Featured Research

from universities, journals, and other organizations

Feast or famine? How appetite cells in the brain respond to fasting

Date:
February 8, 2012
Source:
Cell Press
Summary:
Previous work has shown that the AgRP neurons promote feeding and weight gain, while the POMC cells have been linked with appetite suppression and weight loss. Now a new study uncovers a neural pathway that links fasting with activation of AgRP neurons. The research provides valuable insight into the complex mechanisms that control food seeking behavior.

There are two key cell types in the brain that are central to the regulation of feeding behaviors, agouti-related peptide (AgRP)-expressing neurons and proopiomelancortin (POMC)-expressing neurons. Previous work has shown that the AgRP neurons promote feeding and weight gain, while the POMC cells have been linked with appetite suppression and weight loss. Now a new study published by Cell Press in the February 9 issue of the journal Neuron uncovers a neural pathway that links fasting with activation of AgRP neurons. The research provides valuable insight into the complex mechanisms that control food seeking behavior.

"Given their critical roles in feeding behaviors, there is great interest in understanding the factors that regulate the activity of AgRP and POMC neurons," says senior study author, Dr. Bradford B. Lowell, from Beth Israel Deaconess Medical Center and Harvard Medical School. "However, although both types of neurons receive abundant excitatory and inhibitory inputs, the influence of these upstream signals has not received much attention."

Dr. Lowell and colleagues analyzed the impact of excitatory inputs on AgRP and POMC neurons by manipulating NMDA receptors (NMDARs) in each cell type. These receptors receive inputs from the major excitatory neurotransmitter in the brain. Interestingly, only mice lacking NMDARs on their AgRP neurons, and not those lacking NMDARs on their POMC neurons, exhibited altered body weight and food intake. Thus, this type of excitatory information is only critical for the function of AgRP neurons.

Importantly, the researchers also discovered that fasting, which is known to activate AgRP neurons and promote both food seeking and energy conservation, was associated with an increase in excitatory inputs and an increase in the number of dendritic spines on the AgRP neurons. Dendritic spines are physical protrusions on the neuron that receive incoming signals. These fasting-induced changes in AgRP neurons were also dependent on the presence of NMDARs.

Taken together, the results suggest that excitatory information received by NMDARs plays a critical role in regulating the connectivity of AgRP neurons and governing the cellular and behavioral response to fasting. "The next step will be to identify the neurotransmitters and hormones that modulate the excitatory inputs to AgRP neurons, and the mechanisms by which this modulation occurs," concludes Dr. Lowell. "This is likely to provide a better understanding of how various factors control feeding behavior."


Story Source:

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


Journal Reference:

  1. Tiemin Liu, Dong Kong, BhavikP. Shah, Chianping Ye, Shuichi Koda, Arpiar Saunders, JunB. Ding, Zongfang Yang, BernardoL. Sabatini, BradfordB. Lowell. Fasting Activation of AgRP Neurons Requires NMDA Receptors and Involves Spinogenesis and Increased Excitatory Tone. Neuron, 2012; 73 (3): 511 DOI: 10.1016/j.neuron.2011.11.027

Cite This Page:

Cell Press. "Feast or famine? How appetite cells in the brain respond to fasting." ScienceDaily. ScienceDaily, 8 February 2012. <www.sciencedaily.com/releases/2012/02/120208132255.htm>.
Cell Press. (2012, February 8). Feast or famine? How appetite cells in the brain respond to fasting. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2012/02/120208132255.htm
Cell Press. "Feast or famine? How appetite cells in the brain respond to fasting." ScienceDaily. www.sciencedaily.com/releases/2012/02/120208132255.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
US to Track Everyone Coming from Ebola Nations

US to Track Everyone Coming from Ebola Nations

AP (Oct. 22, 2014) Stepping up their vigilance against Ebola, federal authorities said Wednesday that everyone traveling into the US from Ebola-stricken nations will be monitored for symptoms for 21 days. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Doctors Help Paralysed Man Walk Again, Patient in Disbelief

Doctors Help Paralysed Man Walk Again, Patient in Disbelief

AFP (Oct. 22, 2014) Polish doctors describe how they helped a paralysed man walk again, with the patient in disbelief at the return of sensation to his legs. Duration: 1:04 Video provided by AFP
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