[Importance of initial monoamine oxidase activity to the development of the activating or inhibitory effect of N-methyl- and N-ethyloctahydronaphthoazepines].

Effect of N-methyl- and N-ethyl octahydronaphthazepines upon the MAO activity of brain mitochondria of intact rats and brain homogenates of the animals treated with iproniazid has been investigated in vitro. These compounds (0.1 mumole/ml) stimulated the deamination of noradrenaline in samples with low initial enzymatic activity and inhibited it in samples having high initial enzymatic activity. The MAO activating effect of N-methyl octahydronaphthazepines in the brain homogenates occurred when the enzymatic activity was previously inhibited with iproniazid. In the homogenates, which were not pretreated with iproniazid, the activating effect was observed only in some cases.