Funding for this work was provided by a Garnett Passe and Rodney Williams Memorial Foundation Project grant to R. Lim and A.J. Camp.

1. Animals
<ol>
	<li>Mice were obtained from the Australian Rodent Centre (ARC; Perth, Australia) and held at the University of Sydney Bosch Animal Facility on a normal 12-hr light/dark cycle with environmental enrichment. All experiments described were approved by The University of Sydney Animal Ethics Committee.</li>
	<li>Male and female mice (C57/Bl6) were used for all experiments since this strain are commonly used as the background for genetic manipulation, and can be considered equivalent to wildtype <su...

<ol>
	<li>Dulon, D., Safieddine, S., Jones, S. M., Petit, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Otoferlin+is+critical+for+a+highly+sensitive+and+linear+calcium-dependent+exocytosis+at+vestibular+hair+cell+ribbon+synapses.">Otoferlin is critical for a highly sensitive and linear calcium-dependent exocytosis at vestibular hair cell ribbon synapses.</a> J. Neurosci. 29, 10474-10487 (2009).</li><li>Highstein, S., Art, J., Holstein, G., Rabbitt, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+pre-+and+post-synaptic+recording+from+the+peripheral+vestibular+calyx+and+its+included+type+I+hair+cell.">Simultaneous pre- and post-synaptic recording from the peripheral vestibular calyx and its included type I hair cell.</a> , (2009).</li><li>Kindig, A. E., Lim, R., Callister, R. J., Brichta, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voltage+dependent+currents+in+type+I+and+II+hair+cell+and+calyx+terminals+of+primary+afferents+in+an+intact+in+vitro+mouse+vestibular+crista+preparation.">Voltage dependent currents in type I and II hair cell and calyx terminals of primary afferents in an intact in vitro mouse vestibular crista preparation.</a> , (2009).</li><li>Chatlani, S., Goldberg, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-cell+recordings+from+calyx+endings+in+the+turtle+posterior+crista.">Whole-cell recordings from calyx endings in the turtle posterior crista.</a> , (2010).</li><li>Songer, J. E., Eatock, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transduction+in+the+mammalian+saccule.">Transduction in the mammalian saccule.</a> , (2010).</li><li>Lee, H. Y., Camp, A. J., Callister, R. J., Brichta, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vestibular+primary+afferent+activity+in+an+in+vitro+preparation+of+the+mouse+inner+ear.">Vestibular primary afferent activity in an in vitro preparation of the mouse inner ear.</a> J. Neurosci. Methods. 145, 73-87 (2005).</li><li>Lim, R., Kindig, A. E., Donne, S. W., Callister, R. J., Brichta, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potassium+accumulation+between+type+I+hair+cells+and+calyx+terminals+in+mouse+crista.">Potassium accumulation between type I hair cells and calyx terminals in mouse crista.</a> Exp. Brain Res. 210, 607-621 (2011).</li><li>Camp, A. J., Callister, R. J., Brichta, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibitory+synaptic+transmission+differs+in+mouse+type+A+and+B+medial+vestibular+nucleus+neurons+in+vitro.">Inhibitory synaptic transmission differs in mouse type A and B medial vestibular nucleus neurons in vitro.</a> J. Neurophysiol. 95, 3208-3218 (2006).</li><li>Camp, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attenuated+glycine+receptor+function+reduces+excitability+of+mouse+medial+vestibular+nucleus+neurons.">Attenuated glycine receptor function reduces excitability of mouse medial vestibular nucleus neurons.</a> Neuroscience. 170, 348-360 (2010).</li><li>Briggman, K. L., Euler, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bulk+electroporation+and+population+calcium+imaging+in+the+adult+mammalian+retina.">Bulk electroporation and population calcium imaging in the adult mammalian retina.</a> J. Neurophysiol. 105, 2601-2609 (2011).</li><li>Briggman, K. L., Helmstaedter, M., Denk, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wiring+specificity+in+the+direction-selectivity+circuit+of+the+retina.">Wiring specificity in the direction-selectivity circuit of the retina.</a> Nature. 471, 183-188 (2011).</li><li>Rennie, K. J., Streeter, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voltage-dependent+currents+in+isolated+vestibular+afferent+calyx+terminals.">Voltage-dependent currents in isolated vestibular afferent calyx terminals.</a> J. Neurophysiol. 95, 26-32 (2006).</li><li>Hudspeth, A. J., Lewis, R. 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The authors declare that they have no competing financial interests.

The mechanisms underlying our sense of balance have received limited attention in comparison with other sensory systems, e.g. the visual and auditory systems. Of the studies that have investigated changes in vestibular or balance function, most have focused on behavioral measures including the vestibulo-ocular reflex, with incomplete knowledge of the fundamental building blocks of balance- the vestibular hair cells themselves. Those studies that have concentrated on the hair cells have almost invariably do...

Despite the significant contribution of the vestibular system to our everyday lives, a clear understanding of the processes responsible for the observed decline in vestibular function with age remain elusive. One reason for this lack of knowledge is that decline in vestibular function has almost exclusively been explored using behavioral assays, including the vestibulo-ocular reflex (VOR), a precise indicator of extrinsic vestibular function, but provides limited insights into the changes of intrinsic components. This is a major impediment to our understanding of vestibular hair cell function in health, disease, or aging.
While there have been many studies of individual vestibular hair cells, a major shortcoming has been the reliance on acute hair cell preparations, where hair cells and even calyx afferent terminals are removed from their normal environment via mechanical and/or enzymatic treatment. Such approaches inevitably disrupt the delicate microarchitecture between hair cell and calyx, and hair cell and supporting cell. With the development of semi-intact preparations 1-5, and an isolated mouse labyrinth preparation 6, there is now an opportunity to study the various forms of synaptic communication under conditions that more closely resemble those in vivo. Indeed, Lim et al. (2011) showed marked differences in whole cell currents recorded from acutely isolated type I vestibular hair cells compared to those that remained embedded within the neuroepithelium. Specifically, potassium is thought to accumulate in the intercellular space, between the hair cell and calyx afferent, and significantly alter hair cell response7. This type of information would be impossible to obtain without the semi-intact preparation of the vestibular sensory epithelium described here. We demonstrate the semi-intact preparation of the mouse crista 3, and show representative results obtained from whole-cell patch electrophysiology, and two-photon calcium imaging.

<table border="1">
 <tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>REAGENTS</td>
 </tr>
 <tr>
 <td>Leibovitz medium L-15</td>
 <td>Sigma Aldrich</td>
 <td>L4386-10X1L</td>
 <td></td>
 </tr>
 <tr>
 <td>BAPTA-1-oregon green</td>
 <td>Invitrogen</td>
 <td>O6806 </td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>EQUIPMENT </td>
 </tr>
 <tr>
 <td>Stereo microscope</td>
 <td>Leica Microsystems</td>
 <td>A60S</td>
 <td></td>
 </tr>
 <tr>
 <td>Upright microscope</td>
 <td>Olympus</td>
 <td>BX51WI</td>
 <td></td>
 </tr>
 <tr>
 <td>Two-photon microscope</td>
 <td>Olympus/La Vision</td>
 <td>BX51WI/ TriMScope II</td>
 <td></td>
 </tr>
 <tr>
 <td>Dumont #5 SF Forceps</td>
 <td>FST</td>
 <td>11252-00</td>
 <td></td>
 </tr>
 <tr>
 <td>Friedman-Pearson Rongeurs</td>
 <td>FST</td>
 <td>16221-14</td>
 <td></td>
 </tr>
 <tr>
 <td>Standard Pattern Scissors</td>
 <td>FST</td>
 <td>14001-12</td>
 <td></td>
 </tr>
 <tr>
 <td>InstraTECH A-D converter</td>
 <td>HEKA</td>
 <td>ITC-18</td>
 <td></td>
 </tr>
 <tr>
 <td>Sutter Micromanipulator</td>
 <td>Sutter</td>
 <td>MP-225/M</td>
 <td></td>
 </tr>
 <tr>
 <td>multiclamp amplifier</td>
 <td>Axon Instruments</td>
 <td>700B</td>
 <td></td>
 </tr>
 <tr>
 <td>Data acquisition software (electrophysiology)</td>
 <td>Axograph</td>
 <td>N/A</td>
 <td></td>
 </tr>
 <tr>
 <td>Imspector Data acquisition software (two-photon)</td>
 <td>Max Planck innovation</td>
 <td>N/A</td>
 <td></td>
 </tr>
 </tbody>
</table>

an isolated semi-intact preparation of the mouse vestibular sensory epithelium for electrophysiology and high-resolution two-photon microscopy

Understanding vestibular hair cells function under normal conditions, or how trauma, disease, and aging disrupt this function is a vital step in the development of preventative approaches and/or novel therapeutic strategies. However, the majority of studies looking at abnormal vestibular function have not been at the cellular level but focused primarily on behavioral assays of vestibular dysfunction such as gait analyses and vestibulo-ocular reflex performance. While this work has yielded valuable data about what happens when things go wrong, little information is gleaned regarding the underlying causes of dysfunction. Of the studies that focus on the cellular and subcellular processes that underlie vestibular function, most have relied on acutely isolated hair cells, devoid of their synaptic connections and supporting cell environment. Therefore, a major technical challenge has been access to the exquisitely sensitive vestibular hair cells in a preparation that is least disrupted, physiologically. Here we demonstrate a semi-intact preparation of the mouse vestibular sensory epithelium that retains the local micro-environment including hair cell/primary afferent complexes.

The electrophysiological properties of vestibular hair cells are dependent on the complex microarchitecture within which they are embedded 7. Figure 5 shows that the semi-intact vestibular epithelium preparation can be used to differentiate between type I hair cells (Figure 5A), type II hair cells (Figure 5B), and the calyx primary afferent (Figure 5C) based on characteristic whole cell conductances. These characteristics include a prono...

Watch this Scientific Journal Video about An Isolated Semi-intact Preparation of the Mouse Vestibular Sensory Epithelium for Electrophysiology and High-resolution Two-photon Microscopy at JoVE.com

An Isolated Semi-intact Preparation of the Mouse Vestibular Sensory Epithelium for Electrophysiology and High-resolution Two-photon Microscopy

Analysis of vestibular hair cell function is complicated by their location deep within the hardest part of the skull, the petrous temporal bone. Most functional hair cell studies have used acutely isolated hair cells. Here we describe a semi-intact preparation of mouse vestibular epithelium for electrophysiological and two-photon microscopy studies.

Understanding vestibular hair cells function  under normal conditions, or how trauma, disease, and aging disrupt this  function is a vital step in the ...

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Research

JoVE Journal

Neuroscience

11.8K Görüntüleme.  University of Sydney. Vestibüler saç hücre fonksiyonu analizi kafatası, petröz temporal kemiğin en zor kısmı içinde derin konumlarına göre karmaşıktır. En işlevsel saç hücre çalışmaları akut izole saç hücrelerinin kullandık. Burada elektrofizyolojik ve iki-fotonlu mikroskop çalışmaları için fare vestibüler epitelyum bir yarı sağlam hazırlanması açıklanmaktadır.