Related Experiment Video
Updated: Aug 17, 2026
Two-photon Imaging of Intracellular Ca2+ Handling and Nitric Oxide Production in Endothelial and Smooth Muscle Cells of an Isolated Rat Aorta
Published on: June 10, 2015
[Characterization of Ca-uptake by a microsomal fraction from vascular smooth muscle]
Abstract:
A microsomal fraction was isolated from the media-intima of the bovine carotid artery; the preparation is a mixed fraction of membranal and mitochondrial debris, which is able to bind Ca-ions and to take them up in the presence of ATP. The Ca-uptake is activated within a pCa range from 7--5. The involvement of two different systems in the Ca-uptake is discussed. A Ca-stimulatable ATPase was demonstrated, whose relationship with a Ca-transport system could not be established, however. The substrate for Ca-uptake is MgATP; in addition, free Mg has a stimulating effect. The Na/Kratio has no influence on the Ca-uptake. The influence of the pH-value on the Ca-binding and Ca-uptake was studied. Phosphate increased the Ca-uptake, while oxalate did not. The investigated system is discussed as a model for the action of vaso-active drugs.
Insights
This study investigated calcium (Ca) ion uptake in bovine carotid artery microsomes, finding it dependent on MgATP and influenced by pH and phosphate. The findings offer a model for how vaso-active drugs affect vascular smooth muscle.
Area of Science:
- Biochemistry
- Cell Biology
- Vascular Physiology
Context:
- The media-intima of the bovine carotid artery contains cellular components crucial for vascular function.
- Microsomal fractions provide a model system to study ion transport mechanisms in vascular tissue.
Purpose:
- To characterize the calcium-binding and uptake mechanisms in bovine carotid artery microsomes.
- To investigate the role of ATP, magnesium, and pH in calcium homeostasis within vascular cells.
Summary:
- A microsomal fraction from bovine carotid artery media-intima demonstrated ATP-dependent calcium uptake, active within a pCa range of 7-5.
- Calcium uptake utilized MgATP as a substrate, with free magnesium and phosphate showing stimulatory effects, while Na/K ratio had no influence.
- A Ca-stimulatable ATPase was identified, but its direct link to the Ca-transport system remains unestablished.
Impact:
- The findings provide insights into the cellular mechanisms of calcium regulation in vascular smooth muscle.
- This research serves as a potential model for understanding the action of vaso-active drugs on vascular tone and calcium signaling.
