Excuses, dit zou er bij moeten staan.
Receptor affinity profiles of psychedelic drugs, ordered by decreasing affinity. The vertical axis is normalized pKi (npKi). Horizontal axis is a list of forty-two receptors, arranged in order of decreasing affinity for each individual drug.
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Normalization
The raw Ki values are distributed over several orders of magnitude, thus a log transformation is a good first step in the analysis. In addition, higher affinities produce lower Ki values, thus it is valuable to calculate: pKi = −log10(Ki). Higher affinities have higher pKi values, and each unit of pKi value corresponds to one order of magnitude of Ki value. Table S4 presents the raw data transformed into pKi values. Generally, the highest Ki value generated by NIMH-PDSP is 10,000, which produces a pKi value of −4 (although a value of 10,450 was reported for 5-MeO-TMT). For non-PDSP data gathered from the literature, some Ki values greater than 10,000 are reported (i.e. 12,500, 14,142, 22,486, 39,409 and 70,000 for ibogaine).
When the primary assay did not produce >50% inhibition, the Ki value is treated as >10,000. When the primary assay hit, but the secondary assay was not performed, the Ki value is also treated as >10,000. If a secondary assay produced a Ki value significantly greater than 10,000, it is usually also reported as >10,000. The lowest Ki value in the data set of this study is 0.3 (lisuride at 5-HT1A) and the highest value is 70,000 (ibogaine at D3), thus collectively, the data in this study cover nearly six orders of magnitude of Ki values. However, ignoring values reported as >10,000, the Ki values for a single drug in this study never exceed four orders of magnitude in range.
The goal of the normalization used in this study is to factor out potency, in order to allow easy comparison of the multi-receptor affinity profiles of different drugs. The normalization will adjust the highest pKi value for each drug to a value of 4, and set all Ki values reported as >10,000 to a value of zero. Ki values actually measured as greater than 10,000 are not set to zero (i.e. 5-MeO-TMT and ibogaine). We will call this normalized value npKi. Let the maximum pKi value for each drug be called pKiMax. For each individual drug:
If Ki treated as >10,000, then npKi = 0
npKi = 4+pKi−pKiMax
With this normalization:
higher affinities have higher values
affinities too low to be measured will be reported as zero
for each drug, the highest affinity will be set to a value of 4
each unit of npKi value represents one order of magnitude of Ki value
potency is factored out so that drugs of different potencies can be directly compared
This normalization effectively factors out the absolute potency of each drug, and allows us to focus on the relative affinities of each drug at each receptor.
De tabel volgt één of andere rare normaliseringsregel, zie ik nu.
Each compound is initially assayed at 10 µM against each receptor, transporter or ion channel (primary assay). Those that induce >50% inhibition (“hit”) are then assayed at 1, 10, 100, 1,000, and 10,000 nM to determine Ki values (secondary assay). Each Ki value (equilibrium dissociation constant, concentration at which 50% of the hot ligand is displaced by the test ligand) is calculated from at least three replicated assays. Details of how individual assays were conducted can be found at the NIMH-PDSP web site:
http://pdsp.med.unc.edu/pdspw/binding.php.
Ki van de receptoren staan elders in het onderzoek
Table 5, zoals in bovenstaande post aangegeven Ki van D2=3371 nM, D3=7716nM
Ter vergelijking, Ki van 5HT2b = 13.5 nM.
In dit geval lijkt het om de pKi te gaan: een logaritmische (!) schaal voor bindingssterkten. De leuke verrassing, dus: 2C-B bindt 100 keer zwakker aan deze dopaminereceptoren dan aan de serotoninereceptoren. De auteurs van dit artikel definiëren dat als een "onmerkbaar effect". 
