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Anti-ischaemic activity of various calmodulin antagonists
H W Boddeke1, B Wilffert, J G Hugtenburg
1Division of Pharmacotherapy/Pharmacology, University of Amsterdam, The Netherlands.
Abstract:
The anti-ischaemic activity of the calmodulin antagonists trifluperazine, felodipine, W-7 and calmidazolium has been investigated in electrically paced guinea-pig hearts, perfused according to Langendorff, which were subjected to 60 min of global ischaemia followed by 30 min of reperfusion. At concentrations that induced a comparable reduction in cardiac contractile force, trifluperazine, felodipine and to a lesser extent W-7, were associated with improvement of post-ischaemic functional (LVP and coronary flow) and biochemical parameters (CrP and ATP). Furthermore, felodipine and trifluperazine delayed the onset and suppressed the maximum tension of the ischaemic contracture was observed. In contrast, calmidazolium had no anti-ischaemic effects. This lack of anti-ischaemic activity of the most potent calmodulin antagonist calmidazolium, as well as the significant calcium entry blocking activity of both trifluperazine and felodipine suggest that additional factors besides calmodulin antagonism may contribute to the anti-ischaemic activity of these compounds.
Insights
Calmodulin antagonists like trifluperazine and felodipine show anti-ischaemic effects in guinea-pig hearts, improving function and biochemistry post-ischaemia. Calmidazolium, however, did not demonstrate these protective benefits.
Area of Science:
- Cardiovascular Pharmacology
- Ischaemia-Reperfusion Injury
Background:
- Calmodulin antagonists are investigated for potential cardioprotective effects.
- Understanding the mechanisms of anti-ischaemic activity is crucial for developing new therapies.
Purpose of the Study:
- To evaluate the anti-ischaemic activity of trifluperazine, felodipine, W-7, and calmidazolium.
- To explore the role of calmodulin antagonism and calcium entry blockade in cardioprotection during ischaemia-reperfusion.
Main Methods:
- Langendorff-perfused guinea-pig hearts subjected to global ischaemia and reperfusion.
- Assessment of functional parameters (left ventricular pressure, coronary flow) and biochemical markers (creatine phosphate, ATP).
- Evaluation of ischaemic contracture development.
Main Results:
- Trifluperazine, felodipine, and W-7 improved post-ischaemic functional and biochemical parameters.
- Felodipine and trifluperazine reduced ischaemic contracture.
- Calmidazolium exhibited no significant anti-ischaemic effects.
Conclusions:
- Trifluperazine and felodipine possess anti-ischaemic properties, potentially involving mechanisms beyond calmodulin antagonism, such as calcium entry blockade.
- Calmodulin antagonism alone may not be sufficient for anti-ischaemic activity; other factors are implicated.