Investigation of some ion channel expessions in cochlear nucleus of tinnitus induced rats

Tinnitus is the perception of various phantom sounds without an external sound source. Roughly, 10-15% of general population is affected by this condition and approximately 20% of this ratio require medical attention due to negative effects on quality of daily life. However, formation mechanism of this condition has not been completely understood yet. The aim of this performed study was to investigate expressions of some ion channels (CaV, HCN, NaV, KV, TRPM) in rat noise induced and sodium salicylate induced tinnitus model. Fourty eight, four-month-old male Wistar Albino rats (195-330 gr) were used. The rats were divided into two groups (n=24) according to analysis, Real Time PCR or floursescent immunohistochemistry. Subsequently, these two groups were divided into three sub-groups as noise induced tinnitus group (NT), sodium salicylate induced tinnitus group (SAT) and control group. After tinnitus was induced, cochlear nucleus tissues were collected and analysis was performed. As compared to control groups values, it was observed that mRNAs of HCN1, HCN2, HCN4, SCN1A, SCN2A1, SCN3A, TRPM2, TRPM7, KCNH2, KCNH7, CACNA1B statistically (p<0,05) decreased. However, in flourescent immunohistochemistry analysis made for HCN1, HCN2, HCN4, Erg1-2-3 and Erg3 ion channels, corrected total cell fluorescence obtained from experimental groups were measured less than control groups. Consequently, it was observed that some ion channel expressions were inhibited in cochlear nucleus tissue of rats in noise induced and sodium salicylate induced tinnitus. However, in order to determine where these changes play role in formation mechanism, all expressional changes about ion channels are believed to be examined as a whole. Key Words: Immunohistochemistry, ion channel, Real Time PCR, sodium salicylate, tinnitus.