Normobaric hyperoxia (95% O2 ) stimulates CO2 -sensitive and CO2 -insensitive neurons in the caudal solitary complex of rat medullary tissue slices maintained in 40% O2

Highlights • 95% O2 increases production of superoxide and nitric oxide in medullary slices relative to 40% O2 (control). • 67–81% of solitary complex neurons maintained were stimulated by 95% O2 (hyperoxia). • We suggest using 40% O2 as the control level of O2 in brain slices to avoid confounding effects of cellular oxidation. • Neuronal CO2 -chemosensitivity is retained in 40% O2 (control O2 ) in the caudal solitary complex. • A greater incidence of CO2 -inibition occurs in slices exposed to O2 manipulations.