GABAergic synapses between auditory efferent neurons and type II spiral ganglion afferent neurons in the mouse cochlea

Cochlear outer hair cells (OHCs) are electromotile and implicated in amplification of responses to sound that enhance sound sensitivity and frequency tuning. They send afferent information through glutamatergic synapses onto type II spiral ganglion neurons (SGNs). These synapses are weaker than those from cochlear inner hair cells (IHC) onto type I SGN, suggesting that type II SGNs respond only to intense sound levels. OHCs also receive efferent innervation from medial olivocochlear (MOC) neurons. MOC neurons are cholinergic yet inhibit OHCs due to the functional coupling of alpha9/alpha10 nicotinic acetylcholine receptors (nAChRs) to calcium-activated SK potassium channels. The resulting hyperpolarization reduces OHC activity-evoked electromotility and is implicated in cochlear gain control, protection against acoustic trauma, and attention. MOC neurons also label for markers of GABA and GABA synthesis. GABAB autoreceptor (GABABR) activation on MOC terminals has been demonstrated to re..., Mice and ethical approval
Animal procedures followed National Institutes of Health guidelines, as approved by the National Institute of Neurological Disorders and Stroke/National Institute on Deafness and Other Communication Disorders Animal Care and Use Committee. Male and female mice were used in experiments. Mouse lines included wildtype (WT) C57BL/6J (Jax Cat No: 000664), ChAT-IRES-Cre (Jax Cat No: 028861), ChAT-IRES-Cre Δneo (Jax Cat No: 031661), Ngn-CreERT2 (Jax Cat No: 008529), Ai14 tdTomato reporter mice (Jax Cat No: 007914), and Bhlhb5-Cre (on Sv/129, C57BL/6J mixed background). Mice were housed on a 12/12 hr light/dark cycle, with continuous availability of food and water. Mice were anesthetized by carbon dioxide inhalation at a rate of 20% of anesthesia chamber volume per minute and then killed by decapitation.
Immunohistochemistry
Mice aged postnatal day (P)5- 20 were euthanized as above and used for immunohistochemical experiments in cochlear whole mount preparations. Tempo..., , # GABAergic synapses between auditory efferent neurons and type II spiral ganglion afferent neurons in the mouse cochlea

[https://doi.org/10.5061/dryad.2rbnzs80g](https://doi.org/10.5061/dryad.2rbnzs80g)

## Description of the data and file structure

Access this data at: [https://doi.org/10.5061/dryad.2rbnzs80g](https://doi.org/10.5061/dryad.2rbnzs80g)

We have submitted our raw Patch-Clamp Electrophysiology, Immunohistochemistry, and iGABASnFR optical detection data to support the Bachman, Kitcher et al 2025 manuscript.

**Notes:**

Data and File Structure: All raw data files contained in the .zip file “Bachman et al 2025” 

Excel file “Bachman et al 2025 PNAS files” contains a list of file names, types, and additional details for the dataset.

Nikon files are all Nikon LIM .nd2 file type, but are noted in the attached excel file as Nikon LIM file type. .nd2 files can be viewed in Nikon Elements viewers or ImageJ.

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