In: Anatomy and Physiology
In 2-3 sentences describe how SSRI drugs function as antidepressants. Your description should (i) describe whether SSRI drugs function as agonists or antagonists, (ii) specify which neurotransmitter pathway they act on, and (iii) how the SSRI mechanism of action treats clinical depression with respect to affecting neurotransmitter levels
Given above is a brief description of SSRIs (Selective Serotonin Reuptake Inhibitors) from my personal assignment collections.
(i) SSRI drugs function as agonists of serotonin receptors. They activate serotonin receptors in a manner similar to that of serotonin (5-hydroxytryptamine; 5-HT).
(ii) They act on monoamine neurotransmitter pathways like norepinephrine, serotonin, etc.
(iii) Deficit in function or amount of monoamines is the biology behind depression. Let's take the case of serotonin. When extracellular serotonin binds to receptor on serotonin transporter (SERT), SERT undergo conformational changes to allow movement of serotonin into cells leading to low levels of serotonin in synaptic junctions and hence resulting in depression. SSRIs allosterically inhibit the transporter so that serotonin does not bind and get inside the cell resulting in high levels of serotonin in synaptic junctions.