Cholinergic Modulation of Membrane Properties of Calyx Terminals in the Vestibular Periphery.

Vestibular nerve afferents are divided into regular and irregular groups based on the variability of interspike intervals in their resting discharge. Most afferents receive inputs from bouton terminals that contact type II hair cells as well as from calyx terminals that cover the basolateral walls of type I hair cells. Calyces have an abundance of different subtypes of KCNQ (Kv7) potassium channels and muscarinic acetylcholine receptors (mAChRs) and receive cholinergic efferent inputs from neurons in the brainstem.

Activation of GABA receptors results in excitatory modulation of calyx terminals in rat semicircular canal cristae.

Previous studies have found GABA in vestibular end organs. However, existence of GABA receptors or possible GABAergic effects on vestibular nerve afferents has not been investigated. The current study was conducted to determine whether activation of GABA receptors affects calyx afferent terminals in the central region of the cristae of semicircular canals.

A novel intracochlear injection method for rapid drug delivery to vestibular end organs.

Background: Injection into the inner ear through the round window (RW) or a cochleostomy is a reliable method for delivering drugs or viruses to the cochlea. This method has been less effective for fast deliveries to vestibular end organs.

New Method: We describe a novel approach for rapid delivery of drugs to the vestibular end organ via the oval window (OW) and scala vestibuli in 1-3 month old C57BL/6 mice.