Conductance of epithelial tissues with particular reference to the frog's cornea and gastric mucosa

Abstract

This paper presents an overview of the problem of measuring the conductance of biological tissues by an analysis of the transient voltage response to step currents of constant magnitude. In general, the voltage response of tissues is characterized by a small step change in voltage followed by an exponential like rise. In the case of the gastric mucosa the voltage appears to level off after about 20 msec but this is only apparent; it actually continues to increase for about 100 sec. In the case of the frog cornea the voltage response levels off in about 1 sec. The response of the cornea with the endothelium removed is essentially similar to that of the intact cornea. The response of the cornea with the epithelium removed leaving the endothelium plus stroma behaves like an ohmic resistor with the usual sweep speeds in the msec range. The response of the above tissues are analyzed in light of the problem of determining the resistance of biological tissues.