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Updated: Jun 21, 2026

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development
Published on: January 26, 2018
Clostridium botulinum toxin A inhibits contractility in pregnant human myometrium in vitro
Irina D Burd1, Amen Ness, Paul DiMuzio
1Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107, USA.
Abstract:
Studies were undertaken to evaluate the effect of Botulinum neurotoxin type-A (BoNTA) preparation on oxytocin-induced contractions of pregnant human myometrium in vitro. Human myometrial tissue was exposed to increasing concentrations (1-50 000 U/mL) of BoNT/A. Isometric contractions were measured using a force displacement transducer. The cumulative effect of BoNT/A on myometrial activity (time to half relaxation [TTR50], frequency, and amplitude) was evaluated. The frequency of myometrial contractions was depressed by 40% from baseline (P < .05) and relaxation time was increased by 30% (P < .05) from baseline within a narrow range of concentrations. There was no significant difference in amplitude. The observed effects were rapidly reversed after complete wash out of the tissue. BoNT/A or its analogues with more specific tissue affinity may be of value as future agents for prevention of unwanted uterine contractile activity associated with preterm labor and fetal surgery.
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