|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Integrative Physiology University of North Texas Health Science Center at Fort Worth, TX 76107, USA
We examined the relationship between changes in cardiac output
and middle cerebral artery mean blood velocity (MCA Vmean) in seven healthy volunteer men at rest and during 50% maximal oxygen uptake steady-state submaximal cycling exercise. Reductions in
were accomplished using lower body negative pressure (LBNP), while increases in
were accomplished using infusions of 25% human serum albumin. Heart rate (HR), arterial blood pressure and MCA Vmean were continuously recorded. At each stage of LBNP and albumin infusion
was measured using an acetylene rebreathing technique. Arterial blood samples were analysed for partial pressure of carbon dioxide tension (Pa,CO2. During exercise HR and
were increased above rest (P < 0.001), while neither MCA Vmean nor Pa,CO2 was altered (P > 0.05). The MCA Vmean and
were linearly related at rest (P < 0.001) and during exercise (P= 0.035). The slope of the regression relationship between MCA Vmean and
at rest was greater (P= 0.035) than during exercise. In addition, the phase and gain between MCA Vmean and mean arterial pressure in the low frequency range were not altered from rest to exercise indicating that the cerebral autoregulation was maintained. These data suggest that the
associated with the changes in central blood volume influence the MCA Vmean at rest and during exercise and its regulation is independent of cerebral autoregulation. It appears that the exercise induced sympathoexcitation and the change in the distribution of
between the cerebral and the systemic circulation modifies the relationship between MCA Vmean and
.
(Received 3 August 2005;
accepted after revision 3 October 2005;
first published online 6 October 2005)
Corresponding author S. Ogoh: Department of Integrative Physiology, University of North Texas Health Science Center, 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA. Email: sogoh{at}hsc.unt.edu
This article has been cited by other articles:
![]() |
B. D. Levine, R. Zhang, M. Visocchi, P. N. Ainslie, S. Ogoh, L. Edvinsson, M. Yildiz, O. B. Paulson, G. M. Knudsen, P. A. Cassaglia, et al. Comments on Point:Counterpoint: Sympathetic activity does/does not influence cerebral blood flow. Sympathetic activity does influence cerebral blood flow. J Appl Physiol, October 1, 2008; 105(4): 1369 - 1369. [Full Text] [PDF] |
||||
![]() |
J. J. van Lieshout and N. H. Secher Point:Counterpoint: Sympathetic activity does/does not influence cerebral blood flow J Appl Physiol, October 1, 2008; 105(4): 1364 - 1366. [Full Text] [PDF] |
||||
![]() |
R. A. I. Lucas, J. D. Cotter, S. Morrison, and P. N. Ainslie The effects of ageing and passive heating on cardiorespiratory and cerebrovascular responses to orthostatic stress in humans Exp Physiol, October 1, 2008; 93(10): 1104 - 1117. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Ogoh, N. Hayashi, M. Inagaki, P. N. Ainslie, and T. Miyamoto Interaction between the ventilatory and cerebrovascular responses to hypo- and hypercapnia at rest and during exercise J. Physiol., September 1, 2008; 586(17): 4327 - 4338. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-L. Fan, J. D. Cotter, R. A. I. Lucas, K. Thomas, L. Wilson, and P. N. Ainslie Human cardiorespiratory and cerebrovascular function during severe passive hyperthermia: effects of mild hypohydration J Appl Physiol, August 1, 2008; 105(2): 433 - 445. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Fujii, Y. Honda, K. Hayashi, N. Kondo, S. Koga, and T. Nishiyasu Effects of chemoreflexes on hyperthermic hyperventilation and cerebral blood velocity in resting heated humans Exp Physiol, August 1, 2008; 93(8): 994 - 1001. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. P. Fisher, S. Ogoh, C. N. Young, P. B. Raven, and P. J. Fadel Regulation of middle cerebral artery blood velocity during dynamic exercise in humans: influence of aging J Appl Physiol, July 1, 2008; 105(1): 266 - 273. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. J. E. Lucas, J. D. Cotter, C. Murrell, L. Wilson, J. G. Anson, D. Gaze, K. P. George, and P. N. Ainslie Mechanisms of orthostatic intolerance following very prolonged exercise J Appl Physiol, July 1, 2008; 105(1): 213 - 225. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. S. Larsen, P. Rasmussen, M. Overgaard, N. H. Secher, and H. B. Nielsen Non-selective {beta}-adrenergic blockade prevents reduction of the cerebral metabolic ratio during exhaustive exercise in humans J. Physiol., June 1, 2008; 586(11): 2807 - 2815. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. A. Low, J. E. Wingo, D. M. Keller, S. L. Davis, R. Zhang, and C. G. Crandall Cerebrovascular responsiveness to steady-state changes in end-tidal CO2 during passive heat stress J Appl Physiol, April 1, 2008; 104(4): 976 - 981. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. N. Ainslie, S. Ogoh, K. Burgess, L. Celi, K. McGrattan, K. Peebles, C. Murrell, P. Subedi, and K. R. Burgess Differential effects of acute hypoxia and high altitude on cerebral blood flow velocity and dynamic cerebral autoregulation: alterations with hyperoxia J Appl Physiol, February 1, 2008; 104(2): 490 - 498. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. W. Subudhi, M. C. Lorenz, C. S. Fulco, and R. C. Roach Cerebrovascular responses to incremental exercise during hypobaric hypoxia: effect of oxygenation on maximal performance Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H164 - H171. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. K. Shoemaker Hemodilution Impairs Cerebral Autoregulation, Demonstrating the Complexity of Integrative Physiology Anesth. Analg., November 1, 2007; 105(5): 1179 - 1181. [Full Text] [PDF] |
||||
![]() |
Y. Ogawa, K.-i. Iwasaki, K. Aoki, S. Shibata, J. Kato, and S. Ogawa Central Hypervolemia with Hemodilution Impairs Dynamic Cerebral Autoregulation Anesth. Analg., November 1, 2007; 105(5): 1389 - 1396. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Murrell, L. Wilson, J. D. Cotter, S. Lucas, S. Ogoh, K. George, and P. N. Ainslie Alterations in autonomic function and cerebral hemodynamics to orthostatic challenge following a mountain marathon J Appl Physiol, July 1, 2007; 103(1): 88 - 96. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. A. Rickards, K. L. Ryan, W. H. Cooke, K. G. Lurie, and V. A. Convertino Inspiratory resistance delays the reporting of symptoms with central hypovolemia: association with cerebral blood flow Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R243 - R250. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-S. Kim, R. Krogh-Madsen, P. Rasmussen, P. Plomgaard, S. Ogoh, N. H. Secher, and J. J. van Lieshout Effects of hyperglycemia on the cerebrovascular response to rhythmic handgrip exercise Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H467 - H473. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Zhang and B. D. Levine Autonomic Ganglionic Blockade Does Not Prevent Reduction in Cerebral Blood Flow Velocity During Orthostasis in Humans Stroke, April 1, 2007; 38(4): 1238 - 1244. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. N. Ainslie, K. Burgess, P. Subedi, and K. R. Burgess Alterations in cerebral dynamics at high altitude following partial acclimatization in humans: wakefulness and sleep J Appl Physiol, February 1, 2007; 102(2): 658 - 664. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Ogoh, J. P. Fisher, S. Purkayastha, E. A. Dawson, P. J. Fadel, M. J. White, R. Zhang, N. H. Secher, and P. B. Raven Regulation of middle cerebral artery blood velocity during recovery from dynamic exercise in humans J Appl Physiol, February 1, 2007; 102(2): 713 - 721. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Carter III, S. N. Cheuvront, C. R. Vernieuw, and M. N. Sawka Hypohydration and prior heat stress exacerbates decreases in cerebral blood flow velocity during standing J Appl Physiol, December 1, 2006; 101(6): 1744 - 1750. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. E. Wilson, J. Cui, R. Zhang, and C. G. Crandall Heat stress reduces cerebral blood velocity and markedly impairs orthostatic tolerance in humans Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2006; 291(5): R1443 - R1448. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Ogoh, R. M. Brothers, Q. Barnes, W. L. Eubank, M. N. Hawkins, S. Purkayastha, A. O-Yurvati, and P. B. Raven Effects of changes in central blood volume on carotid-vasomotor baroreflex sensitivity at rest and during exercise J Appl Physiol, July 1, 2006; 101(1): 68 - 75. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |