Chlordiazepoxide specifically impairs nonspatial reference memory in the cued radial arm maze in rats.

Anxiolytic benzodiazepines, at low doses, reportedly impair the radial arm maze with nonspatial visual/tactile but not spatial cues. We replicated the former result controlling for changes in drug state and cue effectiveness. Rats learned an eight-arm radial maze with reward in only four arms. The reward varied in spatial position from trial to trial but was always cued by a piece of sandpaper at the entry to the arm. Chlordiazepoxide (5 mg/kg, ip) impaired acquisition. Rats that switched from saline during acquisition to chlordiazepoxide showed an impairment of performance that only lasted for 1 day. Removal of the cues reduced the performance of controls and switched rats to the level of the rats that received chlordiazepoxide during acquisition but did not affect the latter. These data suggest that chlordiazepoxide does indeed impair nonspatial reference memory in the radial arm maze while leaving working memory, and, possibly, spatial reference memory, intact but that the previous report of this effect was the result of a change in drug state rather than of the drug itself.