Effect of Long-Term Sodium Salicylate Administration on Learning, Memory, and Neurogenesis in the Rat Hippocampus

Abstract

Tinnitus is thought to be caused by damage to the auditory and nonauditory system due to exposure to loud noise, aging, or other etiologies. However, at present, the exact neurophysiological basis of chronic tinnitus remains unknown. To explore whether the function of the limbic system is disturbed in tinnitus, the hippocampus was selected, which plays a vital role in learning and memory. The hippocampal function was examined with a learning and memory procedure. For this purpose, sodium salicylate (NaSal) was used to create a rat animal model of tinnitus, evaluated with prepulse inhibition behavior (PPI). The acquisition and retrieval abilities of spatial memory were measured using the Morris water maze (MWM) in NaSal-treated and control animals, followed by observation of c-Fos and delta-FosB protein expression in the hippocampal field by immunohistochemistry. To further identify the neural substrate for memory change in tinnitus, neurogenesis in the subgranular zone of the dentate gyrus (DG) was compared between the NaSal group and the control group. The results showed that acquisition and retrieval of spatial memory were impaired by NaSal treatment. The expression of c-Fos and delta-FosB protein was also inhibited in NaSal-treated animals. Simultaneously, neurogenesis in the DG was also impaired in tinnitus animals. In general, our data suggest that the hippocampal system (limbic system) may play a key role in tinnitus pathology.

Endoplasmic reticulum stress and mitochondrial injury are critical molecular drivers of AlCl3-induced testicular and epididymal distortion and dysfunction: protective role of taurine

“…The potential protective and therapeutic efficacy of taurine against AlCl 3 -induced deleterious effects was previously reported by Abdel-Moneim (2013), Saad et al (2018), Wenting et al (2014), andNiu et al (2018) on testes, kidney, brain, and memory impairment, respectively. In the current study, we attempted to explore the possible protective effects and the underlying mechanisms of taurine on testes and epididymis Fig.…”

Hippocampal Subgranular Zone FosB Expression Is Critical for Neurogenesis and Learning

“…Previous studies of hippocampal ΔFosB could not address neither subregion nor cell type specificity, as they employed either germline whole body knockouts, local viral effects, or correlations (Kurushima H et al, 2005;Niu H et al, 2018;Yutsudo N et al, 2013). Here we show that specifically knocking out FosB in a subset of DG and CA3 cells overlapping strongly with the SGZ caused both reduced cellular proliferation in the SGZ and learning deficits, without altering basal anxiety or locomotor behavior.…”

Neuroprotective Effect of Valproic Acid on Salicylate-Induced Tinnitus

“…Animals receiving long-term administration of salicylate develop tinnitus and hearing loss due to structural abnormalities in the central auditory system and frontal cortex [ 23 ]. Tinnitus is also caused by the abnormal activity of NMDA receptors in the synapses of inner hair cells [ 24 ].…”