An approach-avoidance experiment found that midazolam-treated rats tolerated higher carbon dioxide concentrations, but none tolerated concentrations needed for unconsciousness.
Six female rats were tested first under control conditions and then after midazolam. Mean avoided carbon dioxide concentration rose from 10.7% to 15.5%. The researchers interpreted the result as supporting an anxiety-related component of carbon dioxide aversion.
Treatment order was intentionally confounded: control sessions preceded midazolam sessions. The authors also identified the small, older, single-strain female sample as a limitation. Increased tolerance does not prove absence of distress or establish a humane endpoint for every animal. Nor can these concentrations or behavioral choices be converted into a human benzodiazepine response threshold. The study supports a limited anxiolytic-like interpretation while preserving the fact that avoidance remained and unconsciousness was not reached.
Original analysis of the supplied journal article, identified as PMC6908729.