N&PD Moderators: Skorpio
Why do humans respond to psychoactive plants?
sghouston5
Ex-Bluelighter
Do we have "opiate receptors" because we evolved on this planet with opiates and consumed them over the years, so our brains just developed an evolutionary need for opiate receptors to interact with the primary psychoactive components from poppy plants? Not the best way to describe that....but that's about the best I can do
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endotropic
Bluelight Crew
It's very hard to prove a "why" with evolutionary phenomena, but to me it makes more sense that animals evolved opiate receptors and internal opiates to help the body control our perception of pain. Later on some ancestor of the poppy by happenstance (random mutation) made a chemical that bound to and activated those opiate receptors. Animals that ate that plant would find it more enjoyable than closely related poppies that didn't make the chemical, so they would eat more of it and thus spread more of its seeds, producing a selective pressure that favored the opiate producing poppy.
That's sort of like the theory for why capsaicin (the hot shit in hot peppers) evolved - but in reverse. When land animals eat a pepper plant they only spread the seeds over a limited range, while a bird will spread the seeds much further. Apparently birds don't have the receptor that responds to capsaicin, so when some ancient pepper plant just so happened to synthesize the capsaicin chemical land animals stopped eating so much of that plant (because it hurt) while birds kept eating just as much, producing a selective pressure by allowing that plant to spread further and faster than the related peppers without capsaicin.
(calling all ethnobotonists to clarify/correct my ramblings 
)
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BlueBull
Moderator: MDMA
Interesting discussion. I have been wondering the same thing for a while now. What I find fascinating is that we have chemicals in our body that bind to these receptors (endorphins for example) but that there are chemicals naturally occurring that also bind to these receptors. I wonder if this is just a coincidence or that the evolution of these receptors is somehow related to naturally occurring opioids. I'm not entirely convinced it is a coincidence but I have nothing to base this claim on. Going to subscribe as I am curious to see what more knowledgeable bluelighters have to say about this
sghouston5
Ex-Bluelighter
FUCKING SCIENCE! I am so glad people are actually interested in this.
Back to the point though, are humans really just a sum of all the humans that have ever lived over the course of history? Are we just the genetic and mathematical products of centuries of evolution. I wonder what reaction came about when the first humans ate psychoactive plants. Did it have any effect? Did we get sick and die off and develop a tolerance? Or were we "created" and we "coincidentally" have these receptors built-in to our brains. Opiods would not work if we did not have the opiod receptors, you follow me ?
Are we really just stardust? A combination of chemical reactions that produces consciousness and everything we do is simply just a process of chemical reactions leading to actual events? It's all just so "coincidental" how the brain functions are THIS complex, even at a microcellular level.
Furthermore, we evolve based on the fact that we no longer need specific body parts to live (appendix, gallbladder, etc.)
In fact, there was a study done on why "babies dance". Yeah, if any of you have had a one year old infant and seen them dancing, evolutionists don't understand why human infants "dance" when music is on, or a show is turned on the television, because, there is no evolutionary benefit to dancing. What are you gonna do, dance in front of a predator to distract it lol ?
endotropic
Bluelight Crew
More than that, we're a sum of every human that preceded us, every homonid that preceded those humans, every primate that preceded those homonids, every mammal that preceded those primates, etc. etc.
In fact we can trace the genetic lineage of HUMAN opioid receptors further back than when jawed FISH diverged from non-jawed FISH. We can thank our ancient aquatic ancestors for those lovely little receptors.
No evolutionary benefit? Are you sure? Displays of happiness by the baby could engender happiness in the mother, making her more likely to pay attention to and care for baby - for example.
You could make the same argument for "why can baby swing his fists, he can't fight off any predators." The trait doesn't have to be useful at every point in life to convey an evolutionary benefit at some point.
For adults though - emotional displays (like dancing) are pretty important because it lets the other group members know "hey let's go interact with that happy dancing guy" or "hey let's avoid that grimacing dude with his shoulders raised - he might bite our heads off".
Humans display a lot of traits that are hard to understand from an evolutionary perspective until you consider the social pressures that govern out survival.
sekio
Bluelight Crew
How about: "because they're there"?
I think it's better to look at it the "other way" around, seeing how awesome it is that there are chemicals that happen to fit into our own receptors either by chance or whatever. I don't, for instance, think that morphine consumption was a required part of human evolution to develop opioids.
endotropic
Bluelight Crew
I came up with this thread title when I split this off from another thread, the OP's actual question was more like: from an evolutionary perspective why do humans have a receptor that responds to a plant chemical? or evolutionarily why would plants produce a chemical that activates human receptors?
I couldn't think of a succinct way of phrasing that exactly though 
4meSM
Bluelighter
I find this subject very interesting.
In addition to the reflections posted above its also interesting to consider co-evolution as something that could have influenced it. Plants also evolve to be more appealing to their consumer (us humans in that case) so maybe that could be the reason that plants who produce chemicals with a high affinity for our receptors exist today. I'm not saying this is the way that happend for all the psychoactive plants but I believe it's one of the factors.
Interesting question, but i think my answer may be unsatisfied to some.
"We dont really know..."
Actually if the questions are asked continually over other questions, you will find that
ultimately science will not provide answer to "why" questions at all. That belongs to
philosophy. sciences will answer "how" but not "why".
It is still true that in basic questions science can answer why, but as the questions got deeper,
"Why" is the things that we cant answer.
endotropic
Bluelight Crew
No disagreement here! The "why" questions (theories) are still useful though, even if you can never "prove" them right or wrong per se. Our attempts at answering those questions provide the overarching framework to direct the scientific questions we actually can answer.
For example, my theory that opium poppies developed the capability to produce opiates because it made them more attractive to local animals leads to the hypothesis that with enough time/generations a non-psychoactive poppy will lose out to its psychoactive equivalent. To test the hypothesis: buy yourself two islands (identical as possible) and wipe out all local wildlife. Repopulate both islands with two versions of the poppy: the normal psychoactive variety and a new genetically modified poppy that doesn't produce active opiates. Fill island #1 with normal mice, island #2 with mice genetically modified so that the mu opiate receptor doesn't respond to the opiates in the poppies.
The hypothesis predicts that eventually island #1 would be populated predominantly with the opiate producing poppy, whereas on island #2 you would be just as likely to find one poppy as the other. Ideally repeat with as many islands as possible
Jonneh
Bluelighter
I agree with those who have surmised that the production of psychoactive compounds evolved to act on existing receptor systems (I think we can be pretty confident of this).
What I find most intriguing is the the variety of the strategies that plants and animals adopt (via their 'choice' of which drug they produce). These speak to the specifics of the evolutionary dynamics involved and the aims (of the drug producer) that emerge therefrom. On the 'defence' front, the seemingly most crude approach, such as that of bacteria (e.g. botulinum toxin, tetrodotoxin [in bacteria in symbiosis with e.g. pufferfish]), snakes (e.g. bugarotoxin, taipoxin) and plants (e.g. picrotoxin), aims to disable, often by acting on fundamentally important targets (e.g. TTX on ion channels) and/or in a non-subtle manner (e.g. picrotoxin on GABA-A receptors compared to other GABA modulators). These organisms don't want humans anywhere near them.
Other organisms take a more subtle approach, while still clearly aiming to neutralise a threat. Deliriants like datura are aversive to (most!) consumers but they don't usually kill their target. These things aren't too keen on being eaten either, it seems. The production of opioids by opium poppies speaks to a different selection pressure, as described nicely by endotropic. They do want to be eaten.
The psychedelics, for me, though, are the most interesting case. These can be more (psilocybe mushrooms) or less (iboga root) 'clean' in their effects, but they all act in a way that tends to produce a less functional human, from their producer's point of view (distracted from mushroom eating, at least). And yet, we love them, and they seem to act on a fundamental axis of order and disorder. Their remarkable nontoxicity and long history of use to me hints at some sort of coevolution between us and them, or at least suggests we need a nuanced view of the possible range of motives a plant may have in producing these compounds, beyond defence and propagation.
chaos_destroy
Bluelighter
I find it very unlikely that plants evolve chemicals to become desirable to eat. The opposite is usually the case. These chemicals are usually pesticides.
This article discusses it
http://mentalfloss.com/article/55372/addictive-drugs-are-actually-pesticides
Jonneh
Bluelighter
Without a doubt, that is the standard model of psychotropic substance teleology (the 'mismatch' theory): the effects on drugs on the human brain are (un)fortunate by-consequences of their intended effects. Their specificity for certain receptor systems is no coincidence, because we have a lot in common with the lower order organisms that are the targets of these compounds, but the fact that morphine gives us pleasure is simply a consequence of the function of opioid receptors in humans. In other words, the evolutionary history of receptor function is a better predictor of drug production (in plants that were in close proximity to these receptors) than current function. It's a good default hypothesis.
We have all sorts of alkaloid-specific responses (genetic changes in cytochrome P450, odour detection, vomiting) which appear to be adaptive consequences of contact with them. None of this implies intention on the part of the plant, but the production of that most terrible of drugs, sugar, certainly evolved for attractive, rather than repulsive, purposes, so there is a precedent for these kinds of motives. Of course, leaves and root bark aren't seed-bearing, so the apparently supportive case of poppy pods starts to look like an anomaly. Given the long history of human use of these plants, the mismatch theory implies that, for the plant, defence against insects has outweighed increased human consumption. The evolutionary 'why?' question (why do plants produce psychoactive drugs?) has another potential contributor: favoured replication of drug-producing genes as a result of human consumption. This could be via cultivation, or some more complex interaction: going back to sugar producers, although the original selective agents were pollinators, at least for some species the variation in amount of sugar produced is better explained by likelihood of cultivation by humans.
I can't think of a specific experiment, but an extension of endotropic's islands sounds fun (and fun is good, right?).
I realise we are discussing the inverse of the OP's question, but it's kind of the same thing.
endotropic
Bluelight Crew
I really like that theory actually. I'm curious about the last paragraph in that article though:
Psychedelic chemicals lure in pollinating insects? Bees trip balls? What's going on there?
sekio
Bluelight Crew
I once read a claim that certain opioid- or sedative- producing flowers increase their "desirability" to local pollinators by basically doping them out if they choose pollinate there, reducing effective flight range.
nature is weird.
DL-ark
Bluelighter
That kind of explains why so many flavones and terpenoids are suspected to be gabaergic in some way.
sghouston5
Ex-Bluelighter
Really brings to light how we are bound to this Earth and it's conditions. We are conscious living creatures, communicating to each other in a common language on an Internet forum, pioneered by centuries of intellectual effort on the behalf of mankind, some of us in different parts of this tiny planet. This tiny planet, despite all its millions of scientific technicalities that the human race pursues through our causal deterministic nature, is but nominal in the grandest scheme. We are the products of a world that spins thousands of miles per hour, revolving around a powerful burning yellow star powered by its own nuclear fission, whose mass is so great, it keeps our dear planet in a perfect or near perfect revolution around it in every one of our calendar years. The gravity on this planet is so strong... Yet humans can defy gravity for brief moments by lifting our hands, or jumping from the ground. Our internal organs rely on the force of gravity to work and function properly, as do many of our industrial devices (water towers, hydroelectric dams, fuel pumps etc.) and many other engineering machines. Our planet is so conveniently placed in our solar system to where a miracle, a phenomenal phenomenon called life is and has been able to endure for several billion years presumably. The creatures, organisms, air, molecules, chemicals, elements, particles, etc. All are connected and all of us are made up of an atomic structure. Make of that what you will, but if you sit and think about our busy little planet, if you can imagine hovering above this little busy planet in the vacuum of space... So silently and just watch the Earth in all its ever-present glory, thinking of all that is happening out there... Each journey that every human being goes through... You can't tell me you wouldn't see life differently. There is an entire universe in your mind and your mind alone. Give it a chance and go explore it before you live too fast.
DL-ark
Bluelighter
Wow, yeah. I think the really interesting revelation is that all of earths flora and fauna have adapted over billions of years to create a perfect, ever evolving environment. Morphine, DMT, Codeine, Cocaine, Cathinone, Ibogaine, and Mescaline are all chemical compounds synthesized by plants, which are all incredibly active in uniquely amazing ways on almost all creatures of this planet. We've spent so much time together as a monolithic ecology that we have created oodles of important structural tweaks which connect each other in immense ways. Of course, we all started from the same small prokaryote floating in a sulfurous cesspool in a disgusting hot mess of a planet. But as we grew apart through mutation, we grew closer through adaptation.
On any other planet, biologically active or not, this relation to the chemicals will not exist to earthlings.
sghouston5
Ex-Bluelighter
Precisely. Why on Earth can't I meet people whom share the same philosophical and scientific ideals as I in "real life". Sigh....
