Double Trouble
Although marijuana advocates continue to bang the drum that this drug in not problematic we keep getting more and more research that there are significant issues that we need to pay attention to.
The largest group that is using marijuana are adolescents so any negative impact on brain function is of particular concern.
This new Ottawa study shows that Marijuana impairs the brain by acting on two types of brain cell at once, and the implication, the lead researcher says, is that there's another side to the brain that neuroscientists hadn't realized.
For the past century, the accepted theory was that marijuana acted on neurons to impair working memory. Working memory is the system of holding on to information so that the brain can think about it and make decisions without being distracted.
For instance, it allows a person to drive a car, listen to the radio, think about what will happen at the end of the car ride and watch for pedestrians all at once. Marijuana impairs working memory, an effect that can last for a day or more after heavy pot-smoking. This should raise further concern and further awareness that driving or operating equipment when using this drug on a regular basis is a bad idea.
Xia Zhang and his team, at the Royal Ottawa Mental Health Centre, have found that there is more to this impairment than interference with neurons. Pot's psychoactive chemical, THC, also acts on a second type of brain cells called astroglial cells.
"Glial cells make up 90 per cent of the brain cells," Zhang said, "whereas neurons only make up 10 per cent." The various types of glial cells have always been seen as having a support role, nourishing and otherwise helping the neurons so that the neurons can do the real brain work, he said. But his study showing that glial cells have a role in memory opens up the possibility that they are far more involved in neuron-like work than anyone had realized.
The study is published in the research journal Cell. The co-author is Giovanni Marsicano, a scientist at France's national health research institute, INSERM. It's likely that brain research will now broaden to explore the roles that glial cells may have in a wide variety of brain functions, he said. Zhang is also on the faculty of the University of Ottawa.
At one of the schools I was working at this week one of the kids was quite proud that she knew lots of rig workers that smoked marijuana all the time and knew how to beat their drug tests... knowing that marijuana slows down memory and processing should cause their co-workers some concern.
Be careful out there....
