In vitro activity: Moclobemide orally administered 2 hours before decapitation preferentially inhibits MAO-A and PEA in rat brain with ED50 of 7.6 μmol/kg and 78 μmol/kg, respectively. Moclobemide orally administered 2 hours before decapitation preferentially inhibits MAO-A and PEA in rat liver with ED50 of 8.4 μmol/kg and 6.6 μmol/kg, respectively. Moclobemide (0.1 mM), which inhibits brain MAO-A activity by over 80%, does not affect benzylamine oxidase (rat heart) and diamine oxidase (rat small intestine) activity in vitro. Moclobemide (10 mM-100 mM) includes in the culture medium during anoxia or with glutamate significantly increases in a concentration-dependent manner the amount of surviving neurons compared to controls in neuronal-astroglial cultures from rat cerebral cortex.

Cell Assay: Moclobemide is a prototype of RIMA agents. It is found to possess antidepressant efficacy with less risk of fatal side-effects like hypertensive crisis. Moclobemide shows a weak but specific inhibition of MAO-A in the in vitro assay using rat brain homogenates. The IC50 values of MAO-A and MAO-B in the assay are 6mM and 1000mM, respectively. In ex vivo animal experiments, moclobemide produces an inhibition of 80% in the brain and liver. Additionally, the long-term administration of high doses of moclobemide is found to down-regulate β-adrenoceptors and increase the agonist binding affinity of α1-adrenoceptors. Moreover, moclobemide is rapidly and almost completely absorbed after oral administration. The bioavailability of moclobemide is about 50% after a single administration of 100 mg .

J Pharmacol Exp Ther. 1989 Jan;248(1):400-14; Neuroendocrinology. 1994 Nov;60(5):509-19.