The effects of potassium channel openers on isolated pregnant human myometrium before and after the onset of labor: potential for tocolysis

Levcromakalim and pinacidil appear to inhibit spontaneous contractions in human myometrium. Levcromakalim and pinacidil are drugs known as potassium channel openers. The myometrium is the muscular layer of the uterus. Myometrial tissue was obtained from 67 pregnant women before they had cesarean sections. Thirty-one of the women were in labor at the time the tissue was obtained. The tissue was prepared and contractile activity was measured. Levcromakalim and pinacidil inhibited both spontaneous and induced contractions in the samples. Glibenclamide, used to treat diabetes, reduced the relaxant response caused by the potassium channel openers. Tolbutamide, also used to treat diabetes, did not affect the tissue's response to the potassium channel openers. Pinacidil and levcromakalim may be useful in suppressing premature labor.