They were pretreated with diethylstilbestrol (0.1mg/kg, i.p.)
24 h prior to the experiment. The animals were then sacrificed by
cervical dislocation and the uterine horns were isolated. Uterine
strips (15mm long) were dissected from both ovarian and cervical
segments of each uterine horn; thus two strips were obtained
from each horn. The strips were mounted under a resting 1 g tension
in a Locke–Ringer filled organ bath aerated with carbogen
and maintained at 37 ◦C. The contractile responses were recorded
isometrically with a Grass FT03 force transducer connected to a
MacLab system running chart v3.5 (ADI Instruments Pty Ltd., Castle
Hill, NSW, Australia) and allowed to equilibrate for 60 min before
starting the experiment, during which time the bathing solution
was exchanged with fresh Locke–Ringer solution every 10 min. The
frequency of the uterine contractions was taken as the number of
contractions recorded over a 10-min period, whereas the force of
contraction was obtained by measuring the mean amplitude of all
the contractions recorded over the same period.
The contractions obtained for 10 min of the stable spontaneous
or the agonist- and KCl-induced contractions before the addition of
the plant extracts or standard drugs were taken as the control. The
effects of each concentration of the extracts or standard drugs on
uterine contraction during the last 10-min incubation period were
expressed as the percent change of the control.