Hey GMT, I'm going to be covering a lot of that in the next post. As I've not had nearly as much time as I'd originally planned I've only really had time to write up the brief introduction you see above but to answer your questions:
- Yes, each cannabinoid has a different affinity for each receptor but I haven't seen anything suggesting that one may activate CB1 without being able to activate CB2. As to the precise affinity, this can vary from individual to individual due to single nucleotide polymorphisms (SNPs) in the genome of each individual. I've not had time to look into SNPs in cannabinoid receptors but presumably there is a fair bit of variation there.
- The functions can vary so much that I'm not even going to try and answer it fully here but suffice to say the effects range from immune cell activation to the regulation of short term plasticity in neurons and from promoting cell replication to encouraging apoptosis...
I'll add a bit more about SNPs because they're actually pretty important to understand:
Evolution is driven by evolutionary pressures, generally affecting those that allow an organism to mature and reproduce successfully and not a whole lot else. When people think of mutations they generally either think of tentacles or turtles however most are far more subtle than this. A mutation is generally a change in a single base in the entirety of the genome and, if this occurs in a germ-line cell (eggs/sperm/pollen), can be passed on to offspring. Provided this mutation does not result in a non-sense protein (Remember DNA -> mRNA -> Protein) or some other catastrophic mishap, there is no pressure to remove the mutation from the genepool. The result of this is a huge variation between the various proteins expressed by individuals which, whilst they affect the ability to, say, process various foods or get over a bad mood/habit or how quickly you can learn something, do not affect the overall ability of the individual to survive and reproduce in a natural setting.
As you can imagine, most of the enzymes (proteins!) involved drug-activated pathways or what have you, are not very sensitive to evolutionary pressures at all. Whilst a completely failure of the cannabinoid system in your body may be pretty catastrophic (i.e. fatal - http://www.pnas.org/content/96/10/5780.full), the ability of your body to be influenced by a foreign psychoactive substance is not really going to stop you breeding.
- Yes, each cannabinoid has a different affinity for each receptor but I haven't seen anything suggesting that one may activate CB1 without being able to activate CB2. As to the precise affinity, this can vary from individual to individual due to single nucleotide polymorphisms (SNPs) in the genome of each individual. I've not had time to look into SNPs in cannabinoid receptors but presumably there is a fair bit of variation there.
- The functions can vary so much that I'm not even going to try and answer it fully here but suffice to say the effects range from immune cell activation to the regulation of short term plasticity in neurons and from promoting cell replication to encouraging apoptosis...
I'll add a bit more about SNPs because they're actually pretty important to understand:
Evolution is driven by evolutionary pressures, generally affecting those that allow an organism to mature and reproduce successfully and not a whole lot else. When people think of mutations they generally either think of tentacles or turtles however most are far more subtle than this. A mutation is generally a change in a single base in the entirety of the genome and, if this occurs in a germ-line cell (eggs/sperm/pollen), can be passed on to offspring. Provided this mutation does not result in a non-sense protein (Remember DNA -> mRNA -> Protein) or some other catastrophic mishap, there is no pressure to remove the mutation from the genepool. The result of this is a huge variation between the various proteins expressed by individuals which, whilst they affect the ability to, say, process various foods or get over a bad mood/habit or how quickly you can learn something, do not affect the overall ability of the individual to survive and reproduce in a natural setting.
As you can imagine, most of the enzymes (proteins!) involved drug-activated pathways or what have you, are not very sensitive to evolutionary pressures at all. Whilst a completely failure of the cannabinoid system in your body may be pretty catastrophic (i.e. fatal - http://www.pnas.org/content/96/10/5780.full), the ability of your body to be influenced by a foreign psychoactive substance is not really going to stop you breeding.
I don't think you'd take another hit/breath again
) and release of the endocannabinoid from the cell membrane into the extracellular matrix. As you can see from the generalized 'effects', it's really not fully understood precisely what is happening.
