Featured Research

from universities, journals, and other organizations

Histamine, Anxiety And Alcoholism

Date:
April 7, 2005
Source:
Alcoholism: Clinical & Experimental Research
Summary:
In a new study, researchers have found that decreased levels of brain histamine, which are associated with a functional polymorphism of histamine N-methyltransferase (HNMT) called Thr105 allele, may also result in higher levels of anxiety which may, in turn, confer vulnerability to alcoholism.

In the brain, histamine regulates a wide variety of physiological processes, including water and food intake, sleep-wake cycles, endocrine homeostasis, locomotion, and memory and learning. In a new study, researchers have found that decreased levels of brain histamine, which are associated with a functional polymorphism of histamine N-methyltransferase (HNMT) called Thr105 allele, may also result in higher levels of anxiety which may, in turn, confer vulnerability to alcoholism. Results are published in the March issue of Alcoholism: Clinical & Experimental Research.

"We were interested in examining the role of the functional Thr105Ile variant of HNMT because this is the enzyme which accounts for the degradation of histamine in mammalian brain," said Gabor Oroszi, a researcher at the National Institute on Alcohol Abuse and Alcoholism and first author of the study. "Since clinical experience with antihistamine drugs has indicated that blockade of histamine 1 receptors results in sedation, anxiolysis and sleepiness – which are very strong in many patients – we hypothesized that altered function of the sole histamine metabolizing enzyme in the brain might alter anxiety, a state frequently encountered by alcoholics."

Oroszi and his colleagues examined two distinct populations of alcoholics – 218 Finnish Caucasians (206 males, 12 females) and 186 Plains American Indians (98 males, 88 females) – for an association among the Thr105lle polymorphism, alcoholism, and "harm avoidance," a dimensional measure of anxious personality. Researchers also examined two groups of nonalcoholic "controls," 313 Finns (220 males, 93 females) and 140 Plains Indians (36 males, 104 females) for comparison's sake.

"We chose these two populations because they were well characterized in terms of both alcohol abuse and dependence, as well as harm avoidance," said Oroszi. "There was a sufficient number of alcoholics and nonalcoholic controls to allow us to compare the distribution of genotypes and alleles between the alcoholic and nonalcoholic groups. Finally, since the populations are independent, meaning genetically distinct, we assumed that if any association with alcoholism and harm avoidance were to be found in the same direction in both populations, it would support a true role of the variant, thereby strengthening the power of the finding."

Harm avoidance, Oroszi added, is a dimensional measure of anxious personality or anxiety proneness. "Harm avoidance measures the range of 'normal' anxiety present in the general populations; it is not a measure of pathological anxiety, although individuals with clinical anxiety disorders tend to have high harm avoidance."

Results showed that Thr105 allele frequencies were significantly higher in the alcoholics, compared to the nonalcoholics, in both populations.

"Our findings can be interpreted in two ways," said Oroszi. "First, the Thr105 allele is more frequent among alcoholics as compared with nonalcoholics, suggesting that the presence of the Thr105 allele might increase vulnerability to the development of alcoholism. Second, the [frequency of the rarer] Ile105 allele is more abundant among nonalcoholics, suggesting that carriers of the Ile105 allele might be protected against the development of alcoholism. Since harm avoidance was also lower among nonalcoholics, it would appear that the protective effect of the Ile105 allele against alcoholism is mediated by lower harm avoidance."

Oroszi said that his study's most important message is that a common functional variant of a histamine-metabolizing enzyme in the human brain may be able to influence behavior and individual vulnerability to various psychiatric diseases such as alcoholism. "What we also need to emphasize is the fact that there is a potent amine in the brain, histamine, whose contribution to anxiety and alcoholism has not been exhaustively investigated." Additionally, he said, the polymorphism may not only be able to influence vulnerability to psychiatric diseases, it might also be able to influence a patient's response to drug treatment or the severity of side effects.

Oroszi cautioned that, although the findings were consistent in two different populations, it is nonetheless a genetic association study. "Our explanation of how the altered histamine levels lead to differences in alcoholism vulnerability and alter harm avoidance is hypothetical, based on previous studies addressing the activity of the enzyme," he said. "In addition, whereas we focused on a common functional variant in the gene of a histamine-metabolizing enzyme, there might be additional, as-yet-unknown variants in this gene which might also contribute to differences in susceptibility to alcoholism, anxiety and other psychiatric diseases."

He plans to further examine and corroborate the role of the polymorphism in alcoholism in other populations and ethnic groups, such as African-Americans. "In addition, we plan to address the role of the polymorphism in flushing response, allergic diseases and other pathological states in which histamine has a putative or well-established role," said Oroszi.

###

Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, "Thr105lle, a functional polymorphism of histamine N-methyltransferase (HNMT), is associated with alcoholism in two independent populations," were: Mary-Anne Enoch, Jeffrey Chun, and David Goldman of the Laboratory of Neurogenetics at the National Institute on Alcoholism and Alcohol Abuse; and Matti Virkkunen of the Department of Psychiatry at the University of Helsinki in Finland. The study was funded in part by the Office of Research on Minority Health.


Story Source:

The above story is based on materials provided by Alcoholism: Clinical & Experimental Research. Note: Materials may be edited for content and length.


Cite This Page:

Alcoholism: Clinical & Experimental Research. "Histamine, Anxiety And Alcoholism." ScienceDaily. ScienceDaily, 7 April 2005. <www.sciencedaily.com/releases/2005/03/050328181920.htm>.
Alcoholism: Clinical & Experimental Research. (2005, April 7). Histamine, Anxiety And Alcoholism. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2005/03/050328181920.htm
Alcoholism: Clinical & Experimental Research. "Histamine, Anxiety And Alcoholism." ScienceDaily. www.sciencedaily.com/releases/2005/03/050328181920.htm (accessed September 19, 2014).

Share This



More Mind & Brain News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Food Addiction Might Be Caused By PTSD

Food Addiction Might Be Caused By PTSD

Newsy (Sep. 18, 2014) New research shows that women who suffer from PTSD are three times more likely to develop a food addiction. Video provided by Newsy
Powered by NewsLook.com
Corporal Punishment on Decline, Debate Renews

Corporal Punishment on Decline, Debate Renews

AP (Sep. 16, 2014) Corporal punishment in the United States is on the decline, but there is renewed debate over its use after Minnesota Vikings running back Adrian Peterson was charged with child abuse. (Sept. 16) Video provided by AP
Powered by NewsLook.com
FDA Eyes Skin Shocks Used at Mass. School

FDA Eyes Skin Shocks Used at Mass. School

AP (Sep. 15, 2014) The FDA is considering whether to ban devices used by the Judge Rotenberg Educational Center in Canton, Massachusetts, the only place in the country known to use electrical skin shocks as aversive conditioning for aggressive patients. (Sept. 15) Video provided by AP
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. 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:
from the past week

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