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Changes on respiratory chemosensitivity after vagotomy in rats
Author(s) -
Moreira Thiago S,
Takakura Ana C
Publication year - 2010
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.24.1_supplement.1026.11
Subject(s) - vagotomy , chemoreceptor , vagus nerve , phrenic nerve , carotid body , respiratory system , control of respiration , anesthesia , ventilation (architecture) , chemistry , tonic (physiology) , brainstem , excitatory postsynaptic potential , medicine , endocrinology , electrophysiology , stimulation , receptor , inhibitory postsynaptic potential , mechanical engineering , engineering
Breathing relies on a rhythmically active network of brainstem neurons that is driven by central chemoreceptors and other sources of tonic excitatory drive. The retrotrapezoid nucleus (RTN) contains central respiratory chemoreceptors that are activated by carotid body and inhibited by lung inflation. In the present study, we examined whether the vagus nerve interfere with the activity of RTN chemosensitive neurons in rats. Mean arterial pressure (MAP), pO2, pCO2, pH, phrenic nerve activity (PNA) and RTN CO2‐activated neurons were recorded in urethane‐anesthetized intact or vagotomized male Wistar rats (250–280 g, n = 7/group). In vagotomized rats, without artificial ventilation, pCO2 increased (48 ± 3, vs. intact rats: 44 ± 6%) and pH is reduced (7.27 ± 0.05, vs. intact rats: 7.45 ± 0.05), without change MAP and pO2. The CO2 threshold of RTN neurons (3.2 ± 0.2%, vs. intact rats: 4.5 ± 0.4%) and PNA (4.1 ± 0.2%, vs. intact rats: 5.6 ± 0.3%) was lower in vagotomized rats. After the connection of the vagotomized rats in artificial ventilation, pCO2 (43 ± 4%), pH (7.48 ±0.16) and CO2 threshold of RTN (4.8 ± 0.9%) and PNA (5.7 ± 0.3%) returned to levels observed in intact anesthetized preparations. The present results support the idea of the importance of the vagus nerve on the control of the respiratory chemosensitivity in rats. Financial support: FAPESP (06/60174‐9 to TSM).