|
|
||||||||
1 Department of Biological Sciences, Tarleton State University, Stephenville 76401; and 2 Department of Physiology, University of Texas Health Science Center, San Antonio, Texas 78229-3900
Short-term intravenous infusion of
angiotensin II (ANG II) into conscious rabbits reduces the range of
renal sympathetic nerve activity (RSNA) by attenuating reflex
disinhibition of RSNA. This action of ANG II to attenuate the arterial
baroreflex range is exaggerated when ANG II is directed into the
vertebral circulation, which suggests a mechanism involving the central
nervous system. Because an intact area postrema (AP) is required for
ANG II to attenuate arterial baroreflex-mediated bradycardia and is
also required for maintenance of ANG II-dependent hypertension, we hypothesized that attenuation of maximum RSNA during infusion of ANG II
involves the AP. In conscious AP-lesioned (APX) and AP-intact rabbits,
we compared the effect of a 5-min intravenous infusion of ANG II (10 and 20 ng · kg
1 · min
1) on
the relationship between mean arterial blood pressure (MAP) and RSNA.
Intravenous infusion of ANG II into AP-intact rabbits resulted in a
dose-related attenuation of maximum RSNA observed at low MAP. In
contrast, ANG II had no effect on maximum RSNA in APX rabbits. To
further localize the central site of ANG II action, its effect on the
arterial baroreflex was assessed after a midcollicular decerebration.
Decerebration did not alter arterial baroreflex control of RSNA
compared with the control state, but as in APX, ANG II did not
attenuate the maximum RSNA observed at low MAP. The results of this
study indicate that central actions of peripheral ANG II to attenuate
reflex disinhibition of RSNA not only involve the AP, but may also
involve a neural interaction rostral to the level of decerebration.
circulating peptides; renal nerves; sympathetic nervous system; blood pressure; kidney
This article has been cited by other articles:
![]() |
M. Maliszewska-Scislo, H. Chen, R. A. Augustyniak, D. Seth, and N. F. Rossi Subfornical organ differentially modulates baroreflex function in normotensive and two-kidney, one-clip hypertensive rats Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2008; 295(3): R741 - R750. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. S. P. Tan, S. Killinger, J. Horiuchi, and R. A. L. Dampney Baroreceptor reflex modulation by circulating angiotensin II is mediated by AT1 receptors in the nucleus tractus solitarius Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2007; 293(6): R2267 - R2278. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Fu, R. P. Shook, K. Okazaki, J. L. Hastings, S. Shibata, C. L. Conner, M. D. Palmer, and B. D. Levine Vasomotor sympathetic neural control is maintained during sustained upright posture in humans J. Physiol., December 1, 2006; 577(2): 679 - 687. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. C. Malpas What sets the long-term level of sympathetic nerve activity: is there a role for arterial baroreceptors? Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2004; 286(1): R1 - R12. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |