scholarly journals The Effect of Short-term Isometric Muscle Contraction and the Valsalva Maneuver on Systemic and Pulmonary Hemodynamics in Patients with Severe Heart Failure

2009 ◽  
Vol 32 (6) ◽  
pp. E31-E38 ◽  
Author(s):  
Miroslav Soucek ◽  
Petr Frana ◽  
Tomas Kara ◽  
Jan Sitar ◽  
Josef Halamek ◽  
...  
2004 ◽  
Vol 555 (1) ◽  
pp. 27-43 ◽  
Author(s):  
Timothy G. West ◽  
N. A. Curtin ◽  
Michael A. Ferenczi ◽  
Zhen-He He ◽  
Yin-Biao Sun ◽  
...  

1998 ◽  
Vol 274 (1) ◽  
pp. H139-H146 ◽  
Author(s):  
Daryl Caringi ◽  
David J. Mokler ◽  
David M. Koester ◽  
Ahmmed Ally

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.


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