Protective effect of adenosine on temporary threshold shift of audition caused by intensive white noise in guinea pigs / 第二军医大学学报

Objective: To investigate the protective effect of adenosine on hearing in acute acoustic trauma and its modulatory action in the cochlea. Methods:Guinea pigs were exposed to 118 dB SPL white noise for 30 min. During the process of exposure, artificial perilymph or artificial perilymph containing 1 mmol/L adenosine was infused into the cochlea through perilymphatic perfusion. Thresholds of compound action potentials (CAP) evoked by click and tone burst were measured before and after noise exposure. Results: Immediately after exposure, the mean threshold shifts evoked by click of the control group and adenosine treated group were (40?6.68) dB and (20?5.70) dB respectively. The threshold shifts evoked by tone burst at 2 8 kHz in the control animals were 32 50 dB, while in the adenosine treated animals, 20 35 dB. There were significant differences between the 2 groups except that at 6 kHz. Two hours after exposure, there was an increase of 4 8 dB at all frequencies in the control group; no changes in the adenosine treated group were found. There were significant differences in threshold shifts between the 2 groups at all test frequencies. Conclusion: Adenosine has protective effect on temporary threshold shift in acute acoustic trauma in guinea pigs. [

Effect of adenosine on perilymph glutamate concentration and compound action potentials in guinea pigs exposed to white noise / 第二军医大学学报

Objective:To investigate the protective effect of adenosine on cochlea in acute acoustic trauma. Methods: Guinea pigs were exposed to 118 dB SPL white noise for 30 min. During the process of exposure, artificial perilymph or artificial perilymph containing adenosine (0.1 mmol/L,1 mmol/L or 5 mmol/L) was infused into the cochlea through perilymphatic perfusion. Concentration of glutamate in perilymph and thresholds of compound action potentials (CAP) were measured before and after noise exposure. Results: After exposure, the concentration of glutamate and the mean threshold shifts evoked by click were significantly higher than those of before exposure. Concentration of glutamate and thresholds of CAP in adenosine (1 mmol/L and 5 mmol/L) treated groups were significantly lower than those of the control group. Conclusion: Adenosine can inhibit the elevation of glutamate and decrease the threshold shift of CAP after exposure to noise,which can protect cochlea in acute acoustic trauma in guinea pigs.