Questa ricerca è stata sostenuta da una sovvenzione dalla Corea Health Technology R & D Project attraverso Corea salute industria Development Institute (KHIDI), finanziato dal Ministero della salute & benessere, Repubblica di Corea (concessione numero: HI15C2651).

Questo studio è stato svolto in conformità delle istituzionali Animal Care e uso Comitato di Seoul National University Hospital (14-0148-C1A1), che è accreditato dall'associazione per la valutazione e l'accreditamento di laboratorio Animal Care Internazionale.
Nota: Gli esperimenti sono stati condotti su ratti maschi Sprague-Dawley (deviazione standard) del 7-8 settimane di età (200/250 g). Ogni animale è stati acclimatati alle condizioni di laboratorio per 1 settimana prima dell'inizio dell'esperimento. Gli animali sono stati alloggiati in una camera a temperatura e umidità controllata con una costante 12-h:12-h chiaro: scuro ciclo con libero accesso a cibo e acqua.
1. Labyrinthectomy
<ol><li>Coprire gli strumenti chirurgici sterilizzati nell'autoclave con un tampone sterile. Disinfettare la zona operativa con etanolo al 70%. Utilizzare un telino sterile e mantenere condizioni di sterilità durante l'intervento chirurgico.</li>
	<li>Indossare un abito, maschera (per coprire naso e bocca), PAC (per coprire la testa) e un paio di guanti sterili. Gli strumenti chirurgici devono solo venire a contatto con superfici sterili.</li>
	<li>Iniettare l'anestetico zolazepam tiletamina (40 mg/kg di peso corporeo) per via intramuscolare nella coscia mediale o intraperitonealmente e xilazina (10 mg/kg di peso corporeo) per via intramuscolare o per via intraperitoneale. Nota: Altre modalità di anestesia generale, incluse inalazione isoflurane, può anche essere utilizzato.</li>
	<li>Posto il ratto su un tappetino riscaldante (inizialmente fissato a 42 ° C). Applicare unguento oculare lubrificante in entrambi gli occhi del ratto per prevenire la secchezza dell'occhio mentre sotto anestesia.</li>
	<li>Posto il ratto sul suo lato destro. Radere il pelo nella zona chirurgica con tosatrici. Disinfettare il sito con etanolo al 70%.</li>
	<li>Iniettare 1% lidocaina cloridrato per via sottocutanea nella zona retroauricular sinistra.</li>
	<li>Utilizzando una lama per bisturi #15, fare un'incisione di retroauricular cm ~5.0. Separare il muscolo e la fascia di esporre il canale uditivo esterno con forbici Iris (Figura 1A). Aprire leggermente il canale uditivo esterno utilizzando la lama #15 o le forbici Iris (Figura 1B). Ampiamente esporre la membrana timpanica (Figura 2A).</li>
	<li>Sotto un microscopio (7.5 X o 12,5 X), rimuovere la membrana timpanica e gli ossicini ad eccezione dello stapes, usando il forcipe. Staccare i muscoli sul crinale lambdoidal con la lama #15 o le forbici Iris (Figura 2B).</li>
	<li>Utilizzando un trapano a bassa velocità (< 3000 giri/min) con una fresa diamantata (2.1 o 1,4 mm), forare l'osso timpanico bulla attorno al punto di uscita del nervo facciale (Figura 3A). Identificare l'arteria stapediali. Fare attenzione a non per danneggiare l'arteria stapediali durante il processo di perforazione.</li>
	<li>Continuare ad esplorare il vestibolo superiore all'arteria stapediali ed esporre la finestra rotonda e il canale semicircolare laterale ossuto. Aprire il canale semicircolare laterale vicino alla sua ampolla. Continuare ad esplorare nel piano del canale semicircolare laterale e forare l'ampolla del canale semicircolare superiore.</li>
	<li>Aspirare il contenuto del vestibolo utilizzando un ago 18-G o 22-G. Iniettare e aspirare 1 cm3 di etanolo 100% 3 x.</li>
	<li>Chiudere i muscoli e la pelle in due strati con i suturare interrotti semplici.</li>
	<li>Non lasciare incustodito un animale fino a quando ha riacquistato coscienza sufficiente per mantenere decubito sternale. Mantenere caldo il ratto fino a quando non risveglia con un rilievo di riscaldamento o una lampada di calore. Dopo il risveglio, spostare il ratto in una gabbia individuale in una sala con le solite condizioni ambientali.</li>
	<li>Somministrare antibiotici (ad es., Cefazoline 20 mg/kg, trimetoprim-sulfonamide 100 µ l per via sottocutanea, o penicillina 300.000 IU) come necessario il giorno 1; un analgesico (non un oppioide; ad esempio, Metacam 2mg/kg, Carprofen 5 mg/kg per via sottocutanea) può anche essere somministrato.</li>
</ol>2. sham chirurgia
<ol><li>Per la chirurgia di sham come controllo, eseguire le stesse procedure chirurgiche e post-chirurgiche (secondo la sezione 1), tra cui l'esposizione del canale uditivo esterno e la membrana timpanica (punto 1.7), la rimozione della membrana timpanica e gli ossicini e la distacco dei muscoli sul lambdoidal colmo (passo 1,8), ma non aprire il canale semicircolare o iniettare etanolo.</li>
</ol>3. controllare la perdita della funzione vestibolare
Nota: La perdita della funzione vestibolare può essere valutata utilizzando sia le prove di funzione comportamentale o vestibolare. 13 , 17 , 18 prove comportamentali includono la valutazione della asimmetria posturale e nistagmo.
<ol><li>Identificare asimmetria posturale che comprende spontanei o evocati barile-rolling, che cade sul lato sinistro, o muoversi mentre sporgendosi verso il lato leso18. Guarda il Video 1.</li>
	<li>Identificare il nistagmo da un controllo visivo del movimento di occhio volontaria. Quando il nistagmo spontaneo è assente in stato di riposo, soffio aria delicatamente sopra la testa dell' animale18. Guarda il Video 2.</li>
</ol>

<ol>
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Y., 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=MicroRNAs+218a-5p,+219a-5p,+and+221-3p+regulate+vestibular+compensation.">MicroRNAs 218a-5p, 219a-5p, and 221-3p regulate vestibular compensation.</a> Scientific Reports. 7 (1), 8701 (2017).</li><li>Bergquist, F., Ludwig, M., Dutia, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+the+commissural+inhibitory+system+in+vestibular+compensation+in+the+rat.">Role of the commissural inhibitory system in vestibular compensation in the rat.</a> The Journal of Physiology. 586 (18), 4441-4452 (2008).</li><li>Cameron, S. A., Dutia, M. 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Questa tecnica è un metodo utile per la creazione di perdita di funzione vestibolare improvvisa, permanente e completa. Questo potrebbe essere utilizzato per lo studio di patologie vestibolari, come neurite vestibolare, un tumore acustico e la malattia di Meniere. Molti studi hanno utilizzato questa tecnica per studiare la plasticità neuronale dei nuclei vestibolari o il relativo processo centrale5,17,18,<sup class=...

L'organo vestibolare è essenziale per il controllo di equilibrio e con gli occhi. Una normale funzione vestibolare dipende simmetrici segnali afferenti dagli organi vestibolari nei due orecchi interni. Ipofunzione vestibolare o perdita induce vertigini, nistagmo e squilibrio posturale. Dopo danno acuto, la funzione vestibolare recupera spontaneamente entro alcuni giorni, un processo conosciuto come il compenso vestibolare1,2. Il compenso vestibolare dei deficit statico è un processo di recupero legata allo squilibrio dell'attività spontanea che riposa fra i nuclei vestibolari ipsilaterale e controlaterali. Il compenso vestibolare dei deficit dinamico avviene principalmente tramite sostituzioni sensoriali e comportamentali (utilizzando input visivo o somatosensoriali)3. Questi processi sono attraenti per plasticità neuronale studi4,5.
Un numero di metodi è stato sviluppato per studiare il sistema vestibolare e i meccanismi alla base della plasticità neuronale durante il compenso vestibolare, come labyrinthectomy chirurgico e chimico e neurectomia vestibolare5,6 ,7,8. Neurectomia vestibolare è un certo modo di indurre perdita vestibolare completa, ma è una procedura più complessa e invasiva e può indurre danni cerebrali8,9. Questo metodo richiede una maggiore abilità chirurgica e richiede più tempo che labyrinthectomy. Labyrinthectomy chimici, tra cui la gentamicina, arsanilate e tetracaina, è più facile e può produrre risultati affidabili10,11,12. Tuttavia, la coclea può anche essere danneggiata e perdita vestibolare può svilupparsi nel tempo11. Inoltre, gli effetti delle sostanze chimiche sul cervello, che deve essere conservato per una valutazione accurata, sono poco chiari. Labyrinthectomy chirurgico è stato introdotto negli studi sugli animali in 184215 e in primo luogo è stato segnalato nel ratto in 193616. Questa tecnica è stata usata da allora in molti animale studia5,17,18,19. Labyrinthectomy chirurgica è un metodo specifico, affidabile e relativamente semplice. 13 , 14 inoltre, i sintomi di danno vestibolare sono visti immediatamente dopo la chirurgia. Qui, descriviamo la nostra tecnica chirurgica per ratto labyrinthectomy.

<table><tbody><tr><td>ASPIRATOR KB-012</td><td>KOH BONG &amp;amp; CO., LTD.</td><td>KB-012</td><td>Medical aspirator</td></tr><tr><td>Blade: #15</td><td>Fine Science Tools</td><td>#10015-00</td><td>Blades for #7 Scalpel Handles, #15</td></tr><tr><td>Carbon Steel Burrs</td><td>Fine Science Tools</td><td>#19007-05</td><td>shaft diameter: 2.3 mm, length: 44 mm, package of 10 burrs</td></tr><tr><td>Carl Zeiss Surgical GmbH</td><td>Carl Zeiss</td><td>#6627100863</td><td>Surgical microscope</td></tr><tr><td>Dumont #3c</td><td>Fine Science Tools</td><td>#11231-20</td><td>Standard tip 0.17 x 0.10 mm, 11 cm</td></tr><tr><td>Dumont #5SF</td><td>Fine Science Tools</td><td>#11252-00</td><td></td></tr><tr><td>Dumont #7B</td><td>Fine Science Tools</td><td>#11270-20</td><td>Serrated 0.17 x 0.10 mm, 11 cm</td></tr><tr><td>Extra Fine Bonn: straight</td><td>Fine Science Tools</td><td>#14084-08</td><td>Iris scissors, best suited for microdissection under high magnification</td></tr><tr><td>Fine Iris Scissors: straight</td><td>Fine Science Tools</td><td>#14094-11</td><td>Made from martensitic stainless steel, combined with molybdenum and vanadium</td></tr><tr><td>Finger Loop Ear Punch</td><td>Fine Science Tools</td><td>#24212-01</td><td>1 mm. Provides stability and control for researchers using the numbering system</td></tr><tr><td>Hartman</td><td>Fine Science Tools</td><td>#13002-10</td><td>Tip width: 1 cm, serrated, 10 cm</td></tr><tr><td>Short Scalpel Handle #7 Solid</td><td>Fine Science Tools</td><td>#10003-12</td><td>#7 short, 12 cm</td></tr><tr><td>Small Vessel Cauterizer</td><td>Fine Science Tools</td><td>#18000-03</td><td>Replacement tip, straight knife, keeps bleeding to a minimum and therefore provides a surgical field clear of clamps and hemostats</td></tr><tr><td>Strong 207S</td><td>SAESHIN</td><td>207S</td><td>Powerful torque at low speed, available with speed or on/off foot controller</td></tr><tr><td>Suction Tubes</td><td>JEUNGDO B&amp;amp;P CO., LTD.</td><td>H-1927-8</td><td>Frazier, 18 cm</td></tr><tr><td>VICRYL</td><td>ETHICON</td><td>W9570T</td><td>Synthetic absorbable sterile surgical suture</td></tr><tr><td>Weitlaner-Locktite</td><td>Fine Science Tools</td><td>#17012-13</td><td>Maximum spread: 4.5 cm, 2 x 3 blunt teeth, 11 cm</td></tr><tr><td>Zoletil</td><td>Virbac, France</td><td></td><td>Tiletamine-zolazepam</td></tr><tr><td>Rompun</td><td>Bayer</td><td></td><td>Xylazine</td></tr><tr><td>Rimadyl</td><td>Pfizer</td><td></td><td>Carprofen</td></tr><tr><td>Septra</td><td>Pfizer</td><td></td><td>Trimethoprim-sulfonamide&amp;nbsp;</td></tr></tbody></table>

surgical labyrinthectomy of the rat to study the vestibular system

Per studiare il sistema vestibolare o il processo di compensazione vestibolare, un numero di metodi è stato sviluppato per causare danno vestibolare, tra cui labyrinthectomy chirurgica o chimica e neurectomia vestibolare. Labyrinthectomy chirurgica è un metodo relativamente semplice, affidabile e rapido. Qui, descriviamo la tecnica chirurgica per ratto labyrinthectomy. Un'incisione postauricular fatta in anestesia generale per esporre il canale uditivo esterno e la membrana timpanica, dopo di che la membrana timpanica e gli ossicini vengono rimossi senza stapes. L'arteria dello stapes, che si trova tra la staffa e la finestra ovale, è una struttura vulnerabile e dovrà essere conservato per ottenere un campo chiaro chirurgico. Un buco a fenestrate il vestibolo è realizzato con una fresa trapano 2,1 mm superiore a stapes. Poi, 100% etanolo è iniettato attraverso questo foro e aspirato più volte. Dissezione meticolosa sotto un microscopio e un attento controllo del sanguinamento sono essenziali per ottenere risultati affidabili. Sintomi di perdita vestibolare, quali nistagmo, inclinazione testa e un movimento di rotolamento, sono visibili immediatamente dopo la chirurgia. Il test di sedia rotarod o rotazione può essere utilizzato per oggettivamente e quantitativamente valutare la funzione vestibolare.

Il successo della chirurgia è stato convalidato da test comportamentali. Tutti gli animali hanno esibito il comportamento tipico di una perdita della funzione vestibolare unilaterale. Barile-rotolamento spontaneo era evidente subito dopo della chirurgia, essere evocato da un soffio di aria sopra la testa o un tocco leggero al corpo nella fase iniziale di recupero (Video 1). 3 d dopo la chirurgia, gli animali spostati sporgendosi verso il lato leso con occasionali cade su...

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Surgical Labyrinthectomy of the Rat to Study the Vestibular System

Questo protocollo descrive la labyrinthectomy chirurgica di un topo, che è un metodo utile per lo studio del sistema vestibolare.

Labyrinthectomy chirurgica del ratto per studiare il sistema vestibolare

To study the vestibular system or the vestibular compensation process, a number of methods have been developed to cause vestibular damage, including ...

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10.0K Views.  Chung-Ang University College of Medicine. Questo protocollo descrive la labyrinthectomy chirurgica di un topo, che è un metodo utile per lo studio del sistema vestibolare.

Video: Surgical Labyrinthectomy of the Rat to Study the Vestibular System

Canalostomy As a Surgical Approach to Local Drug Delivery into the Inner Ears of Adult and Neonatal Mice

Local delivery of therapeutic drugs into the inner ear is a promising therapy for inner ear diseases. Injection through semicircular canals (canalostomy) has been shown to be a useful approach to local drug delivery into the inner ear. The goal of this article is to describe, in detail, the surgical techniques involved in canalostomy in both adult and neonatal mice. As indicated by fast-green dye and adeno-associated virus serotype 8 with the green fluorescent protein gene, the canalostomy facilitated broad distribution of injected reagents in the cochlea and vestibular end-organs with minimal damage to hearing and vestibular function. The surgery was successfully implemented in both adult and neonatal mice; indeed, multiple surgeries could be performed if required. In conclusion, canalostomy is an effective and safe approach to drug delivery into the inner ears of adult and neonatal mice and may be used to treat human inner ear diseases in the future.

Here we describe canalostomy procedure which allows local drug delivery into the inner ears of adult and neonatal mice through the semicircular canal with minimum damage to hearing and vestibular function. This method can be used to inoculate viral vectors, pharmaceuticals, and small molecules into the mouse inner ear.

Canalostomy come un approccio chirurgico alla consegna di droga locale nelle orecchie interno dei topi adulti e neonati

Local delivery of therapeutic drugs into the inner ear is a promising therapy for inner ear diseases. Injection through semicircular canals (canalostomy) ...

Ricerca

Genetica

Survivable Stereotaxic Surgery in Rodents 

The ability to measure extracellular basal levels of neurotransmitters in the brain of awake animals allows for the determination of effects of different systemic challenges (pharmacological or physiological) to the CNS. For example, one can directly measure how the animal's midbrain dopamine projections respond to dopamine-releasing drugs like d-amphetamine or natural stimuli like food. In this video, we show you how to implant guide cannulas targeting specific sites in the rat brain, how to insert and implant a microdialysis probe and how to use high performance liquid chromatography coupled with electrochemical detection (HPLC-EC) to measure extracellular levels of oxidizable neurotransmitters and metabolites. Local precise introduction of drugs through the microdialysis probe allows for refined work on site specificity in a compound s mechanism of action. This technique has excellent anatomical and chemical resolution but only modest time resolution as microdialysis samples are usually processed every 20-30 minutes to ensure detectable neurotransmitter levels. Complementary ex vivo tools (i.e., slice and cell culture electrophysiology) can assist with monitoring real-time neurotransmission.

Survivable Stereotaxic Surgery in Rodents

The monitoring of extracellular neurotransmitter levels in distinct brain regions of freely moving animals offers insights on the link between neurotransmitter release and behavior. In vivo microdialysis coupled with electrochemical detection provides excellent anatomical and chemical resolution; and information on how basal neurotransmission is altered by pharmacological or physiological manipulations.

Survivable Chirurgia Stereotassica in roditori

The ability to measure extracellular basal levels of neurotransmitters in the brain of awake animals allows for the determination of effects of different ...

Biologia

A Video Demonstration of Preserved Piloting by Scent Tracking but Impaired Dead Reckoning After Fimbria-Fornix Lesions in the Rat

Piloting and dead reckoning navigation strategies use very different cue constellations and computational processes (Darwin, 1873; Barlow, 1964; O&#x2019;Keefe and Nadel, 1978; Mittelstaedt and Mittelstaedt, 1980; Landeau et al., 1984; Etienne, 1987; Gallistel, 1990;
Maurer and S&#233;guinot, 1995). Piloting requires the use of the relationships between relatively stable external (visual, olfactory, auditory) cues, whereas dead reckoning requires the integration of cues generated by self-movement. Animals obtain self-movement information from vestibular receptors, and possibly muscle and joint receptors, and efference copy of commands that generate movement. An animal may also use the flows of visual, auditory, and olfactory stimuli caused by its movements. Using a piloting strategy an animal can use geometrical calculations to determine directions and distances to places in its environment, whereas using an dead reckoning strategy it can integrate cues generated by its previous movements to return to a just left location. Dead reckoning is colloquially called "sense of direction" and "sense of distance."

Although there is considerable evidence that the hippocampus is involved in piloting (O&#x2019;Keefe and Nadel, 1978; O&#x2019;Keefe and Speakman, 1987), there is also evidence from behavioral (Whishaw et al., 1997; Whishaw and Maaswinkel, 1998; Maaswinkel and Whishaw, 1999), modeling (Samsonovich and McNaughton, 1997), and electrophysiological (O&#x2019;Mare et al., 1994; Sharp et al., 1995; Taube and Burton, 1995; Blair and Sharp, 1996; McNaughton et al., 1996; Wiener, 1996; Golob and Taube, 1997) studies that the hippocampal formation is involved in dead reckoning. The relative contribution of the hippocampus to the two forms of navigation is still uncertain, however. Ordinarily, it is difficult to be certain that an animal is using a piloting versus a dead reckoning strategy because animals are very flexible in their use of strategies and cues (Etienne et al., 1996; Dudchenko et al., 1997; Martin et al., 1997; Maaswinkel and Whishaw, 1999). The objective of the present video demonstrations was to solve the problem of cue specification in order to examine the relative contribution of the hippocampus in the use of these strategies. The rats were trained in a new task in which they followed linear or polygon scented trails to obtain a large food pellet hidden on an open field. Because rats have a proclivity to carry the food back to the refuge, accuracy and the cues used to return to the home base were dependent variables (Whishaw and Tomie, 1997). To force an animal to use a a dead reckoning strategy to reach its refuge with the food, the rats were tested when blindfolded or under infrared light, a spectral wavelength in which they cannot see, and in some experiments the scent trail was additionally removed once an animal reached the food. To examine the relative contribution of the hippocampus, fimbria&#x2013;fornix (FF) lesions, which disrupt information flow in the hippocampal formation (Bland, 1986), impair memory (Gaffan and Gaffan, 1991), and produce spatial deficits (Whishaw and Jarrard, 1995), were used.

In a piloting scent tracking task, the ability of the rats to return to a refuge with food using visual an odor trail or using dead reckoning in infrared light, the integrated record of previous movements, demonstrates that the hippocampus is necessary for dead reckoning.

Una dimostrazione video di pilotaggio da parte di Conserve Monitoraggio Profumo ma deteriorate Dead Reckoning Dopo Fimbria-fornice lesioni nel ratto

Piloting and dead reckoning navigation strategies use very different cue constellations and computational processes (Darwin, 1873; Barlow, 1964; ...

Assessing the Autonomic and Behavioral Effects of Passive Motion in Rats using Elevator Vertical Motion and Ferris-Wheel Rotation

The overall goal of this study is to assess the autonomic and behavioral effects of passive motion in rodents using the elevator vertical motion and Ferris-wheel rotation devices. These assays can help confirm the integrity and normal functioning of the autonomic nervous system. They are coupled to quantitative measures based on defecation counting, open-field examination, and balance beam crossing. The advantages of these assays are their simplicity, reproducibility, and quantitative behavioral measures. The limitations of these assays are that the autonomic reactions could be epiphenomena of non-vestibular disorders and that a functioning vestibular system is required. Examination of disorders such as motion sickness will be greatly aided by the detailed procedures of these assays.

Protocols are presented to assess the autonomic and behavioral effects of passive motion in rodents using elevator vertical motion and Ferris-wheel rotation.

Valutazione degli effetti autonomi e comportamentali del movimento passivo nei ratti utilizzando il movimento verticale dell'ascensore e la rotazione della ruota panoramica

The overall goal of this study is to assess the autonomic and behavioral effects of passive motion in rodents using the elevator vertical motion and ...

Comportamento

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.

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.

Un isolato semi-intatte Preparazione del mouse vestibolare epitelio sensoriale di Elettrofisiologia e ad alta risoluzione microscopia a due fotoni

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

Neuroscienze

Long-term Sensory Conflict in Freely Behaving Mice

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning in mice. By permanently wearing a device fixed on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages. Therefore, this protocol readily enables the study of the visual system and multisensory interactions over an extended timeframe that would not be accessible otherwise. In addition to lowering the experimental costs of long-term sensory learning in naturally behaving mice, this approach accommodates the combination of in vivo and in vitro experiments. In the reported example, video-oculography is performed to quantify the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) before and after learning. Mice exposed to this long-term sensory conflict between visual and vestibular inputs presented a strong VOR gain decrease but exhibited few OKR changes. Detailed steps of device assembly, animal care, and reflex measurements are hereby reported.

The presented protocol produces a persistent sensory conflict for experiments aimed at studying long-term learning. By permanently wearing a fixed device on their heads, mice are continuously exposed to a sensory mismatch between visual and vestibular inputs while freely moving in home cages.

A lungo termine conflitto sensoriale a comportarsi liberamente topi

Long-term sensory conflict protocols are a valuable means of studying motor learning. The presented protocol produces a persistent sensory conflict for ...

Unraveling the Role of Discrete Areas of the Rat Brain in the Regulation of Ovulation through Reversible Inactivation by Tetrodotoxin Microinjections

Many experimental approaches have been used for studying the role of the brain in the regulation of ovulation. Examples include the lesion and deafferentation of neuronal groups, which are both invasive methods that permanently impair the integrity of the target area. These methods are accompanied by collateral effects that can affect the analysis of acute and temporal regulatory mechanisms. The stereotaxic implantation of guide cannulas aimed at specific brain regions, followed by a recovery period, allows researchers to microinject different drugs after the disappearance of the undesired effects of the surgery. Tetrodotoxin has been used to determine the roles of several brain areas in diverse physiological processes because it transiently inhibits the sodium-dependent action potentials, thus blocking all neural activity in the target region. This protocol combines this method with strategies for the assessment of the estrous cycle and ovulation to reveal the role of discrete brain regions in the regulation of ovulation at particular times of any given stage of the estrous cycle. Awake and unrestrained rats (Rattus norvegicus) were used to avoid the blocking effects that anesthetics and stress hormones exert on ovulation. This protocol can be easily adapted to other species, brain targets and pharmacological agents to study different physiological processes. Future improvements to this method include the design of a microinjection system using glass capillaries of small diameter instead of guide cannulas. This will reduce the amount of tissue damaged during the implantation and decrease the spread of the infused drugs outside the target area.

This protocol describes the construction of a low-cost microinjection system, its stereotaxic implantation into deep-brain structures and the procedure for timed microinjections of tetrodotoxin in awake and unrestrained rats. The goal is to reveal the participation of hypothalamic structures in the regulation of ovulation by inhibiting their neural activity.

Svelare il ruolo delle aree discrete del cervello del ratto nella regolazione dell'ovulazione attraverso l'inattivazione reversibile da microiniezioni di tetrodotossine

Many experimental approaches have been used for studying the role of the brain in the regulation of ovulation. Examples include the lesion and ...

Near Infrared (NIr) Light Increases Expression of a Marker of Mitochondrial Function in the Mouse Vestibular Sensory Epithelium

Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and exercise. However, these approaches do not address the underlying causes of balance decline. Using mice, the impact of near infrared light (NIr) on the metabolism of cells in the vestibular sensory epithelium was assessed. Data collected shows that this simple and safe intervention may protect these vulnerable cells from the deleterious effects of natural aging. mRNA was extracted from the isolated peripheral vestibular sensory epithelium (crista ampullaris and utricular macula) and subsequently transcribed into a cDNA library. This library was then probed for the expression of ubiquitous antioxidant (SOD-1). Antioxidant gene expression was then used to quantify cellular metabolism. Using transcranial delivery of NIr in young (4 weeks) and older (8 - 9 months) mice, and a brief treatment regime (90 sec/day for 5 days), this work suggests NIr alone may be sufficient to improve mitochondrial function in the vestibular sensory epithelium. Since there are currently no available, affordable, non-invasive methods of therapy to improve vestibular hair cell function, the application of external NIr radiation provides a potential strategy to counteract the impact of aging on cellular metabolism inthe vestibular sensory epithelium.

Near Infrared NIr Light Increases Expression of a Marker of Mitochondrial Function in the Mouse Vestibular Sensory Epithelium

Mitochondrial dysfunction is a hallmark of cellular senescence. This paper uses non-invasive near-infrared (NIr) treatment to improve mitochondrial function in the aging mouse vestibular sensory epithelium.

Vicino infrarosso (NIR) Luce aumenta l&#39;espressione di un marcatore di mitocondriale Funzione nel mouse vestibolare sensoriale Epithelium

Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and ...

Isolating and Culturing Vestibular and Spiral Ganglion Somata from Neonatal Rodents for Patch-Clamp Recordings

The compact morphology of isolated and cultured inner ear ganglion neurons allows for detailed characterizations of the ion channels and neurotransmitter receptors that contribute to cell diversity across this population. This protocol outlines the steps necessary for successful dissecting, dissociating, and short-term culturing of the somata of inner ear bipolar neurons for the purpose of patch-clamp recordings. Detailed instructions for preparing vestibular ganglion neurons are provided with the necessary modifications needed for plating spiral ganglion neurons. The protocol includes instructions for performing whole-cell patch-clamp recordings in the perforated-patch configuration. Example results characterizing the voltage-clamp recordings of hyperpolarization-activated cyclic nucleotide-gated (HCN)-mediated currents highlight the stability of perforated-patch recording configuration in comparison to the more standard ruptured-patch configuration. The combination of these methods, isolated somata plus perforated-patch-clamp recordings, can be used to study cellular processes that require long, stable recordings and the preservation of intracellular milieu, such as signaling through G-protein coupled receptors.

Presented here are methods providing detailed instructions for dissecting, dissociating, culturing, and patch-clamp recording from vestibular ganglion and spiral ganglion neurons of the inner ear.

Isolare e coltivare i somata gangliari vestibolari e spirali da roditori neonatali per registrazioni con patch-clamp

The compact morphology of isolated and cultured inner ear ganglion neurons allows for detailed characterizations of the ion channels and neurotransmitter ...

Harvest of Vestibular End-Organs under Physiologic Conditions during Labyrinthectomy

The living human inner ear is challenging to study because it is encased within dense otic capsule bone that limits access to biological tissue. Traditional temporal bone histopathology methods rely on lengthy, expensive decalcification protocols that take 9-10 months and reduce the types of tissue analysis possible due to RNA degradation. There is a critical need to develop methods to access fresh human inner ear tissue to better understand otologic diseases, such as M&#233;ni&#232;re's disease, at the cellular and molecular level. This paper describes a technique for the harvest of human vestibular end organs from a living donor under physiologic conditions. An individual with M&#233;ni&#232;re's disease and 'drops attacks' that were refractory to intratympanic gentamicin injection underwent labyrinthectomy. A traditional mastoidectomy was first performed, and the horizontal and superior semicircular canals (SCC) were identified. The mastoid cavity was filled with a balanced salt solution so that the labyrinth could be opened under more physiologic conditions to preserve cellular integrity. A zero-degree endoscope fit with a lens-cleaning sheath irrigation system was used to visualize the submerged mastoid cavity, and a 2 mm diamond burr was used to skeletonize and open the horizontal and superior SCCs, followed by the vestibule. The ampullae and portion of the canal ducts for the superior and lateral SCCs were harvested. The utricle was similarly harvested. Harvested tissue was immediately placed in an ice-cold buffer and then fixed for one hour in 4% paraformaldehyde in phosphate-buffered saline (PBS). The tissue was rinsed several times in 1x PBS and stored for 48 h at 4 &#176;C. The tissue samples underwent immunostaining with a combination of primary antibodies against tenascin-C (Calyx), oncomodulin (streolar hair cells), calretinin (Calyx and Type II hair cells), synaptic vesicle protein 2 (efferent fibers and boutons), &#946;-tubulin 1 (Calyx and afferent boutons), followed by incubation with fluorophore-conjugated secondary antibodies. The tissue samples were then rinsed and mounted for confocal microscopy examination. Images revealed the presence of ampullar and macular hair cells and neural structures. This protocol demonstrates that it is possible to harvest intact, high-quality human inner ear tissue from living donors and may provide an important tool for the study of otologic disease.

Here, we describe a technique for harvesting human vestibular end-organs under physiologic conditions during labyrinthectomy and their analysis using immunostaining.

Labyrinthectomy chirurgica del ratto per studiare il sistema vestibolare

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