Dispelling common myths about Dopamine

Part of my favourite topics to learn about during my neuroscience degree was learning about the few neurotransmitters in the body, and the vast amount of functions that they have!

Neurotransmitters are small molecules that reside in the presynaptic neuron, that is, the neuron that precedes the synapse. As signals come down the neuron axon into its terminals, this signal also tells neurons to release neurotransmitters from their little bubbles, and into the synapse so that they can travel across to the following, or postsynaptic neuron, and start a whole cascade of signals in that neuron.

Neurotransmitters crossing the synapse. This file is licensed under the Creative CommonsAttribution-Share Alike 3.0 Unported license.

We all know the common neurotransmitters - serotonin and dopamine being the most common and known for being the "happiness hormones", however this isn't completely true.

Myth #1

First off, neurotransmitters and hormones are not interchangeable terms. While some neurotransmitters are also hormones (like epinephrine, whose release causes an "adrenaline rush"), not all neurotransmitters are hormones. It's kind of like how all squares are rectangles, but not all rectangles are squares. While they are similar in that they are both small molecules that transmit signals in the body, the biggest difference between hormones and neurotransmitters is that hormones are released from endocrine glands and travel through the blood stream, while neurotransmitters are synthesized in and released from neurons, acting only upon other neurons.

Myth #2

Second is the misnomer of dopamine being a "happiness" neurotransmitter. While serotonin does give us that feeling of happiness, dopamine does something a little bit different. It drives us to search for that happy feeling. In other words, its a reward seeking neurotransmitter.

Dopamine's chemical structure. This file is made available under the Creative CommonsCC0 1.0 Universal Public Domain Dedication.

Think about it this way - you've been neglecting to clean your room for about a week, and it's starting to get really messy. You're tired of living in the mess and know its time to clean up. Dopamine is what drives us to start the cleaning process, because we know that once it's done, we'll have a sparkling clean room. That's when the serotonin gets released and we finally feel that sensation of happiness.

This is also why dopamine is heavily involved in drug addiction - it really drives the reward seeking behaviours of drug use. But that's a whole other topic for another day!

In summary:

• Dopamine isn't a hormone, it's a neurotransmitter

• Neurotransmitters differ from hormones because of where they are made, how they get released, and the systems through which they circulate

• Dopamine doesn't give us the sensation of happiness, serotonin does, but it drives us to engage in behaviours that will lead to us feeling happy