DMT binds to a LOT of receptors in standard doses. (Scientific note here: We currently know of 13 different serotonin receptors.)
Here are some binding affinities given in npKi form. Fellow neuropsychology lovers, you have my sympathy for being interested in this article:
Psychedelics and the Human Receptorome.
Ki is a standard way of measuring binding affinity. pKi is a logarithmic measure of that. It's like in chemistry where you can measure H+ ion concentration, and then the -log of H+ concentration is called pH. npKi is the normalized form of pKi: the receptor which is bound to most strongly is set at 4.00, and a Ki value greater than 10,000 is assigned an npKi of zero. This, an npKi of 3.00 means that DMT binds to this receptor 1/10th as strongly as it would at 4.00, but it's 10 times stronger than for npKi of 2.00. Most effects will thus come from values above ~2, which are the only ones I'll give.
I tried to format this so it looks pretty, but the forum won't keep all my spaces.
IMPORTANT NOTE: The study does not specify where DMT is agonistic, antagonistic, or inversely agonistic! That means we don't know whether DMT is turning the volume up or down at these sites, so to speak, unless I've found some other source that specified the nature of its activity.
5HT-7: 4.00 (antagonist)
5HT-1d: 3.97 (maybe agonist)
5HT-2b: 3.91 (agonist)
Alpha-2b adrenergic: 3.53 (probably agonistic at most of the adrenoceptors)
Alpha-2c adrenergic: 3.53
Dopamine-1: 3.51 (almost certainly agonist)
5HT-2c: 3.42 (almost certainly agonist)
5HT-1e: 3.28
5HT-6: 3.25
5HT-5a: 3.16
Imidazoline-1: 3.13
Alpha-1b adrenergic: 2.95
Alpha-2a adrenergic: 2.75
Alpha-1a adrenergic: 2.70
5HT 2a: 2.58 (agonist -- responsible for much of the psychedelic effects)
SERT: 2.37 (Serotonin transporter. Binds as a substrate, not an inhibitor like prozac.)
Sigma 1: 2.23 (Why do people say that it barely binds to this receptor at the concentration required to activate 5HT-2a?)
Higher doses of DMT will, of course, activate receptors lower on the list.
DMT also binds to other receptors which were not measured by this study.