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Attenuation of pulmonary chemoreflex following acute cervical spinal cord injury (1178.4)
Author(s) -
Tsai ILun,
Lee KunZe
Publication year - 2014
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.28.1_supplement.1178.4
Subject(s) - medicine , anesthesia , capsaicin , reflex , respiratory system , ventilation (architecture) , cough reflex , phrenic nerve , apnea , lung , mechanical engineering , receptor , engineering
Pulmonary C‐fibers are the main chemosensitive afferents in the lung. Activation of pulmonary C‐fibers can evoke pulmonary chemoreflex characterized by apnea, hypotension and bradycardia which is a critical defense reflex to modulate cardiorespiratory responses. The present study was designed to investigate whether pulmonary chemoreflex is altered following acute cervical spinal injury. Adult Sprague Dawley rats received high cervical unilateral hemisection (C2Hx) or C2 laminectomy (sham) were used. Intra‐jugular capsaicin induced pulmonary reflex was evaluated by measuring respiratory airflow in spontaneously breathing rats and phrenic nerve activity in mechanically‐ventilated rats. Capsaicin treatment evoked a cessation of respiratory airflow and phrenic bursting in sham but not C2Hx animals. In order to clarify whether attenuation of pulmonary chemoreflex in C2Hx animals is merely induced by capsaicin or generally applied to other stimuli that can excite pulmonary C‐fibers, another pulmonary C‐fiber stimulant (phenylbiguanide, PBG) was used to evoke pulmonary chemoreflex in spontaneously breathing rats. We observed that PBG‐induced pulmonary chemoreflex was also blunted in C2Hx animals. These results suggested that pulmonary chemoreflex is attenuated after acute C2Hx and the blunted reflex may unfavorably impact the ability to prevent inhaling respiratory irritants. Grant Funding Source : Supported by NSC 102‐2320‐B‐110‐004‐MY3, NHRI‐EX102‐10223NC