Gap junctions: their presence and necessity in myometrium during parturition.

@article{Garfield1977GapJT,
  title={Gap junctions: their presence and necessity in myometrium during parturition.},
  author={Robert E. Garfield and S M Sims and Edwin E. Daniel},
  journal={Science},
  year={1977},
  volume={198 4320},
  pages={
          958-60
        }
}
Thin sections of longitudinal and circular muscle of myometrium obtained from rats during pregnancy, at term, during delivery, and postpartum were quantitatively examined in the electron microscope. Gap junctions (low resistance pathways) were only present during or immediately prior to delivery and immediately postpartum. The absence of gap junctions during gestation may be necessary for maintenance of pregnancy, while their occurrence during parturition may lead to effective termination of… 

Possible role of gap junctions in activation of myometrium during parturition.

It is proposed that gap junctions are essential for normal labor and delivery for synchronous contraction of the muscle of the uterus and that agents used to stimulate or inhibit labor may do so by affecting gapjunctions.

Presence of gap junctions in the myometrium of women during various stages of menstruation.

Appearance of gap junctions in the myometrium of women during labor.

Hormonal control of gap junction formation in sheep myometrium during parturition.

The ultrastructure of myometrial tissues from nonpregnant, pregnant and postpartum sheep was quantitatively examined and the formation of gap junctions correlated with a rise in fetal estrogens, a fall in maternal progesterone and increases in fetal and maternal estrogen/progesterone ratios.

Control of Myometrial Contractility and Labor

At the end of gestation, the uterus becomes increasingly contractile and reactive to excitatory agents to eventually reach a state in which it forcefully expels the fetus and other products of

Myometrial electrophysiologic activity and gap junctions in the pregnant rabbit.

Modulation of gap junctions in the myometrium of pigs during early gestation, induced abortion and the oestrous cycle.

It remains unclear, which role do oestrogens play in the synthesis of gap junctions at induced abortion, irrespective of the agent used as abortifacient.
...

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