All drugs are in our heads?

I know this might be a stupid question, but that, in part, is why I’m asking it. I was listening to this fascinating Radiolab podcast the other day, and one of the statements in there really caught my attention. Essentially the interviewee said that all of the drugs we make already exist in our heads/bodies. That’s the reason the pills we make work, because we have receptors that take in those chemicals.

This seems to make a sense to me, but I’m not a doctor. So, is it true?

The second part is true, not the first.

Drugs work, generally, because we have receptors that take in those chemicals. (depending on how we define drug that “generally” may not be unnecessary).

But it isn’t true that we already have caffeine, LSD, alcohol etc within our body, or that humans have evolved metabolic pathways specifically for these chemicals.

Depends on the drug. There are many different compounds that act as a drug in the body. Most drugs need some sort of receptor in the body to actually do anything, however, that doesn’t mean that the substance actually exsists in the body itself. There are many drugs that are antagonists and block the action of an endogenous substance, or you have agonists that activate a receptor like the endogenous substance. You also have drugs that compete with binding sites with the substance in the body.

So, drug molecules don’t normally exist already in the body, but they resemble in some way something the body responds to.

Wellllll … if you take in a substance, and your body does not have receptors that bind with that substance, then generally, the substance will simply pass right through you without any noticeable effects. (The example I get off the top of my head is accidentally swallowing a loose tooth when you’re a kid. You don’t get high off it b/c there are no receptors that bind with enamel. Sorry, weird example, I know.)

The podcast may have been referencing how people have, for example, cannabinoid receptors that very conveniently bind with cannabis. We don’t, however, already have THC floating around in our bloodstream naturally from birth or anything like that.

But we don’t have redmapleoid receptors in our brains, so no one goes around smoking the leave of red maples.

All drugs do not exist within our bodies. You may have misunderstood what was said.

Some drugs work by interacting with receptors and mimic naturally-occuring compounds the receptors were “designed” for.

Other drugs interact with enzymes; they may be molecularly similar to the ligand the enzyme normally interacts with, but not necessarily.

Everyone who has responded seems to assume that the OP referred only to psychoactive drugs (which may indeed have been the intent–I gave up mind -reading decades ago). Penicillin, for example, reacts with receptors on bacterial cells, not human cells.

Radiolab is indeed fascinating, usually in the car-wreck sort of way. They’d find a better home at the Discovery Channel, a place much more forgiving of the woo they usually broadcast.

So why is maple syrup so addictive?

…and to be picky, even the ‘receptors’ part isn’t always true. For instance, the dizzying effect of alcohol isn’t caused by any receptors that are sensitive to alcohol. It’s a purely physical effect of adding alcohol to the water-based inner ear fluid causing changes to the density, etc, of the fluid, which makes it move differently than the body is calibrated for.

Excuse me, but why haven’t we moved away from drugs…to actual electrical stimulation of the brain? This would be the solution for drug addiction-you could “dial in” the amount of stimulation you wanted, and dispense with dangerous and addictive drugs.

Because AFAIK right now the only way to do that is to drill holes in the skull. Otherwise you can’t directly stimulate the right parts of the brain. But I agree that more research should be done to move toward direct brain stimulation.

Cite for this? I had believed it was due to interference at multiple levels of the cognitive and the proprioceptive locations within the brain, rather than just futzing with the labyrinthine system.

But I’m certainly interested if it’s been demonstrated to be all in the inner ear.

What’s more elegant? Adding tailored molecules which only act on selected receptors in certain parts of the brain/body to stimulate them, or placing a wire into a general region and disrupting the electrical conduction of everything it touches?

Well, it’s possible that, like Rick in Casablanca, I was misinformed. If so, I expect to be swiftly corrected by your firm and loving hand, uh, tentacle.

Quick search, which is all I have time for now, couldn’t find anything more authoritative than wiki: http://en.wikipedia.org/wiki/Vestibular_system#Pathologies, which seems to say there is indeed a role played by alcohol concentrations affecting the physical properties of inner ear fluid (though that article can’t seem to decide whether it’s viscosity or density that’s at issue).

I certainly am not trying to say that all balance and coordination effects of alcohol are due to inner ear issues. If current thinking is that there is no contribution from the inner ear, then I eagerly await the tentacle of correction.

But if there is any contribution from the inner ear (regardless of what other pathways contribute to balance issues), then the original point stands: which is that alcohol has an effect through a pathway that doesn’t involve alcohol receptors.

Plugging steel bolts wired to 5V batteries straight into one’s brainpan does have that steampunk, orky aesthetic going for it :).

Snout. Xmex-like snout.

After consulting my sources, I find that you are indeed correct that it’s been the longstanding model that infiltration of alcohol into the endolymph of the labyrinth contributes to the vertigo of acute alcohol intoxication.

My literature reviews have shown that the chronic balance disturbances associated with prolonged alcohol use are the ones that involve more central portions of the brain.

Often these two phenomena combine, for one great trip!

Which is fine if one is just trying to re-animate dead tissue or do operant conditioning for yes/no-type behavior.

But it lacks panache (in my opinion.) Plant subtle ideas and alter behavior in myriad ways with designer molecules flitting around from frontal lobes to limbic system to the hypothalamus, that’s the ticket!

And polydactyl tongue.

Collaboration time! Do you want to write the grant proposal, or shall I?

Xymolosely polydactyl tongue. And that’s for special.