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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2003-5-21
pubmed:abstractText
Although smoking during pregnancy is one of the major risk factors of premature delivery, the underlying mechanism by which smoking causes premature delivery is unknown. In the present study, we examined the effects of smoking on uterine contractility induced by oxytocin and prostaglandin F(2alpha). Rats inhaled either cigarette smoke or room air from Day 14 to Day 16 of pregnancy through an inhalation apparatus for experimental animals (type "Hamburg II"). After the rats were killed on Day 17 of pregnancy, the uterine contractile sensitivity and activity on exposure to oxytocin or prostaglandin F2alpha were investigated. The expression levels of oxytocin-receptor mRNA and prostaglandin F(2alpha) receptor mRNA in the uterus were investigated by reverse transcription-polymerase chain reaction. The contractile activity was assessed as the contractile force and the frequency of rhythmic contractions of myometrial strips that were treated with oxytocin or prostaglandin F(2alpha). The contractile sensitivity to oxytocin was significantly higher in the smoking group than in the control group (P < 0.01). Although the contractile force of oxytocin-induced contractions did not differ between the smoking and control groups, the frequency of contractions was significantly higher in the smoking group than in the control group (P < 0.01). On the other hand, no significant differences were found in the contractile sensitivity and activity in response to prostaglandin F(2alpha) between the smoking and control groups. The expression of oxytocin-receptor mRNA in the myometrium was significantly increased in the smoking group compared with the control group (P < 0.01). However, no significant difference was found in the level of expression of prostaglandin F(2alpha)-receptor mRNA between the two groups. These results suggest that smoking during pregnancy increases the contractile sensitivity and activity of the myometrium in response to oxytocin by up-regulating the expression of oxytocin-receptor mRNA. The effects of smoking on the contractile sensitivity and activity of the myometrium in response to oxytocin may increase the risk of premature delivery in smokers.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-3363
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2274-80
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Smoking enhances oxytocin-induced rhythmic myometrial contraction.
pubmed:affiliation
Department of Obstetrics and Gynecology, Kansai Medical University, Moriguchi, Osaka, 570-0074, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't