5-Methoxytryptamine
# 5-Methoxytryptamine

5-Methoxytryptamine (5-MT), also known as mexamine, is a tryptamine derivative closely related to the neurotransmitters serotonin and melatonin. 5-MT has been shown to occur naturally in the body in low levels. It is biosynthesized via the deacetylation of melatonin in the pineal gland.

5-MT acts as a full agonist at the $5-HT_1,$ $5-HT_2,$ $5-HT_4,$ $5-HT_6,$ and $5-HT_7$ receptors. It has no affinity for the $5-HT_3$ receptor and its affinity for the $5-HT_{1E}$ receptor is very weak in comparison to the other $5-HT_1$ receptors. Its affinity for the $5-HT_{5A}$ receptor is unknown.

Measured affinity for some receptors (incomplete list):

* $5-HT_{1B}$ receptors $(K_i$ = 35 nM)
* $5-HT_{1D}$ receptors $(K_i$ = 7.3 nM)
* $5-HT_{1E}$ receptors $(K_i$ = 3151 nM)
* $5-HT_{1F}$ receptors $(K_i$ = 1166 nM)
* $5-HT_{2A}$ receptors $(K_i$ = 295 nM)
* $5-HT_{2B}$ receptors $(K_i$ = 16.4 nM)
* $5-HT_{2C}$ receptors $(K_i$ = 52.48 nM)
* $5-HT_4$ receptors $(K_i$ = 501.18 nM)
* $5-HT_6$ receptors $(K_i$ = 69.18 nM)
* $5-HT_7$ receptors $(K_i$ = 5.01 nM)
