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Role of serotonergic neurons in the caudal medullary raphe (ROb) on ventilatory and thermoregulatory responses to hypercapnia
Author(s) -
Silva Glauber S. F.,
Giusti Humberto,
Benedetti Maurício,
Dias Mirela B.,
Gargaglioni Luciane H.,
Branco Luiz G.,
Glass Mogens L.
Publication year - 2011
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.25.1_supplement.847.3
Medullary raphe (MR) serotoninergic (5‐HT) neurons exert an important role on breathing and thermoregulation. However, the role of caudal MR, specifically nucleus raphe obscurus (ROb) on ventilatory and thermoregulatory responses elicited by hypercapnia are still uncertain. Therefore, we investigated the role of caudal MR (ROb) and specifically its 5‐HT neurons in the ventilatory and thermoregulatory responses to CO2 in unanesthetized rats. To this end, we used specific (anti‐SERT‐SAP) chemical lesion of the caudal MR region. Pulmonary ventilation (VE, whole body plethismography), body temperature (data loggers) and blood gases were measured before, during and after a 30 min hypercapnic challenge (7% CO2). No difference was found during normocapnic condition in any parameters of the control (vehicle, IgG‐SAP) or lesioned groups. During hypercapnia, specific 5‐HT lesion attenuated VE (~ 9%) and CO2 response curves slope (~11%) compared to IgG‐SAP group, which was due to a reduction of VT. Hypercapnia caused a drop in body temperature, which was similar among groups. Our data indicate that 5‐HT ROb neurons play a role in CO2‐drive to breathing, but not in CO2‐induced drop in body temperature.