Featured Research

from universities, journals, and other organizations

Key shift in brain that creates drive to overeat identified

Date:
April 29, 2013
Source:
Indiana University
Summary:
Neuroscientists have identified a cellular change in the brain that accompanies obesity. The findings could explain the body's tendency to maintain undesirable weight levels, rather than an ideal weight, and identify possible targets for pharmacological efforts to address obesity. The study identifies a mechanism for the body's ongoing tendency to return to the heavier weight.

Researchers have identified a key shift in the brain that creates the drive to overeat.
Credit: georgerudy / Fotolia

A team of American and Italian neuroscientists has identified a cellular change in the brain that accompanies obesity. The findings could explain the body's tendency to maintain undesirable weight levels, rather than an ideal weight, and identify possible targets for pharmacological efforts to address obesity.

Related Articles


The findings, published in the Proceedings of the National Academy of Sciences Early Edition this week, identify a switch that occurs in neurons within the hypothalamus. The switch involves receptors that trigger or inhibit the release of the orexin A peptide, which stimulates the appetite, among other behaviors. In normal-weight mice, activation of this receptor decreases orexin A release. In obese mice, activation of this receptor stimulates orexin A release.

"The striking finding is that you have a massive shift of receptors from one set of nerve endings impinging on these neurons to another set," said Ken Mackie, professor in the Department of Psychological and Brain Sciences in the College of Arts and Sciences at IU Bloomington. "Before, activating this receptor inhibited the secretion of orexin; now it promotes it. This identifies potential targets where an intervention could influence obesity."

The work is part of a longstanding collaboration between Mackie's team at the Gill Center for Biomolecular Science at IU Bloomington and Vincenzo Di Marzo's team at the Institute of Biomolecular Chemistry in Pozzuoli, Italy. Both teams study the endocannabinoid system, which is composed of receptors and signaling chemicals that occur naturally in the brain and have similarities to the active ingredients in cannabis, or marijuana. This neurochemical system is involved in a variety of physiological processes, including appetite, pain, mood, stress responses and memory.

Food consumption is controlled in part by the hypothalamus, a portion of the brain that regulates many essential behaviors. Like other important body systems, food consumption is regulated by multiple neurochemical systems, including the endocannabinoid system, representing what Mackie describes as a "balance of a very fine web of regulatory networks."

An emerging idea, Mackie said, is that this network is reset during obesity so that food consumption matches maintenance of current weight, not a person's ideal weight. Thus, an obese individual who loses weight finds it difficult to keep the weight off, as the brain signals the body to eat more in an attempt to return to the heavier weight.

Using mice, this study found that in obesity, CB1 cannabinoid receptors become enriched on the nerve terminals that normally inhibit orexin neuron activity, and the orexin neurons produce more of the endocannabinoids to activate these receptors. Activating these CB1 receptors decreases inhibition of the orexin neurons, increasing orexin A release and food consumption.

"This study identifies a mechanism for the body's ongoing tendency to return to the heavier weight," Mackie said.

The researchers conducted several experiments with mice to understand how this change takes place. They uncovered a role of leptin, a key hormone made by fat cells that influences metabolism, hunger and food consumption. Obesity causes leptin levels to be chronically high, making brain cells less sensitive to its actions, which contributes to the molecular switch that leads to the overproduction of orexin.


Story Source:

The above story is based on materials provided by Indiana University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Luigia Cristino, Giuseppe Busetto, Roberta Imperatore, Ida Ferrandino, Letizia Palomba, Cristoforo Silvestri, Stefania Petrosino, Pierangelo Orlando, Marina Bentivoglio, Kenneth Mackie, and Vincenzo Di Marzo. Obesity-driven synaptic remodeling affects endocannabinoid control of orexinergic neurons. PNAS, April 29, 2013 DOI: 10.1073/pnas.1219485110

Cite This Page:

Indiana University. "Key shift in brain that creates drive to overeat identified." ScienceDaily. ScienceDaily, 29 April 2013. <www.sciencedaily.com/releases/2013/04/130429154214.htm>.
Indiana University. (2013, April 29). Key shift in brain that creates drive to overeat identified. ScienceDaily. Retrieved January 25, 2015 from www.sciencedaily.com/releases/2013/04/130429154214.htm
Indiana University. "Key shift in brain that creates drive to overeat identified." ScienceDaily. www.sciencedaily.com/releases/2013/04/130429154214.htm (accessed January 25, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, January 25, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Mistakes Should Serve a Lesson Says WHO

Ebola Mistakes Should Serve a Lesson Says WHO

AFP (Jan. 25, 2015) The World Health Organization&apos;s chief on Sunday admitted the UN agency had been caught napping on Ebola, saying it should serve a lesson to avoid similar mistakes in future. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Disneyland Measles Outbreak Spreads To 5 States

Disneyland Measles Outbreak Spreads To 5 States

Newsy (Jan. 24, 2015) Much of the Disneyland measles outbreak is being blamed on the anti-vaccination movement. The CDC encourages just about everyone get immunized. Video provided by Newsy
Powered by NewsLook.com
Growing Measles Outbreak Worries Calif. Parents

Growing Measles Outbreak Worries Calif. Parents

AP (Jan. 23, 2015) Public health officials are rushing to contain a measles outbreak that has sickened 70 people across 6 states and Mexico. The AP&apos;s Raquel Maria Dillon has more. (Jan. 23) Video provided by AP
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
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