How does mirtazapine increase central noradrenergic and serotonergic neurotransmission?

Mirtazapine increases central noradrenergic and serotonergic neurotransmission by antagonising presynaptic α2 receptors, with enhanced serotonergic neurotransmission mediated specifically through 5-HT1 receptors because it blocks 5-HT2 and 5-HT3 receptors.