Advances in Physiology Education, Vol 268, Issue 6 26-S31, Copyright © 1995 by American Physiological Society
Xenopus laevis oocyte: using living cells to teach the theory of cell membrane potential
A. Schwab, U. Kersting, H. Oberleithner and S. Silbernagl
Physiologisches Institut, University of Wurzburg, Germany.
We describe a student course in membrane physiology that includes
demonstration of the cell membrane potential of a living cell, the Xenopus
laevis oocyte. By use of K+ macroelectrodes and a computer simulation
program, students are introduced to the membrane concept on the basis of
ion gradients, diffusion potentials, and membrane conductances.
Subsequently, some basic principles are demonstrated in living cells by
measuring the cell membrane potential of a X. laevis oocyte. The dependence
of the cell membrane potential on ion gradients is shown by stepwise
elevation of the extracellular K+ concentration. The clinical relevance of
disturbances of the K+ homeostasis is discussed in this context. The effect
of changing the membrane conductance for particular ions on the cell
membrane potential is demonstrated by applying a K+ channel blocker. The
experiments are discussed in the context of the action of pharmaceuticals
and toxins. This student course on membrane physiology has now been held
for 2 yr for medical and dental students, and their response to the oocyte
demonstration, as evaluated by a student questionnaire, was mainly
positive.
