Related Experiment Video
Updated: May 27, 2026
12:43
Patch Clamp Recordings in Inner Ear Hair Cells Isolated from Zebrafish
Published on: October 17, 2012
HCN channels expressed in the inner ear are necessary for normal balance function
Geoffrey C Horwitz1, Jessica R Risner-Janiczek, Sherri M Jones
1Department of Neuroscience and Department of Otolaryngology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA.
Summary
The hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) is crucial for vestibular hair cell function. HCN1 deficiency impairs balance and vestibular-evoked potentials in mice.
Area of Science:
- Neuroscience
- Ion Channels
- Sensory Biology
Background:
- Hyperpolarization-activated ion channels (I(h)) are present in vestibular hair cells, but their molecular identity and function remain unclear.
- These channels are formed by HCN1-4 subunits and are activated by hyperpolarization.
Purpose of the Study:
- To identify the specific HCN subunits responsible for I(h) in mouse vestibular hair cells.
- To elucidate the functional role of I(h) in vestibular hair cell activity and balance.
Main Methods:
- Examined HCN mRNA expression and protein localization in mouse utricle hair cells.
- Utilized whole-cell voltage-clamp electrophysiology to characterize I(h).
- Investigated I(h) in hair cells from mice with genetic deficiencies in Hcn1 and Hcn2 subunits.
Main Results:
- HCN1 was the predominant subunit, localized to the basolateral membranes of type I and II hair cells.
- I(h) was abolished in Hcn1-deficient mice, indicating HCN1's essential role.
- Hcn1 deficiency led to deficits in vestibular-evoked potentials and balance assays.
Conclusions:
- HCN1 is the primary subunit responsible for I(h) in mouse vestibular hair cells.
- HCN1-mediated I(h) is critical for vestibular hair cell function and contributes significantly to the sense of balance.
Related Concept Videos
01:15Equilibrium and Balance
The inner ear assumes dual functionalities of auditory perception and equilibrium maintenance. The vestibule is the organ responsible for balance. This organ contains mechanoreceptors, specifically hair cells, endowed with stereocilia, which aid in deciphering information regarding the position and motion of our heads. Two intrinsic components, the utricle and saccule, help perceive head position, while the semicircular canals track head movement. Neurological messages initiated in the...
01:29The Vestibular System
The vestibular system is a set of inner ear structures that provide a sense of balance and spatial orientation. This system is comprised of structures within the labyrinth of the inner ear, including the cochlea and two otolith organs—the utricle and saccule. The labyrinth also contains three semicircular canals—superior, posterior, and horizontal—that are oriented on different planes.
01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.
01:17Auditory Perception
The auditory system is essential for sound perception, utilizing various critical structures. When sound waves enter the outer ear, they travel through the ear canal and cause the eardrum to vibrate. These vibrations are then transmitted to the middle ear, where three tiny bones – the malleus, incus, and stapes – amplify the sound. This amplification is crucial, as it ensures that the sound vibrations are strong enough to be conveyed to the inner ear. These vibrations then reach the cochlea, a...
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
01:19Ion Channels
The movement of ions like sodium, potassium, and calcium into and out of the cell is essential to maintain the electrochemical gradient in living cells. The ion channels—a class of membrane transport proteins—help maintain this ionic gradient for the smooth functioning of physiological activities such as maintaining cell size and volume, conducting nerve impulses, and gas and nutrient exchange.
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...