Technology Review - Published By MIT
Advertisement

David Ewing Duncan's blog

Getting real about the life sciences, medicine and biological discovery.

View Complete Bio
Advertisement
Thursday, May 31, 2007

"Natural" Pot Helps Fetal Brains Connect

Marijuana-like cannabinoids appear in a mouse fetus at just the right time to help young neurons connect properly.

Whoa, dude: what's this about?

It's not, like, about smoking dope: it's about researchers in Sweden and Indiana experimenting with fetal mice whose brains naturally produce a chemical similar to Tetrahydrocannabinol (THC), the active ingredient in marijuana.

Scientists have known from studying women who smoke marijuana during pregnancy that when you add cannabinoids to fetal brain cells, it prevents neurons from making strong connections. But why?

The researchers found that the naturally occurring endocannabinoids (made by the brain) help position the rootlike feelers, called axons, that neurons use to communicate with one another. The process is highly sensitive to the amounts of the chemical, when it's released, and its location in the brain. Adding THC-like chemicals from the outside throws off this delicate balance.

When researchers added synthetic cannabinoids to the wee little mouse brains, their axons withdrew from the areas of high concentration and moved in other directions.

According to an article posted on ScientificAmerican.com,

The researchers found two groups of brain cells in embryonic mice that carried the CBR proteins for several days during late development. (Mice gestate in 18 or 19 days.) The cells were located in the cortex, the brain region that controls attention and planning in humans and other mammals.

THC would likely affect very similar brain systems in human fetuses, says neuroscientist Yasmin Hurd of the Mount Sinai School of Medicine in New York City, but its concentration would be much higher than that of any endocannabinoid. "It would have an even more pronounced effect on axonal growth and guidance," she says.

Apparently, a woman's marijuana smoking during pregnancy causes children to learn more slowly than other kids, but they are just as intelligent--and now we know why. This should convince anyone contemplating smoking a bong near a pregnant woman to cease and desist. It also adds new meaning to the term "dazed and confused."

Tags: neuroscience

Comments

  • potplasticity
    Given the growing understanding of neuroplasticity in "adult" brains, could this explain the joked about but real memory and attention problems in chronic pot smokers?

    Could the same cannabinoid pathway be present in mature nueral growth and development?
    Rate this comment: 12345

    kcouldb
    06/01/2007
    Posts:1
    • Re: potplasticity
      Could it also account for the suppression of dreaming due to pot smoking?
      Rate this comment: 12345

      johnnizanni
      06/01/2007
      Posts:8
      Avg Rating:
      5/5
      • Re: potplasticity
        Given the content and the tone of language, this article is merely drug war propaganda masquerading as a serious "scientific" report.  I guess Mr. Duncan's prejudices are just as newsworthy as a serious article. I'll bet he drinks his lunch
        Rate this comment: 12345

        Jeffery21
        06/01/2007
        Posts:1
        Avg Rating:
        5/5
Advertisement

Log In

Forgot your password?     Register »
Advertisement
Technology Review November/December 2009

Current Issue

Natural Gas Changes the Energy Map
The United States has vast supplies of this cleaner fossil fuel. But how should we use it?
•  Subscribe
Save 36%
•  Table of Contents
•  MIT News
» Gift Subscription
» Digital Subscription
» Reprints, Back Issues
» Subscribe
» Table of Contents
» MIT News

More Technology News from Forbes

Advertisement
MIT Massachusetts Institute of Technology © 2009 Technology Review. All Rights Reserved.