Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Spinal cord neurons that control pain and itch

19.03.2015

The spinal cord transmits pain signals to the brain, where they are consciously perceived. But not all the impulses arrive at their destination: Certain neurons act as checkpoints and determine whether a pain signal is relayed or not. Researchers from UZH identified these neurons and their connections. Moreover, they developed means to specifically activate these neurons, which reduces not only pain – but astonishingly also alleviates itch.

Sensing pain is extremely unpleasant and sometimes hard to bear – and pain can even become chronic. The perception of pain varies a lot depending on the context in which it is experienced. 50 years ago, neurobiologist Patrick Wall and psychologist Ronald Melzack formulated the so-called “Gate Control Theory” of pain.

The two researchers proposed that inhibitory nerve cells in the spinal cord determine whether a pain impulse coming from the periphery, such as the foot, is relayed to the brain or not. A team headed by Hanns Ulrich Zeilhofer from the Institute of Pharmacology and Toxicology at the University of Zurich did now reveal which inhibitory neurons in the spinal cord are responsible for this control function: As the study published in the science journal Neuron shows, the control cells are located in the spinal dorsal horn and use the amino acid glycine as an inhibitory messenger.

The pain gate can be manipulated with viruses

With the aid of genetically modified viruses, the research group from UZH managed to specifically interfere with the function of these neurons in mice. They discovered that disabling the glycine-releasing neurons leads to an increased sensitivity to pain and signs of spontaneous pain. Moreover, Zeilhofer‘s team developed viruses that enable these specific pain-control cells to be activated pharmacologically. Mice treated with these viruses were less sensitive to painful stimuli than their untreated counterparts. Activating these nerve cells also alleviated chronic pain. And the surprising additional result: “Evidently, the neurons don’t just control pain, but also various forms of itch,” explains Zeilhofer.

How light touch controls pain

One key aspect of the Gate Control Theory is that various influences can modulate the pain-controlling neurons’ activity. Based on our experience from everyday life, for instance, we know that gently rubbing or holding an injured extremity can alleviate pain in this area. According to the theory, non-painful contact with the skin is supposed to activate the inhibitory cells. Sure enough, the UZH researchers were able to verify this hypothesis and confirm that the inhibitory, glycine-releasing neurons are innervated by such touch-sensitive skin nerves.

Moreover, the pharmacologists were able to demonstrate that neurons on the superficial layers of the spinal cord, where the relay of the pain signals takes place, are primarily inhibited by glycine signals. “These three findings identify for the first the neurons and connections that underlie the Gate Control Theory of pain,” sums up Zeilhofer.

Targeted therapy in humans not yet possible

Can these findings be used to treat pain? “The targeted stimulation or inhibition of particular types of neurons in humans is still a long way off and might only be possible in a few decades’ time,” says Zeilhofer. Another way may well reach the target sooner – namely via the receptors that are activated by the inhibitory neurons: “As these receptors are located on the neurons that relay pain signals to the brain, their specific pharmacological activation should also block pain,” says Hanns Ulrich Zeilhofer. His group has already achieved promising initial results in this field, too.

Literature:

Edmund Foster, Hendrik Wildner, Laetitia Tudeau, Sabine Haueter, William T. Ralvenius, Monika Jegen, Helge Johannssen, Ladina Hösli, Karen Haenraets, Alexander Ghanem, Karl Klaus Conzelmann, Michael Bösl, Hanns Ulrich Zeilhofer (2015) Targeted ablation, silencing and activation establish glycinergic dorsal horn neurons as key components of a spinal gate for pain and itch. Neuron, in press. http://dx.doi.org/10.1016/j.neuron.2015.02.028


Contacts:

Hanns Ulrich Zeilhofer

Institute of Pharmacology and Toxicology

University of Zurich and ETH Zurich

Tel.: +41 44 63 55912

Email: zeilhofer@pharma.uzh.ch

Weitere Informationen:

http://www.mediadesk.uzh.ch

Nathalie Huber | Universität Zürich

Further reports about: Neuron Toxicology activation function inhibitory inhibitory neurons nerve cells neurons pain skin spinal spinal cord viruses

More articles from Life Sciences:

nachricht In focus: Peptides, the “little brothers and sisters” of proteins
12.11.2018 | Technische Universität Berlin

nachricht How to produce fluorescent nanoparticles for medical applications in a nuclear reactor
09.11.2018 | Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

Im Focus: Nanorobots propel through the eye

Scientists developed specially coated nanometer-sized vehicles that can be actively moved through dense tissue like the vitreous of the eye. So far, the transport of nano-vehicles has only been demonstrated in model systems or biological fluids, but not in real tissue. The work was published in the journal Science Advances and constitutes one step further towards nanorobots becoming minimally-invasive tools for precisely delivering medicine to where it is needed.

Researchers of the “Micro, Nano and Molecular Systems” Lab at the Max Planck Institute for Intelligent Systems in Stuttgart, together with an international...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

In focus: Peptides, the “little brothers and sisters” of proteins

12.11.2018 | Life Sciences

Materials scientist creates fabric alternative to batteries for wearable devices

12.11.2018 | Materials Sciences

A two-atom quantum duet

12.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>