Clarithromycin
Inhibits Myometrial Contractions in Isolated
Human Myometrium Independent of Stimulus
H.
CELIK, A. AYAR1
Department of Obstetrics and Gynaecology, and 1Department
of Pharmacology, Faculty of Medicine, Firat
University, Elazig, Turkey
Received February 20, 2001
Accepted October 5, 2001
Summary
Erythromycin has a well-known dual
effect on the contractility of the
gastrointestinal system and recently has also
been shown to inhibit contractions of the rat
myometrium. The aim of the present study was to
investigate the effects of clarithromycin on
oxytocin, prostaglandin F2a (PGF2a) and
KCl-induced contractions of human myometrium in
vitro. Myometrial strips were obtained from
pregnant women undergoing elective Cesarean
section and the strips were suspended in a
jacketed organ bath filled with Krebs solution at
37 oC (pH 7.4) and continuously aired with 95 %
oxygen and 5 % carbon dioxide. Isometric
contractions were measured using a force
displacement transducer. Oxytocin, PGF2a, KCl and
clarithromycin were applied to the tissue bath
and the amplitude and frequency of contractions
were evaluated at 20-min intervals. Freidmann
analysis of variance, Kruskal Wallis and Wilcoxon
Rank tests were used for statistical analysis of
the data. Clarithromycin dose dependently
inhibited the amplitude of contractions
independent of the stimulus. Pre-treatment with
apamin prevented clarithromycin-induced effects
on amplitude and frequency of contractions. We
conclude that the macrolide antibiotic
clarithromycin may have a direct inhibitory
effect on contractions of human myometrium.
Key
words
Myometrium
· Clarithromycin · Oxytocin · Isometric
contraction · Human
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Dr. Ahmet AYAR, Firat University, Faculty of
Medicine (TIP FAK), Department of Pharmacology,
Tr-23119, Elazig, Turkey, Fax: + 90 424 237 91
38, e-mail: aayar@firat.edu.tr
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