Effect of 16,16-dimethyl prostaglandin E₂ on gastric epithelial cell membrane potentials and resistances

Intracellular microelectrode techniques were employed to examine the effects of 16,16-dimethyl prostaglandin E₂ (dmPGE₂) on Necturus antral mucosa epithelial cell membrane potentials and resistances. Necturus antral mucosa was mounted in a modified Ussing chamber and stable intracellular impalements were obtained. Addition of 0.01 μg/ml dmPGE₂ to the mucosal solution produced an increase of the apical cell membrane potential (V(mc)) from -44.3 ± 3.1 to -53.5 ± 3.8 mV (p < 0.001) and of the basolateral cell membrane potential (V(cs)) from -48.8 ± 2.8 to -57.7 ± 3.2 mV (p < 0.001). This reversible, dose-dependent hyperpolarization of both cell membranes was accompanied by a decrease in the electrical resistance of the apical membrane ((R(a)) from 2550 ± 250 Ω/cm² to 1870 ± 210 Ω/cm² (p < 0.05) and a decrease in the resistance of the basolateral membrane (R(b)) from 1020 ± 250 Ω/cm² to 630 ± 80 Ω/cm² (p < 0.05). In addition, there was an increase in the resistance of the shunt (intercellular junction, R(s)), the major route of transepithelial ion flow, from 710 ± 60 Ω/cm² to 750 ± 80 Ω/cm² (p < 0.05). Thus dmPGE₂ increased the cell membrane potentials and reduced the ionic permeability of the intercellular junction.