Cannabis has been used as an analgesic for thousands of years. It is about as effective as many over the counter NSAIDs and more tolerable. How cannabinoids exert this effect in the brain is relatively well understood. However, in the peripheral nervous system, it remains something of a mystery.
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This paper is a technical investigation into the role of the transient receptor potential subtype VI (TRPVI), which is an endocannabinoid receptor and known to play a key role in the “induction of thermal hyperalgesia in inflammatory pain models”, or oversensitivity to heat. The cannabinoid WIN 55,212-2 was examined in its interaction with TRPVI in Chinese hamsters.
It appears that there is a chain of reactions that imply that the cannabinoid WIN is a part of the modulation of sensory neurons via the TRPVI receptor, via a process called phosphorylation. This mechanism could be very useful for evaluating cannabinoids for their use as peripheral analgesics.
The endocannabinoid system is an important function in pain response, as well as dozens of important processes in the brain and body. It is a complex web of:
While the way that the endocannabinoid system modulates pain and pain response in the central nervous system is understood to a fairly high degree, the same is not true for its effects in the peripheral nervous system. This paper shows how cannabinoids can desensitize an important pain receptor via a system of interactions.
The TRPVI receptor is relatively famous, being known as the “spice” receptor because it is affected by capsaicin, the chemical in spicy food that makes them taste “hot”. It is a sensory receptor and is vital for not just heat perception but other forms of sensory input.
Here, it is demonstrated for the first time the cannabinoid receptor TRPVI being affected by the cannabinoid WIN 55,212-2, altering the way that it works and resulting in a change in the way that pain signals are relayed to the central nervous system. The result is desensitization or a reduction in the pain signals being sent to the brain.
This is good news because peripheral nervous system analgesics are relatively rare and because the use of cannabinoids is regarded as safe, there can be new generations of cannabinoid-based analgesics developed.
Analgesics that affect the peripheral nervous system but not the central nervous system are very useful for topical analgesia or numbing specific areas. Peripheral inflammatory hyperalgesia is a serious condition that debilitates thousands of people by making them oversensitive to painful stimulus.
It causes inflammation and tissue damage, which can be extremely painful and debilitating. WIN has the potential to be a relatively safe treatment for reducing this sensitivity and allowing people to have healthier, more enjoyable lives.
The mechanism by which cannabinoids interact with the “spice” receptor, TRPVI, is now partially understood. Because it is a peripheral analgesic, the cannabinoid WIN 55,212-2 has potential applications not just in treating peripheral inflammatory hyperalgesia but also other forms of localized pain and inflammation without necessarily producing central nervous system effects.