ROLE OF BRADYKININ IN THE REGULATION OF BLOOD PRESSURE AND RENAL HEMODYNAMICS.

在麻醉SD大鼠、自发性高血压大鼠(SHR)、DOCA盐性高血压大鼠和日本大白兔上观察了缓激肽竞争性拮抗剂B4147对血压(BP)和肾血流(RBF)的调节作用。在SD大鼠，静脉注射B4147可使外源性缓激肽的降压作用抑制69%。SD大鼠注射B4147 25-100µg后，血压升高，RBF下降，呈剂量依赖关系。血管紧张素11拮抗剂或α1受体阻滞剂不能阻断血压的升高。卡托普利能显著降低血压。然而，在给予卡托普利后注射B4147引起的血压增加了43%，是卡托普利引起的最初下降的43%。这些结果表明，B4147对血压和RBF的作用不是通过血管紧张素11或交感神经α1刺激介导的。外源…更多的美国缓激肽可能有助于维持SD大鼠的血压和RBF。此外，缓激肽可能部分参与了转化酶抑制剂卡托普利的急性降压作用。SHR的血压变化幅度明显低于对照组(WKY)。WKY组较SHR组RBF下降更明显。缓激肽有助于维持两个菌株的BP和RBF。然而，SHR中缓激肽系统的缺陷可能在一定程度上参与了高血压的发生或维持。在DOCA高血压大鼠中，DOCA高血压大鼠的血压升高幅度显著低于DOCA高血压大鼠。与对照组相比，DOCA高血压大鼠的RBF下降幅度较小。这些结果提示DOCA-高血压大鼠高血压病程中内源性缓激肽受到抑制。麻醉兔肾动脉注射缓激肽拮抗剂后，RBF和GFR均显著降低。提示内源性激肽可能参与了RBF和GFR的调节。较少

To examine a possible role of endogenous bradykinin in the regulation of blood pressure(BP) and renal blood flow(RBF), a competitive antagonist of bradykinin(B4147) was studied in anesthetized Sprague Dawley(SD) rats, spontaneously hypertensive rats(SHR), DOCA salt hypertensive rats and Japanese albino rabbits. In SD rats, the intravenous infusion of B4147 inhibited the depressor effect of exogenous bradykinin by 69%. After an injection of B4147 at a dose of 25-100 mug in SD rats, BP increased and RBF decreased in a dose dependent fashion. The increase in BP was not blocked by treatment with angiotensin 11 antagonist or alpha_1-blocker. The administration of captopril decreased BP significantly. However, the injection of B4147 after the administration of captopril elicited an increase in BP of 43% of the initial decrease induced by captopril. These results suggest that the effects of B4147 on BP and RBF are not mediated through angiotensin 11 or sympathetic alpha_1-stimulation. Exogeno … More us bradykinin could contribute to the maintenance of BP and RBF in SD rats. Furthermore, bradykinin may partly participate in the acute hypotensive effect induced by the converting enzyme inhibitor captopril. In SHR, the magnitude in the change in BP was significantly lower in SHR than in control(WKY). The reduction of RBF was greater in WKY than in SHR. Bradykinin contributes to the maintenance of BP and RBF in both strains. However, deficiency in the bradykinin system in SHR may contributes partly to the development or the maintenance of hypertension. In DOCA-hypertensive rats, the magnitude of the increase in BP was significantly lower in DOCA hypertensive rats. The extent of the fall in RBF was reduced in DOCA hypertensive rats compared with control. These results suggest that endogenous bradykinin is depressed in the established phase of hypertension in DOCA-hypertensive rats. After the administration of bradykinin antagonist into the renal artery in anesthetized rabbits, both RBF and GFR were decreased significantly. These results indicate that endogenous kinins may participate in the regulation of RBF and GFR. Less