Pharmacological profile of the antidepressant adinazolam, a triazolobenzodiazepine

Adinazolam, which is a 1-dimethylaminomethyl triazolobenzodiazepine, is an effective anxiolytic agent as defined by suppression of stress-induced increases in plasma corticosteroids. Adinazolam is also an effective antagonist of pentylenetetrazole. The 1-dimethylaminoethyl triazolo analog, U-43,465F, was inactive in the stressed rat test and only weakly active against pentylenetetrazole. Adinazolam and U-43,465F have been previously shown to have antidepressant activity in classical screening tests. They have also been found to potentiate the effect of norepinephrine and this is consistent with the activity of the known antidepressants; U-43,465F was found to be equieffective to imipramine in this test. Adinazolam was also effective; however, the magnitude of the potentiation was not as great. The uptake of norepinephrine was only weakly affected by either compound. Potentiation or uptake of serotonin were not significantly-altered pharmacological factors. Receptor binding studies were negative except at the benzodiazepine receptor. Chronic treatment with adinazolam did not decrease the number of beta-adrenergic receptors in the cerebral cortex of the rat, in contrast to the positive effect of imipramine. The discovery of triazolobenzodiazepines with antidepressant activity is of special interest. These agents will hopefully have lower toxicity than the tricyclic antidepressants and thus possess a more favourable therapeutic index. This would be advantageous in the treatment of depression.