Alright, so one thing to note about neurotransmitters is that they're not all necessarily going to bind to receptors on the postsynaptic neuron. Sometimes we end up with basically just leftover neurotransmitters kind of hanging out in that synapse, and we want to keep that synapse nice and clean for two main reasons. First, we don't want to sustain that signal for longer than necessary, and second, we want to keep that synapse nice and clean so that our next message can come through uninterrupted. So, leftover neurotransmitters are going to be removed from the synapse through a few different mechanisms, and we are going to go over each of them just very briefly for you. So the first mechanism is quite simple; it is called diffusion, and this is when neurotransmitters literally just drift or diffuse out of the synapse and into the extracellular space.

So, they basically just kind of float away, so it looks something like this. They are just diffusing out of that synapse. So, that one is nice and easy. All right. So, our next one is called degradation, and this is when a chemical reaction basically breaks neurotransmitters down.

So basically, some little enzymes come and literally just kind of break the neurotransmitters into tinier pieces in the synapse. So that looks a little bit something like this. Some little purple enzymes are coming and just breaking apart those neurotransmitters. You don't have to know what type of enzymes they are or anything like that, just know that it involves breaking the neurotransmitters down. And then finally, we have reuptake, and this is arguably the most important one for you to remember because this is a mechanism that some psychopharmacological treatments are going to be using, and you'll learn about those a little bit later in the course.

But reuptake is when neurotransmitters are basically reabsorbed back into the presynaptic terminal. So they basically get sucked back up by the neuron that originally released them, kind of like recycling. So it looks a little something like this. You can see how they're kind of going back up into that presynaptic neuron and then they can get used again. So again, it's very efficient, basically recycling.

Alright. So those are some of the mechanisms that we use to get neurotransmitters out of that synapse, and I will see you guys in our next video. Bye-bye.