抄録
Acetazolamide is a diuretic which acts to inhibit the carbonic anhydrase in the kidney tubule. The authors reported that acetazolamide causes a depression of CM. In this paper it was studied what effects acetazolamide might have on the CM modified by NaCl-crystals on the round window membrane. The following results were obtained.
1. The placement of NaCl-crystals caused an increase of CM for 3 min. and 20 sec., a decrease to 55.0% of the initial value of the CM within 15 min., a gradual recovery to 71.0% within 40 min. and then a gradual second depression.
2. The placement of NaCl-crystals on the round window membrane with the premedication of 50mg/kg of acetazolamide caused an overshoot of CM and a gradual decrease.
3. The placement of NaCl-crystals on the round window membrane with the premedication of 200mg/kg of acetazolamide caused an overshoot for 4 min. and 10 sec. and then a gradual decrease. This pattern is similar to the CM of No.2.
As compared with the control, the overshoot was long and the primary depression and a recovery ware not observed. But the variation of CM since the 45 th minute was almost the same. Acetazolamide would surpress the invasion of NaCl into the inner ear fluids through the round window membrane and surpress the increase in the volume of the inner ear fluids as well as other diuretics. But it seemed that acetazolamide is different from other diurectics in some action points in the mechanism of endolymphatic production and absorption. The pattern of CM modified by the placement of NaCl on the round window membrane with the premedication of acetazolamide was similar to those which were caused by the placement of NaCl on the round window membrane with the premedication of norepinephrine or propranolol.
