5-Nitrotryptamine, also known as Nitro-I, is a serotonin receptor modulator and psychedelic drug of the tryptamine family. It is the 5-nitro derivative of tryptamine.
The drug is a biased agonist of the serotonin 5-HT<sub>2A</sub> receptor (K<sub>i</sub> = 490âÂÂ2,050nM; = 0.11âÂÂ491nM; = 44âÂÂ108%). It shows high selectivity (10-fold) for activation of the G<sub>ñq</sub> pathway over ò-arrestin2 recruitment and very high selectivity (>50-fold) for activation of the G<sub>ñq</sub> pathway over the G<sub>ñi1</sub> pathway.
Given via intracerebroventricular injection, Nitro-I produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents. This effect is absent in serotonin 5-HT<sub>2A</sub> receptor knockout mice. Unlike 5-phenoxytryptamine (OVT2), Nitro-I does not produce serotonin 5-HT<sub>2A</sub> receptor-mediated long-term memory deficits.
The chemical synthesis of Nitro-I has been described.
Nitro-I was first described in the scientific literature by 1953. Subsequently, it was studied and described in greater detail in 2015 and 2024.