Featured Research

from universities, journals, and other organizations

Chronic marijuana smoking affects brain chemistry, molecular imaging shows

Date:
June 13, 2011
Source:
Society of Nuclear Medicine
Summary:
Definitive proof of an adverse effect of chronic marijuana use could lead to potential drug treatments and aid other research involved in cannabinoid receptors, a neurotransmission system receiving a lot of attention.

Definitive proof of an adverse effect of chronic marijuana use revealed at SNM's 58th Annual Meeting could lead to potential drug treatments and aid other research involved in cannabinoid receptors, a neurotransmission system receiving a lot of attention. Scientists used molecular imaging to visualize changes in the brains of heavy marijuana smokers versus non-smokers and found that abuse of the drug led to a decreased number of cannabinoid CB1 receptors, which are involved in not just pleasure, appetite and pain tolerance but a host of other psychological and physiological functions of the body.

Related Articles


"Addictions are a major medical and socioeconomic problem," says Jussi Hirvonen, MD, PhD, lead author of the collaborative study between the National Institute of Mental Health and National Institute on Drug Abuse, Bethesda, Md. "Unfortunately, we do not fully understand the neurobiological mechanisms involved in addiction. With this study, we were able to show for the first time that people who abuse cannabis have abnormalities of the cannabinoid receptors in the brain. This information may prove critical for the development of novel treatments for cannabis abuse. Furthermore, this research shows that the decreased receptors in people who abuse cannabis return to normal when they stop smoking the drug."

According to the National Institute on Drug Abuse, marijuana is the number-one illicit drug of choice in America. The psychoactive chemical in marijuana, or cannabis, is delta-9-tetrahydrocannabinol (THC), which binds to numerous cannabinoid receptors in the brain and throughout the body when smoked or ingested, producing a distinctive high. Cannabinoid receptors in the brain influence a range of mental states and actions, including pleasure, concentration, perception of time and memory, sensory perception, and coordination of movement. There are also cannabinoid receptors throughout the body involved in a wide range of functions of the digestive, cardiovascular, respiratory and other systems of the body. Currently two subtypes of cannabinoid receptors are known, CB1 and CB2, the former being involved mostly in functions of the central nervous system and the latter more in functions of the immune system and in stem cells of the circulatory system.

For this study, researchers recruited 30 chronic daily cannabis smokers who were then monitored at a closed inpatient facility for approximately four weeks. The subjects were imaged using positron emission tomography (PET), which provides information about physiological processes in the body. Subjects were injected with a radioligand, 18F-FMPEP-d2, which is a combination of a radioactive fluorine isotope and a neurotransmitter analog that binds with CB1 brain receptors.

Results of the study show that receptor number was decreased about 20 percent in brains of cannabis smokers when compared to healthy control subjects with limited exposure to cannabis during their lifetime. These changes were found to have a correlation with the number of years subjects had smoked. Of the original 30 cannabis smokers, 14 of the subjects underwent a second PET scan after about a month of abstinence. There was a marked increase in receptor activity in those areas that had been decreased at the outset of the study, an indication that while chronic cannabis smoking causes downregulation of CB1 receptors, the damage is reversible with abstinence.

Information gleaned from this and future studies may help other research exploring the role of PET imaging of CB1 receptors -- not just for drug use, but also for a range of human diseases, including metabolic disease and cancer.


Story Source:

The above story is based on materials provided by Society of Nuclear Medicine. Note: Materials may be edited for content and length.


Cite This Page:

Society of Nuclear Medicine. "Chronic marijuana smoking affects brain chemistry, molecular imaging shows." ScienceDaily. ScienceDaily, 13 June 2011. <www.sciencedaily.com/releases/2011/06/110606131705.htm>.
Society of Nuclear Medicine. (2011, June 13). Chronic marijuana smoking affects brain chemistry, molecular imaging shows. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2011/06/110606131705.htm
Society of Nuclear Medicine. "Chronic marijuana smoking affects brain chemistry, molecular imaging shows." ScienceDaily. www.sciencedaily.com/releases/2011/06/110606131705.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com
You Don't Have To Be Alcohol Dependent To Need Treatment

You Don't Have To Be Alcohol Dependent To Need Treatment

Newsy (Nov. 21, 2014) A study by the Centers for Disease Control and Prevention found 9 out of 10 excessive drinkers in the country are not alcohol dependent. Video provided by Newsy
Powered by NewsLook.com
Your Complicated Job Might Keep Your Brain Young

Your Complicated Job Might Keep Your Brain Young

Newsy (Nov. 20, 2014) Researchers at the University of Edinburgh found the more complex your job is, the sharper your cognitive skills will likely be as you age. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins