False neurotransmitter
A false neurotransmitter is a chemical compound which closely imitates the action of a neurotransmitter in the nervous system. An example would be 5-MeO-αMT mimicking serotonin.
These chemicals can be taken up by a nerve and then released with other neurotransmitters when an action potential provides the necessary stimulus for release.
There is growing evidence that a large number of well known exogenous chemicals work as substitute neurotransmitters, though the distinction between the classical model and the substitute neurotransmitter model only becomes apparent with neurotransmitters central to the signaling in the conscious brain, like dopamine and serotonin (as mentioned above). By extension, drugs that affect the uptake affinity of neurotransmitter transporters directly affect the efficacy of these substitute neurotransmitters, as shown by the interference that selective serotonin reuptake inhibitors have on serotonergic psychedelic drugs.