Objective:To study the effect and mechanism of quate rnary ammonium sa lt derivative(F 2)of haloperidol on isolated rat
thoracic aorta sp iral strips. Methods: Using the bioassay of rat aorta spiral strips, F 2( 2×10 -6 ?6 32×10 -6 ?2×10 -5 mol/L)was added into the bath medium prior to KCl(10～40mmol/L)admi nistration to observe the effect of F 2 on dose respons e curve of
constriction in duced by KCl, respectively. The blocking effect of F 2(10 -4 mol/L)on the constriction induce d by KCl(30 and 80mmol/L)was recorded. The effects of F 2(10 -4 mol/L) and Glibe nclamide (10 -6 ～10 -4 mol/L)on the aorta strips were also observed. Results: F 2 d ecreased the constriction curve obviously in dose dependent manner(pD2=5 13 ±0 33). The constriction induced by KCl(80 mmol/L) was inhibited by F 2(10 - 4 mol/L). Glibenclamide did not counteract the diastolic effect of F 2 on the constricti on induced by KCl of 30 mmol/L. Conclusion: The constriction induced by KCl on rat aorta strips is inhibited by F 2. Refer to other related experiments, the effe ct of F 2 is due to blocking
calcium channel and opening potassium channel which is not ATP sensitive type.