Ulrik V. Lassen

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1. In order to evaluate the membrane potentials calculated from the distribution of chloride ions in human red cells and plasma, it is desirable to have a direct measurement of the transmembrane potential of these cells.2. A method has been devised for introducing a capillary micro-electrode into human red cells. The method allows simultaneous measurements(More)
Intracellular potentials were measured, using a piezoelectric electromechanical transducer to impale Ehrlich ascites tumor cells with capillary microelectrodes. In sodium Ringer's, the potential immediately after the penetration was -24±7 mV, and decayed to a stable value of about -8 mV within a few msec. The peak potentials disappeared in potassium(More)
Fluxes of D-xylose-1-C(14) (xylose) across the wall of the isolated intestine of the bullfrog were studied. When sodium was the principal cation in the mucosal bathing fluid, the transport rate of xylose from the mucosa to the serosa was about 5 times greater than the transport rate from the serosa to the mucosa, indicating an active intestinal transport(More)
Like most other red cells, the giant erythrocytes of Amphiuma means possess a system for rapid exchange of chloride across the membrane. Also, there are indications that the net transport of chloride in these cells is slow. The size of Amphiuma erythrocytes allows direct measurements of membrane potential with microelectrodes. The present work exploits the(More)
1. It has previously been demonstrated that an increase in extracellular Ca2+ conce-tratio- induces a trandient increase in K+ permeability and associated hyperpolarization of the red cell membrane of the giant salamander, Amphiuma meand. This phenomenon is analogous to the Ca2+-induced KCl loss observed in ATP-depleted human red cells and red cell ghosts.(More)
An increase in extracellular Ca concentration causes the membrane of giant red cells of the salamander, Amphiuma means, to undergo a marked, transient hyperpolarization. This hyperpolarization is caused by an increase in K permeability of the membrane as judged from the K sensitivity of the membrane potential and from the rate of K loss under influence of(More)