Inhibitory effect of alprostadil against sevoflurane-induced myometrial relaxation in rats

• Published in: Journal of anesthesia Vol. 21; no. 3; pp. 361 - 366
• Main Authors: Ohashi, Yayoi, Sumikura, Hiroyuki, Tateda, Takeshi
• Format: Journal Article
• Language: English
• Published: Japan 01-01-2007
• Subjects: Alprostadil - pharmacology; Anesthetics, Inhalation - antagonists & inhibitors; Animals; Area Under Curve; Dose-Response Relationship, Drug; Female; Methyl Ethers - antagonists & inhibitors; Muscle Relaxation - drug effects; Muscle Relaxation - physiology; Myometrium - drug effects; Myometrium - physiology; Polymerase Chain Reaction; Pregnancy; Rats; Rats, Sprague-Dawley; Uterine Contraction - drug effects; Vasodilator Agents - pharmacology
• ISSN: 0913-8668; 1438-8359
• DOI: 10.1007/s00540-007-0536-8

For anesthetic management of cesarean sections, regardless of the use of regional or general anesthesia, it is crucial to achieve sufficient uterine contraction immediately following the delivery of an infant in order to reduce excessive bleeding. No previous study has investigated the ability of alprostadil, a synthesized prostaglandin, to inhibit myometrial relaxation induced by volatile anesthetics. The aim of the present study was to investigate the inhibitory effects of alprostadil on sevoflurane-induced myometrial relaxation using myometrial strips isolated from pregnant rats.
Myometrial strips were isolated from Sprague-Dawley rats (300-400 g) in the late stage of gestation (19-21 days). The time course of changes in spontaneous myometrium contraction was studied in the presence and absence of sevoflurane. Additionally, alprostadil was titrated at three different concentrations during continuous introduction of sevoflurane 2%, and myometrium contraction was studied. As an index of contraction, the area under the contraction curve was used, and data were analyzed by repeated measure one-way analysis of variance.
We have shown a significant decrease in myometrium contraction as a result of the use of sevoflurane (2%). Additionally, alprostadil has been shown to inhibit myometrial relaxation induced by sevoflurane in a dose-dependent manner. The areas under the contraction curve were 87%, 87%, 129%, and 172% of the baseline value for the control and at low, medium, and high concentrations of alprostadil, respectively.
The ability of alprostadil to inhibit myometrial relaxation induced by sevoflurane suggests that the use of alprostadil during general anesthesia for cesarean section may be advantageous for the reduction of postpartum bleeding.