Central Sensitization Theory
The central sensitization theory emphasizes the role of a hypersensitized central nervous system as the primary driver of chronic pain rather than a repetitive localized trauma in a particular region of an individual’s body. In the case of central sensitization, the frequent pain associated with pain conditions is the result of undesirable neuroplastic changes in the actual properties of neurons within the central nervous system; in particular, the activities of pain generating neurons.1
In the human body, there are two general components to the nervous system, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS is comprised of neurons in the spinal cord and the brain while the PNS is best thought of as neurons existing in physical structure outside of the spinal cord and brain.
For pain information to reach the CNS from the PNS, there is a pathway made up of two types of pain fibers, C-fibers, and A-Delta Fibers. C-Fibers carry slower, duller pain and A-Delta fibers carry quick, sharp pain. These fibers, along with others, communicate a great deal of useful information about the external world. When they have undergone certain changes which alters the accuracy of the information they are carrying, pain perception is increased. This therefore makes them the primary targets of a botanical-based chemical approach; one that is intended to support changes that can help improve the accuracy of the information they carry.
How the Botanicals Work
The A-Delta and C-Fibers carry information thanks to the receptors embedded within. Two of the key receptors in this discussion are the capsaicin receptors and the menthol receptors, both of which have the primary responsibility of communicating pain (and temperature) information within the human body. Research has suggested that in cases of chronic pain, there is a detectable change in both receptors with regards to increased sensitivity. This is one of the reasons that the capsaicin receptors are among the most heavily researched receptors.2
With a combination of CBD, CBG, capsaicin and menthol, these two receptors are uniquely targeted to promote the restoration of normal function. In the case of the first receptor, the capsaicin receptor, capsaicinand cannabidiol (CBD) are utilized. In the latter case, the menthol receptors, it is mentholand cannabigerol(CBG).
Capsaicin and CBD
Capsaicin is an active chemical compound found within certain type of chili peppers and responsible for the heat normally experienced when eating or handling these types of peppers. Research demonstrates the ability of capsaicin to reduce pain by first activating (creating a burning sensation) and depolarizing the capsaicin receptor (depleting the nerve’s existing level of stored substance P, a neuropeptide), and then once completely depolarizing the receptor, desensitizing it to create an analgesic effect.3
To expedite neuroplastic changes at the capsaicin receptor, cannabidiol (CBD), a newly accessible, non-intoxicating compound from the hemp plant (a low-THC version of the plant Cannabis sativa L) can be used. Cannabidiol, in emerging research, has been shown to have a wide variety of beneficial effects in the human body due to its adaptogen-like influence on numerous receptors. Among those receptors is the capsaicin receptor, where CBD has been proven to exert anti-hyperalgesia benefits.4,5
Through the combined chemical inputs of capsaicin and cannabidiol, there may be both a short-term change (activation and depolarization via capsaicin) and long-term change (neuromodulation via cannabidiol) on the capsaicin receptors.
Menthol and CBG
Much like capsaicin and cannabidiol act on the capsaicin receptor in the ways described above, the menthol receptor is influenced in a similar way by menthol and cannabigerol (CBG). Menthol, an active compound found in peppermint leaves, creates the cooling sensation one experiences when ingesting it. Cannabigerol, like cannabidiol, is found within the hemp plant and has been shown to have similar diverse yet unique actions on various receptors within the human body.
In the case of menthol, the cool sensation works in a similar fashion to the heat of capsaicin to activate, depolarize and desensitize the menthol receptor. In the case of CBG, it has been shown to block & neuromodulate the menthol receptor. 6,7
While the science behind this subject is a lot more complex, the ideas presented here demonstrate not just the value of creating synergistic formulations, but the way new compounds (like those found in hemp) can be used to support and synergize those we may be more familiar with.
REFERENCES
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2750819/
2 https://pubmed.ncbi.nlm.nih.gov/12206052/
3 https://www.sciencedirect.com/topics/neuroscience/trpv1
4 https://par.nsf.gov/servlets/purl/10206894
5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340993/
6 https://www.sciencedirect.com/science/article/pii/S0960982206019701
7 https://jpet.aspetjournals.org
