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ATP-sensitive potassium channels in cultured arterial segments
T Kleppisch1, B Winter, M T Nelson
1Department of Pharmacology, University of Vermont, Colchester 05446-2500, USA. kleppisch@ipt.med.tu-muenchen.de
The American Journal of Physiology
|December 1, 1996
Summary
This study shows that ATP-sensitive potassium (KATP) channels in cultured rabbit arteries remain functional for up to 7 days. This arterial smooth muscle model is suitable for investigating KATP channel regulation and growth responses.
Area of Science:
- Vascular biology
- Ion channel physiology
- Pharmacology
Background:
- Organ cultures of arteries are used to study vascular responses.
- The function of specific ion channels, particularly ATP-sensitive potassium (KATP) channels, in cultured arteries remains largely uninvestigated.
- KATP channels are crucial for regulating arterial tone.
Purpose of the Study:
- To determine the functional state of KATP channels in cultured rabbit mesenteric arteries.
- To assess the viability of using cultured arteries for studying KATP channel function and vascular responses over time.
Main Methods:
- Rabbit mesenteric artery segments were cultured for 2-7 days.
- Isometric force measurements using a resistance-vessel myograph assessed contractility.
- Whole-cell patch-clamp electrophysiology recorded KATP currents in isolated smooth muscle cells.
- Effects of KATP channel modulators (pinacidil, glibenclamide) and vasoactive substances (histamine, norepinephrine, serotonin, acetylcholine, sodium nitroprusside) were examined.
Main Results:
- KATP current density and membrane capacitance in smooth muscle cells were unchanged in cultured arteries compared to controls.
- Glibenclamide-sensitive KATP currents and their modulation by histamine remained functional in cultured arteries for up to 4 days.
- Cultured arteries exhibited dose-dependent relaxation to pinacidil, with functional KATP channels evident for up to 7 days.
- While constrictor responses to histamine, norepinephrine, and serotonin diminished after 5 days, relaxation to sodium nitroprusside was maintained.
Conclusions:
- ATP-sensitive potassium (KATP) channels in arterial smooth muscle maintain their functional integrity in cultured arteries for at least 7 days.
- Contractile responses in arterial segments are largely preserved in this culture model.
- This arterial culture system provides a valuable tool for investigating long-term regulation of KATP channels and their role in vascular growth responses.