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Intracellular Ca2+ and force determined simultaneously in isolated resistance arteries
R D Bukoski1, C Bergmann, A Gairard
1Laboratoire de Physiologie et Pharmacodynamie, Faculte de Pharmacie, Universite Louis Pasteur, Strasbourg, France.
The American Journal of Physiology
|November 1, 1989
Summary
This study introduces a new method to measure intracellular calcium (Ca2+) and force in arteries simultaneously. The findings show that reduced Ca2+ levels initiate relaxation responses in blood vessels.
Area of Science:
- Physiology
- Pharmacology
- Biochemistry
Background:
- Simultaneous measurement of intracellular calcium ([Ca2+]i) and force generation in isolated resistance arteries is crucial for understanding vascular function.
- Existing methods may not fully capture the dynamic interplay between calcium signaling and mechanical responses in arteries.
Purpose of the Study:
- To describe a novel method for simultaneous measurement of [Ca2+]i and force generation in isolated resistance arteries.
- To investigate the role of [Ca2+]i in the relaxation of arteries induced by various agents.
Main Methods:
- Isolated rat mesenteric resistance arteries were mounted on a wire myograph and loaded with the fluorescent Ca2+ indicator fura-2.
- The myograph was integrated with a microscope and fluorometer for simultaneous recording of [Ca2+]i and force.
- Arteries were stimulated with KCl and norepinephrine, followed by washout or treatment with forskolin or sodium nitroprusside.
Main Results:
- Stimulation with KCl and norepinephrine caused a rapid increase in [Ca2+]i preceding force development.
- Artery relaxation induced by agonist washout, forskolin, or sodium nitroprusside was associated with a decrease in [Ca2+]i.
- Forskolin and sodium nitroprusside induced relaxation preceded by a reduction in intracellular calcium levels.
Conclusions:
- The described method allows for simultaneous assessment of [Ca2+]i and force in isolated resistance arteries.
- A reduction in [Ca2+]i appears to be an initiating event in the relaxation of arteries induced by forskolin and sodium nitroprusside.
- This technique is valuable for studying calcium-dependent mechanisms of vasoactive compounds.