Origins of cannabis plant, and related Q about t9 receptor

I was having a conversation w/ a acquaintance and he believed humans are suppose to have some association with this plant. He says there is a (IIRC) T9 receptor in the brain and the ONLY thing on this earth that will ‘dock’ with it is produced by cannabis. Perhaps I’ll give him the benefit of the doubt and take it as the only natural thing that would dock…

Anyway, some questions
1 - Is there a ‘pot’ receptor in the brain?
2 - Is pot the only thing that will ‘dock’ with this receptor?
3 - Are there undockable receptors in the brain, meaning a receptor we haven’t found a use for as we can’t find anything to work w/ it?
4 - If the answers to the above is basically yes, what are the chances that it is pure coincidence that pot ‘docks’ w/ these receptors?
5 - What area of the world did cannabis come from and how long were humans around before they stumbled into this area?
6 - Is there enough time for humans to ‘evolve’ this receptor when humans first came into contact with cannabis?

Hey kanicbird,

Not surprisingly, PubMed tells us that there is no such thing as a T9 receptor in the brain. Here are some answers to some of your questions:

  1. There exists a family of receptors for cannabinoids.
  2. No. Your body produces substances called endocannabinoids (such as anandamide) that signal through these receptors.
  3. Proteins of unknown function in the human body are constantly being found by bioinformatic analyses. Some of these will turn out to be receptors in the brain. However, the way in which scientists search for receptors usually means that they know the ligand (i.e. the “docking substance”) before they find the receptor.
  4. I’m not sure what you mean. Ligand-receptor interactions are usually highly specific. The chance of taking a random molecule and a random receptor, putting them together, and seeing a response, is virtually zero.
  5. Don’t know this one.
  6. The receptor evolved to respond to the endocannabinoids. It just so happens that cannabis mimics these molecules.


Cannabis sativa (Family: Cannabaceae) has been with humans for quite some time. The origin is probably somewhere in Central Asia. Marijuana is actually related to Hops (Humulus lupulus), which as any beer drinker knows is what flavors beer (the flower structures of hops looks similar to an enlarged version of the Marijuana flowers).

There are apparently three species of Cannabis:

  • C. sativa - common marijuana/hemp. This is the more economically important and useful species
  • C. indica - has a stronger THC content and has leaves that are generally wider than C. sativa. This is where Hashish is obtained.
  • C. ruderalis - a short plant that has low THC content and is useless for hemp.

All of the different types you get are simply varieties of C. sativa.

Some other info i just forgot to add:

Cannabis is also within the Nettles order (urticales). Both plants have Trichomes (hairs) which in nettles are sharp and sting you, but in C. sativa often have resin on them.

Some of the plants the order includes are: stinging nettles; mulberry, fig, and elm trees; hop vines; and the hemp, or marijuana, plant.

As a general note, there’s a big difference between:
What are the chances that a given random molecule will match a human neuroreceptor? (pretty small) and
What are the chances that at least one compound, out of all the millions of organic compounds found in non-human plants and animals, will match a human neuroreceptor? (pretty good)

In other words, the chance of any given plant getting you high is pretty small. But try enough plants and it’s not surprising if you find one that will (*Warning – if you try this personally you’ll likely find one that kills you first *). No big mystery or luck there.