par Shlyonsky, Vadim 
Référence Advances in physiology education, 37, 4, page (392-400)
Publication Publié, 2013-12
Référence Advances in physiology education, 37, 4, page (392-400)
Publication Publié, 2013-12
Article révisé par les pairs
| Résumé : | In the presentarticle, a novel model of artificial membranes that provides efficientassistance in teaching the origins of diffusion potentials is proposed.These membranes are made of polycarbonate filters fixed to 12-mmplastic rings and then saturated with a mixture of creosol and n-decane.The electrical resistance and potential difference across these membranescan be easily measured using a low-cost volt-ohm meter and home-madeAg/AgCl electrodes. The advantage of the model is the lack of ionicselectivity of the membrane, which can be modified by the introductionof different ionophores to the organic liquid mixture. A membrane treatedwith the mixture containing valinomycin generates voltages from -53 to -25 mV in the presence of a 10-fold KCl gradient (in to out) and from-79 to -53 mV in the presence of a bi-ionic KCl/NaCl gradient (in toout). This latter bi-ionic gradient potential reverses to a value from +9 to +20 mV when monensin is present in the organic liquid mixture. Thus,the model can be build stepwise, i.e., all factors leading to the developmentof diffusion potentials can be introduced sequentially, helpingstudents to understand the quantitative relationships of ionic gradients anddifferential membrane permeability in the generation of cell electrical signals. © 2013 The American Physiological Society. |
