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The Role of Ionotropic Glutamate Receptors in the Nucleus Raphe Magnus on Hypercapnia‐induced Hyperpnea and Regulated Hypothermia
Author(s) -
Nucci Tatiane Borodinas,
Gargaglioni Luciane Helena,
Branco Luiz Guilherme
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.954.4
Subject(s) - hypercapnia , ionotropic effect , nucleus raphe magnus , hyperpnea , microinjection , anesthesia , chemistry , glutamate receptor , medicine , receptor , endocrinology , respiratory system , serotonin , serotonergic
Nucleus Raphe Magnus (NRM) is one of the cellular groups of the brainstem that is involved in the physiological responses to hypercapnia. We assessed the role of ionotropic glutamate receptors in the NRM in the ventilatory responses to hypercapnia. Methods: Pulmonary ventilation (VE) and body temperature (Tb) of male Wistar rats were measured before and after microinjection of Kinurenic Acid (KY, an ionotropic glutamate receptors antagonist, 10ηmol/0,1μL) into the NRM, followed by 60 min of hypercapnia exposure (7% CO 2 ). Results: Intra‐NRM microinjection of vehicle or KY did not affect VE or Tb under normoxic conditions. Hypercapnia caused an increase of pulmonary ventilation in all groups, which resulted from increases in respiratory frequency and tidal volume (VT). The hypercapnic ventilatory response was significantly increased in Kinurenic Acid microinjected group compared with vehicle. The hypercapnia‐induced regulated hypothermia was not affected by Kinurenic Acid treatment. Conclusion: This data suggest that the glutamate acting on ionotropic receptors in the NRM exerts an inhibitory modulation on the hypercapnia‐induced hyperpnea. Supported by:CNPq and FAPESP.