Can animal tests of anxiety detect panic-promoting agents?

Sodium lactate (60 and 120 mg/kg), isoproterenol (0·1–0·6 mg/kg), and yohimbine (1·25-5 mg/kg) were investigated in two animal tests of anxiety (the elevated plus-maze and the social interaction test). Rats were also scored for panic-like behaviour following administration of these panic-inducing agents and following inhalation of air supplemented with CO2 (5 and 20 per cent). None of the drugs changed the time spent in social interaction or evoked panic-like behaviour. In the elevated plus-maze, sodium lactate was without effect. The highest dose of isoproterenol (0·6 mg/kg) reduced the percentage of time spent on the open arms, and yohimbine reduced both the percentage of entries made onto the open arms and the percentage of time spent on the open arms, indicating anxiogenic activity. The lack of a strong anxiogenic profile with the pro-panic compounds suggests that anxiety and panic may be biologically distinct.