What are endocannabinoids?
Endocannabinoids are cannabinoid molecules produced in the human body; the unshortened version is “endogenous cannabinoid”. These include anandamide (AEA) and 2-arachidonoylglycerol (2-AG). Both AEA and 2-AG are agonists of CB1 receptors, but 2-AG is equally potent at CB2 as well. These are the receptors found in the human body that bind to endo- and phyto- cannabinoids and mediate their respective physiological effects. CB1 receptors are found primarily in the brain, and CB2 is located throughout the immune system. CB1 is actually the most numerous receptor expressed in the human brain, and it is believed that both receptor types serve major roles in homeostasis and biofeedback mechanisms.
For example, CB1 receptors in the brain take part in what’s called retrograde signalling. In general, a brain signal is fired from one neuron to a second neuron, and the signal is carried by neurotransmitters across a tiny gap between the two neurons called a synapse. The neuron that fired the signal is called the presynaptic neuron, and the receiving neuron is the postsynaptic cell. Retrograde signalling occurs after the main signal is sent, when the postsynaptic neuron releases cannabinoids to signal the presynaptic neuron to either release more or less of the primary neurotransmitter, such as dopamine or serotonin. All of the cannabinoids have a slightly different effect on this system, and those effects can compound one another to produce truly revolutionary therapeutic effects with negligible side-effects.
2-arachidonoylglycerol (2-AG) is one of the two primary endocannabinoids found in humans. It is a full agonist of both CB1 and CB2 receptors, and it is one of the most abundant neurotransmitters found in the brain. In addition, it appears to be a key mediator in many different immune system processes, including the activation of B- and T-cells, and the secretion of different cytokines and immune recruiting hormones. 2-AG also plays a role in appetite and satisfaction. The levels of both endocannabinoids are inversely correlated with the presence of leptin, which is a hormone that can be thought of as “the feeling of being full.” This means less endocannabinoids, less hunger. The delicate balance between the two ECs plays a role in the delicate balance of hunger and satiety.
Anandamide/N-arachidonoylethanolamine (AEA) is considered the bliss molecule, as its name is taken from the sanskrit word for bliss or ecstasy. This study suggests that 2-AG is competitively antagonized by anandamide, which would help to define more clear cut roles for the two of these compounds in the processes of homeostasis. If anandamide and 2-AG are both battling for the same receptor spot, and they both carry out essentially the same function, but to varying degrees, then a regulation of their effects will take place.
There are several other less well-known endocannabinoids, and as more research is conducted into their nature and purpose, more and better treatments will arise for all sorts of conditions.