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Updated: Jan 25, 2026
11:56
Training Rats to Voluntarily Dive Underwater: Investigations of the Mammalian Diving Response
Published on: November 12, 2014
12.8K
Decrease of tetrahydrobiopterin and NO generation in endothelial cells exposed to simulated diving
Ronja Hesthammer1,2, Torunn Eide2, Einar Thorsen1,2
1Norwegian Centre for Maritime and Diving Medicine, Haukeland University Hospital, Bergen, Norway.
Summary
Simulated diving and hyperoxia decrease nitric oxide (NO) production in endothelial cells. While hyperoxia reduces tetrahydrobiopterin (BH4), it is not the sole factor limiting NO generation during diving.
Area of Science:
- Physiology
- Biochemistry
- Diving Medicine
Background:
- Nitric oxide (NO) plays a crucial role in preventing bubble formation and decompression sickness.
- Tetrahydrobiopterin (BH4) is an essential cofactor for NO synthesis.
Purpose of the Study:
- To investigate the hypothesis that oxidation of BH4 leads to decreased NO production during simulated diving.
- To examine the effects of hyperoxia and simulated diving on BH4 levels and NO generation in human endothelial cells.
Main Methods:
- Human umbilical vein endothelial cells (HUVEC) were exposed to hyperoxia or simulated diving.
- Biopterin levels (BH4, BH2, B) were quantified using LC-MS/MS.
- NO production was assessed by measuring L-arginine to L-citrulline conversion.
Main Results:
- Hyperoxia dose-dependently decreased BH4 levels.
- Both hyperoxia and simulated diving reduced NO production.
- No additive or synergistic effects of hyperbaria and hyperoxia on BH4 or NO were observed.
Conclusions:
- NO generation in HUVEC is reduced by simulated diving and hyperoxia.
- BH4 levels are primarily affected by hyperoxia, not simulated diving alone.
- BH4 is not the sole determinant of NO generation in endothelial cells under these conditions.
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