Changes in Perfusion Related to Muscle Length Affect the Pressor Response to Isometric Muscle Contraction

2009 ◽  
pp. 371-377 ◽  
Author(s):  
Masaki Mizuno ◽  
Ken Tokizawa ◽  
Isao Muraoka
Keyword(s):  
Muscle Contraction ◽  
Pressor Response ◽  
Muscle Length ◽  
Isometric Muscle Contraction ◽  
Isometric Muscle

Rostral ventrolateral medullary opioid receptor activation modulates pressor response to muscle contraction

1998 ◽  
Vol 274 (1) ◽  
pp. H139-H146 ◽  
Author(s):  
Daryl Caringi ◽  
David J. Mokler ◽  
David M. Koester ◽  
Ahmmed Ally
Keyword(s):  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Tibial Nerve ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Receptor Activation ◽  
Ventrolateral Medulla ◽  
Tibial Nerve Stimulation ◽  
Isometric Muscle Contraction ◽  
Isometric Muscle

The effects of an opioid agonist, [d-Ala2]methionine enkephalinamide (DAME), administered into the rostral ventrolateral medulla (rVLM) or caudal ventrolateral medulla (cVLM) on cardiovascular responses to isometric muscle contraction were determined in anesthetized rats. A 30-s contraction evoked by tibial nerve stimulation increased mean arterial pressure (MAP) and heart rate (HR) by 34 ± 6 mmHg and 40 ± 7 beats/min, respectively, with a developed tension of 322 ± 30 g, after bilateral insertion of microdialysis probes into the rVLM. Thirty-minute dialysis of DAME (10 and 100 μM) attenuated the contraction-evoked cardiovascular changes dose dependently (10 μM: MAP = 25 ± 4 mmHg, HR = 27 ± 3 beats/min, tension = 333 ± 25 g; 100 μM: MAP = 14 ± 4 mmHg, HR = 16 ± 5 beats/min, tension = 330 ± 34 g). Preadministration of an opioid antagonist, naloxone (100 μM), augmented contraction-evoked MAP and HR responses and blocked effects of 100 μM DAME. Microdialysis of DAME into the cVLM produced no changes in the pressor response to contraction. At end of each experiment, tibial nerve stimulation after neuromuscular blockade evoked no MAP or HR change. Results demonstrate that opioid receptor activation within the rVLM modulates cardiovascular responses to isometric muscle contraction.

scholarly journals Actomyosin energy turnover declines while force remains constant during isometric muscle contraction

2004 ◽  
Vol 555 (1) ◽  
pp. 27-43 ◽  
Author(s):  
Timothy G. West ◽  
N. A. Curtin ◽  
Michael A. Ferenczi ◽  
Zhen-He He ◽  
Yin-Biao Sun ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Energy Turnover ◽  
Isometric Muscle Contraction ◽  
Isometric Muscle
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