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Receptors for bradykinin and kallidin
Canadian Journal of Physiology and Pharmacology
|April 1, 1979
Summary
Bradykinin (BK) and Lys-bradykinin (Lys-BK) act on the same receptors. Experiments on cat ileum and rabbit aorta confirm that these kinins bind to identical receptor types, specifically B1 and B2 receptors.
Area of Science:
- Pharmacology
- Biochemistry
- Physiology
Background:
- Bradykinin (BK) and Lys-bradykinin (Lys-BK), also known as kallidin, are vasoactive peptides.
- Understanding their receptor interactions is crucial for pharmacology and physiology.
Purpose of the Study:
- To determine if BK and Lys-BK act on the same or different receptors.
- To characterize receptor subtypes B1 and B2 involved in kinin activity.
Main Methods:
- Experiments were conducted on isolated tissues: cat terminal ileum (receptor B2) and rabbit aorta (receptor B1).
- Receptor identity was assessed using desensitization (cat ileum) and measurement of apparent affinity (pA2) of a specific BK inhibitor (rabbit aorta).
Main Results:
- Desensitization of cat ileum with BK or Lys-BK significantly reduced or abolished the response to the other kinin, while histamine sensitivity remained.
- The BK inhibitor [Leu-OMe8,des-Arg9]-BK showed identical apparent affinity values against both BK and Lys-BK on the rabbit aorta.
Conclusions:
- The findings indicate that BK and Lys-BK interact with the same receptor types.
- This suggests a shared receptor mechanism for these two kinins on B1 and B2 receptors.