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Ventilation of hypoxic gas results in changes in whole nerve vagal recordings in the newborn rat
Author(s) -
Qaqish Robert T,
Vincent Sandra,
Fisher John T,
Yeger Herman,
Cutz Ernest
Publication year - 2009
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.23.1_supplement.621.27
Subject(s) - vagus nerve , anesthesia , hypoxia (environmental) , chemistry , ventilation (architecture) , 5 ht receptor , atropine , muscarinic acetylcholine receptor , stimulation , serotonin , endocrinology , medicine , receptor , oxygen , mechanical engineering , organic chemistry , engineering
Pulmonary neuroepithelial bodies (NEBs) form clusters of specialized epithelial cells situated within the airway mucosa. They express a unique membrane delimited oxygen (O 2 ) sensor (Nature. 1993; 365(6442):153‐5). NEBs are innervated by afferents within the vagus nerve and synthesize serotonin (5HT) that is released as a neurotransmitter of hypoxia stimulus. NEBs and their vagal afferents express the ionotropic 5HT 3 receptor (5HT 3 ‐R) involved in hypoxia chemotransduction. We hypothesized that hypoxia, via NEB activation, would increase vagal nerve activity. Newborn rat pups between days 1 to 10 were anesthetised, paralyzed (pancuronium 0.25 mg/kg) and mechanically ventilated. Muscarinic receptor blockade was achieved with atropine (0.25 mg/kg). The right cervical vagus was exposed and whole nerve activity was recorded using a platinum bipolar electrode. Ventilation with hypoxic gas (10% O 2 ) caused an increase (P<0.001 ANOVA) in the integrated nerve activity (8.66 ± 4.96 %) compared to control (100% O 2 ). Preliminary studies using the 5HT 3 ‐R blocker (ICS 205‐930) resulted in a partial inhibition of the hypoxia‐induced increase in whole nerve vagal activity. We conclude that ventilation with hypoxic gas resulted in gross changes in integrated vagal nerve activity. We propose that these gross changes in global vagal activity as a result of ventilation with 10% O 2 are the result of NEB stimulation via its membrane bound oxygen‐sensor. (Supported by CIHR Grants MOP‐12742 and MPG‐15270)