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Autonomic function decline observed in hypoglycemia is attenuated during hyperoxia: potential role of carotid bodies in mediating cardio‐vagal activity
Author(s) -
Taylor Jennifer Lynne,
Wehrwein Erica A,
Curry Timothy B,
Basu Rita,
Basu Ananda,
Joyner Michael J
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.876.1
Subject(s) - hyperoxia , hypoglycemia , medicine , heart rate , endocrinology , chemoreceptor , heart rate variability , vagal tone , anesthesia , autonomic nervous system , cardiology , blood pressure , lung , insulin , receptor
Cardio‐vagal tone (CVT) and heart rate variability (HRV) are reduced during hypoglycemia. Carotid body (CB) peripheral chemoreceptors are multi‐modal; therefore we hypothesized a correlation between CB activity and CVT during hypoglycemia. Seven healthy adults (4M/3F) underwent two 180 min hyperinsulemic (2mU/kg FFM/min), hypoglycemic (3.33 mmol/L) clamps one week apart, randomized to normoxia (arterial P O2 (P a O 2 ) 111 ± 6.3 mmHg) or hyperoxia (P a O 2 345 ± 80.6 mmHg) to desensitize the CB. CVT was assessed via the high frequency (HF) component of HRV from 5 min periods of 5‐lead ECG recording under baseline (euglycemia) and hypoglycemia. HF values decreased significantly from baseline during hypoglycemia, however this reduction was attenuated under hyperoxia (Normoxia (N): −69% vs. Hyperoxia (H): −41%, p=0.04). Heart rate increased significantly during hypoglycemia (N: 59.7 bpm ± 2.4 vs. 71.9 ± 4.0; H: 60.6 bpm ± 1.9 vs. 68.5 ± 3, p<0.001), however, this increase was not different between normoxia and hyperoxia, despite differences in CVT and HRV. These data indicate that the CB chemoreceptors may be partially responsible for the reduction in CVT associated with hypoglycemia, and they provide evidence for a role of the CB chemoreceptors in parasympathetic tone to the heart. Future studies are required to determine whether inhibition of the CB may serve to improve CVT function during hypoglycemia. T32 DK07352, F32 DK84624‐01 A1, CTSA 1 UL 1 RR024150 , R01DK 29953