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Carotid body denervation does not affect CO2 sensitivity in multiple rat strains
Author(s) -
Mouradian Gary Charles,
Miller Justin,
Muere Clarissa,
Forster Hubert V.,
Hodges Matthew R.
Publication year - 2012
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.26.1_supplement.894.12
Subject(s) - hypercapnia , chemoreceptor , carotid body , denervation , control of respiration , ventilation (architecture) , hypoxia (environmental) , chemistry , hypoventilation , medicine , respiratory system , anesthesia , endocrinology , peripheral chemoreceptors , hypoxic ventilatory response , respiration , oxygen , electrophysiology , anatomy , receptor , organic chemistry , mechanical engineering , engineering
O 2 and CO 2 /pH are detected by the carotid bodies (CBs) and central respiratory chemoreceptors, respectively. CB activity appears to modulate central chemoreceptor activity, suggesting chemoreceptor interdependence. Here, we studied the effects of CB denervation in CO 2 ‐insensitive Brown Norway (BN) and CO 2 ‐sensitive Dahl Salt‐sensitive (SS) and Sprague Dawley (SD) rats by chronic measurements of ventilation (V E ) and blood gases at rest, and during hypercapnia (7% CO 2 ) or hypoxia (12% O 2 ) before and for 21 days (d) after CBD. Peak eupneic hypoventilation (Δ PaCO 2 ) occurred 1–2 d post‐CBD in all strains, increasing 11.0 (SS), 9.4 (BN) and 7.0 (SD) mmHg. Resting PaCO 2 returned to control by 12 d post‐CBD (BN and SD), but remained elevated (+3.9 mmHg) in SS rats. SS and SD rats showed high sensitivity (V E ~300% of control) and BN rats a low sensitivity (V E ~150% of control) to hypercapnia pre‐CBD, which was unaffected by CBD. In addition, CO 2 sensitivity (measured as ΔV E /ΔPaCO 2 ) was also unaffected by CBD in all strains, despite a near‐complete loss of the hypoxic ventilatory response and attenuation of the ventilatory response to i.v. NaCN. As seen in other species, these data suggest that CBD in rats leads to eupneic hypoventilation and elimination of the hypoxic ventilatory response, but the lack of effect on CO 2 sensitivity does not support the concept of chemoreceptor interdependence. Supported by NIH HL097033.