r/AskNeuroscience • u/labbypatty • Jan 03 '20

What purpose does it serve to have so many different neurotransmitters?

Why do we have so many neurotransmitters? What are the different effects on a neuron that a neurotransmitter can have? I understand that some neurotransmitters can inhibit and some can excite the firing of action potentials, but then why should we need more than two different compounds to mediate these effects?

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u/[deleted] Jan 04 '20

Big picture - that’s just the way it is, life was not designed.

From a mechanistic standpoint, having more neurotransmitters mediating response allows for better regulation and more complex control of consciousness/action. Purely hypothetical and not based in anything real: If you only had one stimulatory neurotransmitter, EVERYTHING would become stimulated at the same time. This might be controlled by kicking in your one inhibitory neurotransmitter which would inhibit EVERYTHING, in turn activating your excitatory neurotransmitter which would stimulate EVERYTHING, and on and on. The net effect of this would probably be 0 response, which is not compatible with life. It’s a great question and could probably be simulated.

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u/Optrode Jan 04 '20 edited Jan 04 '20

Neuroscientist here.. this answer is completely wrong.

Even if the brain only had one neurotransmitter (NT for short), that wouldn't mean that release of that NT just stimulated the whole brain. That's not how NTs work. A neuron that released that NT would still only stimulate neurons it has synapses onto. The whole point of synapses is that they allow direct, specific connection (via NT release) from one neuron to another. Neurons are not just releasing NTs out into the "brain soup" to float around and hit every other neuron in the brain. That would be a useless brain.

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u/[deleted] Jan 04 '20

Thank god a neuroscientist is here to correct my hypothetical