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Selective block of gap junction channel expression with connexin-specific antisense oligodeoxynucleotides
The American Journal of Physiology
|November 1, 1994
Summary
Vascular smooth muscle gap junctions, formed by connexin 43 (Cx43) and connexin 40 (Cx40), exhibit distinct conductances. Antisense oligodeoxynucleotides targeting Cx43 reduced larger conductance channels, while Cx40 targeted smaller ones.
Area of Science:
- Cardiovascular Biology
- Cellular Physiology
- Molecular Medicine
Background:
- Gap junctions in vascular smooth muscle are crucial for regulating vascular tone.
- A7r5 cells, derived from rat aorta, express connexin 43 (Cx43) and connexin 40 (Cx40).
Purpose of the Study:
- To investigate the specific connexin composition of different gap junction channel conductances in A7r5 cells.
- To determine the role of Cx43 and Cx40 in forming distinct gap junction channels.
Main Methods:
- Utilized patch-clamp electrophysiology to record unitary currents from A7r5 cell gap junctions.
- Employed antisense oligodeoxynucleotides (ODNs) to selectively reduce Cx43 and Cx40 expression.
- Analyzed changes in channel event frequency and conductance following ODN treatment.
Main Results:
- Identified three distinct unitary conductances (70, 108, and 141 pS) in A7r5 cell gap junctions.
- Antisense Cx43 ODN treatment decreased the frequency of 108- and 141-pS channel events.
- Antisense Cx40 ODN treatment decreased the frequency of 70-pS channel events.
Conclusions:
- Cx43 forms the 108- and 141-pS gap junction channels in A7r5 cells.
- Cx40 forms the 70-pS gap junction channels in A7r5 cells.
- This differential channel formation by connexins contributes to the complexity of vascular smooth muscle communication.