This suggests an explanation for
the laidback behavior of potheads. They
simply forget the sense of urgency. Way
more important, this means that the drug is just about the last thing you want
to use while preparing for an examination or even taking a course and it is
clear why scholarship ends with a pot habit.
I have long observed a loss of
cognitive edge with users although not of the elements of established
memory. The same effect is never as
obvious with alcohol use unless one goes and seriously overindulges.
These are casual observations but
they lead to the same place. The brain
is not something one wants to play with through misapplication of drugs.
How Marijuana Impairs Memory
ScienceDaily (Mar. 1, 2012) — A major downside of the medical
use of marijuana is the drug's ill effects on working memory, the ability to
transiently hold and process information for reasoning, comprehension and
learning. Researchers reporting in the March 2 print issue of the Cell
Press journal Cell provide new insight into the source of those
memory lapses. The answer comes as quite a surprise: Marijuana's major
psychoactive ingredient (THC) impairs memory independently of its direct
effects on neurons. The side effects stem instead from the drug's action on
astroglia, passive support cells long believed to play second fiddle to active
neurons.
The findings offer important new insight into the brain and raise
the possibility that marijuana's benefits for the treatment of pain, seizures
and other ailments might some day be attained without hurting memory, the
researchers say.
With these experiments in mice, "we have found that the starting
point for this phenomenon -- the effect of marijuana on working memory -- is
the astroglial cells," said Giovanni Marsicano of INSERM in France
"This is the first direct evidence that astrocytes modulate
working memory," added Xia Zhang of the University
of Ottawa in Canada
The new findings aren't the first to suggest astroglia had been given
short shrift. Astroglial cells (also known as astrocytes) have been viewed as
cells that support, protect and feed neurons for the last 100 to 150 years,
Marsicano explained. Over the last decade, evidence has accumulated that
these cells play a more active role in forging the connections from one neuron
to another.
The researchers didn't set out to discover how marijuana causes its
cognitive side effects. Rather, they wanted to learn why receptors that respond
to both THC and signals naturally produced in the brain are found on astroglial
cells. These cannabinoid type-1 (CB1R) receptors are very abundant in the
brain, primarily on neurons of various types.
Zhang and Marsicano now show that mice lacking CB1Rs only on astroglial
cells of the brain are protected from the impairments to spatial working memory
that usually follow a dose of THC. In contrast, animals lacking CB1Rs in
neurons still suffer the usual lapses. Given that different cell types express
different variants of CB1Rs, there might be a way to therapeutically activate
the receptors on neurons while leaving the astroglial cells out, Marsicano
said.
"The study shows that one of the most common effects of
cannabinoid intoxication is due to activation of astroglial CB1Rs," the
researchers wrote.
The findings further suggest that astrocytes might be playing
unexpected roles in other forms of memory in addition to spatial working
memory, Zhang said.
The researchers hope to explore the activities of endogenous
endocannabinoids, which naturally trigger CB1Rs, on astroglial and other cells.
The endocannabinoid system is involved in appetite, pain, mood, memory and many
other functions. "Just about any physiological function you can think of
in the body, it's likely at some point endocannabinoids are involved,"
Marsicano said.
And that means an understanding of how those natural signaling
molecules act on astroglial and other cells could have a real impact. For
instance, Zhang said, "we may find a way to deal with working memory
problems in Alzheimer's."
No comments:
Post a Comment