Ketamine Intoxication in Rats
Technical Report,01 Oct 2016,07 Jun 2017
US Army Medical Research Institute of Chemical Defense Aberdeen Proving Ground United States
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This report provides preliminary information on overt toxicity and incapacitation following intraperitoneal injection of ketamine in rats. The ketamine doses were 37.5, 75.0, and 150.0 mgkg, and selected to be below the lethal range but potentially intoxicating. Rapid immobilization was observed at the two highest doses, whereas the lower dose produced only transient ataxia and light sedation. Behavioral performance was indexed by the acquisition of a two-way discriminated active shuttle avoidance response 24 hours after ketamine injection. This assessment revealed no apparent differences from vehicle control performance, suggesting complete to near complete functional recovery by this time. Overnight food consumption revealed no robust or lingering effects of ketamine injection, but weight loss was observed at the highest ketamine dose. These data and their conclusions are limited by the small number of subjects, limited ranges of doses, and inclusion of only one exposure route. Nevertheless, this study provides important preliminary information on the rapid onset and relatively short duration of intoxication that can be achieved by ketamine in a rat model. Utilizing this same animal model, more prompt and comprehensive operant behavioral testing following ketamine exposure appears warranted to more extensively characterize this potent incapacitating drug and for discovering effective medical countermeasures for ketamine intoxication.