Neomycin inhibition of hormone-stimulated smooth muscle contractions in myometrial tissue.

These studies sought to determine the effects of neomycin, a phospholipase C inhibitor, on hormone-stimulated myometrial contractions. For these studies, computer digitalized in vitro isometric contraction data were analyzed for changes in contractile activity in response to oxytocin and aluminum fluoride with and without neomycin. Neomycin (1-5 mM) produced dose-related inhibition of oxytocin and aluminum fluoride-stimulated myometrial contractions. This neomycin effect was apparent within 2-3 minutes of addition and was completely reversible, with resolution of its inhibitory effects within 6-8 minutes of washout. This study is the first to demonstrate the functional effect of neomycin inhibition of the phosphatidylinositol signaling pathway in myometrial smooth muscle tissue.