RELEVANCE OF REVERSIBLE INHIBITORS OF MONOAMINE-OXIDASE TYPE-A AND OFREUPTAKE INHIBITION FOR NORADRENALINE TURNOVER

Noradrenaline (NA) and serotonin, monoamines that increase neurotransm ission at the monoaminergic synapses, remain primary targets for antid epressant drugs. To help elucidate NA's role in the action of antidepr essants, a model was set up allowing for a simulation of NA turnover u nder various conditions examining 3 compartments: newly synthesized ve sicular NA, released synaptic NA, and vesicular NA reuptake across neu ronal membranes. We compared the influence of the reversible MAO inhib itor, moclobemide, and the NA reuptake inhibitor, desipramine, both us eful in regaining baseline synaptic NA concentrations. Moclobemide app ears less sensitive to fluctuations either in drug concentrations and/ or physiological determinants of NA turnover; we conclude that it may influence brain function in a more regulatory way than reuptake inhibi tors.