title: Intracellular activities of sodium and potassium.
abstract: The intracellular contents of Na+ and K+ appear to modulate a variety of cellular and tissue functions, including transepithelial transport. However these total ionic contents appear to consist of heterogeneous populations of Na+ and K+. No more than a few percent of intracellular Na+ and K+ appear bound. Thus, the heterogeneity of the intracellular ionic contents must reflect subcellular compartmentalization. Recent technical advances in the preparation and use of ion-selective microelectrodes have permitted progress in defining the possible sites of such intracellular compartmentalization. Furthermore, intracellular recording with microelectrodes and micropipettes now provides a technique with which to directly monitor the chemical activities of Na+ and K+ within the cytoplasm as a function of the state of transepithelial transport. This approach has already provided information necessitating a reexamination of certain classical concepts of transport physiology.
mesh_terms: D000818:Animals; D001001:Anura; D001665:Binding Sites; D001693:Biological Transport, Active; D012831:Bombyx; D002463:Cell Membrane Permeability; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004734:Energy Metabolism; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D008433:Mathematics; D008839:Microelectrodes; D011188:Potassium / Q000378:metabolism*; D012469:Salivary Glands / Q000378:metabolism; D012964:Sodium / Q000378:metabolism*; D001743:Urinary Bladder / Q000378:metabolism
chemical_list: D012964:Sodium; D011188:Potassium