Researchers Study Neurons

SAN JOSE, Calif. - Mother Nature created a way to ``tune in, turn on'' long before pot-smokers rolled their first joint, Stanford scientists have found.

Eavesdropping on the conversations between brain cells, the research team found that neurons make their own marijuana-like chemicals called cannabinoids, which indirectly alter the way information is received and filtered.

When the chemicals are released, ``neurons have a harder time deciding which are the relevant things to pay attention to,'' said investigator John R. Huguenard, associate professor of neurology and neurological sciences at Stanford University School of Medicine.

For a long time, scientists thought that marijuana altered the mind in a messy and random way.

Now they've identified an elegant modus operandi. It adds to a growing body of research that explains the mechanism behind getting ``high.'' Marijuana mimics the cannabinoids made naturally by our brain -- chemicals that influence a smorgasbord of body functions including movement, thought and perception.

The research sheds light on a powerful neurochemical system. In their Stanford lab, Huguenard and colleagues David Prince and Alberto Bacci injected electric current into rat brain cells, then watched the chatter between the brain's two major types of cells.

When overly excited, one type of neuron releases cannabinoids, which create a calming effect, they found. In effect, the brain cell drugs itself.

But this mellowed-out cell falls down on its job, which is to filter the flow of information rushing into a second type of cell.

Without a good filter, the researchers think, this second neuron is flooded with sensory information that affects memory, perception, mood and movement.

Something very similar happens with marijuana use, the scientists believe.

In an accident of nature and chemistry, the compounds in pot are shaped similarly and trigger similar effects.

``Marijuana use . . . affects the way we think,'' said Huguenard. The new research shows that ``part of that is because of changes in the way our brain cells receive incoming information, like sensory information or memories or emotion.''

Because so much information is always flowing into the brain, ``each neuron has to make a decision based on the signals it gets,'' he said. ``They have to make sense of it . . . and decide what's relevant.''

``Marijuana loosens a natural filter that exists in neurons, so they tend to be flooded with information,'' Huguenard said.

The research is published in today's issue of the journal Nature.

Ed. It is amazing how many people (doctors) do not connect the dots. As if there is a huge psychological resistance to simply accept the facts of all the trial results?! All of which seem to indicate that cannabis prevents people from getting cancer?! But above all, let's not legalize this and let's keep cigarettes legal, go figure!