Navigation Links
Machinery of the 'marijuana munchies'

Marijuana--or more specifically its active ingredient, tetrahydrocannabinol--has a well-documented tendency to stimulate hunger. And while scientists have traced this property to cannabinoid receptors in the brain, they have had little understanding of the neural circuitry underlying this effect.

Understanding this circuitry has important practical implications because blocking the cannabinoid receptor, CB1, offers a promising approach to treating obesity. One such compound, rimonabant (trade name AcompliaTM) is already undergoing clinical testing.

In an article in the December 22, 2005, issue of Neuron, Young-Hwan Jo and colleagues report how the circuitry of CB1 is integrated with signaling by the appetite-suppressing hormone leptin. The CB1 receptor is normally triggered by natural regulatory molecules, called endocannabinoids.

In their studies, the researchers concentrated on the lateral hypothalamus (LH) of the brain, known to be a center of control of food intake. Their studies involved detailed electrophysiological measurements of the effects of specific neurons that they had identified in previous studies as being important in endocannabinoid signaling.

Their studies revealed that activation of CB1 receptors, as by endocannabinoid molecules, induced these neurons to be rendered more excitable by a mechanism called "depolarization-induced suppression of inhibition" (DSI).

What's more, they found that leptin inhibits DSI. However, they found that leptin did not interfere with the CB1 receptors themselves. Rather, leptin "short-circuits" the endocannabinoid effects by inhibiting pore-like channels in the neurons that regulate the flow of calcium into the neurons. Such calcium is necessary for the synthesis of endocannabinoids.

In further studies of mice genetically altered to be leptin deficient, the researchers found the DSI to be more prolonged than in normal mice. Thus, they said, the findings "i mplicate this mechanism for leptin receptor/endocannabinoid signaling in contributing to the maintenance of weight balance?" The researchers also included that "upregulation of endocannabinoid signaling in the LH may explain, at least in part, the increased body weight consistent with a prior report of elevated endocannabinoids" in such leptin-deficient mice.

The researchers concluded that their findings "are consistent with the hypothesis that the integration of endocannabinoid and leptin signaling regulates the excitability of neurons on appetite-related circuits."

They also wrote that "the cellular mechanisms of recently developed antiobesity drugs, such as rimonabant, may include decreased endocannabinoid signaling and hence decreased excitability of LH circuits related to appetite, even in the context of leptin insufficiency or resistance."


'"/>

Source:Cell Press


Related biology news :

1. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
2. Scientists Replicate Hepatitis C Virus in Laboratory
3. Scientists detect probable genetic cause of some Parkinsons disease cases
4. Scientists find missing enzyme for tuberculosis iron scavenging pathway
5. Scientists seek answers on what activates deadly anthrax spores
6. Yale Scientists Find MicroRNA Regulates Ras Cancer Gene
7. Scientists collaborate to assess health of global environment
8. Scientists decipher genome of fungus that can cause life-threatening infections
9. Scientists discover the cellular roots of graying hair
10. Scientists rid stem cell culture of key animal cells
11. Scientists develop new color-coded test for protein folding
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/19/2016)... , UAE, April 20, 2016 ... be implemented as a compact web-based "all-in-one" system solution ... the biometric fingerprint reader or the door interface with ... of modern access control systems. The minimal dimensions of ... ID readers into the building installations offer considerable freedom ...
(Date:4/14/2016)... 14, 2016 BioCatch ™, ... today announced the appointment of Eyal Goldwerger ... Goldwerger,s leadership appointment comes at a time ... the deployment of its platform at several of the ... which discerns unique cognitive and physiological factors, is a ...
(Date:3/31/2016)... March 31, 2016  Genomics firm Nabsys has completed ... Barrett Bready , M.D., who returned to the ... original technical leadership team, including Chief Technology Officer, ... Development, Steve Nurnberg and Vice President of Software and ... company. Dr. Bready served as CEO of ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016   Boston Biomedical ... novel compounds designed to target cancer stemness pathways, ... been granted Orphan Drug Designation from the U.S. ... of gastric cancer, including gastroesophageal junction (GEJ) cancer. ... designed to inhibit cancer stemness pathways by targeting ...
(Date:6/23/2016)... Prostate Cancer Foundation (PCF) is pleased to announce 24 new Young ... cancer. Members of the Class of 2016 were selected from a pool of ... More About the Class of 2016 PCF Young Investigators ... ... ...
(Date:6/23/2016)... , ... June 23, 2016 , ... In a new ... in Denmark detail how a patient who developed lymphedema after being treated for breast ... results could change the paradigm for dealing with this debilitating, frequent side effect of ...
(Date:6/23/2016)... ... 23, 2016 , ... ClinCapture, the only free validated electronic ... showcase its product’s latest features from June 26 to June 30, 2016 for ... Disrupting Clinical Trials in The Cloud during the conference. DIA (Drug Information ...
Breaking Biology Technology: