298:In Vitro Techniques; D007834:Lasers; D009132:Muscles / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D011898:Ranidae; D012964:Sodium / Q000378:metabolism*
D002586:Cesium; D012964:Sodium; D011188:Potassium