Researchers at the Sahlgrenska Academy, Gothenburg, have discovered a new brain mechanism involved in alcohol addiction involving the stomach hormone ghrelin. When ghrelin’s actions in the brain are blocked, alcohol’s effects on the reward system are reduced. It is an important discovery that could lead to new therapies for addictions such as alcohol dependence.
Ghrelin is a hormone produced by the stomach and, by signalling in the brain, increases hunger. The new finding, that it is also involved in alcohol addiction, highlights the reward system of the brain as a key target for ghrelin’s effects. "Ghrelin’s actions in the brain may be of importance for all kinds of addictions, including chemical drugs such as alcohol and even food" says Suzanne Dickson, Professor of Physiology, a leading expert in appetite regulation.
The work emerged from a unique collaboration between the research groups of Prof Suzanne Dickson and Prof Emeritus Jörgen Engel, including researchers Dr Elisabet Jerlhag and Dr Emil Egecioglu. They show that mice treated with ghrelin increase their alcohol consumption. When ghrelin’s actions are blocked, for example, by administering ghrelin receptor antagonists, mice no longer show preference for an alcohol-associated environment -in other words, alcohol is no longer able to produce its addictive effects, that include reward searching behaviour (akin to craving in alcoholic patients).
"If we can develop drugs that block the receptors for ghrelin, we could have a new effective treatment for alcohol dependence. It may however take several years until such a pharmacological treatment will reach the patient", says Professor Emeritus Jörgen Engel, an authority on research on alcohol dependency at the Sahlgrenska Academy. The group has submitted a patent application for this invention.
It is estimated that five percent of the adult Swedish population are alcohol dependent. Alcohol dependence is a complex and chronic disease which leads to adverse consequences affecting not only the patient but also their immediate family and has a profound economic burden on society (estimated to be around 60-100 billion kronor per year). Each year about 8,000 Swedes die of alcohol-related diseases.
- Elisabet Jerlhag, Emil Egecioglu, Sara Landgren, Nicolas Salomé, Markus Heilig, Diedrik Moechars, Rakesh Datta, Daniel Perrissoud, Suzanne L. Dickson, Jörgen A. Engel. Requirement of central ghrelin signaling for alcohol reward. Proceedings of the National Academy of Sciences (PNAS), (in press)
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