Serotonin antagonist and reuptake inhibitors (SARIs) are a class of drugs used mainly as antidepressants, but also as anxiolytics and hypnotics. They act by antagonizing serotonin receptors such as 5-HT2A and inhibiting the reuptake of serotonin, norepinephrine, and/or dopamine. Additionally, most also antagonize α1-adrenergic receptors. The majority of the currently marketed SARIs belong to the phenylpiperazine class of compounds.
The binding profiles of SARIs and some metabolites in terms of their affinities (Ki, nM) for various receptors and transporters are as follows:[2]
Compound | SERT | NET | DAT | 5-HT1A | 5-HT2A | 5-HT2B | 5-HT2C | 5-HT3 | 5-HT6 | 5-HT7 | α1 | α2 | D2 | H1 | mACh | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Etoperidone | 890 | 20,000 | 52,000 | 85 | 36 | ND | ND | ND | ND | ND | 38 | 570 | 2,300 | 3,100 | >35,000 | |
Hydroxynefazodone | 165–1,203 | 376–1,053 | ND | 56–589 | 7.2–34 | ND | ND | ND | ND | ND | 8.0–145 | 63–2,490 | ND | ND | 11,357 | |
mCPP | 202–432 | 1,940–4,360 | ND | 44–400 | 32–398 | 3.2–63 | 3.4–251 | 427 | 1,748 | 163 | 97–2,900 | 106–570 | >10,000 | 326 | >10,000 | |
Nefazodone | 200–459 | 360–618 | 360 | 80 | 26 | ND | 72 | ND | ND | ND | 5.5–48 | 84–640 | 910 | ≥370 | >10,000 | |
Trazodone | 160–367 | ≥8,500 | ≥7,400 | 96–118 | 20–45 | 74–189 | 224–402 | >10,000 | >10,000 | 1,782 | 12–153 | 106–728 | ≥3,500 | 220–1,100 | >10,000 | |
Triazoledione | ≥34,527 | >100,000 | ND | 636–1,371 | 159–211 | ND | ND | ND | ND | ND | 173 | 1,915 | ND | ND | >100,000 | |
Values are Ki (nM). The smaller the value, the more strongly the drug binds to the site. For assay species and references, see the individual drug articles. Most but not all values are for human proteins. |
These drugs act as antagonists or inverse agonists of the 5-HT2A, α1-adrenergic, and H1 receptors, as partial agonists of the 5-HT1A receptor,[3] and as inhibitors of the transporters. mCPP is an antagonist of the 5-HT2B receptor, an agonist of the 5-HT1A,[3] 5-HT2C, and 5-HT3 receptors,[4][5] and acts as a partial agonist of the human 5-HT2A[6] and 5-HT2C receptors.[7]