Research: The Biology Behind Cannabinoid Control of Spasticity

Baker D et al. The Biology that underpins the therapeutic potential of cannabis based medicines for the control of spasticity in multiple sclerosis. MultipleSclerosisandRelatedDisorders (2012), doi:10.1016/j.msard.2011.11.001

Cannabis-based medicines have recently been approved for the treatment of pain and spasticity in multiple sclerosis (MS). This supports the original perceptions of people with MS, who were using illegal street cannabis for symptom control and pre-clinical testing in animal models of MS. This activity is supported both by the biology of the disease and the biology of the cannabis plant and the endocannabinoid system. MS results from disease that impairs neurotransmission and this is controlled by cannabinoid receptors and endogenous cannabinoid ligands. This can limit spasticity and may also influence the processes that drive the accumulation of progressive disability.

Glutamate is the major excitatory nerve transmitter chemical. GABA is the major inhibitory nerve transmitter chemical that down regulates glutamate activity

This study describes the role of the cannabinoid system through which cannabis acts to control excessive nerve-impulse transmission during spasticity. It starts with MSers reporting their experiences and then our experimental evidence that provided the first objective evidence to support those experiences. That was part of the equation that lead to unraveling of what the cannabinoid system does and importantly to the eventual delivery of a drug that has some benefit for the control of spasticity.

Sativex has been licenced for treatment of MS in Canada and some European Countries (UK, Spain Germany, Denmark and Sweden), but has yet to recieve NICE approval in the UK and is therefore sometimes difficult to get access to the drug.

This study also reports on future avenues that could provide the next generation of cannabis-like drugs that avoids the side-effects associated with cannabis use. It also explains how this system can be manipulated to have a potential benefitical effect in Progressive MS. A trial to test this idea is already fully recruited (600MSers) and is ongoing with the UK.

CoI: This work was undertaken by Team G. It provides a rational for and demonstrates (supported by GW pharmaceuticals) the activity of Sativex in the control of spasticity. GW pharmaceuticals had no influence on the content of the article.