(Hypertension. 2001;37:1362.)
© 2001 American Heart Association, Inc.
Scientific Contributions |
Quantification of Mechanical and Neural Components of Vagal Baroreflex in Humans
From the Laboratory for Cardiovascular Research, Hebrew Rehabilitation Center for Aged Research and Training Institute; and Division on Aging, Harvard Medical School, Boston, Mass.
Correspondence to J. Andrew Taylor, PhD, Laboratory for Cardiovascular Research, Research and Training Institute, Hebrew Rehabilitation Center for Aged, 1200 Centre St, Boston, MA 02131. E-mail ataylor{at}mail.hrca.harvard.edu
Abstract—Traditionally, arterial baroreflex control of vagal neural outflow is quantified by heart period responses to falling and/or rising arterial pressures (ms/mm Hg). However, it is arterial pressure–dependent stretch of barosensory vessels that determines afferent baroreceptor responses, which, in turn, generate appropriate efferent cardiac vagal outflow. Thus, mechanical transduction of pressure into barosensory vessel stretch and neural transduction of stretch into vagal outflow are key steps in baroreflex regulation that determine the conventional integrated input-output relation. We developed a novel technique for direct estimation of gain in both mechanical and neural components of integrated cardiac vagal baroreflex control. Concurrent, beat-by-beat measures of arterial pressures (Finapres), carotid diameters (B-mode ultrasonography), and R-R intervals (ECG lead II) were made during bolus vasoactive drug infusions (modified Oxford technique) in 16 healthy humans. The systolic carotid diameter/pressure relationship (r2=0.79±0.008, mean±SEM) provided a gain estimate of dynamic mechanical transduction of pressure into a baroreflex stimulus. The R-R interval/systolic diameter relationship (r2=0.77±0.009) provided a gain estimate of afferent-efferent neural transduction of baroreflex stimulus into a vagal response. Variance between repeated measures for both estimates was no different than that for standard gain (P>0.40). Moreover, in these subjects, the simple product of the 2 estimates almost equaled standard baroreflex gain (ms/mm Hg=0.98x+2.27; r2=0.93, P=0.001). This technique provides reliable information on key baroreflex components not distinguished by standard assessments and gives insight to dynamic mechanical and neural events during acute changes in arterial pressure.
Key Words: arterial pressure • carotid arteries • ultrasonography
This article has been cited by other articles:
 |
|
 |
|
  K. D. Monahan A new answer to an old question: does ageing modify baroreflex control of vascular sympathetic outflow in humans? J. Physiol., May 1, 2009; 587(9): 1857 - 1857. [Full Text] [PDF]
|
|
|
|
|
|
Pét. Studinger, R. Goldstein, and J. A. Taylor Age- and fitness-related alterations in vascular sympathetic control J. Physiol., May 1, 2009; 587(9): 2049 - 2057. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Deley, G. Picard, and J. A. Taylor Arterial Baroreflex Control of Cardiac Vagal Outflow in Older Individuals Can Be Enhanced by Aerobic Exercise Training Hypertension, May 1, 2009; 53(5): 826 - 832. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Deley, R. D. Lipman, J. P. Kannam, C. Bartolini, and J. A. Taylor Stress responses and baroreflex function in coronary disease J Appl Physiol, February 1, 2009; 106(2): 576 - 581. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. E. Hunt, R. Tamisier, G. S. Gilmartin, M. Curley, A. Anand, and J. W. Weiss Baroreflex responsiveness during ventilatory acclimatization in humans Am J Physiol Heart Circ Physiol, October 1, 2008; 295(4): H1794 - H1801. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Ptaszynski, T. Klingenheben, B. Gerritse, and L. Kornet Risk stratification after myocardial infarction: a new method of determining the neural component of the baroreflex is potentially more discriminative in distinguishing patients at high and low risk for arrhythmias Europace, February 1, 2008; 10(2): 227 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Studinger, R. Goldstein, and J. A. Taylor Mechanical and neural contributions to hysteresis in the cardiac vagal limb of the arterial baroreflex J. Physiol., September 15, 2007; 583(3): 1041 - 1048. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Hesse, N. Charkoudian, Z. Liu, M. J. Joyner, and J. H. Eisenach Baroreflex Sensitivity Inversely Correlates With Ambulatory Blood Pressure in Healthy Normotensive Humans Hypertension, July 1, 2007; 50(1): 41 - 46. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. S. Olufsen, H. T. Tran, J. T. Ottesen, Research Experiences for Undergraduates Program, L. A. Lipsitz, and V. Novak Modeling baroreflex regulation of heart rate during orthostatic stress Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2006; 291(5): R1355 - R1368. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. E. Alvarez, B. M. Davy, T. P. Ballard, S. D. Beske, and K. P. Davy Weight loss increases cardiovagal baroreflex function in obese young and older men Am J Physiol Endocrinol Metab, October 1, 2005; 289(4): E665 - E669. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Lenard, P. Studinger, B. Mersich, G. Pavlik, and M. Kollai Cardiovagal autonomic function in sedentary and trained offspring of hypertensive parents J. Physiol., June 15, 2005; 565(3): 1031 - 1038. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. E. Hunt and W. B. Farquhar Nonlinearities and asymmetries of the human cardiovagal baroreflex Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1339 - R1346. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. Lenard, P. Studinger, B. Mersich, L. Kocsis, and M. Kollai Maturation of Cardiovagal Autonomic Function From Childhood to Young Adult Age Circulation, October 19, 2004; 110(16): 2307 - 2312. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. D. Lipman, J. K. Salisbury, and J. A. Taylor Spontaneous Indices Are Inconsistent With Arterial Baroreflex Gain Hypertension, October 1, 2003; 42(4): 481 - 487. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Studinger, Z. Lenard, Z. Kovats, L. Kocsis, and M. Kollai Static and dynamic changes in carotid artery diameter in humans during and after strenuous exercise J. Physiol., July 15, 2003; 550(2): 575 - 583. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Mukai, M. Gagnon, I. Iloputaife, J. W. Hamner, and L. A. Lipsitz Effect of Systolic Blood Pressure and Carotid Stiffness on Baroreflex Gain in Elderly Subjects J. Gerontol. A Biol. Sci. Med. Sci., July 1, 2003; 58(7): M626 - 630. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. D. Lipman, P. Grossman, S. E. Bridges, J.W. Hamner, and J. A. Taylor Mental Stress Response, Arterial Stiffness, and Baroreflex Sensitivity in Healthy Aging J. Gerontol. A Biol. Sci. Med. Sci., July 1, 2002; 57(7): B279 - 284. [Abstract] [Full Text]
|
|
|
|
 |
|
 P. Kaushal and J. A. Taylor Inter-relations among declines in arterial distensibility, baroreflex function and respiratory sinus arrhythmia J. Am. Coll. Cardiol., May 1, 2002; 39(9): 1524 - 1530. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. A. Kingwell, J. D. Cameron, A. M. Dart, K. D. Monahan, H. Tanaka, F. A. Dinenno, and D. R. Seals Large Artery Stiffness and Baroreflex Function Response Circulation, February 26, 2002; 105 (8): e56 - e56. [Full Text] [PDF]
|
|
|
|
|
|
K. D. Monahan, H. Tanaka, F. A. Dinenno, and D. R. Seals Central Arterial Compliance Is Associated With Age- and Habitual Exercise-Related Differences in Cardiovagal Baroreflex Sensitivity Circulation, October 2, 2001; 104(14): 1627 - 1632. [Abstract] [Full Text] [PDF]
|
|