Archives internationales de physiologie, de biochimie et de biophysique. vol:99 issue:1 pages:83-8
The effects of the protein cross-linker glutaraldehyde (GA) on the transepithelial short-circuit current (Isc), conductance (Gt) and impedance of the isolated frog skin were investigated at GA concentrations between 0.1 and 10 mM, i.e. up to three orders of magnitude less than used in fixative procedures. Below 0.5 mM GA increases Isc, with large variations among preparata. Millimolar GA concentrations induce fairly reproducible irreversible inhibitions of Isc, which proceed for about 3 h. The rate of Isc decrease and the amplitudes of the initial drop and subsequent recovery depend on GA concentration in a sigmoidal dose-effect way, reaching saturation at 10 mM. At this GA concentration, Gt is increased up to 5 times the control value. Transepithelial impedance measurements confirm the decreases in epithelial resistance (Rm) and show significant increases in epithelial capacitance (Cm). Rm is diminished by 20% at 0.5 mM GA and by 75% at 10 mM GA, while Cm is maximally augmented by 55% at 2.5 mM GA. It is concluded that protein cross-linking by mild GA treatment is a convenient procedure for changing the electrical characteristics of epithelia.