The effects of acute stress-induced sleep disturbance on acoustic trauma-induced tinnitus in rats

Biomed Res Int. 2014:2014:724195. doi: 10.1155/2014/724195. Epub 2014 Aug 3.

Abstract

Chronic tinnitus is a debilitating condition and often accompanied by anxiety, depression, and sleep disturbance. It has been suggested that sleep disturbance, such as insomnia, may be a risk factor/predictor for tinnitus-related distress and the two conditions may share common neurobiological mechanisms. This study investigated whether acute stress-induced sleep disturbance could increase the susceptibility to acoustic trauma-induced tinnitus in rats. The animals were exposed to unilateral acoustic trauma 24 h before sleep disturbance being induced using the cage exchange method. Tinnitus perception was assessed behaviourally using a conditioned lick suppression paradigm 3 weeks after the acoustic trauma. Changes in the orexin system in the hypothalamus, which plays an important role in maintaining long-lasting arousal, were also examined using immunohistochemistry. Cage exchange resulted in a significant reduction in the number of sleep episodes and acoustic trauma-induced tinnitus with acoustic features similar to a 32 kHz tone at 100 dB. However, sleep disturbance did not exacerbate the perception of tinnitus in rats. Neither tinnitus alone nor tinnitus plus sleep disturbance altered the number of orexin-expressing neurons. The results suggest that acute sleep disturbance does not cause long-term changes in the number of orexin neurons and does not change the perception of tinnitus induced by acoustic trauma in rats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal
  • Hearing Loss, Noise-Induced / physiopathology
  • Intracellular Signaling Peptides and Proteins / biosynthesis
  • Neurons / metabolism*
  • Neurons / pathology
  • Neuropeptides / biosynthesis
  • Orexins
  • Rats
  • Sleep Wake Disorders / genetics
  • Sleep Wake Disorders / physiopathology*
  • Tinnitus / physiopathology*

Substances

  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Orexins