Transmitters and Pathways Mediating Inhibition of Spinal Itch-Signaling Neurons by Scratching and Other Counterstimuli
2011

How Scratching Reduces Itch in Mice

Sample size: 45 publication 10 minutes Evidence: high

Author Information

Author(s): Akiyama Tasuku, Iodi Carstens Mirela, Carstens Earl

Primary Institution: University of California Davis

Hypothesis

Scratching inhibits spinal itch-signaling neurons through the action of inhibitory neurotransmitters GABA and glycine.

Conclusion

Scratching significantly reduces the activity of spinal neurons associated with itch, primarily through the release of GABA and glycine.

Supporting Evidence

  • Scratching reduced neuronal firing by over 30% in most units tested.
  • The glycine antagonist strychnine significantly reduced scratch-evoked inhibition.
  • Cold-block of the upper cervical spinal cord reduced the inhibitory effect of scratching by 30%.
  • Scratching activated both segmental and supraspinal circuits to inhibit itch signaling.

Takeaway

When you scratch an itch, it helps calm down the nerves that make you feel itchy, kind of like how a hug can make you feel better when you're sad.

Methodology

The study used a mouse model to investigate the effects of scratching on spinal itch-signaling neurons, measuring neuronal activity before, during, and after scratching.

Limitations

The study was conducted in a mouse model, which may not fully replicate human itch mechanisms.

Participant Demographics

ICR mice (25–42 g)

Statistical Information

P-Value

p<0.001

Statistical Significance

p<0.001

Digital Object Identifier (DOI)

10.1371/journal.pone.0022665

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