AJP - Regulatory, Integrative and Comparative Physiology, Vol 270, Issue 4 728-R737, Copyright © 1996 by American Physiological Society

ARTICLES

Converting enzyme inhibitors cause pressure-independent resetting of baroreflex control of sympathetic outflow

C. M. Heesch, M. E. Crandall and J. A. Turbek
Department of Physiology, Ohio State University, Columbus 43210-1218, USA.

The current study was performed to determine whether baroreflex resetting after acute administration of converting enzyme inhibitors (CEIs) was dependent on the concomitant decrease in mean arterial pressure (MAP). Reflex changes in lumbar sympathetic nerve activity (LSNA) due to increases and decreases in MAP [i.v. phenylephrine (PE) and nitroprusside infusions] were determined in normotensive and renal hypertensive (1-kidney, 1-clip) anesthetized WKY rats 1) before (control), 2) 15 min after intravenous captopril (2 mg/kg) or enalaprilat (300 micrograms), and 3) 15 min after MAP was returned to pre-CEI levels with intravenous PE. CEIs decreased MAP and caused a leftward shift of the MAP-LSNA curve toward a lower operating pressure range in all hypertensive and in one group of normotensive rats. The baroreflex curve remained shifted to the left even after MAP was restored to pre-CEI levels by infusion of PE. Thus CEIs cause a pressure-independent resetting of baroreflex control of sympathetic outflow within 15 min. This effect of CEIs is most likely due to elimination of a central nervous system effect of circulating angiotensin II and could contribute to the antihypertensive actions of this class of compounds.

This article has been cited by other articles:

				M. Vitela, M. Herrera-Rosales, J. R. Haywood, and S. W. Mifflin Baroreflex regulation of renal sympathetic nerve activity and heart rate in renal wrap hypertensive rats Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2005; 288(4): R856 - R862. [Abstract] [Full Text] [PDF]

				M. G. Sanderford and V. S. Bishop Central mechanisms of acute ANG II modulation of arterial baroreflex control of renal sympathetic nerve activity Am J Physiol Heart Circ Physiol, May 1, 2002; 282(5): H1592 - H1602. [Abstract] [Full Text] [PDF]

				G. F. DiBona Nervous Kidney : Interaction Between Renal Sympathetic Nerves and the Renin-Angiotensin System in the Control of Renal Function Hypertension, December 1, 2000; 36(6): 1083 - 1088. [Abstract] [Full Text] [PDF]

				T. J. Scislo, R. A. Augustyniak, and D. S. O'Leary Differential arterial baroreflex regulation of renal, lumbar, and adrenal sympathetic nerve activity in the rat Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1998; 275(4): R995 - R1002. [Abstract] [Full Text] [PDF]

				G.-H. Yi, D. Burkhoff, H. Zhang, S.-M. Zhu, D. Zwas, and J. Wang Hemodynamic Effects of a Calcium Channel Promoter, BAY y 5959, are Preserved after Chronic Administration in Ischemic Heart Failure in Conscious Dogs J. Pharmacol. Exp. Ther., August 1, 1998; 286(2): 760 - 766. [Abstract] [Full Text]

				L. Xu, J. P. Collister, J. W. Osborn, and V. L. Brooks Endogenous ANG II supports lumbar sympathetic activity in conscious sodium-deprived rats: role of area postrema Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1998; 275(1): R46 - R55. [Abstract] [Full Text] [PDF]

				Q. Li, M. J. Sullivan, W. E. Dale, E. M. Hasser, E. H. Blaine, and J. T. Cunningham Fos-Like Immunoreactivity in the Medulla after Acute and Chronic Angiotensin II Infusion J. Pharmacol. Exp. Ther., March 1, 1998; 284(3): 1165 - 1173. [Abstract] [Full Text]

				M. Sanchez-Palacios, S. Y. Jones, and G. F. Dibona Role of angiotensin in renal sympathetic activation in nephrotic syndrome Am J Physiol Regulatory Integrative Comp Physiol, March 1, 1998; 274(3): R808 - R813. [Abstract] [Full Text] [PDF]