Effect of Diamox on potential difference resistance and secretory rate of dog's stomach

¹ Departments of Physiology and Chemistry, University of Louisville, Louisville, Kentucky

The effect of intravenous acetazoleamide (Diamox) was determined on secretory rate, potential difference (PD), and electrical resistance of the anesthetized dog's stomach, using the chambered gastric segment preparation. In dogs with high initial secretory rates, inhibition of H⁺ ion secretion exceeded 93%, whereas in dogs with low initial secretory rates, inhibition ranged from 27 to 75%. Diamox resulted in an initial decrease in PD and an initial increase in resistance in the secreting stomach. Finally, in a new steady state, the average secretory rate was about 10% of controls and PD 17 mv. less. Diamox did not produce a decrease of PD or a change in resistance of the resting stomach. Compared to controls, stimulation after Diamox injection resulted in a greater decrease in PD, a smaller decrease in resistance and a much lower H⁺ ion secretory rate. Application of electric current, following Diamox, from serosa to mucosa resulted in an increase in H⁺ ion secretory rate. It is concluded that the effects of Diamox are dependent on the presence of acid secretory activity and that Diamox inhibits both the H⁺ and Cl^– ion mechanisms.