The following is a hypothetical and extremely unrealistic dialogue between my hypothetical friend Johnny and me. The conversation takes place at a Wesleyan party and concerns Johnny's decision to snort cocaine. The reason I chose cocaine for the topic of this dialogue is because of its widespread prevalence on campus, as well as the fact that several friends of mine frequently do coke for recreational purposes.
Me. Hey Johnny, what you up to?
Johnny. Nothing much dude, just doin' some lines. You in?
Me. No Johnny, I think I'll have to pass.
Johnny. What's the problem, you broke?
Me. Well actually I've been taking this class called biopsych where I'm learning all this cool stuff about drugs and what they do to your brain, and--
Johnny. `Cause I mean I can spot you some cash if you're low on bills.
Me. Dude, are you even listening to what I'm saying?
Johnny. What? Oh my bad. What did you say you learned?
Me. Well for one thing I learned exactly how coke works in your brain.
Johnny. Really? That sounds like something I should probably know about, but I really don't know like nothing about biology and stuff.
Me. That's ok, I'd be happy to explain it to you. Ok I'll start from the basics. I'm sure you know that all electrical signals in your brain and body are carried via cells called neurons.
Johnny. Uh, right.
Me. Well the way this electrical impulse travels down the neuron is by rapidly depolarizing the cell's membrane, opening ion channels in it. When the impulse, also known as the action potential, reaches the end of the neuron, (the axon terminal), it triggers in influx of calcium ions into the presynaptic membrane.
Me. Ok I'm going too fast--a synapse is the site at which two different neurons meet. It is here that the electrical impulse is or is not transmitted to the next neuron via chemical messengers called neurotransmitters.
Johnny. Oh, I've heard of those!
Me. Good for you Johnny, good for you. As I was saying, when the calcium ions flood in, they cause these little sacs called vesicles which are filled with neurotransmitters to fuse with the membrane and release them into the area between the two neurons, called the synaptic cleft. The neurotransmitters then bind to receptors on the postsynaptic membrane of the other neuron. Once bound, these receptors, which are also ion channels, will open, allowing the inward flow of ions, which has the ability to create once again an action potential that will continue down the next neuron.
Johnny. That's great, I'm not sure I got all of it, but thanks for your enthusiasm...What does this have to do with coke again?
Me. I'm getting there Johnny my boy, patience is a virtue. You see, what cocaine does is it messes with your neurotransmitters. Do you know what an agonist or an antagonist is Johnny?
Johnny. Um, antagonists are in books and stuff...
Me. ...wow. Ok let me explain. Agonists are chemicals that enter the...