Mirtazapine’s effects on brain systems using norepinephrine and serotonin

Mirtazapine preferentially blocks noradrenergic alpha2 receptors, influencing neurotransmitter release.

• Mirtazapine has a low affinity for serotonin 1A receptors but effectively blocks 5-HT2 and 5-HT3 receptors.
• It increases the firing of serotonergic cells in the dorsal raphe and enhances serotonin release in the hippocampus.
• The drug's effects are attributed to noradrenergic enhancement of serotonin cell-firing and inhibition of noradrenaline's suppressive effects on serotonin release.
• Only serotonin 1-mediated transmission is enhanced due to the blockade of 5-HT2 and 5-HT3 receptors.
• The mechanism of action may underlie mirtazapine's therapeutic activity and its potential to reduce side effects associated with non-selective serotonin activation.

Simplified