Key result
Hyperoxia alters MSNA during hyperinsulinemia, implicating carotid chemoreceptors in insulin-mediated sympathoexcitation.
Why the study?
Does carotid chemoreceptor desensitization via hyperoxia reduce muscle sympathetic nerve activity during hyperinsulinemia in young healthy subjects?
Does carotid chemoreceptor desensitization via hyperoxia reduce muscle sympathetic nerve activity during hyperinsulinemia in young healthy subjects?
Carotid chemoreceptors may contribute to insulin-mediated sympathoexcitation in humans, as hyperoxia differentially affects MSNA during hyperinsulinemia compared to baseline.
Answers are grounded in this paper and cite their sources.
May support carotid chemoreceptor role in insulin sympathoexcitation; hypothesis-generating in small cohort, larger studies needed.
Objective: Given recent evidence from rodents supporting a novel role for the carotid bodies in insulin‐mediated sympathoexcitation, we sought to determine whether carotid chemoreceptor desensitization would reduce muscle sympathetic nerve activity (MSNA) during hyperinsulinemia in humans. Methods: Young, healthy subjects (n=4, 30±2 yrs) breathed hyperoxic gas (End‐tidal O2 = 100%, PaO2 505±13 mmHg) for 15 min at baseline and during steady‐state hyperinsulinemia (5±1 vs 53±1 µU/mL). Hyperinsulinemia was achieved using a 90‐min hyperinsulinemic (1 mU/kg FFM/min), euglycemic (108±4 mg/dL) clamp. CO2 was maintained at resting levels (PaCO2 41±1 mmHg). Changes in heart rate, blood pressure, minute ventilation, and MSNA (microneurography of the peroneal nerve) were assessed. Results: Hyperinsulinemia increased MSNA [burst frequency (p<0.01), burst incidence (p=0.02), total activity (p=0.02)]. Hyperoxia decreased heart rate (p=0.01) and minute ventilation (p=0.11), and increased mean blood pressure (p=0.04). Consistent with our hypothesis, the effect of hyperoxia on MSNA (Δ) was different between baseline and hyperinsulinemia (burst frequency, p=0.03; burst incidence, p=0.10). Conclusion: These data are the first to suggest the carotid chemoreceptors may contribute to insulin‐mediated sympathoexcitation in humans.
No takes yet. Share an insight, caveat, or question.
Limberg et al. (2014) studied Healthy (n=4). Hyperoxic gas vs. Baseline was evaluated on Change in muscle sympathetic nerve activity (MSNA) burst frequency (p=0.03). Hyperoxia had a differential effect on muscle sympathetic nerve activity burst frequency between baseline and hyperinsulinemia (p=0.03), suggesting carotid chemoreceptors contribute to insulin-mediated sympathoexcitation.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: