A comparison of the acute behavioral effects of alkylbenzenes using a functional observational battery in mice

The acute neurobehavioral effects of six alkylbenzenes (benzene, toluene, ethylbenzene, propylbenzene, m-xylene, and cumene) were evaluated after 20-min inhalation exposures using a functional observational battery (FOB) in mice. In order to do this, an explicit protocol for the FOB developed for rats by Moser was adapted for use in mice with inhalation exposures. All six alkylbenzenes, in the concentration range of 2000 to 8000 ppm, produced a nearly identical profile of effects, a profile that was also produced by ip administration of the central nervous system depressant drug pentobarbital. These effects included changes in posture, decreased arousal and rearing, increased ease of handling, disturbances of gait, mobility, and righting reflex, decreased forelimb grip strength, increased landing foot splay, and impaired psychomotor coordination. The response to various sensory stimuli was also decreased by the alkylbenzenes and pentobarbital. These acute effects of alkylbenzenes were short-lived, with recovery beginning within minutes of removal from the exposure chamber. The finding that the alkylbenzenes produce a profile of neurobehavioral effects similar to that of pentobarbital is consistent with a growing body of other evidence that many solvents produce a profile of acute effects similar to that of central nervous system depressant drugs and ethanol.