Serotonin, or 5-hydroxytryptamine (5-HT), acts as a hormone and as a neurotransmitter in human organism. Most of serotonergic neurons reside in hypothalamus and limbic system of human brain.
Upon neuronal impulse conduction neurotransmitters are released into synaptic cleft and bind receptors on the postsynaptic membrane. Then the process is terminated either by degradation (in this particular case by monoaminoxidase (MAO) or catechol-O-methyltransferase (COMT)), or reuptake of neurotransmitters by corresponding receptors on presynaptic membrane.
SSRIs (selective serotonin reuptake inhibitors) bind to post-synaptic 5-HT receptors and function as competitive antagonists increasing levels of serotonin in the synaptic cleft and thus enhancing stimulus conduction. The described effect is used in the synthesis of new psychotic compounds for the treatment of depression, anxiety disorders, and some personality disorders.
