Nicotine increases chemoreflex sensitivity to hypoxia in non-smokers
(2008) Journal of Hypertension — Vol. 26, n° 2, p. 284-294 (2008)
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- Abstract
- BACKGROUND: The peripheral chemoreflex contributes to cardiovascular regulation and represents the first line of defence against hypoxia. The effects of nicotine on chemoreflex regulation in non-smoking humans are unknown. METHOD: We conducted a prospective, randomized, crossover, and placebo-controlled study in 20 male non-smokers to test the hypothesis that nicotine increases chemoreflex sensitivity. The effects of two intakes of 2 mg nicotine tabs and placebo on sympathetic nerve activity to muscle circulation (muscle sympathetic nerve activity; MSNA), minute ventilation (Ve), blood pressure and heart rate were assessed during normoxia, moderate isocapnic hypoxia, hyperoxic hypercapnia and an isometric handgrip in 10 subjects. Maximal end-expiratory apnoeas were performed at baseline and at the end of the fifth minute of hypoxia. In a second experimental setting, we studied the ventilatory response to a more marked isocapnic hypoxia in 10 other volunteers. RESULTS: Mean MSNA and Ve were not modified by nicotine during the 5 min of normoxia or moderate hypoxia. In the presence of nicotine MSNA was related to oxygen desaturation (P < 0.01). The sympathoexcitatory effects of nicotine became especially evident when apnoeas achieved oxygen saturations less than 85% (511 ± 44% increase in MSNA after the first intake, and 436 ± 43% increase after the second intake versus 387 ± 56% and 338 ± 31% with placebo, respectively, P < 0.05). Nicotine also increased the ventilatory response compared with placebo when oxygen saturation decreased to less than 85% (P < 0.05). CONCLUSION: This is the first study to demonstrate that nicotine increases peripheral chemoreflex sensitivity to large reductions in arterial oxygen content in healthy non-smokers. © 2008 Lippincott Williams & Wilkins, Inc.
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Argacha, J.-F., Xhaet, O., Gujic, M., Adamopoulos, D., Beloka, S., Dreyfuss, C., Degaute, J.-P., & Van De Borne, P. (2008). Nicotine increases chemoreflex sensitivity to hypoxia in non-smokers. Journal of Hypertension, 26(2), 284-294. https://doi.org/10.1097/HJH.0b013e3282f2b93c (Original work published 2008)