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Diaphragm Muscle Activity Following High Cervical Spinal Cord Injury (SCI) in Rats
Author(s) -
Bezdudnaya Tatiana,
DeFinis Jaclyn,
Marchenko Vitaliy,
Lane Michael A
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1055.11
Subject(s) - medicine , diaphragm (acoustics) , spinal cord injury , phrenic nerve , anesthesia , spinal cord , respiratory system , physics , psychiatry , acoustics , loudspeaker
Diaphragm dysfunction occurs following high cervicall spinal cord injury (SCI). As the diaphragm is a primary respiratory muscle its dysfunction often necessitates assited‐ventiation, dramatically impacting quality of life and increasing risk of mortality in injured individuals. Despite these devastating outcomes, functional plasticity and recovery of diaphragm activity, albeit limited, can occur spontaneously over the time. Understanding of the mechanisms underlying this recovery will facilitate developing new therapeutic strategies to treat respiratory impairment post‐SCI. In the current study, a C2 cervical spinal cord hemisection (C2Hx) was used to explore spontaneous plasticity ‐ known as the spontaneous crossed phrenic phenomenon – in awake behaving animals. While previous studies have assessed functional under anesthesia, the present study monitored changes in diaphragm activity using chronically implanted diaphragm EMG electrodes in behaving rats up to 8 weeks. Our EMG recording data show that recovery of diaphragm activity in awake animal occurs in one‐two weeks post injury, but inspiratory bursts on the injured side differ from the contralateral. Even when the amplitude of ipsilateral bursts is comparable with uninjured side, intraburst spike frequency is significantly lower especially during quiet breathing. Recording diaphragm EMG activity under anesthesia (isoflurane or ketamine) can eliminate ipsilateral diaphragm activity up to 100% indicating that recovery seen in behaving rats is mostly attributed to NMDA receptor activation. Ongoing studies are assessing this progressive functional recovery in more detail. Support or Funding Information Supported by Conquer Paralysis Now (CPN) and the Edward Jekkal Muscular Dystrophy Association Fellowship (Drexel).