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Surprising Brain Effects From Pot-Like Drug

Synthetic Drug May Have Increased Rats' Brain Cells, Study Shows
By
WebMD Health News
Reviewed by Louise Chang, MD

Oct. 13, 2005 -- A drug modeled on marijuana's active ingredient increased brain cells and appeared to cut anxious, depressed behavior in rats, researchers report.

The drug is called HU210. It's a synthetic drug that is chemically similar to pot's active ingredient and activates cannabinoid receptors in the brain.

But HU210 isn't pot. Pot contains a mix of chemicals, and the body may handle marijuana smoke differently than the administration of HU210.

The researchers included Xia Zhang of the University of Saskatchewan in Canada. They didn't study people and don't make any recommendations about pot use.

The study appears in the Journal of Clinical Investigation.

Rat Results

Anxiety and depression were gauged by the rats' behavior in two tests. Anxious and depressed behavior appeared to decrease after regular treatment with HU210, write the researchers.

They also found new brain cells in the rats' brains after chronic use of HU210. Those new cells were in the hippocampus, a brain area that's associated with motivation, emotion, and memory formation.

The brain effects were seen when rats got HU210 for a month. One-time-only treatment didn't show the same results.

Point of Controversy

It hasn't been clear if cannabinoids can spur the creation of new brain cells in the hippocampus, according to the researchers.

They also note "discrepancies" in scientific research about cannabinoids' effects on anxiety and depression. That difference could stem from the dose and length of treatment, the researchers suggest.

The findings suggest that cannabinoids are the only illicit drug that can promote the creation of new hippocampal brain cells in adults after chronic administration, write Zhang and colleagues.

They point out that other drugs (such as opiates, alcohol, nicotine, and cocaine) have been shown to block the creation of new brain cells in the hippocampus.

The Brain on Marijuana

Marijuana is the most commonly used illicit drug in the U.S, according to the National Institute on Drug Abuse (NIDA).

Here is what the NIDA's web site says about pot's effects on the brain:

"The short-term effects of marijuana can include problems with memory and learning, distorted perception, difficulty in thinking and problem solving, loss of coordination, and increased heart rate," states the NIDA.

NIDA's web site notes research on pot's active ingredient, THC.

"Research findings for long-term marijuana use indicate some changes in the brain similar to those seen after long-term use of other major drugs of abuse," states the NIDA.

"For example, cannabinoid (THC or synthetic forms of THC) withdrawal in chronically exposed animals leads to an increase in the activation of the stress-response system and changes in the activity of nerve cells containing dopamine. Dopamine neurons are involved in the regulation of motivation and reward, and are directly or indirectly affected by all drugs of abuse," states the NIDA.

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