Monoamine oxidase inhibitors

Monoamine oxidase inhibitors, or MAOIs, are a class of medications used in the treatment of depression, which is a mood disorder that causes a persistent feeling of sadness and loss of interest in everyday activities.

Even though the exact cause of depression is still unknown, there is some evidence that suggests it’s related to low levels of serotonin, norepinephrine, and dopamine, which are also called monoamines because they have only one amine group.

Now, monoamine oxidase inhibitors work by increasing levels of serotonin, norepinephrine, and dopamine, which helps to alleviate the symptoms of depression.

Alright, now within the brain, there are many different types of neurons, but we’re going to focus only on three: serotonergic neurons that release serotonin, noradrenergic neurons that release norepinephrine, and dopaminergic neurons that release dopamine.

Each of these neurons synthesizes and stores neurotransmitters in small vesicles, so when an action potential reaches the presynaptic membrane, these vesicles fuse with the membrane, releasing neurotransmitters in the synaptic cleft.

Serotonergic neurons release serotonin, which then binds to 5-HT2 receptors, thereby increasing neural stimulation and regulating mood, feeding, and reproductive behavior.

On the other hand, noradrenergic neurons release norepinephrine, which hooks up to norepinephrine receptors (NE receptors), boosting alertness and focus.

Lastly, dopaminergic neurons release dopamine, which binds to dopamine receptors, stimulating cognitive functions, motivation, and awakeness.

As long as there’s a high enough concentration of neurotransmitters in the synaptic cleft, the postsynaptic neurons will continue to fire.

Now, each of these presynaptic neurons has small reuptake proteins, which pump the neurotransmitters from the synaptic cleft back into presynaptic neurons.