Serotonin neurons (5-HT)
Serotonin, norepinephrine, and dopamine all utilize tyrosine as a substrate for synthesis.
Extra info: Norepinephrine and dopamine use tyrosine, but serotonin uses L-tryptophan as a substrate for synthesis.
Intracellular metabolism of serotonin via monoamine oxidase requires energy from axonal mitochondria.
Extra info: Mitochondria are the principal chemical energy transducers of the cell (except for the 10 reactions of the glycolytic pathway), and thus are responsible for the energy needed for MAO.
The stimulation of 5-HT3 receptors is associated with an increase in nausea.
Extra info: Drugs such as ondansetron which is used for chemotherapy-induced emesis are 5HT3 antagonists.
The 5-HT1D receptor agonists (like sumatriptan) which are used for migraine headaches cause a decrease in serotonin neurotransmission.
Extra info: As can be seen from the graphic, 5HT1D is a presynaptic receptor that inhibits 5HT neurotransmission.