A new animal model for the prediction of antidepressant activity

Animal models presently in use for the screening of potential antidepressant drugs yield numerous false positives and false negatives. In search of a more specific model, we have studied the effects of psychotropic compounds on the behavioural changes induced in rats by the removal of the olfactory bulbs. We have observed that subchronic treatment with antidepressants in general reverses the behavioural alterations displayed by bulbectomized rats in tests of conditioned behaviour. The present paper describes a brief test, the so-called anxiosoif test, which may be used to assess the effects of drugs on the behaviour of bulbectomized rats. Removal of the olfactory bulbs leads to increased water intake in the anxiosoif test and to an attenuation of avoidance when the drinking spout is electrified. This latter effect can be reversed by subchronic treatment with the antidepressant drugs amitriptyline and mianserine (Org GB 94). It is suggested that the behavior of bulbectomized rats may be used as a specific tool in the prediction of antidepressant activity of novel compounds.