Your brain on drugs
Oct. 25th, 2005 01:58 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
zdashamberI just sat in on a lunch talk meant for administrators where someone finally explained brain/drug stuff on very basic terms. Which is great. I studied genetics. I can explain DNA/gene stuff in mindblurring detail... But this anatomy of the brain stuff was completely uncovered in my classes. It's really nifty... I'm going to talk about drugs here, though.
So, basically, your mind is a creation of a bunch of neurons connected one to the next. The patterns of the circuits form thoughts and plans and memories and so forth.
A neuron looks sort of like a tree, with a bunch of inputs at the roots and a bunch of outputs at the tips of the branches, except each branch tip touches the root of another neuron. Or nearly so, there's a tiny little gap there, called the synaptic cleft. When a neuron has a signal to send, it spits out a neurotransmitter at the synaptic cleft. Neurotransmitters are a class name for these little molecules, some of the more popularly known of which are dopamine, serotonin, and endorphin. Each neuron can spit out only one kind of neurotransmitter, so you have dopamine neurons, serotonin neurons, etc. They create these neurotransmitters and leave them hanging around in little pockets to call on when they're needed, much like Bush's FEMA doesn't.
The sending neuron spits out the neurotransmitter, it rattles around in the tiny space of the synaptic cleft, and eventually it runs into the receptor on the receiving neuron. Once a lot of these receptors are full, the receiving neuron says, "oho, something's afoot," and fires an electrical burst throughout itself, from root to tip. Once the electrical burst hits the tip, the pockets of neurotransmitter hanging around there are summoned and spit forth into the synaptic cleft, and the next batch of neurons gets the signal.
Some chemicals enhance the amounts of a specific neurotransmitter in the synapse, so the receiving neuron gets more signal and fires more. If many of these neurons are in circuits related to reward or anti-anxiety or vision, this means more good feelings/peace/hallucinations. Thus, "drugs of abuse."
Cocaine: so, the neurotransmitters are released (in cocaine's case, dopamine), they find their receptors, and then they are in some cases kicked off their receptors. Also, some never find their receptors. But you don't want them finding their receptors seconds after it's right to send the signal, and also, it's expensive to make them. So they're recycled. The sending neuron has some transporters that suck them up again, swapping a hydrogen ion out to get a dopamine molecule in, repackaging it so it's ready to go again.
The cocaine molecule latches on to the dopamine transporters and blocks dopamine from using them. So dopamine is left to rattle around in the synaptic cleft, setting off the receiving cell again and again.
Heroin, LSD, pot, nicotine, pretty much everything else: these are all molecules that look somewhat like some specific neurotransmitter: enough so that they can fit into the receptors on the receiving neuron and set them off.
However: Meth, amphetamine, and ecstacy: these guys work by reversing the transporters. So the transporters take hydrogen ions into the sending neuron, and dump serotonin (and others, for meth and amphetamine) out into the synaptic cleft. Trouble is, hydrogen ions are what make an acid. You get a high enough concentration into a place, and it will burn like you dropped hydrochloric acid onto it. So E will literally burn out the serotonin neurons, leaving a brain with broken circuits and no way to get serotonin.
So: other drugs, can make you do stupid things; can strengthen circuits wrongly in your brain. But they don't actually do brain damage.
At least, that's the way I heard it from a scientist who wasn't on purpose lying for the government.
So, basically, your mind is a creation of a bunch of neurons connected one to the next. The patterns of the circuits form thoughts and plans and memories and so forth.
A neuron looks sort of like a tree, with a bunch of inputs at the roots and a bunch of outputs at the tips of the branches, except each branch tip touches the root of another neuron. Or nearly so, there's a tiny little gap there, called the synaptic cleft. When a neuron has a signal to send, it spits out a neurotransmitter at the synaptic cleft. Neurotransmitters are a class name for these little molecules, some of the more popularly known of which are dopamine, serotonin, and endorphin. Each neuron can spit out only one kind of neurotransmitter, so you have dopamine neurons, serotonin neurons, etc. They create these neurotransmitters and leave them hanging around in little pockets to call on when they're needed, much like Bush's FEMA doesn't.
The sending neuron spits out the neurotransmitter, it rattles around in the tiny space of the synaptic cleft, and eventually it runs into the receptor on the receiving neuron. Once a lot of these receptors are full, the receiving neuron says, "oho, something's afoot," and fires an electrical burst throughout itself, from root to tip. Once the electrical burst hits the tip, the pockets of neurotransmitter hanging around there are summoned and spit forth into the synaptic cleft, and the next batch of neurons gets the signal.
Some chemicals enhance the amounts of a specific neurotransmitter in the synapse, so the receiving neuron gets more signal and fires more. If many of these neurons are in circuits related to reward or anti-anxiety or vision, this means more good feelings/peace/hallucinations. Thus, "drugs of abuse."
Cocaine: so, the neurotransmitters are released (in cocaine's case, dopamine), they find their receptors, and then they are in some cases kicked off their receptors. Also, some never find their receptors. But you don't want them finding their receptors seconds after it's right to send the signal, and also, it's expensive to make them. So they're recycled. The sending neuron has some transporters that suck them up again, swapping a hydrogen ion out to get a dopamine molecule in, repackaging it so it's ready to go again.
The cocaine molecule latches on to the dopamine transporters and blocks dopamine from using them. So dopamine is left to rattle around in the synaptic cleft, setting off the receiving cell again and again.
Heroin, LSD, pot, nicotine, pretty much everything else: these are all molecules that look somewhat like some specific neurotransmitter: enough so that they can fit into the receptors on the receiving neuron and set them off.
However: Meth, amphetamine, and ecstacy: these guys work by reversing the transporters. So the transporters take hydrogen ions into the sending neuron, and dump serotonin (and others, for meth and amphetamine) out into the synaptic cleft. Trouble is, hydrogen ions are what make an acid. You get a high enough concentration into a place, and it will burn like you dropped hydrochloric acid onto it. So E will literally burn out the serotonin neurons, leaving a brain with broken circuits and no way to get serotonin.
So: other drugs, can make you do stupid things; can strengthen circuits wrongly in your brain. But they don't actually do brain damage.
At least, that's the way I heard it from a scientist who wasn't on purpose lying for the government.
no subject
Date: 2006-04-27 09:02 am (UTC)It's rather interesting that SSRI's do with serotonin what cocaine does with dopamine, in a sort of slow, spread-out way (but then I'm pretty sure the usual serotonin cycle is more slow and spread out than the usual dopamine cycle -- I don't feel like prying through excerpts and abstracts right now, but I know most of the drugs that play with dopamine have shorter durations than those which alter serotonin processing. Yep -- a search on the duration of cocaine shows that it's similar to the duration of caffeine, while both MDMA (illegal) and 5-HTP (legal, used as antidepressant, serotonin precursor) last roughly six hours.