Studies of diaphragm function have been greatly facilitated by the ready accessibility of the cervical phrenic rootlets enabling controlled diaphragmatic activation by phrenic nerve stimulation. By means of phrenic stimulation, both the mechanical and intrinsic contractile properties of the diaphragm can be assessed. Use of intercostal muscle stimulation for this purpose has been hampered by the lack of an accurate and reproducible means of producing a coordinated contraction of this muscle group. Consequently, much less is known about the mechanical function of the intercostal muscles and mechanisms by which these muscles are synchronously activated. In preliminary experiments, we have shown that activation of the intercostal muscles by spinal cord stimulation (post-phrenicotomy) results in large inspired volumes (approaching 35-40% of inspiratory capacity), suggesting that coordinated electrical activation of these inspiratory muscles can be achieved. In the proposed studies, to be performed in anesthetized dogs, we intend to use the spinal cord stimulation technique as a method of assessing intercostal muscle function. We plan to evaluate (a) the mechanisms whereby intercostal muscles are activated to produce a coordinated displacement of the rib cage during inspiration, (b) the intrinsic contractile properties of intercostal muscles including their force-length, force-frequency, twitch, velocity of shortening and endurance characteristics, and (c) the mechanical interaction between diaphragm and intercostal muscle contraction in force generation and volume displacement. The results of these studies should provide insights into the mechanical behavior and physiologic characteristics of intercostal muscle contraction as compared to the better studied diaphragm.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
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Respiratory and Applied Physiology Study Section (RAP)
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Case Western Reserve University
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Romaniuk, Jaroslaw R; Dick, Thomas E; Bruce, Eugene N et al. (2017) Bifurcation of the respiratory response to lung inflation in anesthetized dogs. Respir Physiol Neurobiol 244:26-31
DiMarco, Anthony F; Kowalski, Krzysztof E (2008) Effects of chronic electrical stimulation on paralyzed expiratory muscles. J Appl Physiol 104:1634-40
Romaniuk, Jaroslaw R; Dick, Thomas E; Kowalski, Krzysztof E et al. (2007) Effects of pulse lung inflation on chest wall expiratory motor activity. J Appl Physiol 102:485-91
DiMarco, Anthony F; Kowalski, Krzysztof E; Romaniuk, Jaroslaw R (2007) Effects of diaphragm activation on airway pressure generation during lower thoracic spinal cord stimulation. Respir Physiol Neurobiol 159:102-7
Kowalski, Krzysztof E; Romaniuk, Jaroslaw R; DiMarco, Anthony F (2007) Changes in expiratory muscle function following spinal cord section. J Appl Physiol 102:1422-8
DiMarco, Anthony F; Takaoka, Yoshiro; Kowalski, Krzysztof E (2005) Combined intercostal and diaphragm pacing to provide artificial ventilation in patients with tetraplegia. Arch Phys Med Rehabil 86:1200-7
DiMarco, A F; Connors Jr, A F; Kowalski, K E (2004) Gas exchange during separate diaphragm and intercostal muscle breathing. J Appl Physiol 96:2120-4
DiMarco, A F; Kowalski, K E; Supinski, G et al. (2002) Mechanism of expiratory muscle activation during lower thoracic spinal cord stimulation. J Appl Physiol 92:2341-6
DiMarco, A F; Romaniuk, J R; Supinski, G et al. (2000) Effects of lung volume on parasternal pressure-generating capacity in dogs. Exp Physiol 85:331-7
DiMarco, A F; Romaniuk, J R; Kowalski, K E et al. (1999) Pattern of expiratory muscle activation during lower thoracic spinal cord stimulation. J Appl Physiol 86:1881-9

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