Fig. 1.Flow diagram of the study. A total of 16 late-pregnancy
rats were used. In Experiment 1, 3 myometrial strips were
isolated from each of 4 rats and randomly distributed to baseline, control
(equilibration in PSS for 2 hrs) and experimental groups (treatment with 10 M oxytocin for 2 hrs). In Experiment 2, 4 myometrial strips
were isolated from each of 12 rats in order to test the dose-response of oxytocin
(10 to 10 M), misoprostol (10 to 10 M), carboprost
(10 to 10 M) and PSS. Before the dose-response testing, two
myometrial strips were equilibrated in PSS for 2 hrs (control group) and the
other two were treated with 10 M oxytocin for 2 hrs (experimental group).
The control group and the experimental group for the same drug were evaluated
simultaneously, and the uterine smooth muscle isolated from the same rat. The
number in each box reflects the sample size.