Medical cannabinoids can reduce pathological tremors by turning on astrocyte cells
Although the use of cannabinoids in medical practice has gained popularity in recent years, their use is surrounded by controversies regarding their safe administration, adverse effects and the lack of therapeutic indications due to limited clinical research.
Cannabinoids are compounds present in the plant Cannabis Sativa and also produced by our central nervous system where they act on specific cannabinoid receptors located in different brain cells.
The effects of cannabinoids in the brain are known mainly for their impact on neurons responsible for memory and cognitive abilities. But a new study published in Nature Neuroscience earlier this year focused on the effect of cannabinoids on another brain cell, that among other functions govern synaptic transmission for signalling between neurons — the so called astrocytes
In this study, scientists at the University of Copenhagen showed that the cannabinoid WIN55,212-2 — a synthetic analogue of THC the primary active compound in Cannabis Sativa — reduced pathological tremors when injected in the spinal cord of an animal model of essential tremor.
Essential tremor is a neurological disorder that causes involuntary and rhythmic shaking and is the most common movement disorder in humans, affecting around 4% of people over 40 years of age. Some other pathological tremors are associated with motor disorders, multiple sclerosis, stroke, neurodegenerative diseases and traumatic brain injury. Patients of some of these disorders have reported a reduction of tremor symptoms by using cannabinoid-containing drugs.
A switch to turn off electrical impulses
Tremors are triggered when the spinal cord's motor neurons, activated by electrical impulses send conflicting messages to their connecting muscles leading to involuntary contraction and movement.
By measuring the electrical cell activity in the spinal cord´s region responsible for the movement of the limbs, the team demonstrated that cannabinoids activate astrocytes. This activation leads to the release of adenosine, a molecule that turns off the synaptic transmission and dampens nerve activity
Adenosine has the opposite effect of caffeine, when we drink a lot of coffee we experience the opposite of slowing down neuronal activity. Adenosine then acts as a moderator in this neuronal conversation.
Turning down these electrical messages transmitted between neurons, specifically, in the spinal cord reduced the undesired shaking in the animal model of essential tremor.
Targeted use of cannabinoids could reduce undesired effects
The fact that cannabinoids-activated astrocytes act as interlocutors in this electrical conversation between neurons is an entirely new avenue to understanding the medical effects of Cannabis Sativa.
This study opens up the possibility of new approaches in using medical cannabis for treatment of tremors by targeting astrocytes in the spinal cord. With this approach, the potential adverse effects of medical cannabinoids can be avoided.
As of today, there is one ongoing clinical trial that will use cannabis in an oral capsule to treat essential tremor. This clinical trial will be the first double-blind, placebo-control clinical trial of cannabis.
However, other clinical trials are required to determine if the approach of targeting astrocytes in the spinal cord has the same beneficial effect on patients suffering from pathological tremors.
This study has inspired the following poem:
