Reserpine Action in Subjects Treated with Monoamine Oxidase Inhibitors

Daily treatment of rats and rabbits with iproniazid (Marsilid), pheniprazine (Catron) and phenylisobutylhydrazine (JB-835) results in psychomotor excitation and sympathomimetic effects.1,2Daily treatment of cats with these same monoamine oxidase (MAO) inhibitors does not produce psychomotor excitation.1,3The administration of reserpine to rabbits or mice pretreated with iproniazid causes marked central excitation and sympathomimetic responses, instead of the usual reserpine responses.1,4-7The administration of reserpine to cats pretreated with iproniazid produces the typical depressant and sympatholytic effects of reserpine.6 Analysis of the data presented above indicates that treatment with MAO inhibitor results in psychomotor excitation and reversal of reserpine action in animals in which the levels of both brainstem serotonin and norepinephrine are elevated, e.g., rat, mouse, rabbit. Treatment with an MAO inhibitor does not result in psychomotor excitation and reversal of reserpine action in those animals in which