CBD and THC: differences between the 2 great cannabinoids

CBD and THC are the two most abundant cannabinoids found in Cannabis. Plants, cannabidiol (CBD) and tetrahydrocannabinol (THC) are by far the two most studied.

Nervous system

The action of cannabinoids in our body occurs mainly through their interaction with the Endocannabinoid System, a complex vital signaling system that is responsible for regulating a variety of functions, including:

• Pain
• Appetite
• Humour
• Memory
• Immune response
• Sleep
• Among others

The physiological action of these two cannabinoids is similar to that of the endocannabinoids (those that are produced by the body itself), stimulating not only the cannabinoid receptors but also a series of other fundamental receptors for the proper functioning of the organism. Each cannabinoid, regardless of origin, has a specificity in relation to which receptor it can activate – or inactivate. Therefore, the composition of medicinal cannabis products must be carefully chosen for each clinical condition.

Below, we compare some aspects of the two cannabinoids:

Psychoactivity

• THC . This cannabinoid exerts this effect through the activation of type 1 cannabinoid receptors, or simply CB1, located mainly in the central nervous system. THC also activates type 2 cannabinoid receptors, or CB2, which are directly related to immune activity, as this receptor is mainly located in structures of the immune system.
• CBD, on the other hand, does not have the same interaction profile with these receptors. Studies show that its affinity for cannabinoid receptors is low, and it can behave as what we call a negative allosteric modulator of the CB1 receptor. This means that, by interacting with the receptor responsible for the famous "cheap", CBD reduces the physiological effect of activation of this receptor by a ligand such as THC. Thus, in addition to not causing the known effects related to the adult use of the plant, CBD also modulates the effects of THC.

It is worth saying that both are psychoactive; after all, both act on the central nervous system. The correct term to differentiate them is to say that THC is psychotomimetic; that is, it triggers effects similar to a state of psychosis, and CBD is not.

THC and CBD come from marijuana or hemp?

• To answer this question, we first need to understand that both names refer to a single species: Cannabis sativa L. Hemp is the term used to designate plants with a low concentration of THC. Some countries adopt laws to classify plants that do not have the potential to cause the effects associated with adult cannabis use.
• This is possible because some plants have such low levels of THC that, if consumed, they will not have this effect. Countries generally adopt a concentration limit of 0.3% THC so that cannabis plants can be classified as hemp.
• CBD and THC are found in greater amounts in the plant's flowers. However, some clinical conditions call for higher levels of CBD, so plants have been developed that have higher levels of this cannabinoid.
• For decades, the plant has been manipulated and selected for the specific purpose of increasing the concentration of a cannabinoid of interest, and this was mainly by seeking higher levels of THC to produce stronger effects. The concentration of THC in the plant can reach up to 30% of the dry weight of its inflorescences, and the average is currently expected to be above 12% based on this 2016 study.
• With the discovery of the properties of CBD, crosses and selections started to be made looking for higher levels of this cannabinoid as well, and plants with a percentage higher than 20% in dry weight can be found.
  

Distinct molecular structures

CBD and THC are considered structural isomers; As mentioned above, THC can partially activate CB1 and CB2 receptors, while CBD does not have the capacity to activate these receptors, acting as a negative allosteric modulator mentioned above or even a weak antagonist.

Interaction with other receivers

Much has been discussed about the real affinity of these components with cannabinoid receptors, but it is important to emphasize that the action of these substances is not limited only to these specific receptors.

• Cannabinoids are considered "promiscuous molecules". 5-HT1A, 5-HT2A, 5-HT3A), dopaminergic (D2), opioid (μ, δ), atypical cannabinoid receptors (GPR18, GPR55), transient potential receptor channels (TRPVs 1 to 4, TRPA1, TRPM8) among many others.
  It is through this myriad of possibilities that cannabinoids act in the maintenance of our organism's homeostasis, that is, in the maintenance of a state of "balance".
• An interesting scientific article that discusses the pharmacological targets of phytocannabinoids in detail can be found
• CBD and THC are considered structural isomers; that is, they share the same molecular formula (C21H30O2), but their "atomic arrangement" is slightly different.
• Although at first, this difference goes almost unnoticed, it is enough for completely different pharmacological effects to be provoked. As mentioned above, THC can partially activate CB1 and CB2 receptors, while CBD does not have the capacity to activate these receptors, acting as a negative allosteric modulator mentioned above or even a weak antagonist.
• It is through this myriad of possibilities that cannabinoids act in the maintenance of our organism's homeostasis, that is, in the maintenance of a state of "balance".
• An interesting scientific article that discusses the pharmacological targets of phytocannabinoids in detail can be found here.