He explains that GLP-1 and nicotine are the two substances that affect the brain’s reward system. Nicotine from tobacco, for example, releases a large amount of dopamine in the brain, which acts as a kind of reward. This is one of the reasons why it is so hard to quit nicotine products.
“Seeing as our study has a different focus, i.e. to determine whether the two substances interact to promote weight loss, we did not pursue the surprising effect on the dopamine system, and more research is therefore needed to determine whether treatment with liraglutide will cause mice to ingest less nicotine,” adds Christoffer Clemmensen.
New clinical trials focussing on nicotine dependence
In the study, which has been published in the journal Cell Reports, the researchers studied two known appetite inhibitors: GLP-1 and nicotine. GLP-1 is used in various diabetes and weight loss drugs.
The researchers already knew that nicotine increases energy expenditure, and many who quit nicotine products subsequently gain weight.
Together, the two substances appear to promote weight loss, while GLP-1 alone seems to reduce nicotine cravings. And, according to the international database of clinical trials, many researchers are currently testing whether GLP-1-based drugs can help people quit smoking.
Explore the database here.
Collaboration with UCPH brain researchers
Christoffer Clemmensen explains that it was only recently discovered that a combination of GLP-1 and nicotine has a greater effect on the body than either of the two substances alone.
The two substances affect the same neurons in specific parts of the brain, and the researchers have been able to demonstrate that GLP-1 affects the body’s response to nicotine.
“Initially, we therefore wanted to see whether a combination of nicotine and GLP-1 could effectively reduce overweight. Our animal models showed some interesting effects. So we did more tests focussing on the reward and appetite regulating systems,” says Christoffer Clemmensen.
“We were surprised to learn how extensively GLP-1 and nicotine interact. It is a well-known fact that both substances affect food intake, and this effect seems to be even greater when you combine the two substances. It not only reduces food intake; it also causes the body to release less dopamine, reducing nicotine cravings,” he says.
The trials focussing on the brain’s reward system were conducted together with the Gether Lab at the Department of Neuroscience, University of Copenhagen, who measured dopamine release in the brain.
The researchers are not planning to conduct clinical trials of the interaction between GLP-1-based drugs and nicotine, but they hope their work will encourage pharmaceutical companies to consider the potential of the area.
Read the full study here: ’GLP-1 and nicotine combination therapy engages hypothalamic and mesolimbic pathways to reverse obesity’.
