What is the mechanism of action of Selective Serotonin Reuptake Inhibitors (SSRIs)?

Selective Serotonin Reuptake Inhibitors (SSRIs) work primarily by inhibiting the reuptake of serotonin into the presynaptic neurons. This action leads to an increase in the concentration of serotonin in the synaptic cleft, which enhances serotonergic neurotransmission. By preventing the reabsorption of serotonin, SSRIs effectively prolong its availability and action on the postsynaptic receptors, which is associated with their therapeutic effects in treating depression and anxiety disorders.

The mechanism of SSRIs specifically targets the serotonin transporter (SERT), which is responsible for the reuptake of serotonin from the synaptic cleft back into the neuron. The inhibition of SERT by SSRIs results in an increase in serotonin levels available for binding to receptors, leading to improved mood and emotional regulation.

Understanding this mechanism helps clarify the roles of other neurotransmitters in different classes of medications. For instance, the increase of dopamine levels is more characteristic of other types of antidepressants or stimulants, while blocking norepinephrine receptors or decreasing serotonin levels is not relevant to the action of SSRIs. Instead, SSRIs focus exclusively on enhancing serotonin function, which is crucial in the management of various mood disorders.