Effect of cupula shrinkage on the semicircular canal activity

Abstract

Conclusion: With half-sized cupula, the semicircular canal nerve potentials decreased under slow stimulus, thus potentially leading to reduced caloric response. This also suggests that shrunken cupula may cause dizziness because of its hypermobility. Objectives: To examine the physiological effect of half-sized cupula on the semicircular canal nerve potential. Methods: The isolated cupula of the bullfrog was sectioned in half with fine scissors and was replaced on the crista. Mechanical endolymphatic flow and slow and fast stimuli were delivered and the evoked action potentials were recorded. Results: The cupula was successfully sectioned in half and was replaced on the crista. With the half-sized cupula, the action potentials became smaller under slow stimulus than under fast stimulus.

Keywords::

• Cupula replacement
• caloric response
• dizziness

Acknowledgment

This study was supported by a Health and Labor Science Research Grant for Research on Specific Disease (Vestibular Disorders) from the Ministry of Health, Labor and Welfare, Japan (2009) and a Grant-in Aid for Scientific Research (C) (19591989) provided by the Ministry of Education, Science and Culture, Japan.

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