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)... April 20, 2016 The new ... a compact web-based "all-in-one" system solution for all door ... reader or the door interface with integration authorization management ... control systems. The minimal dimensions of the access control ... the building installations offer considerable freedom of design with ...
(Date:4/15/2016)... , April 15, 2016 ... the,  "Global Gait Biometrics Market 2016-2020,"  report to ... http://photos.prnewswire.com/prnh/20160330/349511LOGO ) , ,The global gait biometrics ... of 13.98% during the period 2016-2020. ... angles, which can be used to compute factors ...
(Date:4/13/2016)... , April 13, 2016  IMPOWER physicians supporting Medicaid ... setting a new clinical standard in telehealth thanks to ... leveraging the higi platform, IMPOWER patients can routinely track ... and body mass index, and, when they opt in, ... convenient visit to a local retail location at no ...
Breaking Biology News(10 mins):
(Date:5/24/2016)... May 24, 2016   MedyMatch Technology Ltd ., the ... intelligence, real-time decision support tools in the emergency room, announced ... 2016 Israeli Advanced Technology Industries (IATI) BioMed Conference. ... 15th National Life Sciences and Technology Week, and ... Intercontinental Hotel in Tel Aviv, Israel . ...
(Date:5/23/2016)... ... May 23, 2016 , ... PrecisionAg® Media ... in 2017 and Beyond. The paper outlines the key trends that are creating ... , “We’ve witnessed a lot of highs and lows as the precision agriculture ...
(Date:5/23/2016)... ... May 23, 2016 , ... ... and services based in Aurora, Ohio, has broken ground on a new building ... Research Triangle Park area, this new location solidifies a commitment to business in ...
(Date:5/20/2016)... ... , ... Kablooe Design, a leading provider of product design and development services ... the business. “We have worked hard to build long-term relationships,” says President and CEO, ... honor of serving their product design and development needs through the years.” , Kablooe ...
Breaking Biology Technology: