Overview
Signaling at the Vestibular Calyx Synapse (First Award Fellowship)
Principal Investigator:
Frances L. Meredith, Ph.D.
Organization:
University of Colorado
Technical Summary
The vestibular system is responsible for the sense of balance. Hair cells in the vestibular system of the inner ear send signals to the brain in the form of action potentials. Signals from the brainstem are also known to modulate the firing of such action potentials. Precisely how mechanical signals that are generated by head movements are detected and transformed into electrical signals by hair cells and the nerve fibers that contact them is poorly understood.
The project’s goal is to better understand the transfer of information between hair cells and afferents. The vestibular system of mammals has two types of hair cells. Type I hair cells have unusual features including an afferent calyx nerve terminal that surrounds most of the hair cell’s basolateral membrane. The researchers have developed preparations to record from and visualize calyx terminals that are isolated or in the sensory epithelium. These preparations will allow the researchers to study how transmission at the type I hair cell/calyx synapse is shaped by mechanisms on either side of the synapse under a variety of conditions.
Currently, there are many therapeutic interventions used in attempts to treat dizziness, vertigo and space motion sickness. However, the mechanism of action of such treatments is mostly unknown. The proposed studies will elucidate cellular mechanisms underlying balance sensation in rodents. A better understanding of how sensory information is transformed by vestibular hair cells into neural signals will elucidate signaling mechanisms in a normal environment and conditions such as spaceflight, where gravity is altered. This could drive future studies incorporating pharmacological interventions to combat vestibular dysfunction.