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RAPHE OBSCURUS (ROb) MODULATES THE VENTILATORY RESPONSE TO FOCAL ACIDIFICATION OF THE RETROTRAPEZOID NUCLEUS (RTN)
Author(s) -
Dias Mirela Barros,
Li Aihua,
Branco Luiz Guilherme,
Nattie Eugene E
Publication year - 2008
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.22.1_supplement.1172.8
Subject(s) - chemoreceptor , raphe , raphe nuclei , chemistry , dialysis , control of respiration , ventilation (architecture) , anesthesia , plethysmograph , central chemoreceptors , wakefulness , respiratory system , anatomy , endocrinology , medicine , serotonin , neuroscience , biology , serotonergic , receptor , mechanical engineering , electroencephalography , engineering
Recent data suggest that the caudal medullary raphe (MR) does not contribute to chemoreception directly but modulates breathing by interaction with the RTN (Li et al ., J Physiol 2006). To investigate this hypothesis, we dialyzed artificial cerebrospinal fluid equilibrated with 25% CO 2 into RTN and ROb simultaneously in male rats in a whole body plethysmograph at a temperature within the rat thermoneutral zone (30°C). We compared data from animals with both probes correctly placed to data from rats with both probes misplaced. Simultaneous acidification of RTN and ROb increased VE up to 23%, compared with the baseline and up to 28% compared to the control group, since focal acidification in the control group decreased VE . The responses were similar in wakefulness and sleep. For single site dialysis experiments, both probes received 25% CO 2 dialysis, but just one of the probes was correctly placed. The 25% CO 2 dialysis into RTN caused a small increase in VE (∼8%; n=05), and this effect was due to an increased f . The focal acidification of the ROb had no effect on VE (N=04). Although there was no response to CO 2 dialysis in the ROb, the simultaneous dialysis into the RTN and ROb potentiated the effect of the focal acidification of RTN alone. These results indicate a modulatory role of caudal MR with respect to central chemoreception at the RTN. (Supported by FAPESP and R37 HL 28066)