| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 6 1417-R1423, Copyright © 1990 by American Physiological Society
ARTICLES |
M. E. Crandall and C. M. Heesch
Department of Physiology and Biophysics, University of Kentucky, Lexington 40546-0236.
Arterial baroreflex control of renal sympathetic nerve activity (RSNA) was compared in nonpregnant (NP) and near-term pregnant (P) chloralose-anesthetized rats. Baroreflex curves were obtained by recording reflex changes in RSNA (expressed as a percent of base line) due to increases and decreases in mean arterial pressure (MAP) [intravenous phenylephrine and nitroprusside (NTP)]. The slope, midpoint (EP50), and threshold pressures of the baroreflex curves were compared. Base-line MAP was significantly lower in the pregnant animals (P = 96 +/- 3 vs. NP = 113 +/- 5 mmHg). The baroreflex curves of pregnant animals also had significantly lower threshold (P = 95 +/- 3 vs. NP = 110 +/- 5 mmHg) and midpoint values (P = 105 +/- 4 vs. NP = 119 +/- 5 mmHg). The response to unloading the baroreceptors was attenuated in the pregnant animals as indicated by a decrease in slope of the NTP portion of the baroreflex curve (P = 0.95 +/- 0.17 vs. NP = 1.61 +/- 0.29% nerve activity/mmHg). Responses to blockade of angiotensin-converting enzyme with captopril (2 mg/kg iv) were also examined. There were no differences in EP50 or slope among the control, captopril, and recovery baroreflex curves within either the nonpregnant or pregnant animals. However, after captopril, MAP decreased to a greater extent in the pregnant rats, yet RSNA increased to the same level for the two groups. Thus pregnancy results in a leftward shift of the baroreflex function curve toward a lower operating pressure range. In addition, pregnant rats demonstrated an impaired ability to increase sympathetic outflow above base-line values in response to a hypotensive challenge.
This article has been cited by other articles:
|
|
 |
|
  L. Kvochina, E. M. Hasser, and C. M. Heesch Pregnancy increases baroreflex-independent GABAergic inhibition of the RVLM in rats Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2007; 293(6): R2295 - R2305. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. McDowall and R. A. L. Dampney Calculation of threshold and saturation points of sigmoidal baroreflex function curves Am J Physiol Heart Circ Physiol, October 1, 2006; 291(4): H2003 - H2007. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Ma, F. M. Abboud, and M. W. Chapleau Analysis of afferent, central, and efferent components of the baroreceptor reflex in mice Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2002; 283(5): R1033 - R1040. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. L. Brooks, K. A. Clow, and K. P. O'Hagan Pregnancy and acute baroreflex resetting in conscious rabbits Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2002; 283(2): R429 - R440. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. D. Laiprasert, R. L. Hamlin, and C. M. Heesch Afferent baroreceptor discharge in pregnant rats Am J Physiol Heart Circ Physiol, December 1, 2001; 281(6): H2456 - H2462. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. P. O'Hagan, K. A. Skogg, and J. B. Stevenson AT1 receptor block does not affect arterial baroreflex during pregnancy in rabbits Am J Physiol Heart Circ Physiol, May 1, 2001; 280(5): H1996 - H2005. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Hines Baroreceptor afferent discharge in the pregnant rat Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2000; 278(6): R1433 - R1440. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Hines and W. A. Herzer Effect of cardiac receptor stimulation on renal vascular resistance in the pregnant rat Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2000; 278(1): R171 - R178. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Chen, M. Hirasawa, Y. Takahashi, R. Landgraf, and Q. J. Pittman Suppression of PGE2 fever at near term: reduced thermogenesis but not enhanced vasopressin antipyresis Am J Physiol Regulatory Integrative Comp Physiol, August 1, 1999; 277(2): R354 - R361. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. S. Curtis, J. T. Cunningham, and C. M. Heesch Fos expression in brain stem nuclei of pregnant rats after hydralazine-induced hypotension Am J Physiol Regulatory Integrative Comp Physiol, August 1, 1999; 277(2): R532 - R540. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M. Foley, H. W. Vogl, P. J. Mueller, M. Hay, and E. M. Hasser Cardiovascular response to group I metabotropic glutamate receptor activation in NTS Am J Physiol Regulatory Integrative Comp Physiol, May 1, 1999; 276(5): R1469 - R1478. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. P. O'Hagan and S. M. Casey Arterial baroreflex during pregnancy and renal sympathetic nerve activity during parturition in rabbits Am J Physiol Heart Circ Physiol, May 1, 1998; 274(5): H1635 - H1642. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. D. Laiprasert, R. C. Rogers, and C. M. Heesch Neurosteroid modulation of arterial baroreflexsensitive neurons in rat rostral ventrolateral medulla Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1998; 274(4): R903 - R911. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. F. M. Slangen, I. C. M. Out, B. J. A. Janssen, and L. L. H. Peeters Blood pressure and heart rate variability in early pregnancy in rats Am J Physiol Heart Circ Physiol, October 1, 1997; 273(4): H1794 - H1799. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
