 We've already talked a little bit about how drugs can act as agonists or antagonists for neurotransmitters, and that can be a mechanism for how a drug works. So we're going to look at a little bit general, a little bit specific. We're not going to look at specific drugs, but we're going to look at if a drug acts like an agonist. Then what are some mechanisms that it can use to do that? And if the drug acts like an antagonist, what are some mechanisms that it could use to do that? So remember an agonist is something that's going to increase the effect of the neurotransmitter, of a neurotransmitter. So if a drug is an agonist to a neurotransmitter, it's going to basically do the same thing that the neurotransmitter does, and there's several ways that this can happen. If a drug is an antagonist, it's going to decrease the effect of the neurotransmitter, and there's several ways that that can happen. Okay, let's talk about agonists first. In fact, what would be awesome is if you pushed pause and then just like brainstorm, like what are some things that a drug could do to increase the action of the neurotransmitter or to mimic the effect of the neurotransmitter? And well, dude, that's the very first one on my list is that it can basically look like the neurotransmitter. It looks and acts like, that's as like the neurotransmitter. It seems kind of obvious, but that means that it's going to bind to the proper receptor and stimulate the same response. What else can it do? An agonist could increase the neurotransmitter release. So an agonist could come in and bind to calcium channels and open up calcium channels, allow more calcium in, barf out more neurotransmitter, done. It increases the amount of neurotransmitter in there and so increases the effect of that neurotransmitter. That's an agonist action. It could also open, and this is kind of a weird one. It's even a channel that the neurotransmitter opens. So that's essentially having the same effect that the neurotransmitter has. And this is a huge one. An agonist molecule could come in and block the neurotransmitter enzyme. Now talk to me about that one. If a molecule comes in and blocks Pac-Man, what's going to happen to the neurotransmitter in the synapse? It's going to stay there. It's going to increase the drug blocked the enzyme and thereby increase the action of the neurotransmitter because it stayed in the synapse. Otherwise it would have gotten functionalized. Not a real word. Agonist actions. They're real folks, they're real. Look at these. I mean, I've said it. Did I say antagonist or agonist? I don't know. I meant antagonist actions. If an agonist opens the channel that a neurotransmitter opens, an antagonist is going to close it. Shut that door, dog. If an agonist, yeah, yeah, yeah. Let's actually look at this one. An agonist can block, think about this one, the sodium potassium pump. Does that blow your mind? What happens if the sodium potassium pump is blocked? You're not going to be able to maintain your membrane potential. And then can your neuron fire? No. And can you get neurotransmitter in the synapse if you don't get an action potential traveling down your neuron? No. I act like an antagonist. And my last one says I can block. I can block channels. I can close them and I can block them. What's the difference? Block channels or block channels? Dude, why don't we just block some channels? All right, I'll write it down. We'll block channels. How's that? A few block channels. Let's antagonize the system. Okay, we should be able to, as we go through the course, as you mess with your integration projects, you probably are going to be looking at treatments for various conditions. And one of the things, often treatments are drugs. And you should be able to identify is this drug acting as an agonist for something or an antagonist for something. Now the last thing we're going to talk about is an example of an illegal drug and some mechanisms by which it has the effect that it has.