[MUSIC] Okay, so we left off with action potential. So we've got a message going from one end of a cell to another end of a cell, and now we're going to get that message across to another cell through something called a synapse. But the this like, so, so getting the action potential is like I have breathed out all this air, and now I just have to form my lips to, to make sound, but in the case of the neuron. This neuron is obviously not talking in sound. It's talking in chemistry. It's talking in things like neurotransmitters. And neurotransmitters, are a list of, or a number of molecules. They serve other functions in the body, but they also serve very critical functions for the nervous system as neurotransmitters, as the things that that communicate from one neuron to another neuron. And what we're going to look at right now, is how neurotransmitters are made and how they're packaged. So this is a drawing of a cell, here's the cell body, the nucleus with the DNA, here are some mitochondria, this is the powerhouse of the cell. The endoplasmic reticulum, which is essentially the manufacturing centre of the cell where proteins are made, and then we have an axon which leads down to a synaptic terminal. And this synaptic terminal has these entities here, which are called synaptic vesicles and they're small little, organelles. They're little vesicles, they, they're made of a membrane, just like the, the cell is, has a, has a cell membrane, these vesicles have a vesicular membrane, and if we look at one of these. So it has a membrane, remember that the membrane looks something like this but we're not going to draw that all. So here's the membrane, and inside here is neurotransmitter. Is a, is a neurotransmitter. And, the neurotransmitter can be any number of of a number of different molecules. Here are just a few of them Glutamate, GABA, Serotonin, Dopamine, Acetylcholine. There's a more complete list that you can see and the only other thing I want to add is, why is this important? Why is it important? Well, first of all, it's important that the neurotransmitters are packaged in, is vesicles and that'll be important in, in a moment. The second thing that's important about this is that we can use this. We can use the synthesis of a neurotransmitter as a, as a, as a therapeutic tool. So, for instance Dopamine is missing in Parkinsons disease. It's not that dopamine isn't made per say, that's there's a problem with making it. It's that the cells that make it die. So, or, or a group of the cells that do make Dopamine die, and so what do you do about that? Well it turns out that there's something called Mass Effect which means, that you take the starting chemical. The, the, the substrate. What we call the substrate and then through a series of enzymatic Processes reaction through a series of enzymatic reactions, we end up with a neurotransmitter and in the case of Dopamine, in Parkinson's there is lack of Dopamine and what happ, what do we do to treat in most people Parkinson's. We give them the substrate, and so that is what Sinemet which is also in, in other countries called Parcopa. so, th-, these are drugs that provide a lot of this, and even if only a little bit of this gets made, much less than what you start with, it's more than what the, the person has, and it enables them, it, it alleviates their symptoms of Parkinson's. So you flood the system with substrate, and the goal is to get a little bit of that neurotransmitter out of the system. Okay. So that's how we're going to speak what's coming out of the neurons mouth, so to speak. Is not sound, but neurotransmitter. Neurotransmitter that is packaged in vesicles, and in the next segment we are going too see how. How it actually gets out of the mouth. [MUSIC]