Transepithelial transport of guinea pig gastric mucous cell monolayers

Guinea pig gastric mucous epithelial cells were isolated, enriched, cultured in collagen cups, and put into Ussing chambers for electrophysiological studies. The cultured mucous cell monolayers, which retain the morphology of surface cells found in the intact tissue, had a maximal resistance (R) of 272 ± 12 Ω.cm² and a potential difference (PD) of -3.8 ± 0.4 mV (apical negative) between 4 and 10 days later (n = 33). The current-voltage and conductance-concentration relationships of the cultures were both nonlinear (n = 12). In addition, NaCl concentration gradients across the monolayer also gave asymmetrical and nonlinear dilution potentials, with the side of lower chemical potential always becoming electrically negative (n = 10). Calculation of the average Cl^--to-Na⁺ permeability ratio at pH 7.4 was 1.35, indicating a slightly greater conductance of anions over cations. Amiloride (0.1-1.0 μM) had no effect on PD or R when given from the apical or basal side (n = 18), but at higher concentrations (0.1-1.0 mM) there was a decrease in the PD. 4,4',-Diisothiocyanostilbene-2,2'-disulfonic acid at 10^-4 M increased R from the apical side only (n = 14), and acetazolamide at 5 x 10^-4 M reduced the PD to -0.5 mV (n = 8). Only ouabain at 10^-4 M from the serosal side was effective in reducing the monolayer PD to zero. This culture preparation will prove useful for future studies in determining specific functions for this gastric cell type and how those functions relate to barrier function in the stomach.