کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6258456 | 1612974 | 2014 | 6 صفحه PDF | دانلود رایگان |
- Gap induced prepulse inhibition is a summary of the prepulse inhibition caused by the onset and the offset of the silent gap.
- High doses of salicylate causes onset-gap induced facilitation of acoustic startle response .
- The onset-gap induced facilitation may be more likely caused by tinnitus or hyperacusis, but not by hearing loss.
- Vigabatrin treatment did not reduce salicylate induced startle enhancement, but reduces gap induced facilitation and inhibition.
Prepulse inhibition of acoustic startle reflex (PPI), a well-established method for evaluating sensorimotor gating function, has been used to detect tinnitus in animal models. Reduced gap induced PPI (gap-PPI) was considered as a sign of tinnitus. The silent gap used in the test contains both onset and offset signals. Tinnitus may affect these cues differently. In this experiment, we studied the effects of a high dose of salicylate (250Â mg/kg, i.p.), an inducer of reversible tinnitus and sensorineural hearing loss, on gap-PPI induced by three different gaps: an onset-gap with 0.1Â ms onset and 25Â ms offset time, an offset-gap with 25Â ms onset and 0.1Â ms offset time, and an onset-offset-gap with 0.1Â ms onset and offset time. We found that the onset-gaps induced smaller inhibitions than the offset-gaps before salicylate treatment. The offset-gap induced PPI was significantly reduced 1-3Â h after salicylate treatment. However, the onset-gap caused a facilitation of startle response. These results suggest that salicylate induced reduction of gap-PPI was not only caused by the decrease of offset-gap induced PPI, but also by the facilitation induced by the onset-gap. Since the onset-gap induced PPI is caused by neural offset response, our results suggest that salicylate may cause a facilitation of neural response to an offset acoustical signal. Treatment of vigabatrin (60Â mg/kg/day, 14Â days), which elevates the GABA level in the brain, blocked the offset-gap induced PPI and onset-gap induced facilitation caused by salicylate. These results suggest that enhancing GABAergic activities can alleviate salicylate induced tinnitus.
Journal: Behavioural Brain Research - Volume 258, 1 January 2014, Pages 187-192