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The persistence of active smooth muscle in the female rat cervix through pregnancy (865.2)
Author(s) -
Ferland David,
Watts Stephanie
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.865.2
Subject(s) - cervix , uterus , pregnancy , myosin , smooth muscle , isometric exercise , uterine contraction , contraction (grammar) , actin , smooth muscle tumor , calponin , medicine , muscle contraction , vagina , anatomy , biology , microbiology and biotechnology , genetics , cancer
A controversy exists as to whether functional smooth muscle exists in the cervix before and during pregnancy, potentially continuous with the uterus. We hypothesized that smooth muscle persists through pregnancy, remaining active. Uteri and cervices were taken from female virgin, 11 day‐ and 20 day (near labor)‐pregnant rats. Three different smooth muscle proteins (smooth muscle α actin, SM‐22α, and Calponin‐1) allowed immunohistochemical detection of the continuous nature of the smooth muscle from vagina, cervix and uterus. Uterus and cervix from virgin and 20‐day pregnant rats were hung in isolated tissue baths for measurement of isometric contraction. The virgin and day 20 cervices contracted 2.52g±0.27g and 3.88g±0.49g (respectively) to 100 mM KCl (general smooth muscle depolarization). Cervices also contracted to carbamylcholine in a concentration‐dependent fashion (maximum=133%±18.2% KCl contraction, n=4). Uterine and cervical homogenates were also used in Western analyses. Smooth muscle α actin was detected in virgin tissue (291.3±32.2 arbitrary densitometry units/β actin; n=5), in day 11 [416.8±19.5 (n=5)] and day 20 pregnant tissue [293.0±34.4 (n=5)]. These findings strongly support that smooth muscle is: 1) present in the cervix through pregnancy, 2) continuous with the uterus and 3) supports the overarching hypothesis that the smooth muscle of the cervix plays a role in pregnancy and labor. Grant Funding Source : Supported by a CTSI grant to Stephanie W. Watts