Screening of 64 Tryptamines at NMDA, 5-HT1A, and 5-HT2A Receptors: A Comparative Binding and Modeling Study
Authors: L. Berger, M.; Palangsuntikul, R.; Rebernik, P.; Wolschann, P.; Berner, H.
Source: Current Medicinal Chemistry, Volume 19, Number 18, June 2012 , pp. 3044-3057(14)
Publisher: Bentham Science Publishers
Abstract:Tryptamine (T) and several T derivatives (Ts) inhibit in a voltage-dependent manner the NMDA receptor (NR). This effect is influenced by substituents at various positions, but has not yet been subjected to a detailed SAR study. Here, 64 Ts have been tested as inhibitors of [3H]MK-801 binding to NRs on rat brain membranes. For comparison, they were also tested as inhibitors of [3H]8-OHDPAT binding to 5-HT1A and of [3H]ketanserin binding to 5-HT2A receptors. Since most of these Ts have not been tested before at any of these receptors, we start with a review of the effects of Ts on 5-HT1A and 5-HT2A binding sites. NRs were inhibited with IC50s from 2 to 7 μM by Ts with alkyl or halogen at positions 2, 5, and/or 7. Inhibition by some Ts was attenuated more than 10-fold by 30 μM spermine. The most potent inhibitors at 5-HT1A receptors were 5-carboxamido-T (IC50 0.00015 μM) and serotonin (0.0016 μM), at 5-HT2A receptors 2-Me-4,7-Cl2-T (1.2 μM) and 2,7-Me2-4-Cl-T (2.0 μM). Fujita-Ban modified Free-Wilson analyses pointed to the individual significance of particular substituents. Also QSARs based on molecular operating environment descriptors resulted in sound correlations at all 4 targets. No similarities between the NR and 5-HT receptors could be found. At the NR, only L-Trp-NH2 bound 10 times better than at both 5-HT receptors studied. L-Trp-NH2 may be a structural lead to endogenous non-competitive NR antagonists.
Document Type: Research Article
Affiliations: Center for Brain Research, Medical University of Vienna, A-1090 Spitalgasse 4, Austria.
Publication date: June 1, 2012
- Current Medicinal Chemistry covers all the latest and outstanding developments in medicinal chemistry and rational drug design. Each issue contains a series of timely in-depth reviews written by leaders in the field covering a range of the current topics in medicinal chemistry. Current Medicinal Chemistry is an essential journal for every medicinal chemist who wishes to be kept informed and up-to-date with the latest and most important developments.