Human astrocyte. The vivid color is from GFP, not drugs.
The real news is the importance of a type of brain cells called astroglia, which have long been ignored while researchers focus on neurons. THC, the psychoactive chemical in marijuana, impairs working memory by connecting to astroglia, according to a new paper published in Cell. So the star-shaped astroglia turn out to be the real star of this study.
Drugs have a habit of making their way from our bodies into the environment: they’ve frequently been found in waste water, drinking water, and rivers (not to mention on dollar bills). But they could also be rising into the air, and a new study suggests their aerial concentrations could give scientists a clue to what, exactly, is happening on the ground below. Following up on earlier research showing that cocaine was present in the air above the cities of Taranto and Rome, Italian researchers at the Institute of Atmospheric Pollution Research in Rome took about 60 samples of air in various regions and tested for a number of contaminants, including cocaine, cannabinoids (chemicals found in marijuana), and more common pollutants, like ozone and hydrocarbons. When they looked to see whether there was a correlation between cocaine concentration and addicts’ requests for treatment in particular geographical areas, they found a very strong relationship. Weaker correlations existed between cocaine concentration and police seizures of cocaine and concentration and seizure of all kinds of illicit substances.
The team is excited about the possibility of using aerial cocaine concentration to get a sense of drug use levels, a notoriously slippery thing to measure, and possibly other activities that sometimes occur in tandem with drug use, like robberies. However, their approach didn’t turn up any significant correlations between crime-related activities and cannabinoids, which is interesting—what does that mean about the social correlates of marijuana use (or, alternatively, about the fraction of cannabinoids that actually make into the air)? If you’re worried about getting high from the air, it seems unlikely that concentrations are high enough to have an effect. But who knows—that’s a question that has yet to be addressed.
What’s The News: Three 16-year-old teenage boys in Texas had heart attacks shortly after smoking a product called k2, or Spice, according to a study published this month in the journal Pediatrics. The report highlights a growing public health problem: the increased availability and use of synthetic cannabinoids, which when smoked mimic the effects of marijuana but typically can’t be detected in drug tests. While the U.S. Drug Enforcement Agency secured an emergency, one-year ban of five synthetic cannabinoids in March of this year, most of the hundreds of such chemicals remain basically legal, widely available, little understood, and potentially harmful.
Placebos are inactive treatments that shouldn’t, in some sense, have a real effect. And yet they often do. But the chemical basis of the placebo effect, despite its enormous importance, is still largely a mystery. A study published this week in Nature Medicine shows that cannabinoid receptors are involved in the placebo response to pain, which hasn’t been demonstrated before. The finding implies that the brain’s own endocannabinoids can fight pain, and actually do it via the same pathway as several compounds in the cannabis plant.
When rats were injected with a chemical similar to marijuana’s main ingredient, THC, shortly after a undergoing a severely stressful event, they showed a significant reduction in symptoms like those seen in people with post-traumatic stress disorder. The study tested a synthetic cannabinoid called WIN 55,212-2, which was injected directly into the animals’ amygdala, a brain region involved in the regulation of emotions like fear and anxiety. Timing was important. Rats given the drug two and 24 hours after the stressor—being forced to swim for 15 minutes—appeared less “traumatized” when tested a week later, compared with those given the drug 48 hours later or given no drug at all. While the study adds to the already large and complex pile of evidence that the cannabinoid system has a vital role in regulating emotions like anxiety, it’s far from proving that cannabinoids will be useful for treating PTSD in humans.