Pain-initiating function of glial cells identified for the first time

November 11, 2016
Pain-initiating function of glial cells identified for the first time

The sensation of pain occurs when neural pathways conduct excitation generated by tissue damage to the spinal cord, where the nociceptive information is extensively pre-processed. From there, the information is transmitted to the human brain, where the sensation of "pain" is finally created. This is the general belief. However, researchers from the Division of Neurophysiology at MedUni Vienna's Center for Brain Research have now discovered that pain is not just a matter of nerves but that non-neuronal cells, the glial cells, are also involved in clinically relevant pain models and their activation is sufficient to amplify pain. The study has now been published in the leading journal Science.

Glial cells are the commonest type of cells in the and . They surround neurons but are distinct from them and play an important supporting role – for example, in material transport and metabolism or the fluid balance in the brain and spinal cord.

Novel explanation for puzzling pain phenomena

At the same time, however, when they are activated – by processes, for example ¬– glial cells are themselves able to release messenger substances, such as inflammatory cytokines. Glial cells therefore have two modes: a protective and a pro-inflammatory mode. "The activation of glial cells results in a pain-amplifying effect, as well as spreading the pain to previously unaffected parts of the body. For the very first time, our study provides a biological explanation for this and for other hitherto unexplained pain phenomena in medicine," says Jürgen Sandkühler, Head of the Division of Neurophysiology at MedUni Vienna's Center for Brain Research.

Over-activation of glial cells in the spinal cord can, for example, be caused by strong pain stimuli from a wound or surgical intervention, or even by opiates. Sandkühler: "This could also explain why opiates are initially very good at relieving pain but then often cease to be effective. Another example is the phenomenon of "withdrawal" in drug addicts, where activated glial cells cause severe pain throughout the body."

A healthy lifestyle can beneficially impact the glial cell system

According to Sandkühler, neuroinflammatory diseases of the brain, environmental factors and even the person's own lifestyle can lead to activation of . Examples from the current literature are: depression, anxiety disorders and chronic stress, multiple sclerosis or Alzheimer's and diabetes, as well as lack of exercise and poor diet. Sandkühler: "Glial are an important factor in ensuring the equilibrium of a person's neuroinflammatory system." The study results give grounds for speculation that improvements in a person's lifestyle could have a beneficial impact upon this system and ensure that they generally suffer less pain or "minor niggles", says Sandkühler: "It is therefore in our own hands: thirty minutes of moderate exercise three or four times a week, a healthy diet and avoiding putting on excess weight can make a huge difference."

Explore further: Narcotic painkillers prolong pain in rats, study finds

More information: Gliogenic LTP spreads widely in nociceptive pathways. Science  10 Nov 2016: DOI: 10.1126/science.aah5715

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TogetherinParis
not rated yet Nov 14, 2016
Oligodendrocytes are shared capacitance cells. By providing a conduit for capacitance among many neurons, a concerted effort is arranged. Patterns form coordinations.
The reason capacitor-Schwanns are uniform on a motor nerve is the inverse summation of capacitance: it doesn't pay to total capacitance in any other way. Physics 101, design a circuit with capacitors, they're all the same size or else they'll cost more. Serial capacitance discharge of Schwann cells across the zener diodes of the nodes of Ranvier propagates saltative conduction and assures one way transmissions.
Heat of capacitance is why myelin does not consume enough O2 to account for its generation of heat.
3 phases: inductance, capacitance, and conductance (1/r) all utilized, why? No copper, so capacitance is easier to propagate. See any coronal section of a Schwann or oligodendritic wrap to identify an obvious capacitor. Looking at the lines of tissue shows them to be alternating most/least conductive.

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