Improved intraepithelial two-dimensional cable analysis with application to necturus gastric antral mucosa.

Previously 2D cable analysis has been performed with two microelectrodes, one for passing intraepithelial current and the other for measuring the voltage response in multiple cells along the distance scale. This requires that the epithelium must be in a stable state for a considerably long period because of the multiple impalements. To follow changes of intraepithelial resistances in chambered Necturus antral mucosa with good temporal resolution, four/five electrodes were used to impale cells in the same preparation and the intraepithelial current (6.5-20 nA) was conducted sequentially to three/four of the electrodes, one at a time, to obtain six/ten independent voltage response measurements along the distance scale. The solution to the 2D cable equations was fitted to results and apical, basolateral and shunt resistances were calculated. It was found that an incorrect distance configuration can ruin the precision of the measurement. The distance configuration can, however, be optimized. The resistance values calculated with the 2D cable analysis were very close to those obtained by the amiloride exposure technique in the same tissues. The improvement gained with this work is better temporal resolution (even <10 s) when measuring epithelial resistances.