Reference: The Endocannabinoid System, Cannabinoids and Pain
Perry G. Fine, M.D.1* and Mark J. Rosenfeld, M.S., Ph.D.
Pain is an unpleasant, commonly occurring, and universal human experience; it is also a very complex phenomenon. The experience of pain and the resultant emotional state depends as much or perhaps more on the contextual circumstances (how, when, where, and why) of the pain-inciting event as the intensity of the noxious stimulus. And a seemingly similar pain-producing event may be experienced (and communicated) quite differently from person to person, situation to situation, and among various cultures. The neurophysiology of acute pain due to a brief single noxious event is best understood. The nociceptive components of the peripheral and central nervous systems are highly refined to signal warnings of potential or actual tissue damage; reflex and conscious responses are usually adaptive for self-protection. Fortunately, most occurrences of pain are self-limited, resolving quickly with discontinuation of the noxious stimulus or in tandem with tissue healing or resolution of the insult to somatic or visceral structures. But pain that continues relentlessly due to on-going nociceptive stimulation from unresolved disease (nociceptive pain) or pathophysiological changes within the nervous system (neuropathic pain) serves little purpose. In contrast to acute pain, unresolved pain leads to subliminal and conscious reflex responses that are often maladaptive. CBD
Cannabinoid refers to a pharmacological class of about 60 naturally occurring compounds (phyto-cannabinoids) found in plants of the genus Cannabis (i.e. marijuana and hemp) and structur-ally related synthetic analogues (e.g. Δ3,4-tetra-hydrocannabinol and HU-210, which is 100–800 times more potent psychoactively than natural THC22). This classification has been generalized to include a wide range of exogenous and endoge-nously produced compounds that exhibit similar pharmacodynamic properties as the phytocannabi-noids or demonstrate activity at the same receptor binding sites. Cannabis sativa has two subspecies, indica and sativa. A variety of the former, hemp, has industrially and nutritionally useful qualities. Hemp has a very low amount of the psychoactive consti-tuent Δ9-tetrahydrocannabinol (THC) but higher quantities of cannabidiol (CBD)Cannabinoids and Pain