Marijuana Causes Memory Impairment
June 11, 2012 § 2 Comments
A study published in the March issue of the Cell Press Journal Cell reveals the detrimental cognitive effects of medicinal marijuana. Cannabis sativa, or marijuana, impairs memory by disrupting one’s ability to hold onto information long enough to perform reasoning, comprehension and learning.
Giovanni Marsicano of INSERM in France comments upon the experiments performed with mice, “we have found that the starting point for this phenomenon – the effect of marijuana on working memory – is the astroglial cells.” Xia Zhang of the University of Ottawa in Canada says, “This is the first direct evidence that astrocytes modulate working memory.”
Marsicano goes on to explain that Astroglial cells, for the last 100 to 150 years, have been thought of as cells that support, protect, and feed neurons, but recent findings suggest that these cells also play a more important role in the construction of connections between neurons.
The researchers in this study initially commenced with the intention of learning why receptors (that respond to marijuana-initiated THC signals and receptors that respond to the brain’s natural THC signals were both found in the astroglial cells. They did not intend to stumble upon this new information regarding marijuana’s cognitive side effects. The receptors, cannabinoid type-1 (CB1R), are found in the brain in copious amounts. Therefore the effects of cannabinoid intoxication are due to the activation of the astroglial CB1Rs.
Researchers found that mice that lacked CB1R on astroglial cells were not affected by the spatial memory impairments that typically occur when they receive THC. Those lacking CBR1s in neurons, however, did suffer the memory lapses. Marsicano suggests there may be a way to activate the receptors on neurons without activating the astroglial cells.
The study also suggests that astroglial cells are playing a more active role in memory besides spatial working memory.
Further research will be conducted to explore the effects of endogenous endocannabinoids on astroglial cells. This system is linked to appetite, pain, mood, memory, and other functions. Zhang suggests that a better understanding of the natural signaling of these molecules may help, “find a way to deal with working memory problems in Alzheimer’s.”
“How Marijuana Impairs Memory”. (March 1, 2012). Neuroscience News. March 2, 2012. http://neurosciencenews.com/marijuana-impairs-memory-astroglia-cb1r-thc/.