Abstract
1. The effects of N-methyl- and N-isobutyl-1,2-diphenyl ethanol amine (compounds M & E), respectively and diltiazem (D) were examined on the spontaneous and evoked uterine contractions of pregnant rats in vitro.
2. Addition of compound M (75-300-mu-M), compound E (15-60-mu-M) or D (100-400 nM) to the uterine tissues, inhibited the spontaneous contractions in a dose-dependent manner. The potency order was D > E > M.
3. The inhibitions were reversed by elevating the extracellular Ca2+ concentration by 20 mM. The compounds also antagonised CaCl2-evoked contractions.
4. Treatment of rats with either compound during pregnancy days (1-16) did not affect the implantation process and did not induce any teratogenicity.
5. The uterine inhibitory effects of the compounds may be due to blockade of uterine Ca2+ channels.