Images

A schematic of the saggital view of the brain.

When a nerve impulse arrives at a 5-HT or noradrenaline nerve terminal the neurotransmitter is released from the synaptic vesicle into the synaptic cleft.

When a nerve impulse arrives at a noradrenaline nerve terminal, noradrenaline is released from synaptic vesicles into the synaptic cleft.

The mechanism of action of tricyclic antidepressants (TCAs) – a group of drugs used to treat affective, or ‘mood’, disorders.

When a nerve impulse arrives at a serotonin (5-HT) nerve terminal, 5-HT is released from synaptic vesicles into the synaptic cleft.

Depression is associated with reduced levels of the monoamines in the brain, such as noradrenaline. The selective noradrenaline re-uptake inhibitors are thought to restore the levels of noradrenaline in the synaptic cleft.