We currently understand the mental effects of psychedelics to be caused by agonism or partial agonism of 5-HT_2A (and possibly 5-HT_2C) receptors (serotonin-2A and serotonin-2C receptors). This understanding was first developed in the 1980s and has since been confirmed by a large body of evidence, as reviewed recently by Nichols. However, many authors have commented that other receptors may also play a role. In this post-genome era of high-throughput assays, it is time to take a broader view, move beyond the common-denominator approach, and begin to explore the role of other receptors in shaping the mental effects of psychedelics, especially the qualitative differences among them.

The objective of this paper is to present the receptor binding profiles of the thirty-five drugs (Fig. 1, Fig. 2) of this study in such a way that they can be easily compared in both their similarities and their differences. This is intended to serve as a reference work on the multi-receptor affinity pharmacology of psychedelic drugs. The tables and figures are the heart of this manuscript. Some of them have been included as “supporting information,” because they exceed the size limits of standard tables and figures. However, this supporting information is no less central to the manuscript than the standard tables and figures.

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