title: Effects of local anesthetics on contractions of pregnant and non-pregnant rat myometrium in vitro.
abstract: In order to determine whether local anesthetics directly affect the propagation and strength of myometrial contractions, we compared the effects of bupivacaine, ropivacaine, lidocaine and tetracaine on the contractions of myometrium isolated from pregnant and non-pregnant rats. Full-thickness myometrial strips were obtained from 18- to 21-day pregnant and non-pregnant Sprague-Dawley rats and incubated in an organ bath. When spontaneous contractions became regular, strips were exposed to cumulative concentrations of the four local anesthetics ranging from 0.01 to 300 μmol/L and the amplitude and frequency of contraction were recorded. All four compounds caused a concentration-dependent inhibition of the contractility of pregnant and non-pregnant uterine muscle. In pregnant myometrium, the concentration that caused 50% inhibition (IC(50)) was 100 μmol/L for bupivacaine, 157 μmol/L for ropivacaine, > 1000 μmol/L for lidocaine, and 26.3 μmol/L for tetracaine. In non-pregnant myometrium, the IC(50) was 26.9 μmol/L for bupivacaine, 40 μmol/L for ropivacaine, 384 μmol/L for lidocaine, and 7.4 μmol/L for tetracaine. These results suggested that local anesthetics do inhibit myometrial contractions in pregnant and non-pregnant rats in a concentration-dependent manner.
authors.affiliation: Chinese Medicine Hospital of Jingshan County Department of Medicine Hubei, Jinshan China.
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Wei
authors.affiliation: Zhejiang University Department of Anesthesiology, Women's Hospital, School of Medicine Hangzhou, Zhejiang 310006 China.
authors.forename: Zhe-Bin
authors.initials: ZB
authors.lastname: Jin
authors.affiliation: Zhejiang University Department of Anesthesiology, Women's Hospital, School of Medicine Hangzhou, Zhejiang 310006 China.
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: Zhejiang University Zhejiang Respiratory Drugs Research Laboratory of the SFDA of China, School of Medicine Hangzhou China.
authors.forename: Qiang-Min
authors.initials: QM
authors.lastname: Xie
authors.affiliation: Zhejiang University Zhejiang Respiratory Drugs Research Laboratory of the SFDA of China, School of Medicine Hangzhou China.
authors.forename: Ji-Qiang
authors.initials: JQ
authors.lastname: Chen
authors.affiliation: Zhejiang University Department of Anesthesiology, Women's Hospital, School of Medicine Hangzhou, Zhejiang 310006 China.
authors.forename: Zi-Gang
authors.initials: ZG
authors.lastname: Li
authors.affiliation: Zhejiang University Zhejiang Respiratory Drugs Research Laboratory of the SFDA of China, School of Medicine Hangzhou China.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Tang
mesh_terms: D000577:Amides / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D002045:Bupivacaine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077212:Ropivacaine; D013748:Tetracaine / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D013748:Tetracaine; D000077212:Ropivacaine; D008012:Lidocaine; D002045:Bupivacaine
keywords: bupivacaine; in vitro; lidocaine; local anesthetics; myometrium; non-pregnant; pregnant; rat; ropivacaine; tetracaine