Related Experiment Video
Updated: Jun 22, 2026
09:54
Morphological and Functional Evaluation of Ribbon Synapses at Specific Frequency Regions of the Mouse Cochlea
Published on: May 10, 2019
Nogo in the Mammalian cochlea
Antje Caelers1, Arianne Monge, Jochen Michael
1Inner Ear Research, Department of Biomedicine University Hospital Basel and the Klinik für Ohren-, Nasen-, Halskrankheiten University Hospital Basel, Basel, Switzerland.
Summary
The Nogo system, including Nogo A, B, C, and its receptor, is expressed in the mammalian cochlea. Deleting Nogo A does not impact cochlear structure or hearing function in mice.
Area of Science:
- Neuroscience
- Otolaryngology
- Cell Biology
Background:
- The Nogo system inhibits neurite outgrowth in the central nervous system.
- Its role in the mammalian cochlea remains largely unknown.
Purpose of the Study:
- To investigate the expression of Nogo system components in the cochlea.
- To determine the impact of Nogo A deletion on cochlear structure and hearing.
Main Methods:
- Reverse-transcriptase-polymerase chain reaction (RT-PCR) for gene expression analysis.
- Immunohistochemistry to localize protein expression.
- Auditory brainstem response (ABR) audiometry in Nogo A knockout and wild-type mice.
Main Results:
- Nogo A, B, C, and Nogo receptor mRNA are expressed in the organ of Corti, spiral ganglion, and stria vascularis.
- Nogo A and Nogo receptor proteins are localized to spiral ganglion neurons.
- Nogo A is also found in outer and inner hair cells; its absence does not affect cochlear microanatomy or hearing levels in adult mice.
Conclusions:
- Various Nogo family members are expressed within the mammalian cochlea.
- Nogo A deletion does not lead to observable changes in cochlear microanatomy or hearing function.
Related Concept Videos
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.
01:22Hair 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.
01:16Anatomy of the Ear
Auditory sensation, commonly called hearing, involves the transformation of sonic waves into neural impulses facilitated by the structures of the auditory organ. The prominent, flesh-like structure on the side of the head, called the auricle, directs sound waves towards the auditory canal. The auricle is often mislabeled as the pinna, a term more aligned with mobile structures like a feline's external ear. The auditory canal penetrates the cranium via the external auditory meatus of the...
01:15Auditory Pathway
Auditory pathways constitute the complex neural circuits responsible for transmitting and interpreting auditory information from the peripheral auditory system to the brain. Sound waves are initially captured by the outer ear, funneled through the ear canal, and reach the tympanic membrane (eardrum). These vibrations are transmitted via the middle ear's ossicles to the inner ear's cochlea.
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking the...
01:11The Auditory Ossicles
The auditory ossicles of the middle ear transmit sounds from the air as vibrations to the fluid-filled cochlea. The auditory ossicles consist of two malleus (hammer) bones, two incus (anvil) bones, and two stapes (stirrups), one on each side. These bones develop during the fetal stage and are the ones to ossify first. They are fully mature at birth and do not grow afterward.
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
01:31Hearing
When we hear a sound, our nervous system is detecting sound waves—pressure waves of mechanical energy traveling through a medium. The frequency of the wave is perceived as pitch, while the amplitude is perceived as loudness.