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Effect of gap junction number and permeability on intercellular coupling in rat myometrium
M G Blennerhassett1, R E Garfield
1Department of Pathology, McMaster University Health Sciences Center, Hamilton, Ontario, Canada.
The American Journal of Physiology
|December 1, 1991
Summary
Gap junctions (GJ) increase before labor, enhancing myometrial cell coupling. This study shows GJ permeability and number modulate myometrial electrical coupling during labor.
Area of Science:
- Physiology
- Cell Biology
- Reproductive Biology
Background:
- Gap junctions (GJ) increase in myometrial cells preceding labor.
- The role of GJ in myometrial cell-to-cell coupling requires further investigation.
Purpose of the Study:
- To provide evidence for the role of gap junctions in myometrial cell-to-cell coupling.
- To evaluate input resistance and intercellular spread of Lucifer yellow in rat myometrium.
Main Methods:
- Intact preparations of rat longitudinal myometrium were used.
- Evaluated input resistance (Ro) and intercellular spread of Lucifer yellow (LY).
- Tested effects of octanol, K+ depolarization, and oxytocin on myometrial preparations.
Main Results:
- Lucifer yellow spread rapidly in term/preterm delivering rats, but slowly in controls.
- Input resistance (Ro) dropped significantly at delivery, indicating decreased coupling.
- Octanol increased Ro, suggesting GJ uncoupling; contractile agonists also increased Ro.
Conclusions:
- Myometrial coupling is modulated by GJ permeability (seconds) and number (hours).
- Gap junctions play a crucial role in myometrial electrical coupling during labor.
- Contractile agonists may reduce myometrial cell-to-cell coupling during labor.