Diazepam reduces excitability of amygdala and further influences auditory cortex following sodium salicylate treatment in rats

Abstract

Conclusion: Diazepam can reduce the excitability of lateral amygdala and eventually suppress the excitability of the auditory cortex in rats following salicylate treatment, indicating the regulating effect of lateral amygdala to the auditory cortex in the tinnitus procedure.

Objective: To study the spontaneous firing rates (SFR) of the auditory cortex and lateral amygdala regulated by diazepam in the tinnitus rat model induced by sodium salicylate.

Materials and methods: This study first created a tinnitus rat modal induced by sodium salicylate, and recorded SFR of both auditory cortex and lateral amygdala. Then diazepam was intraperitoneally injected and the SFR changes of lateral amygdala recorded. Finally, diazepam was microinjected on lateral amygdala and the SFR changes of the auditory cortex recorded.

Results: Both SFRs of the auditory cortex and lateral amygdala increased after salicylate treatment. SFR of lateral amygdala decreased after intraperitoneal injection of diazepam. Microinjecting diazepam to lateral amygdala decreased SFR of the auditory cortex ipsilaterally and contralaterally.

Keywords:

• Auditory cortex
• diazepam
• lateral amygdala
• microinjection
• single unit discharge
• sodium salicylate

Acknowledgments

At the end of the paper, I would like to express my sincere thanks to all those who helped me in the course of animal experiments and writing of the paper. Liu Junxiu helped me in the detailed techniques during animal experiments, my supervisor Ma Furong helped me in the design of the study and funding support, Mao Lanqun provided me with the national key laboratory where most of the experiments were completed. I would also like to thank my colleagues such as Zhang Ke, Ke Jia, Li Tao, & Xin Ying, who helped me in the discussion, statistics, and language revision of the paper. Without their help, it would be much harder for me to finish my study and this paper.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Funding information

The research was financially supported by the NSF of China (Grant no. 21272018, 21372020, 21402004 and 81500783), the Key Clinical Project from the Ministry of Health (Grant no. 6245010) and the Beijing Natural Science Foundation of China (Grant no. 7164307).