| 1. |
- Ax, M., et al.
(author)
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Regional lung ventilation in humans during hypergravity studied with quantitative SPECT
- 2013
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In: Respiratory Physiology & Neurobiology. - : Elsevier BV. - 1569-9048 .- 1878-1519. ; 189:3, s. 558-564
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Journal article (peer-reviewed)abstract
- Recently we challenged the view that arterial desaturation during hypergravity is caused by redistribution of blood flow to dependent lung regions by demonstrating a paradoxical redistribution of blood flow towards non-dependent regions. We have now quantified regional ventilation in 10 healthy supine volunteers at normal and three times normal gravity (1G and 3G). Regional ventilation was measured with Technegas (Tc-99m) and quantitative single photon emission computed tomography (SPECT). Hypergravity caused arterial desaturation, mean decrease 8%, p<0.05 vs. 1G. The ratio for mean ventilation per voxel for non-dependent and dependent lung regions was 0.81+/-0.12 during 1G and 1.63+/-0.35 during 3G (mean+/-SD), p<0.0001. Thus, regional ventilation was shifted from dependent to non-dependent regions. We suggest that arterial desaturation during hypergravity is caused by quantitatively different redistributions of blood flow and ventilation. To our knowledge, this is the first study presenting high-resolution measurements of regional ventilation in humans breathing normally during hypergravity.
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| 2. |
- Jonsson, M., et al.
(author)
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Neuromuscular blocking agents block carotid body neuronal nicotinic acetylcholine receptors
- 2004
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In: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 497:2, s. 173-180
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Journal article (peer-reviewed)abstract
- Neuromuscular blocking agents predominantly block muscle type nicotinic acetylcholine receptors as opposed to the neuronal type. However, there is growing evidence that neuromuscular blocking agents have affinity to some neuronal nicotinic acetylcholine receptors. The carotid body chemoreceptor as the essential oxygen-sensing cell, relies on cholinergic signalling. Atracurium and vecuronium impair carotid body chemoreceptor activity during hypoxia. Here, we characterize atracurium and vecuronium as antagonists at nicotinic receptors of the carotid body chemoreceptor. Isolated rabbit carotid body preparations with carotid sinus nerve were used, and chemoreceptor activities were recorded. There was a concentration-dependent reduction in the chemoreceptor responses to nicotine, with an IC50 to 50 µg nicotine of 3.64 and 1.64 µM and to 500 µg nicotine of 27.00 µM and 7.29 µM for atracurium and vecuronium, respectively. It is concluded that atracurium and vecuronium depress nicotine-induced chemoreceptor responses of the carotid body in a dose-dependent fashion. © 2004 Elsevier B.V. All rights reserved.
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