Cocaine produces panic-like flight responses in mice in the mouse defense test battery

There is an emerging body of clinical evidence that cocaine use in humans can result in serious fear or panic-related emotional disturbances. The present study evaluated the effects of cocaine administration upon defensive responses of mice to a predator (rat) in a Mouse Defense Test Battery (MDTB) that permits the display of the full range of the mouse defensive behaviors: avoidance/escape, flight, freezing, defensive upright, and defensive threat and attack. Mice were tested 30 min following intraperitoneal (IP) injections of either 0, 10, 20, or 30 mg/kg cocaine hydrochloride suspended in physiological saline. Cocaine produced an increase in flight and escape responses throughout the subtests comprising the MDTB. The percentage of subjects exhibiting escape increased in cocaine-treated mice in the Predator Avoidance Test. Cocaine increased mean flight speed and maximum flight speed in the Flight/Chase Test; frequency of flight responses in the Straight Alley Test; and the number of flight attempts in the Forced Contact test. The predominance of flight responding throughout the tests masked any possible cocaine effects on other defenses. The present findings indicate that cocaine may exert its panic-producing effects by acting upon particular neurobehavioral systems subserving defensive behavior.