Tryptoline
chemical compound
Tryptoline, also known as 1,2,3,4-tetrahydro-β-carboline (THβC) and tetrahydronorharmane (THN), is a natural organic derivative of β-carboline. It is an alkaloid chemically related to tryptamines. Derivatives of tryptoline have a variety of pharmacological properties and are known collectively as tryptolines.
Use and effects
The properties and effects of tryptoline in humans do not appear to be known.
Pharmacology
Pharmacodynamics
Tryptolines are competitive selective inhibitors of the enzyme monoamine oxidase type A (MAO-A). 5-Hydroxytryptoline and 5-methoxytryptoline are the most active monoamine oxidase inhibitors (MAOIs) with IC50 values of 500 nM and 1,500 nM, respectively.
Tryptolines are also potent reuptake inhibitors of serotonin and epinephrine, with a significantly greater selectivity for serotonin.
Tryptoline shows weak affinity for the serotonin 5-HT1A, 5-HT2A, and 5-HT2C receptors (Ki = 2,510–4,310 nM, 3,040–3,900 nM, and >10,000 nM, respectively). However, it showed a high affinity (Ki) of 28 nM against tryptamine-labeled binding sites, whereas affinity for serotonin- and spiperone-labeled sites were much lower (Ki = 6,030 nM and 12,030 nM, respectively). The drug shows substantially lower affinity for serotonin receptors than tryptamine.
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