Hyperbaric exposure acts as an ethanol antagonist: evidence from chronic ethanol studies

Hyperbaric exposure has been shown to antagonize the acute depressant effect of ethanol on behavior. The present studies extended the investigation to animals chronically treated with ethanol. The results indicate that exposure to 12 atmospheres absolute (ATA) helium-oxygen (HEOX) precipitated and exacerbated withdrawal signs in ethanol dependent C57BL/6 mice compared to dependent animals exposed to 1 ATA air or HEOX. A second study found that hyperbaric exposure during acquisition significantly reduced the development of chronic, functional ethanol tolerance measured by sleep-times and wake-up ethanol concentrations. Further investigations suggest that hyperbaric exposure during dependence acquisition also attenuates the development of ethanol dependence. These results support the hypothesis that hyperbaric exposure directly antagonizes molecular actions of ethanol leading to acute intoxication, tolerance and physical dependence.