The inhibition of MAO-A prevents metabolism of serotonin and catecholamines in the presynaptic terminal, and thus increases the amount of neurotransmitters available for release into the synaptic cleft.
The inhibition of MAO-A halts the metabolism of serotonin and catecholamines in the presynaptic terminal, leading to an increase in their availability for release into the synaptic cleft.