Anorexic and behavioural effects of a new imidazo-isoindole derivative (mazindol) in comparison with d-amphetamine in the rat.

The effect of an imidazo-isoindole derivative (mazindol) upon motor and feeding activity and two different avoidance behaviours have been compared with those of d-amphetamine in rats. It was found that both drugs depress feeding activity in a dose-related manner and increase the motor activity of the animals. However, the ratio of the lowest motility-increasing dose and the lowest appetite suppressant dose is 0.5 for d-amphetamine and 2 for mazindol. Mazindol, like d-amphetamine, caused a stereotyped behaviour in rats when given in very high doses, but the range between the anorexic and the stereotyped behaviour dose is much higher for mazindol than for d-amphetamine. The shuttle-box avoidance behaviour suppressed by tetrabenazine is completely restored by d-amphetamine and partially by mazindol. Lever-pressing avoidance suppressed by tetrabenazine is restored by d-amphetamine while mazindol at the doses used is ineffective. It is concluded that mazindol could be an anorexic agent better suited than d-amphetamine for clinical use.