E mais: tudo que dizem que não presta, presta! e agora? "THC joins nicotine, alcohol and caffeine as agents that, in moderation, have shown some protection against inflammation in the brain that might translate to better memory late in life. "
2008/11/20 Oswaldo Ribeiro <[EMAIL PROTECTED]> > > > ---------- Forwarded message ---------- > From: Robert Karl Stonjek <[EMAIL PROTECTED]> > Date: 2008/11/20 > Subject: [Mind and Brain] News: Scientists are high on idea that marijuana > reduces memory impairment > To: Mind and Brain <[EMAIL PROTECTED]>, Psychiatry-Research < > [EMAIL PROTECTED]> > > > *Scientists are high on idea that marijuana reduces memory impairment* > ** > > *The more research they do, the more evidence Ohio State University > scientists find that specific elements of marijuana can be good for the > aging brain by reducing inflammation there and possibly even stimulating the > formation of new brain cells. > * > The research suggests that the development of a legal drug that contains > certain properties similar to those in marijuana might help prevent or delay > the onset of Alzheimer's disease. Though the exact cause of Alzheimer's > remains unknown, chronic inflammation in the brain is believed to contribute > to memory impairment. > > Any new drug's properties would resemble those of tetrahydrocannabinol, or > THC, the main psychoactive substance in the cannabis plant, but would not > share its high-producing effects. THC joins nicotine, alcohol and caffeine > as agents that, in moderation, have shown some protection against > inflammation in the brain that might translate to better memory late in > life. > > "It's not that everything immoral is good for the brain. It's just that > there are some substances that millions of people for thousands of years > have used in billions of doses, and we're noticing there's a little signal > above all the noise," said Gary Wenk, professor of psychology at Ohio State > and principal investigator on the research. > > Wenk's work has already shown that a THC-like synthetic drug can improve > memory in animals. Now his team is trying to find out exactly how it works > in the brain. > > The most recent research on rats indicates that at least three receptors in > the brain are activated by the synthetic drug, which is similar to > marijuana. These receptors are proteins within the brain's endocannabinoid > system, which is involved in memory as well as physiological processes > associated with appetite, mood and pain response. > > This research is also showing that receptors in this system can influence > brain inflammation and the production of new neurons, or brain cells. > > "When we're young, we reproduce neurons and our memory works fine. When we > age, the process slows down, so we have a decrease in new cell formation in > normal aging. You need those cells to come back and help form new memories, > and we found that this THC-like agent can influence creation of those > cells," said Yannick Marchalant, a study coauthor and research assistant > professor of psychology at Ohio State. > > Marchalant described the research in a poster presentation Wednesday > (11/19) at the Society for Neuroscience meeting in Washington, D.C. > > Knowing exactly how any of these compounds work in the brain can make it > easier for drug designers to target specific systems with agents that will > offer the most effective anti-aging benefits, said Wenk, who is also a > professor of neuroscience and molecular virology, immunology and medical > genetics. > > "Could people smoke marijuana to prevent Alzheimer's disease if the disease > is in their family? We're not saying that, but it might actually work. What > we are saying is it appears that a safe, legal substance that mimics those > important properties of marijuana can work on receptors in the brain to > prevent memory impairments in aging. So that's really hopeful," Wenk said. > > One thing is clear from the studies: Once memory impairment is evident, the > treatment is not effective. Reducing inflammation and preserving or > generating neurons must occur before the memory loss is obvious, Wenk said. > > Marchalant led a study on old rats using the synthetic drug, called > WIN-55212-2 (WIN), which is not used in humans because of its high potency > to induce psychoactive effects. > > The researchers used a pump under the skin to give the rats a constant dose > of WIN for three weeks – a dose low enough to induce no psychoactive effects > on the animals. A control group of rats received no intervention. In > follow-up memory tests, in which rats were placed in a small swimming pool > to determine how well they use visual cues to find a platform hidden under > the surface of the water, the treated rats did better than the control rats > in learning and remembering how to find the hidden platform. > > "Old rats are not very good at that task. They can learn, but it takes them > more time to find the platform. When we gave them the drug, it made them a > little better at that task," Marchalant said. > > In some rats, Marchalant combined the WIN with compounds that are known to > block specific receptors, which then offers hints at which receptors WIN is > activating. The results indicated the WIN lowered the rats' brain > inflammation in the hippocampus by acting on what is called the TRPV1 > receptor. The hippocampus is responsible for short-term memory. > > With the same intervention technique, the researchers also determined that > WIN acts on receptors known as CB1 and CB2, leading to the generation of new > brain cells – a process known as neurogenesis. Those results led the > scientists to speculate that the combination of lowered inflammation and > neurogenesis is the reason the rats' memory improved after treatment with > WIN. > > The researchers are continuing to study the endocannabinoid system's role > in regulating inflammation and neuron development. They are trying to zero > in on the receptors that must be activated to produce the most benefits from > any newly developed drug. > > What they already know is THC alone isn't the answer. > > "The end goal is not to recommend the use of THC in humans to reduce > Alzheimer's," Marchalant said. "We need to find exactly which receptors are > most crucial, and ideally lead to the development of drugs that specifically > activate those receptors. We hope a compound can be found that can target > both inflammation and neurogenesis, which would be the most efficient way to > produce the best effects." > > Source: Ohio State University > http://www.physorg.com/news146320102.html > Posted by > Robert Karl Stonjek > > > > > -- > ÿØÿà > > Ørf > > "Não mostre para os outros o endereço eletrônico de seus amigos. Use Cco ou > Bcc (cópia oculta) > > Retire os endereços dos amigos antes de reenviar. Dificulte a disseminação > de vírus, spams, hoaxes e banners." > > -- ÿØÿà Ørf "Não mostre para os outros o endereço eletrônico de seus amigos. Use Cco ou Bcc (cópia oculta) Retire os endereços dos amigos antes de reenviar. Dificulte a disseminação de vírus, spams, hoaxes e banners."
