Marijuana-like chemical lifts depression

IRVINE, Calif., Nov. 7 (UPI) -- A U.S.-Italian study suggests increasing levels of a marijuana-like neurotransmitter initiates anti-depressant effects in rats.

The researchers, led by Professor Daniele Piomelli of the University of California-Irvine, noted the neurotransmitter anandamide acts on a class of neurons called the brain’s endocannabinoid system. That system has important analgesic, anti-anxiety and anti-depressant roles, and is also involved in the regulation of food intake and weight.

The research team studied non-stressed rats, as well as a group of chronically stressed rats showing behaviors similar to those observed in depressed humans. Some of the stressed rats were given a drug that blocks the degradation of anandamide, thereby increasing its levels in the brain.

The researchers discovered stressed rats treated with the drug behaved like unstressed animals.

While marijuana has shown no clinical use for depression, Piomelli said the specific drugs that amplify the actions of natural marijuana-like transmitters in the brain show great promise.

The study appears in the journal Biological Psychiatry.