Source: Independent, The (UK) Contact: http://www.independent.co.uk/ Pubdate: Sun, 19 Jul 1998 Author: Vanessa Thorpe CHEMICALS HELP BRAIN DAMAGE AFTER A STROKE Scientists at the United States National Institute of Mental Health released research results last week which show that taking cannabis could protect the brain from the damage inflicted by a stroke. The chemicals examined, known as cannabinoids, are believed to work independently of the more widely advertised euphoric effects of the cannabis plant. After experimenting in the laboratory on the brains of foetal rats, Aiden Hampson and his colleagues at the Washington-based federal institute found that some of the cannabinoids acted as a useful block to other more dangerous chemicals in the brain. These toxic neurochemicals are the ones which systematically kill cells if the oxygen supply is cut off, as, for example, the result of a blood clot leading to a stroke. Brain cells which are starved of oxygen release large amounts of glutamate, a neurotransmitter or message-carrying chemical. This overstimulates nerve cells and quickly kills them. It has already been medically established for some time that other chemicals in the group known as antioxidants can also counter this damaging activity in the brain, but Hampson's team is now suspecting that cannabinoids might prove just as, or even more, effective. The two cannabinoids which were tested on the brains of rats were cannabidiol and THC, the active ingredient in the drug that causes its psychoactive effects. It was the former, cannabidiol, which gave the scientists most cause for hope. Unlike THC, it does not cause a "high" in the patient. "This is a better candidate," said Mr Hampson, who suggests that, in the test tube at least, the substance seemed to be both potent and protective. The federal scientists' research was published in Tuesday's edition of the journal Proceedings Of The National Academy of Sciences, and the article made it clear that it is still too early to tell to what extent cannabidiol will be able to help humans. The scientists involved were also unable to confirm the idea that simply taking the drug recreationally would afford some kind of protection against brain damage in the event of a stroke. Meanwhile, less authoritative research in the States is beginning to indicate that some of the properties of cannabis might be used to help people withdraw from addictions to cocaine and heroin. Veteran American pro-cannabis campaigner Dana Beal is calling for more research to clarify the positive uses of cannabis. "This is further proof that the government has been consistently wrong to connect cannabis use with those of harder drugs. Its effects are entirely different and it may actually be possible to use it as part of a recovery from addiction," he told the Independent on Sunday. - --- Checked-by: (Joel W. Johnson)