Related Experiment Videos
Voltage-dependent calcium channels in smooth muscle cells
T B Bolton1, I MacKenzie, P I Aaronson
1Department of Pharmacology, St. George's Hospital Medical School, London, England.
Journal of Cardiovascular Pharmacology
|January 1, 1988
Summary
This study identifies and characterizes calcium channels in smooth muscle cells, revealing distinct low- and high-threshold components. These findings are crucial for understanding vascular smooth muscle function and drug interactions.
Area of Science:
- Cardiovascular Physiology
- Molecular Physiology
- Pharmacology
Background:
- Smooth muscle cells possess voltage-gated calcium channels crucial for contraction.
- These channels are present in smooth muscle cells regardless of their ability to generate action potentials.
Purpose of the Study:
- To characterize the properties of voltage-gated calcium channels in rabbit ear artery smooth muscle cells.
- To investigate the influence of different calcium concentrations and nifedipine on calcium channel currents.
Main Methods:
- Voltage clamp electrophysiology was used on single smooth muscle cells from rabbit ear artery.
- Inward currents were measured by stepping membrane potentials to various positive values.
Main Results:
- A sustained inward current, carried by calcium or barium and blocked by cadmium, cobalt, or manganese, was observed.
- Distinct low- and high-threshold current components were identified, suggesting different calcium channel populations.
- Nifedipine exhibited differential effects on current amplitude based on test and holding potentials.
Conclusions:
- Rabbit ear artery smooth muscle cells express voltage-gated calcium channels with distinct properties.
- These channels play a significant role in regulating vascular tone.
- Nifedipine's action is dependent on the membrane potential, impacting calcium influx differently.