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

  title={Gap junctions: their presence and necessity in myometrium during parturition.},
  author={Robert E. Garfield and S M Sims and Edwin E. Daniel},
  volume={198 4320},
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.



The structural basis of electrical coupling (cell-to-cell contacts) in rat myometrium.

The ultrastructure of rat myometrium was studied to determine the types and relative number of cell-to-cell contacts between smooth muscle cells after various hormonal treatments and the mechanisms for electrical coupling between uterine muscle cells.


This general theory of endocrine control of the myometrium in pregnancy is proposed, based on observations pointing to a local effect of placentiil progesterone and a brief review, in historical order, of the data.

Changes in electrical properties of rat myometrium during gestation and following hormonal treatments.

The membrane potential was highest during the middle stage of gestation, but the spike amplitude within a burst was not uniform, and the resting and active membrane properties of the progresterone treated myometrium were similar to those observed during themiddle stages of gestation.

Cell contacts in duodenal smooth muscle layers.

Experiments in which cells were shrunk by perfusion with a hypertonic solution or strongly contracted by acetylcholine or high potassium left both types of contact intact indicates that they are resistant to mechanical separation, and also that the observed uncoupling of slow waves in intestinal muscle under these conditions cannot be due simply to gross disruption of nexuses.

Voltage-Clamp Studies on Uterine Smooth Muscle

  • N. Anderson
  • Biology
    The Journal of general physiology
  • 1969
These studies indicate a sodium-dependent, regenerative excitation mechanism in strips of uterine smooth muscle that resulted in a family of ionic currents with voltage- and time-dependent characteristics.

Intercellular Connection between Smooth Muscle Cells: the Nexus

High-resolution electron microscopy has revealed that the regions of contact between smooth muscle cells from dog intestine are areas of fusion of adjacent cell membranes. For morphological and

Freeze-fracture studies of nexuses between smooth muscle cells. Close relationship to sarcoplasmic reticulum

Many nexuses in the guinea pig sphincter pupillae, chicken gizzard, and toad stomach show a close relationship with sarcoplasmic reticulum, and the possibility that this may have some role in current flow across this specialized junction is discussed.


The nexuses which occur in epithelia in frog skin and rat salivary gland are distributed as though to provide seals against electrochemical backleaks and sites of chemical exchange between cell interiors.

Electrical Transmission at the Nexus between Smooth Muscle Cells

The structural and functional changes in smooth muscle due to hypertonicity correlate with the hypothesis that nexuses between cells are responsible for the core conductor properties of tissues, especially where one cell sends a large bulbous projection into a neighbor.

Structure and function of intercellular junctions.