Is there a "non-MAO" macromolecular target for L-deprenyl?: Studies on MAOB mutant mice.

Several irreversible inhibitors of monoamine oxidase B, can promote survival of damaged neurons in several animal models of cerebral injury. Today it is evident that this effect is not a consequence of monoamine inhibition. Instead it has been proposed that L-deprenyl may act via an unrelated non-monoamine oxidase type- of binding site. In the present study we have investigated if brain tissue from MAOB knockout mice contain such "non-MAO" binding sites for radiolabelled deprenyl. Interestingly, no binding of L-deprenyl was observed indicating that the mother compound does not act directly via a macromolecular target. This is enticing since several alternative mechanisms of action have been proposed in the literature.