This study investigated the effect of systemic salicylate on central auditory
and non-auditory structures in mice. Since cochlear hair cells are known to be
one major target of salicylate, cochlear effects were reduced by using
kanamycin to remove or impair hair cells. Neuronal brain activity was measured
using the non-invasive manganese-enhanced magnetic resonance imaging
technique. For all brain structures investigated, calcium-related neuronal
activity was increased following systemic application of a sodium salicylate
solution: probably due to neuronal hyperactivity. In addition, it was shown
that the central effect of salicylate was not limited to the auditory system.
A general alteration of calcium-related activity was indicated by an increase
in manganese accumulation in the preoptic area of the anterior hypothalamus,
as well as in the amygdala. The present data suggest that salicylate-induced
activity changes in the auditory system differ from those shown in studies of
noise trauma. Since salicylate action is reversible, central pharmacological
effects of salicylate compared to those of (permanent) noise-induced hearing
impairment and tinnitus might induce different pathophysiologies. These should
therefore, be treated as different causes with the same symptoms