NewsBriefs BUTTONS

Second Endogenous Substance Similar to THC Found


September-October 1997

The discovery in the human brain of a substance highly similar to THC, the primary active ingredient in marijuana, may lead to further knowledge of how marijuana affects the human brain, according to a report in the journal Nature (Daniele Piomelli, Paul Schweitzer and Nephi Stella, "A second endogenous cannabinoid that modulates long-term potentiation," Nature, Vol. 388, no. 6644, August 21, 1997, p. 733; UPI, "Chemical in brain has drug effect," Washington Times, August 21, 1997, p. A10; David Brown, "Substance Resembling a Marijuana Component Helps Brain Sort, Store Information," Washington Post, August 21, 1997, p. A25).

Researchers Nephi Stella, Daniele Piomelli and Paul Schweitzer have succeeded in isolating a chemical known as 2-AG. The isolating of 2-AG first occurred in the intestines of dogs, and was found to activate a brain cell molecule known as a cannabinoid receptor. The chemical is believed to be essential for storing information in the brain, as well as forgetting certain memories and actions.

Piomelli said, "2-AG's ability to block long-term potentiation, and with it, presumably, memory formation, helps explain some of marijuana's effects -- that heavy or frequent pot-smoking impairs short-term memory." The impairment of short-term memory observed in frequent marijuana smokers may "be an indiscriminate over-driving of a mechanism for forgetting that has a physiological role," according to Piomelli. The effects of this new discovery could lead to further discovery of the role that the cannabinoid system plays within the human body, and to additional knowledge of how drug addiction comes about.

The first substance similar to THC found in the human brain is called anandamide. Scientists isolated anandamide in 1992, and found that it is widely distributed throughout the brain (See, "Chocolate May Mimic Marijuana," NewsBriefs, October 1996).

For a copy of the article, contact: Nature, 345 Park Avenue South, New York, NY 10010-1707, Tel: (212) 726-9200, Fax: (212) 696-9006, E-mail: