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Inhibition of respiratory‐related activity of the facial nerve by pulmonary vagal C‐fiber activation in the rat
Author(s) -
Lee KunZe,
Lu IJung,
Yang ShuJu,
Hwang JiChuu
Publication year - 2007
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.21.6.a1289
Subject(s) - capsaicin , phrenic nerve , medicine , respiratory system , anesthesia , facial nerve , expiration , hypercapnia , anatomy , receptor
We have previously reported that respiratory‐related facial nerve activity can be modulated by hypercapnia, lung inflation, and positive end‐expired pressure (PEEP). Whether respiratory‐related rhythmic activities of the facial nerve could be modulated by pulmonary C‐fiber activation is unclear. Activity of the facial and phrenic nerve was recorded simultaneously in the anesthetized and ventilated adult rat. Activation pulmonary C‐fiber by intra‐jugular injection of capsaicin produced a dose‐dependent reduction of amplitude and onset of the facial nerve activity. Furthermore, uncoupled facial activity (persistent rhythmic activity during phrenic cessation) evoked by increasing PEEP could be also suppressed by capsaicin injection. Single fiber recording from the facial nerve revealed that capsaicin treatment produced inhibition on activity of expiratory‐inspiratory (EI) motoneuron during expiration such that became inspiratory motoneurons and of pre‐inspiratory motoneurons. In addition, capsaicin injection could attenuate the uncoupled activity of EI from the phrenic burst caused by PEEP manipulation. These results implied that capsaicin might differentially inhibit pre‐inspiratory than inspiratory facial activity.