Quipazine is a serotonergic drug of the arylpiperazine group which is used in scientific research.[1] [2] [3] It was first described in the 1960s and was originally intended as an antidepressant but was never developed for medical use.[4]
| Affinity (Ki, nM) | ||
|---|---|---|
| 230–>10,000 | ||
| 1,000 | ||
| 1,000–3,720 | ||
| 59–2,780 | ||
| 49–178 | ||
| 54–339 | ||
| 2.0–4.0 (Ki) 1.0 | ||
| >10,000 (guinea pig) | ||
| >10,000 (mouse) | ||
| 3,600 | ||
| 3,033 | ||
| >10,000 (rat) | ||
| 5,000 (rat) | ||
| 5,600 | ||
| 2,900 (rat) | ||
| >10,000 | ||
| >10,000 | ||
| 3,920 (rat) | ||
| >10,000 (rat) | ||
| 30 | ||
| Notes: The smaller the value, the more avidly the drug binds to the site. All proteins are human unless otherwise specified. Refs: [5] [6] | ||
Quipazine is a serotonin 5-HT3 receptor agonist and to a lesser extent a serotonin 5-HT2A receptor agonist, ligand of the serotonin 5-HT2B and 5-HT2C receptors, and serotonin reuptake inhibitor. Activation of the serotonin 5-HT3 is implicated in inducing nausea and vomiting as well as anxiety, which has limited the potential clinical usefulness of quipazine.
Quipazine produces a head-twitch response and other psychedelic-consistent effects in animal studies including in mice, rats, and monkeys. These effects appear to be mediated by activation of the serotonin 5-HT2A receptor, as they are blocked by serotonin 5-HT2A receptor antagonists like ketanserin. Quipazine did not produce psychedelic effects in humans up to a dose of 25mg, which was the highest dose tested due to serotonin 5-HT3 receptor-mediated side effects of nausea and gastrointestinal discomfort.[7] Alexander Shulgin has anecdotally claimed that a fully effective psychedelic dose could be reached by blocking serotonin 5-HT3 receptors using the serotonin 5-HT3 receptor antagonist ondansetron.[8]
Quipazine can produce tachycardia, including positive chronotropic and positive inotropic effects, through activation of the serotonin 5-HT3 receptor.
Quipazine is a substituted piperazine and quinoline. It is structurally related to 6-nitroquipazine.
It is synthesized by reacting 2-chloroquinoline with piperazine.