| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
INTEGRATIVE |
1 Penn State Heart and Vascular Institute, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA
It is suggested that mechanoreceptors in muscle play an important role in the exercise pressor reflex. However, it has not been verified whether isolated stimulation of the mechanoreceptors can induce responses in muscle sympathetic nerve activity (MSNA) in young healthy individuals. We tested the hypothesis that passive stretch of muscle can evoke an increase in MSNA in healthy individuals. In 12 young subjects, leg calf muscles were passively stretched, or actively contracted for 5 s followed by a 15–25 s (random length) relaxation period. Stretch and contraction were each repeated 25 times. MSNA, heart rate and blood pressure were analysed, and averaged according to the onset of the force on a beat-by-beat basis. At the 1st to the 3rd heart beat from the onset of stretch, MSNA (199 ± 30%, P < 0.05) as well as heart rate (102.5 ± 0.7%, P < 0.05) increased transiently but significantly from the prior stretch baseline (100%), followed (from 3rd to 7th beat from the onset of stretch) by a transient increase in mean blood pressure (101.9 ± 0.3%, P < 0.05) from the baseline. Similar response patterns were observed during active muscle contractions. The present data show that MSNA responses to isolated stimulation of mechanoreceptors are measurable. Because of baroreflex engagement, the magnitude of the response is small and transient, and the haemodynamic consequences using this protocol may be limited.
accepted after revision 26 July 2006;
first published online 27 July 2006)
Corresponding author L. I. Sinoway: Heart and Vascular Institute, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033, USA. Email: lsinoway{at}psu.edu
This article has been cited by other articles:
|
|
 |
|
  R. C. Drew, D. B. McIntyre, C. Ring, and M. J. White Local metabolite accumulation augments passive muscle stretch-induced modulation of carotid-cardiac but not carotid-vasomotor baroreflex sensitivity in man Exp Physiol, September 1, 2008; 93(9): 1044 - 1057. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Cui, R. Moradkhan, V. Mascarenhas, A. Momen, and L. I. Sinoway Cyclooxygenase inhibition attenuates sympathetic responses to muscle stretch in humans Am J Physiol Heart Circ Physiol, June 1, 2008; 294(6): H2693 - H2700. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Fisher, C. N. Young, and P. J. Fadel Effect of muscle metaboreflex activation on carotid-cardiac baroreflex function in humans Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2296 - H2304. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. C. Drew, M. P. D. Bell, and M. J. White Modulation of spontaneous baroreflex control of heart rate and indexes of vagal tone by passive calf muscle stretch during graded metaboreflex activation in humans J Appl Physiol, March 1, 2008; 104(3): 716 - 723. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Cui, V. Mascarenhas, R. Moradkhan, C. Blaha, and L. I. Sinoway Effects of muscle metabolites on responses of muscle sympathetic nerve activity to mechanoreceptor(s) stimulation in healthy humans Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2008; 294(2): R458 - R466. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Koba, J. Xing, L. I. Sinoway, and J. Li Differential sympathetic outflow elicited by active muscle in rats Am J Physiol Heart Circ Physiol, October 1, 2007; 293(4): H2335 - H2343. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. H. Pennestri, J. Montplaisir, R. Colombo, G. Lavigne, and P. A. Lanfranchi Nocturnal blood pressure changes in patients with restless legs syndrome Neurology, April 10, 2007; 68(15): 1213 - 1218. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
