Cargando…
Exercise pressor reflex function following acute hemi-section of the spinal cord in cats
Cardiovascular disease is a leading cause of morbidity and mortality in patients post spinal cord injury (SCI). The prescription of exercise as a therapeutic modality for disease prevention in this population is promising. It is logical to suggest that the sooner an exercise program can begin the mo...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2013
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566549/ https://www.ncbi.nlm.nih.gov/pubmed/23403764 http://dx.doi.org/10.3389/fphys.2013.00003 |
_version_ | 1782258578332057600 |
---|---|
author | Murphy, Megan N. Ichiyama, Ronaldo M. Iwamoto, Gary A. Mitchell, Jere H. Smith, Scott A. |
author_facet | Murphy, Megan N. Ichiyama, Ronaldo M. Iwamoto, Gary A. Mitchell, Jere H. Smith, Scott A. |
author_sort | Murphy, Megan N. |
collection | PubMed |
description | Cardiovascular disease is a leading cause of morbidity and mortality in patients post spinal cord injury (SCI). The prescription of exercise as a therapeutic modality for disease prevention in this population is promising. It is logical to suggest that the sooner an exercise program can begin the more benefit the patient will receive from the therapy. However, the time point after injury at which the requisite circulatory responses needed to support exercise are viable remains largely unknown. The skeletal muscle exercise pressor reflex (EPR) significantly contributes to cardiovascular control during exercise in healthy individuals. Experiments in patients with a chronic lateral hemi-section of the spinal cord (Brown-Séquard syndrome) suggest that the EPR, although blunted, is operational when examined months to years post injury. However, whether this critically important reflex remains functional immediately after lateral SCI or, in contrast, experiences a period of reduced capacity due to spinal shock has not been established. This study was designed to assess EPR function after acute lateral transection of the spinal cord. The EPR was selectively activated in seven decerebrate cats via electrically stimulated static contraction of the triceps surae muscles of each hindlimb before and after lateral hemi-section of the T(13)–L(2) region of the spinal cord. Compared to responses prior to injury, increases in mean arterial pressure (MAP) were significantly decreased when contracting the hindlimb either ipsilateral to the lesion (MAP = 17 ± 3 mmHg before and 9 ± 2 mmHg after) or contralateral to the lesion (MAP = 22 ± 5 mmHg before and 12 ± 4 mmHg after). The heart rate (HR) response to stimulation of the EPR was largely unaffected by induction of acute SCI. The findings suggest that the EPR maintains the ability to importantly contribute to cardiovascular regulation during exercise immediately following a Brown-Séquard-like injury. |
format | Online Article Text |
id | pubmed-3566549 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-35665492013-02-12 Exercise pressor reflex function following acute hemi-section of the spinal cord in cats Murphy, Megan N. Ichiyama, Ronaldo M. Iwamoto, Gary A. Mitchell, Jere H. Smith, Scott A. Front Physiol Physiology Cardiovascular disease is a leading cause of morbidity and mortality in patients post spinal cord injury (SCI). The prescription of exercise as a therapeutic modality for disease prevention in this population is promising. It is logical to suggest that the sooner an exercise program can begin the more benefit the patient will receive from the therapy. However, the time point after injury at which the requisite circulatory responses needed to support exercise are viable remains largely unknown. The skeletal muscle exercise pressor reflex (EPR) significantly contributes to cardiovascular control during exercise in healthy individuals. Experiments in patients with a chronic lateral hemi-section of the spinal cord (Brown-Séquard syndrome) suggest that the EPR, although blunted, is operational when examined months to years post injury. However, whether this critically important reflex remains functional immediately after lateral SCI or, in contrast, experiences a period of reduced capacity due to spinal shock has not been established. This study was designed to assess EPR function after acute lateral transection of the spinal cord. The EPR was selectively activated in seven decerebrate cats via electrically stimulated static contraction of the triceps surae muscles of each hindlimb before and after lateral hemi-section of the T(13)–L(2) region of the spinal cord. Compared to responses prior to injury, increases in mean arterial pressure (MAP) were significantly decreased when contracting the hindlimb either ipsilateral to the lesion (MAP = 17 ± 3 mmHg before and 9 ± 2 mmHg after) or contralateral to the lesion (MAP = 22 ± 5 mmHg before and 12 ± 4 mmHg after). The heart rate (HR) response to stimulation of the EPR was largely unaffected by induction of acute SCI. The findings suggest that the EPR maintains the ability to importantly contribute to cardiovascular regulation during exercise immediately following a Brown-Séquard-like injury. Frontiers Media S.A. 2013-02-07 /pmc/articles/PMC3566549/ /pubmed/23403764 http://dx.doi.org/10.3389/fphys.2013.00003 Text en Copyright © 2013 Murphy, Ichiyama, Iwamoto, Mitchell and Smith. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc. |
spellingShingle | Physiology Murphy, Megan N. Ichiyama, Ronaldo M. Iwamoto, Gary A. Mitchell, Jere H. Smith, Scott A. Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title | Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title_full | Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title_fullStr | Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title_full_unstemmed | Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title_short | Exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
title_sort | exercise pressor reflex function following acute hemi-section of the spinal cord in cats |
topic | Physiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566549/ https://www.ncbi.nlm.nih.gov/pubmed/23403764 http://dx.doi.org/10.3389/fphys.2013.00003 |
work_keys_str_mv | AT murphymegann exercisepressorreflexfunctionfollowingacutehemisectionofthespinalcordincats AT ichiyamaronaldom exercisepressorreflexfunctionfollowingacutehemisectionofthespinalcordincats AT iwamotogarya exercisepressorreflexfunctionfollowingacutehemisectionofthespinalcordincats AT mitchelljereh exercisepressorreflexfunctionfollowingacutehemisectionofthespinalcordincats AT smithscotta exercisepressorreflexfunctionfollowingacutehemisectionofthespinalcordincats |