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Receptor-mediated contraction of aortic valve leaflets
A H Chester1, M Misfeld, M H Yacoub
1Department of Cardiothoracic Surgery, Heart Science Centre, NHLI, Imperial College of Science Technology and Medicine, UK.
The Journal of Heart Valve Disease
|April 20, 2000
Summary
Aortic valve leaflets contract in response to various vasoactive agents acting on specific receptors. Endothelin-1 and thromboxane A2 mimetics induced the strongest contractions, mediated by ET(A/B) and TXA2 receptors, respectively.
Area of Science:
- Cardiovascular Biology
- Pharmacology
- Biochemistry
Background:
- Aortic valve function regulation is not fully understood.
- Cusp tissue exhibits contractile properties, but mediating receptors are largely unknown.
Purpose of the Study:
- To investigate the receptors mediating contractile responses in porcine aortic valve leaflets.
- To characterize the effects of various vasoactive agents on aortic valve leaflet contraction.
Main Methods:
- Isolated organ baths were used to test the response of porcine aortic valve leaflets.
- Leaflets were exposed to endothelin-1, noradrenaline, adrenaline, U46619 (TXA2 mimetic), 5-HT, histamine, and angiotensin II.
- Leaflet viability was confirmed using 90 mM KCl.
Main Results:
- Most agents, except angiotensin II, caused concentration-dependent contractions.
- Endothelin-1 and U46619 produced the most potent contractions.
- Specific receptor antagonists identified mediating receptors: ET(A/B) for endothelin-1, alpha2-adrenoceptors for catecholamines, H1 for histamine, 5-HT2A for 5-HT, and TXA2 for U46619.
Conclusions:
- Aortic valve leaflet contraction is mediated by a diverse range of receptor systems.
- Further research is needed to understand the physiological and pathophysiological roles of these receptors in aortic valve function.