Let’s talk about neurotransmitters. Monoamine transmitters to be specific: dopamine, norepinephrine, serotonin, and histamine. These monoamines are split into three categories of amines: catecholamines, indolamines, and ethylamines. Dopamine and norepinephrine are catecholamines, serotonin is an indolamine, and histamine is an ethylamine.
All monoamine transmitters are similar in that they all contribute some level of response when an inhibitory or excitatory drug is introduced into the body and specifically targets the receptors associated with these transmitters.
Here is a further breakdown of each monoamine:
Dopamine: Dopamine can particularly influence our movements and attention focus, as well the reward/pleasure system that is often associated with dopamine influencing substances. And because dopamine can be manipulated with both antagonistic and agonistic mechanisms, various drugs have helped treat disorders ranging from behavioral issues and chronic pain to Parkinson’s Disease.
Norepinephrine: Norepinephrine, interchangeably known as noradrenalin, has its own special role as a neurotransmitter: a large portion of the brain interfaces with noradrenergic neurons. Moreover, because norepinephrine functions essentially as a hormone, therapies that target noradrenergic receptors can affect appetite regulation and influence sexual behavior.
Serotonin: Serotonin, a rather commonly known neurotransmitter – namely, the word comes up in non-academic conversations as well (for example, many people who take anti-depressants can explain that serotonin is involved) – spawns from a precursor amino acid called tryptophan and is found in many drug-related therapies. Some drugs even modulate serotonin – for instance, fenfluramine not only triggers serotonin, but also inhibits it, helping regulate mood disorders.
Histamine: Histamine, a product of histidine decarboxylase, contains histaminergic neurons that interface with the cerebral cortex. These neurons are not spread out across the brain – rather, they exist in a single area called the tuberomammillary nucleus. As any of us who have dealt with allergies know, some anti-histamine products can make you sleepy. That’s because histamine deals directly with our awake and sleep states. Thankfully, some anti-histamine products do not cause drowsiness – which, of course, is especially useful while doing school work!
Carlson, N. R. (2013). Physiology of Behavior (11th ed.). Retrieved from https://phoenix.vitalsource.com
NIMH (2015). Brain Basics. Retrieved from https://www.nimh.nih.gov/brainbasics/index.html.