Direct Effect of Ethanol on Acid Secretion in Isolated Canine Gastric Mucosa

Abstract

The direct effects of ethanol on resting and secreting (histamine = H, pentagastrin = G, and acetylcholine = A) gastric mucosa were determined using an in vitro chamber preparation. Ethanol (E) produced no effect on acid (H⁺) secretion during resting conditions but concentrations above 2% (4% and 8%) decreased electrical potential difference (PD), short-circuit current (I_sc) and resistance (R). With H-induced H⁺ secretion, E at 8% on mucosal side decreased H⁺ secretion (4.11 ± 0.34 to 0.64 ± 0.45 µEq/cm²hr), PD (32 ± 2 to 4.9 ± 0.6 mV), I_sc (5.0 ± 0.3 to 1.1 ± 0.1 µEq/cm² hr), and R (237 ± 15 to 174 ± 68 hm·cm²). Washout of E produced recovery in all parameters. With P-induced H⁺ secretion, E decreased H⁺ secretion (1.63 ± 0.11 to 0.51 ± 0.18), PD (42 ± 5 to 13 ± 3), I_sc (5.71 ¡À 0.38 to 2.22 ¡À 0.45), and R (274 ± 21 to 218 ± 13). With A-induced H⁺ secretion, E decreased H⁺ secretion (1.16 ± 0.06 to 0.45 ± 0.23), PD (38 ± 1 to 12 ± 1), I_sc (5.69 ± 0.40 to 1.94 ± 0.09) and R (253 ± 22 to 226 ±22). When E was placed on the serosal side, 10% was necessary to inhibit H⁺ secretion and all the electrical parameters increased. Hypertonic sucrose (695.6 mM in mucosal side) produced an immediate decrease in H⁺ secretion, PD and I_sc but increased R. These data indicate that the direct action of E is not to stimulate but rather to inhibit secretagogue-induced gastric H⁺ secretion.