Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Key trigger of opioid withdrawal symptoms found

03.02.2005


Researchers have discovered an important chemical in the brain’s neuronal machinery that triggers some of the withdrawal symptoms of opioid drugs like morphine and heroin.



They believe that drugs to inhibit the chemical--called a transporter--could relieve some of the early physical symptoms of withdrawal, such as teeth-chattering, uncontrolled shaking, and jumpiness. Such drugs could become part of the arsenal of medicines and behavioral techniques aimed at helping addicts kick their habits.

To zero in on the machinery underlying withdrawal symptoms, researchers led by Elena Bagley and Macdonald Christie of the Pain Management Research Institute at Royal North Shore Hospital (a division of the University of Sydney) performed biochemical studies on brain slices from mice that had been treated with morphine. Their objective was to understand what happens to a particular region of the midbrain--called the periaqueductal gray (PAG)--known to be involved in such withdrawal symptoms. Opiate addiction inhibits neuron activity in this region, which alters the neuronal machinery to compensate for this inhibition. Upon opiate withdrawal, the neurons rebound, becoming hyperactive.


The scientists’ analysis revealed that a transporter molecule for the neurotransmitter GABA was responsible for the electrical abnormalities that produce a hyperexcitability in the neurons. Neurotransmitters are the molecular ammunition that one neuron fires at its neighbor to trigger a nerve impulse in the neighbor. Propagation of such nerve impulses through the networks of neurons in the brain is the basis of all neural activity. Transporter molecules are the proteins that retrieve neurotransmitter molecules from the spaces between neurons after they trigger nerve impulse, to reload the neuron for its next signaling burst.

Bagley and her colleagues also discovered that a molecular switch called protein kinase A was part of the triggering machinery involved in activating the abnormal GABA transporter activity.

Importantly, the researchers found that drugs that inhibit either the GABA transporter activity or protein kinase A eliminate the hyperexcitability of the PAG neurons in the mouse brain slices.

The researchers cited other studies showing that treatment with opioids also altered levels of the transporter for the neurotransmitter glutamate, "suggesting that neurotransmitter transporters may prove to be useful targets for management of opioid dependence," they wrote. The researchers also wrote that, since GABA is a neurotransmitter that inhibits nerve impulses, drugs to inhibit the GABA transporter "could produce their therapeutic effect through altering extracellular GABA concentrations as well as directly altering the excitability of GABAergic neurons."

Heidi Hardman | EurekAlert!
Further information:
http://www.cell.com

More articles from Life Sciences:

nachricht Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery
20.01.2017 | GSI Helmholtzzentrum für Schwerionenforschung GmbH

nachricht Seeking structure with metagenome sequences
20.01.2017 | DOE/Joint Genome Institute

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>