Marijuana-Like Chemicals Guide Fetal Brain Cells

Marijuana-Like Chemicals Guide Fetal Brain Cells
Posted by CN Staff on May 31, 2007 at 11:26:48 PT
By JR Minkel 
Source: Scientific American 
USA -- Natural marijuana like chemicals may direct key brain cells to make proper connections while in the womb, according to a new study. Researchers report that the molecules, called cannabinoids, serve as guideposts for young cells in the attention and decision-making parts of fetal mouse brains. The finding may help explain studies showing that the children of mothers who smoked marijuana during pregnancy are slower to process information than their peers (although they are just as intelligent overall).
Tetrahydrocannabinol (THC), the active ingredient in marijuana, might knock the cell-guiding machinery off course by overstimulating the brain. Researchers, however, say they are still a long way from determining exactly what effects endocannabinoids and THC have on developing human brains. "I would say yes there is human relevance," says study co-leader and neurobiologist Tibor Harkany of the Karolinska Institute in Stockholm, "but I cannot prove this, and these findings will not prove this." Scientists know that particular receptor proteins on human and animal adult brain cells respond to THC-like chemicals, or cannabinoids, which prevent the cells from making strong connections to one another, Harkany says. But they were in the dark about the role of endocannabinoids—the kind made by the brain—during fetal development. So Harkany and his colleagues cultured mouse embryonic brain cells that expressed cannabinoid receptor proteins (CBRs) and exposed them to gradients of synthetic cannabinoids. The cells withdrew their rootlike feelers, or axons, from the high concentration of cannabinoids; the axons, which seek out and communicate with neighboring cells, veered instead in other directions, the group reports in a paper published online today in Science. In effect, "if you activate the cannabinoid system" of these cells, Harkany says, "it will send a message to the cell that 'I don't want to grow there, I want to grow somewhere else'" and connect to another cell. 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. Neuroscientist Ken Mackie of Indiana University, another leader of the new study, says that natural cannabinoids can reach very high concentrations but are secreted by the brain in precise locations. THC would activate CBRs indiscriminately, he says. "The effects of endocannabinoids released in a regulated fashion," he says, "will almost always be different from THC from smoked cannabis." Note: Molecules may help young brain cells forge the right connections—but only at the right time and place.Source: Scientific American (US)Author: JR Minkel Published: May 24, 2007 Copyright: 2007 Scientific American, Inc.Contact: editors sciam.comWebsite: Medical Marijuana Archives
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Comment #4 posted by afterburner on June 14, 2007 at 00:31:32 PT
More Benefits
I'm 120 but my joints are OKDecember 04, 2006A GREAT-great granny reveals how she has lived to be 120 ... by smoking CANNABIS every day.Fulla Nayak – believed to be the world’s oldest woman – puffs “ganja” cigars and drinks strong palm wine in her cow-dung hut in India.She lives with her 92-year-old daughter and grandson, 72, by the Indian Ocean.Fulla said: “I don’t know how I’ve survived so long. Many relatives much younger than me have died.”
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Comment #3 posted by Hope on June 13, 2007 at 23:41:25 PT
Something about this particular scientific article
sounds kind of like they are making it up as they go along.
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Comment #2 posted by MMJ MINISTRY on June 13, 2007 at 23:21:32 PT
Despite political pressure to have it otherwise, Dr. Dreher's research reveals that pot-smoking moms can have smart, healthy babies.When Dreher released solidly researched reports showing that children of ganja-using mothers were better adjusted than children born to non-using mothers, she encountered political and professional turbulence.Dr. Melanie Dreher is one of a handful of scientists who have researched marijuana objectively and intelligently in the last three decades.Dr Dreher is Dean of the University of Iowa's College of Nursing, and also holds the post of Associate Director for the University's Department of Nursing and Patient Services. She's a perpetual overachiever who earned honours degrees in nursing, anthropology and philosophy before being awarded a PhD in anthropology from prestigious Columbia University in 1977.Governmental and private organizations, including the US State Department, have funded Dreher's many research projects, some of which focused on ganja's role in Jamaican culture, and the effects of ganja and cocaine on Jamaican women and children.
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Comment #1 posted by FoM on May 31, 2007 at 11:32:26 PT
Natural Pot Helps Fetal Brains Connect
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