Microelectrode studies of fundic gastric mucosa: Cellular coupling and shunt conductance
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Necturus fundic gastric mucosa was studied to define the magnitude of cellular and shunt conductance. Electrotonic coupling of surface epithelial cells by a low resistance pathway was shown by analysis of current spread within the epithelial sheet. From this analysis cellular conductance was found to be 4.18 ± 1.57 × 10−4 Ω−1 cm−2, and transepithelial shunt conductance was 1.1 × 10−4 Ω−1 cm−2. The ratio of cell-to-shunt conductance was 3.80. These results are confirmed by a second technique in which the Δp. d. across the serosal membrane of surface cells was compared to the transepithelial Δp. d. resulting from a Δ[K+] in the serosal solution. The data were analyzed using an electrical circuit equivalent to a mucosa composed of two highly coupled cell types. By this technique cell conductance was 3.07 × 10−4 Ω−1 cm−2, and transepithelial shunt conductance was 0.830 × 10−4 Ω−1 cm−2. The cell/shunt conductance ratio was 3.70. Thus, by two independent techniques the transepithelial shunt contributes only 1/5 of the conductance ofNecturus fundic gastric mucosa.
KeywordsEpithelial Cell Electrical Circuit Conductance Ratio Surface Epithelial Cell Cell Conductance
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