Cardiovascular responses at the onset of exercise with partial neuromuscular blockade in cat and man

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

1. In decerebrated cats the cardiovascular, heart rate and blood pressure responses to static muscle contractions were followed from the onset of stimulation of the cut L7-S1 ventral roots. Heart rate and blood pressure were also followed during maximal voluntary and electrically induced static muscle contractions in man using one leg. In both cat and man contractions were performed under control conditions and tubocurarine-induced neuromuscular blockade. 2. In the cat, heart rate and blood pressure increased 1.7 s after the onset of the contraction. No cardiovascular responses were seen when the muscle contraction was blocked by tubocurarine. 3. In man, both heart rate and blood pressure increased at the onset of voluntary contractions. Partial curarization reduced strength to 39% of control. The heart rate response was unaffected by tubocurarine while the blood pressure response was reduced from 61 to 32 mmHg. 4. Electrical stimulation of the muscles resulted in 75% of voluntary strength in man. The heart rate response was delayed one R-R interval in the electrocardiogram but was as large as during voluntary contractions. During partial curarization the heart rate response was significantly smaller and the blood pressure response was reduced from 11 to 8 mmHg. 5. In conclusion, processes in active muscles elicit an increase in heart rate and blood pressure which depends on the intensity of the muscle contraction developed. However, the immediate cardiovascular responses at the onset of voluntary muscle contractions cannot be accounted for by reflexes generated in the working muscles alone.

Original languageEnglish (US)
Pages (from-to)39-47
Number of pages9
JournalJournal of Physiology
VolumeVol. 384
StatePublished - 1987

Fingerprint

Neuromuscular Blockade
Cats
Heart Rate
Exercise
Muscle Contraction
Blood Pressure
Tubocurarine
Muscles
Spinal Nerve Roots
Electric Stimulation
Reflex
Leg
Electrocardiography
Skeletal Muscle

ASJC Scopus subject areas

  • Physiology

Cite this

@article{2ab80b8ffd044b4191236cae408ccd60,
title = "Cardiovascular responses at the onset of exercise with partial neuromuscular blockade in cat and man",
abstract = "1. In decerebrated cats the cardiovascular, heart rate and blood pressure responses to static muscle contractions were followed from the onset of stimulation of the cut L7-S1 ventral roots. Heart rate and blood pressure were also followed during maximal voluntary and electrically induced static muscle contractions in man using one leg. In both cat and man contractions were performed under control conditions and tubocurarine-induced neuromuscular blockade. 2. In the cat, heart rate and blood pressure increased 1.7 s after the onset of the contraction. No cardiovascular responses were seen when the muscle contraction was blocked by tubocurarine. 3. In man, both heart rate and blood pressure increased at the onset of voluntary contractions. Partial curarization reduced strength to 39{\%} of control. The heart rate response was unaffected by tubocurarine while the blood pressure response was reduced from 61 to 32 mmHg. 4. Electrical stimulation of the muscles resulted in 75{\%} of voluntary strength in man. The heart rate response was delayed one R-R interval in the electrocardiogram but was as large as during voluntary contractions. During partial curarization the heart rate response was significantly smaller and the blood pressure response was reduced from 11 to 8 mmHg. 5. In conclusion, processes in active muscles elicit an increase in heart rate and blood pressure which depends on the intensity of the muscle contraction developed. However, the immediate cardiovascular responses at the onset of voluntary muscle contractions cannot be accounted for by reflexes generated in the working muscles alone.",
author = "Iwamoto, {G. A.} and Mitchell, {J. H.} and M. Mizuno and Secher, {N. H.}",
year = "1987",
language = "English (US)",
volume = "Vol. 384",
pages = "39--47",
journal = "Journal of Physiology",
issn = "0022-3751",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Cardiovascular responses at the onset of exercise with partial neuromuscular blockade in cat and man

AU - Iwamoto, G. A.

AU - Mitchell, J. H.

AU - Mizuno, M.

AU - Secher, N. H.

PY - 1987

Y1 - 1987

N2 - 1. In decerebrated cats the cardiovascular, heart rate and blood pressure responses to static muscle contractions were followed from the onset of stimulation of the cut L7-S1 ventral roots. Heart rate and blood pressure were also followed during maximal voluntary and electrically induced static muscle contractions in man using one leg. In both cat and man contractions were performed under control conditions and tubocurarine-induced neuromuscular blockade. 2. In the cat, heart rate and blood pressure increased 1.7 s after the onset of the contraction. No cardiovascular responses were seen when the muscle contraction was blocked by tubocurarine. 3. In man, both heart rate and blood pressure increased at the onset of voluntary contractions. Partial curarization reduced strength to 39% of control. The heart rate response was unaffected by tubocurarine while the blood pressure response was reduced from 61 to 32 mmHg. 4. Electrical stimulation of the muscles resulted in 75% of voluntary strength in man. The heart rate response was delayed one R-R interval in the electrocardiogram but was as large as during voluntary contractions. During partial curarization the heart rate response was significantly smaller and the blood pressure response was reduced from 11 to 8 mmHg. 5. In conclusion, processes in active muscles elicit an increase in heart rate and blood pressure which depends on the intensity of the muscle contraction developed. However, the immediate cardiovascular responses at the onset of voluntary muscle contractions cannot be accounted for by reflexes generated in the working muscles alone.

AB - 1. In decerebrated cats the cardiovascular, heart rate and blood pressure responses to static muscle contractions were followed from the onset of stimulation of the cut L7-S1 ventral roots. Heart rate and blood pressure were also followed during maximal voluntary and electrically induced static muscle contractions in man using one leg. In both cat and man contractions were performed under control conditions and tubocurarine-induced neuromuscular blockade. 2. In the cat, heart rate and blood pressure increased 1.7 s after the onset of the contraction. No cardiovascular responses were seen when the muscle contraction was blocked by tubocurarine. 3. In man, both heart rate and blood pressure increased at the onset of voluntary contractions. Partial curarization reduced strength to 39% of control. The heart rate response was unaffected by tubocurarine while the blood pressure response was reduced from 61 to 32 mmHg. 4. Electrical stimulation of the muscles resulted in 75% of voluntary strength in man. The heart rate response was delayed one R-R interval in the electrocardiogram but was as large as during voluntary contractions. During partial curarization the heart rate response was significantly smaller and the blood pressure response was reduced from 11 to 8 mmHg. 5. In conclusion, processes in active muscles elicit an increase in heart rate and blood pressure which depends on the intensity of the muscle contraction developed. However, the immediate cardiovascular responses at the onset of voluntary muscle contractions cannot be accounted for by reflexes generated in the working muscles alone.

UR - http://www.scopus.com/inward/record.url?scp=0023162232&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023162232&partnerID=8YFLogxK

M3 - Article

VL - Vol. 384

SP - 39

EP - 47

JO - Journal of Physiology

JF - Journal of Physiology

SN - 0022-3751

ER -