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Gap junction permeability is diminished in proliferating vascular smooth muscle cells
D T Kurjiaka1, T D Steele, M V Olsen
1Department of Physiology, University of Arizona, Tucson, Arizona 85724, USA.
The American Journal of Physiology
|December 9, 1998
Summary
Gap junction function in vascular smooth muscle cells (SMCs) differs between proliferating and growth-arrested states. Proliferating SMCs show altered junctional permselectivity, suggesting independent regulation of chemical coupling for growth control and vascular function.
Area of Science:
- Cell Biology
- Cardiovascular Physiology
- Biophysics
Background:
- Vascular smooth muscle cells (SMCs) proliferate and increase gap junction expression in atherosclerosis and hypertension.
- Understanding gap junction function in different SMC states is crucial for vascular health.
Purpose of the Study:
- To investigate differences in gap junction function between proliferating and growth-arrested SMCs.
- To determine if junctional permselectivity varies with SMC proliferation state.
Main Methods:
- Used A7r5 cells (embryonic rat aortic SMCs) cultured in low-serum media to induce growth arrest.
- Measured dye and electrical coupling, and junctional conductances using various solutions (potassium glutamate, tetraethylammonium chloride, KCl).
Main Results:
- Electrical coupling was comparable in proliferating and growth-arrested SMCs, but dye coupling was reduced in growth-arrested cells.
- Junctional conductances in growth-arrested cells were predicted by solution conductivities.
- In proliferating cells, junctional conductances exceeded predictions, indicating altered permselectivity for anions and cations.
Conclusions:
- A7r5 cells regulate chemical coupling independently of electrical coupling.
- This independent regulation may facilitate growth control while preserving vasomotor responsiveness.
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