Bradykinin dilates rat middle cerebral artery and its large branches via endothelial B2 receptors and release of nitric oxide |
| |
Authors: | C Görlach M Wahl |
| |
Institution: | Department of Physiology, LMU Munich, 80336, Munich, Germany |
| |
Abstract: | Ring segments of rat middle cerebral artery (MCA) were prepared for measurement of isometric force and precontracted with 10?4 M uridine triphosphate (UTP). Concentration-effect curves (CEC) were constructed for bradykinin (BK, 10?8–10?5 M) in segments with functionally intect (E+) or denuded (E?) endothelium. E? segments did not dilate to BK. The BK receptor was characterized by application of specific B1 or B2 antagonists des-Arg9-Leu8] BK (10?5 M) and
-Arg0-Hyp3-Thi5-
-Tic7-Oic8] BK (HOE140,3 × 10?7 M), respectively, or B1 agonist des-Arg9] BK (10?8–10?4 M). Involvement of nitric oxide (NO) was tested with NG-nitro-
-arginine (LNNA, 10?4 M). BK induced concentration-dependent relaxation with a maximal effect (Emax) of 40.86 ± 1.50% at 10?6 M and a pD2 (?log10 EC50) of 6.818 ± 0.044. This relaxation could be prevented with HOE140 or LNNA, but was not influenced by des-Arg9-Leu8] BK. des-Arg9] BK did not induce any effect. These results demonstrate that BK induced relaxation via endothelial B2 receptors and release of NO in isolated rat MCA. |
| |
Keywords: | Bradykinin NO B2 receptor Cerebral circulation Rat Isolated middle cerebral artery |
本文献已被 ScienceDirect 等数据库收录! |
|