Navigation Links
How the brain learns to become addicted

Researchers have identified a key signaling molecule in the brain that appears to trigger the brain to "learn" a craving for cocaine. Their finding could offer an important target for drugs to treat addiction by short-circuiting that adaptive process.

In an article in the February 16, 2006, issue of Neuron, Antonello Bonci and colleagues established that a short protein, or peptide, called orexin A acts on a brain region central to the adaptation to addictive drugs. Specifically, they found in their studies with rats that orexin A induces an adaptation that is necessary for the development of behaviors associated with drug-craving in human addicts. The latest findings follow an earlier discovery by the same group that another molecule, corticotropin releasing factor (CRF), acts similarly.

Such adaptations are believed to create a need that is far more compelling than the simple memory of drug-induced pleasure and represent a "rewiring" of the brain into an addictive state.

In a preview article on the paper in the same issue of Neuron, NIH neuroscientist Roy Wise commented that "Inasmuch as arousal or stress can trigger drug-seeking in drug-free animals, the neuroadaptations discovered by the Bonci group are important not only for how rewarding the drug is after an animal starts taking it, but, perhaps more importantly, for how likely the animal is to initiate drug-seeking during periods of abstinence.

"Because it is during periods of abstinence, not periods of intoxication, that addicts seek treatment, the peptide signaling pathways for orexin and CRF may prove to be fruitful targets in the search for addiction medications."

Bonci and his colleagues based their experiments on past studies by other researchers showing that orexins are important regulatory peptides released by a brain center called the lateral hypothalamus. It was also known that orexins tend to activate circuitry in a region called the ventral tegmental area (VT A), known to be a critical site of neural adaptation, or plasticity, induced by addictive drugs. However, it wasn't known whether orexin actually induced such plasticity.

In experiments with rat brain slices, the researchers demonstrated that orexin A does increase activity of neurons in the VTA associated with such plasticity.

And in experiments with whole animals, the researchers found that orexin A was required for "behavioral sensitization" to cocaine. This sensitization shows itself as a long-lasting increase in activity by the animals when they receive the drug and is an indicator that the animals are experiencing an increased craving for the drug.

Importantly, when the researchers "microinjected" directly into the VTA region of animals a drug that blocks orexin receptors, they found they could block the development of behavioral sensitization.

"The findings presented here establish a potential mechanism for the role of orexin signaling in plasticity related to addiction," concluded the researchers. The researchers wrote that this orexin-induced plasticity in the VTA "is likely an important substrate of behaviors relevant to addiction, as we show that activation of [orexin] receptors in the VTA is necessary for the development of cocaine-mediated behavioral sensitization. Thus, orexin receptors may provide novel pharmacotherapeutic targets for motivational disorders such as addiction.


'"/>

Source:Cell Press


Related biology news :

1. Controversial drug shown to act on brain protein to cut alcohol use
2. Mouse brain cells rapidly recover after Alzheimers plaques are cleared
3. Mouse brain tumors mimic those in human genetic disorder
4. New imaging method gives early indication if brain cancer therapy is effective, U-M study shows
5. First atlas of key brain genes could speed research on cancer, neurological diseases
6. NYU study reveals how brains immune system fights viral encephalitis
7. Stem cells from brain transformed to produce insulin at Stanford
8. Birds brains reveal source of songs
9. Loves all in the brain: fMRI study shows strong, lateralized reward, not sex, drive
10. Revolutionary nanotechnology illuminates brain cells at work
11. A puzzle piece found in unraveling the wiring of the brain
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:1/25/2016)...  Glencoe Software, the world-leading supplier of image data ... provide the data management solution OMERO Plus for the ... Photo - http://photos.prnewswire.com/prnh/20160125/325328LOGO ... Phenotypic analysis measures the characteristics and behavior of ... states such as health and disease, the presence or ...
(Date:1/21/2016)... --> ... report "Emotion Detection and Recognition Market by Technology (Bio-Sensors, NLP, ... Voice Recognition and Others), Services, Application Areas, End ... published by MarketsandMarkets, the global Emotion Detection and ... Billion by 2020, at a CAGR of 31.9%, ...
(Date:1/20/2016)... SAN JOSE, Calif. , Jan. 20, 2016 ... leading developer of human interface solutions, today announced ... touch controller solution for wearables and small screen ... appliances such as printers. Supporting round and rectangular ... the S1423 offers excellent performance with moisture on ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... ... February 09, 2016 , ... Tunnell Consulting, Inc. announced that ... Paris, he will focus on acquiring new accounts and work closely with existing Tunnell ... , “Fred brings to our European clients more than 15 years of experience in ...
(Date:2/9/2016)... ... February 09, 2016 , ... PharmApprove ... for the National Organization for Rare Disorders (NORD). Dorman will lead PharmApprove efforts ... are heard throughout the drug regulatory review process. , “Adding Diane Dorman is ...
(Date:2/9/2016)... LONDON , February 9, 2016 ... replace paper and protect IP   E-WorkBook ... will be rolled out in Germany ... and protect valuable IP. Users will be able to search ... or experiment as part of the application, to boost collaboration ...
(Date:2/9/2016)... Feb. 9, 2016 ... 2016", report provides in depth insights on ... around the Protein-Tyrosine Phosphatase 1B (PTP1B) Inhibitors. ... in various stages of development including Discovery, ... III and Preregistration. Report covers the product ...
Breaking Biology Technology: