Cannabinoids might reduce spasticity in multiple sclerosis

Cannabinoids, the active ingredients found in marijuana, may help control the tremors and muscle spasticity experienced by patients with multiple sclerosis, says a new study (Nature 2000;404:84-7).

Growing marijuana for medical use: cannabis may help to reduce tremors in patients with multiple sclerosis (AU PHOTO?RANDI LYNN BEACH)

Researchers examined mice with chronic relapsing experimental allergic encephalomyelitis, an autoimmune disease which has symptoms considered to be closely related to those of multiple sclerosis.

The animals were given synthetic cannabinoid compounds, and then the frequency with which their limbs became spastic was measured. When the cannabinoids were given, tremors and spasticity improved within minutes, and often the symptoms did not return for hours.

The compounds injected into the mice stimulated cannabinoid receptors on the surface of nerve cells. This indicates that the receptors are involved in regulating muscle tone, according to David Baker of University College London, who is lead author of the study.

The symptoms were not eased merely by the sedative effect of cannabinoids, since some of the compounds do not bind with the receptor known to be responsible for the euphoria associated with marijuana. Other signs of sedation, such as a drop in body temperature, also were not found, Dr Baker said.

The benefit of cannabis in treating some of the symptoms associated with multiple sclerosis has been supported by small clinical studies, many of which had non-quantifiable outcomes.

"Although not a cure, our research suggests that cannabinoids can play a crucial role in controlling some of the neuro-muscular problems seen with [multiple sclerosis]," said Dr Baker.

Scott Gottlieb, New York


studentBMJ 2000;08:89-130 April ISSN 0966-6494