This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bjørnstad-Østensen, A. Articles by Berg, T. Search for Related Content PubMed PubMed Citation Articles by Bjørnstad-Østensen, A. Articles by Berg, T. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Medline Plus Health Information High Blood Pressure Low Blood Pressure Hazardous Substances DB NITRIC OXIDE PHENTOLAMINE

(Hypertension. 1997;29:53.)
© 1997 American Heart Association, Inc.

Research Articles (Issue 1, Part 1)

Amplification of Kinin-Induced Hypotension by Nitric Oxide Synthesis in Spontaneously Hypertensive Rats

Anniken Bjørnstad-Østensen; Hege Ruge Holte; Torill Berg

the Department of Physiology, Institute of Basic Medical Sciences, University of Oslo (Norway).

Correspondence to Torill Berg, Institute of Physiology, Box 1103, Blindern, 0317 Oslo 3, Norway.

We studied the role of nitric oxide and adrenergic activation in the blood pressure (BP) response to exogenous bradykinin in spontaneously hypertensive rats (SHR) compared with normotensive Wistar-Kyoto rats (WKY). Rats were pretreated with the nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (L-NAME), the -adrenergic receptor antagonist phentolamine together with L-NAME, or phentolamine alone. Sham-injected rats were used as controls. All rats subsequently received bradykinin (3, 6, and 30 µg/kg IV). Bradykinin induced a concentration-dependent fall in BP in both WKY and SHR (P<.0005). The change in BP was greater in SHR than WKY (P<.0001). BP before bradykinin administration was elevated in the L-NAME group in both strains. In WKY, L-NAME or L-NAME plus phentolamine did not alter the BP concentration-response curve to bradykinin (P=NS), whereas in SHR, the BP concentration-response curve was attenuated (P<.0048). The attenuation was observed for the two lower bradykinin doses (P<.0005) but not the highest. In SHR, phentolamine alone reduced BP before bradykinin to the same level as in WKY controls, and its BP concentration-response curve was not different from that of the normotensive controls or L-NAME and L-NAME plus phentolamine SHR groups. No difference was observed in the duration of the hypotensive response in SHR compared with WKY. The present results confirm that in normotensive rats, the hypotensive effect of bradykinin was mediated by an unknown mechanism other than through the release of nitric oxide. However, in SHR, this mechanism was amplified by additional activation of nitric oxide synthesis. This bradykinin-activated nitric oxide production may be a pressure-induced mechanism to counteract the hypertensive condition.

Key Words: bradykinin • endothelium-derived relaxing factor • nitric oxide • blood pressure • rats, inbred SHR

This article has been cited by other articles:

				H. Chai, W. Zhou, P. Lin, A. Lumsden, Q. Yao, and C. Chen Ginsenosides block HIV protease inhibitor ritonavir-induced vascular dysfunction of porcine coronary arteries Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2965 - H2971. [Abstract] [Full Text] [PDF]

				A. Dendorfer, S. Wolfrum, M. Wagemann, F. Qadri, and P. Dominiak Pathways of bradykinin degradation in blood and plasma of normotensive and hypertensive rats Am J Physiol Heart Circ Physiol, May 1, 2001; 280(5): H2182 - H2188. [Abstract] [Full Text] [PDF]

				L. Fernandes, Z. B. Fortes, D. Nigro, R. C. A. Tostes, R. A. S. Santos, and M. H. Catelli de Carvalho Potentiation of Bradykinin by Angiotensin-(1-7) on Arterioles of Spontaneously Hypertensive Rats Studied In Vivo Hypertension, February 1, 2001; 37(2): 703 - 709. [Abstract] [Full Text] [PDF]

				E. D. Frohlich Risk Mechanisms in Hypertensive Heart Disease Hypertension, October 1, 1999; 34(4): 782 - 789. [Abstract] [Full Text] [PDF]