Pregnant and non-pregnant mature guinea-pigs
weighing between 250 g and 400 g were used. The
uterine horn was dissected out and was mounted
vertically in a 50 ml organ bath according to
standard procedures. The bath contained De
Jalon solution with the following composition
(g/l): NaCI, 9.0: KCI, 0.42; NaHCO~, 0.5:CaC12,
0.3; glucose, 0.5. The bath was aerated with a
mixture of 95% oxygen and 5% CO, and was
maintained at 33°C_+ 0.5°C. The tension of the
tissue was about 1 g and the contractions were
recorded with a fi'ontal writing lever on smoked
paper mounted on a rotating kymograph drum.
Increasing concentrations of oxytocin (0.2 4
ng/ml) were administered to the tissue until maximal
contraction was obtained. The effects of increasing
concentrations of histamine (0.02 0.4
mg/ml) and the extract (1 8 mg/ml) were also
recorded on the same uterine horn. The drug