Related Experiment Videos
Nicardipine diminished equinatoxin II-induced decrease of coronary flow in isolated rat and pig hearts.
Matjaz Bunc1, Janez Rozman, Alenka Vidmar
1Department of Patophysiology, Zalozka 4, Medical Faculty, Ljublana, Slovenia.
Cellular & Molecular Biology Letters
|July 5, 2002
Summary
Equinatoxin II (EqT II) reduces coronary blood flow by activating L-type calcium channels. Nicardipine, a calcium channel blocker, partially reversed this effect in isolated hearts, indicating a key role for these channels.
Area of Science:
- Pharmacology
- Cardiovascular Physiology
- Toxicology
Background:
- Equinatoxin II (EqT II) is a basic, cardiotoxic polypeptide with known vasoconstrictory effects.
- The precise mechanisms underlying EqT II-induced coronary vasoconstriction are not fully elucidated.
- L-type calcium channels are critical regulators of vascular tone and cardiac function.
Purpose of the Study:
- To investigate the role of L-type calcium channels in the cardiotoxic effects of Equinatoxin II on coronary flow.
- To compare the effects of EqT II and nicardipine on isolated porcine and rat coronary arteries and hearts.
Main Methods:
- Isolated Langendorff-perfused porcine and rat hearts were used to assess coronary flow.
- Equinatoxin II was administered alone and in the presence of nicardipine, an L-type calcium channel antagonist.
- Dose-dependent effects on coronary flow were measured and statistically analyzed.
Main Results:
- Equinatoxin II decreased coronary flow in a dose-dependent manner in both porcine and rat hearts.
- Nicardipine partially diminished the vasoconstrictory effects of EqT II on coronary flow.
- The inhibitory effect of nicardipine was more pronounced in porcine hearts compared to rat hearts (p<0.05).
Conclusions:
- The activation of L-type calcium channels is a significant mechanism contributing to the reduction in coronary flow induced by Equinatoxin II.
- These findings highlight the involvement of calcium channel modulation in the cardiovascular toxicity of EqT II.