Yazarlar erken embriyonik dönemde piliç iç kulak anatomisi üzerine uzmanlık için görüntüleme teknikleri ve Dr Doris Wu ile öneri ve yardım için Dr Candace Hsieh teşekkür etmek istiyorum. Bu çalışma NSF IOS-0642346, NIH T32-DC010775, NIH T32-GM008620, NIH R01-DC010796 ve DOE GAANN P200A120165 tarafından desteklenmiştir.

1. Aşağıdaki Diseksiyon araçları ve Reaktifler hazırlayın <ul><li> Yapay serebrospinal akışkan (aCSF, 130 mM NaCl, 3 mM KCI, 1.2 mM KH 2 PO 4, 20 mM NaHCO 3, 3 mM HEPES, 10 mM glikoz, 2 mM CaCl2, 1.3 mM MgSO4) sürekli olarak% 95 O ile aşılanmış Oda sıcaklığında 2 /% 5 CO2. Infüzyon için 2/3 kapağı açılmış bir delik olan bir 500 ml geniş ağızlı Nalgene kavanoza doldurun. Tank kavanoz kapağı delikten aCSF nüfuz bir bardak kök bubbler için tüp tarafından eklenecektir. Sıvının yaklaşık 1/3 ulaşmak ancak jant üzerine sıçramasına neden olacak kadar güçlü değildir kabarcıklar sabit bir akım elde etmek için baskı ayarlayın. Birbirlerinden ve gaz akışı türbülans tek tek örnekleri ayırmak için Nalgene kavanozun içine daldırın 5 ml cam şişe (6&#39;ya kadar). ACSF herhangi bir doku inkübasyondan önce en azından 20 dakika için oksijenli olmalıdır. </li><li> Küçük silikon diseksiyon çanak (35 mm x 10 mmküçük altıgen polistiren içine yerleştirilen iki diseksiyon işaretçilerine (47 mm alt)) Sylgard Elastomere Kit kullanarak mm Petri kaplı tekne tartın. </li><li> İki ince uçlu forseps, bir eğri uçlu forseps, 50 ml beher, ve doku atıklar için bir kap. </li><li> Cam mikropipet (1.2 OD / 0.9 ID) ucunda açılış yaklaşık 20-50 mikron kadar kırılmış ve bir 6.25% çözüm rodamin dekstran amin (RDA, MW = 3.000, Invitrogen) ile dolu Pulled% 0.4 Triton PBS X-100 . Mikromanipülatör picospritzer ve stabilize etmek için ince tüp ile takın. </li></ul> 2. Mikro-disseksiyon E8 4,5 az Baziler Papilla Ortaya Çıkardı <ol><li> Kavisli bir forseps ile tekne tartmak içinde silikon kaplı diseksiyon çanak üzerine doğrudan başkanı yerleştirerek, sadece beyin sapı aşağıya E8 embriyo kesti. </li><li> Ilgi tarafındaki kulağınızı hafifçe görünür şekilde diseksiyon işaretçilerine kullanarak, bir ventral görünümü ile baş konumlandırmak, başını hafifçe dorsal eğik ve 10-30 derece uzaklıkta ce gelen işaretnter (Şekil 2A). Hemen işaretçilerine ile kafa sabitleyin. Iki taraflı izleme istenirse, merkez 0 derece kafası, ya da bir tam alttan görünüşü her iki taraftan erişilebilir. Sol tarafta ulaşılabilir, böylece Benzer bir şekilde, sol taraflı enjeksiyon için, merkezi -10 ila -30 dereceye kadar kafa sabitleyin. </li><li> 50 ml&#39;lik beher kullanarak, tam doku daldırarak, çanak içine oksijenli aCSF, 30 ml aktarın. </li><li> Hafifçe kavrayın ve ince ucu forseps kullanılarak alt çene aşağı soyma, ardından faiz tarafındaki alt gözkapağı çıkarın. </li><li> Kalan damak ve gırtlak gibi, üstteki damar dokusu çıkarın. Bu yumuşak dokular sıyırın yüzeyinin de farklı vertebral arterler ile chondrocranium geliştirme pürüzsüz bir yüzey ifşa edilmelidir. Bu noktada, karakteristik beyaz otoconial kitle görünür olmalıdır. </li><li> Içinde bırakarak dış meatus, çene eklem kıkırdağı ve orta kulak çevresindeki deri dikkatlice teşrihner kulak sağlam. Yavaşça bu kıkırdak yapıları kesip almak için forseps kullanın. </li><li> Ince forseps ipuçları nazik bir süpürme hareketi ile vertebral arterler ve kan göllenmesi çıkarın. Kan görünüm belirsiz olabilir ve koagülasyon enjeksiyon pipeti açılış fişi olabilir. </li><li> Bitişik duyusal epitel (baziler papilla) ve akustik gangliyon ile koklear kanal chondrocranium 6 altında yer alır ve anterior yakın distal-en uç (apeks) ile, ventral iç kulak uzanan uzunlamasına bir parmak şeklinde projeksiyon olarak görüntülenebilmektedir midline 5. Görselleştirme yardımcı olabilir koklear kanal (Şekil 2B) apekste disseksiyon ve / veya otolithic kireçlenmeler (beyaz) küçük bir kan havuzu (kırmızı) olabilir. Apekste lagenar makula, bir duyu yama vestibüler fonksiyonun 7,8 olduğu düşünülmektedir. </li></ol> 3. CN VIII İşitsel Elyaf seçici Etiketleme <ol><li&gt; Koklear kanal ve baziler papilla bölgede embriyonun yüzeyine yakın enjeksiyon pipeti yerleştirin. </li><li> Yavaş yavaş ilk ponksiyon kafatasına mikropipet indirin. Bu kranial bölgenin çevresindeki alanlarda daha ince ve daha az güç nüfuz gerektirir. Mikropipet şimdi koklea kanal içinde olmalıdır. Opsiyonel: izleme boya küçük bir enjeksiyon baziler papilla görüntülenmesine yardım için burada yapılabilir. </li><li> Mikropipet konumlandırarak olmadan, sadece ihlal koklear kanalın derin sınırına (Şekil 1) kadar düşürerek devam edin. Burada bir enjeksiyon yapın ve vestibüler lagena bulunduğu en proksimal bahşiş hariç, baziler papilla (Şekil 2C, 2D) uzunluğu boyunca birden çok bölgede tekrarlayın. 10-30 psi arasında yer alan picospritzer ile, birden çok enjeksiyon yapılır. Enjekte boya sıvı hacmi değişir ve istenilen etiketlenme ölçüde bağlıdır. Her enjeksiyon floresan boya-la yol açmalıdıryaklaşık 200 Beled nokta - 400 mikron çapında (Şekil 2B). </li><li> Enjeksiyon tamamlandıktan sonra, beyin sapı Yukarıdaki örnek transeksiyonu ve sürekli% 95 O 2 /% 5 CO 2 ile perfüze olan aCSF kapsayıcı içinde küçük bir kavanoza kaudal bölümünü yerleştirmek için bir transfer pipet kullanmak için forseps kullanabilir. </li><li> Her bir embriyo için istenen merkezi izleme ve mesafeye bağlı olarak, boya transferi için 20-30 dk bekleyin. </li><li> Dokular temizlenir ve histolojik kesit için hazırlamak. Burada gösterilen örnekte, doku% 4 paraformaldehit (1X PBS içerisinde) bir karışımı, gece boyunca,% 30 sakaroz (1X PBS içinde) batırılır. </li></ol> 4. Counterstaining ve Analiz <ol><li> Counterstaining orient sıra ilgi belirli bölgelerini belirlemek gibi anatomik konuma gözlemci yardım etmek yararlıdır. Bu preparat içinde etkili bir counterstain kuvvetle l nörofilaman immün (Şekiller 1, 3B, 3E), birAbels akson ve MSS aksonal yollarının çizilmesi için izin verir. </li><li> Çıkıntılar rostro eksen boyunca birkaç yüz mikron ya da daha fazla uzatmak gibi analizi, etiketli bölge boyunca yapılmalıdır. Temel analiz bazı örnekler şunlardır: hedef hata oranları, zamanlama ve / veya projeksiyon modellerinin sapma değişiklikleri. RDA-etiketli aksonlar yüksek çözünürlüklü (Şekil 3A, 3B) ile periferik ve santral sinir sisteminde görüntülenmiştir. </li></ol>

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Çıkar çatışması ilan edilir.

VIII.yy. sinirin erken geliştirme çalışmaları nedeniyle birden çok farklı gangliyon kaynaklanan embriyonik aksonlar tanımada zorluk kısmen sınırlı kalmıştır. Çeşitli çalışmalar erken gelişimi sırasında işitsel ve vestibüler duyu hücre ve ganglion hücre kaderi rehberlik moleküler sinyaller, 5,11,12 araştırdı fakat merkezi innervasyon düzenleyen süreçler belirlenecek henüz. Az ilköğretim çekirdekler için projelendirme merkezi süreçleri hakkında bilinenler ise akustik ga...

<table border="1"><tbody><tr><td> Reaktif / Malzeme Adı </td><td> Şirket </td><td> Katalog Numarası </td><td> Yorumlar </td></tr><tr><td> Polistiren Bulaşık tartılır </td><td> Fisher Scientific </td><td> 02-202-101 </td><td></td></tr><tr><td> Petri Dish, 35 X 10 mm </td><td> Fisher Scientific </td><td> 50820644 </td><td> Silikon diseksiyon çanak yapmak için kullanın </td></tr><tr><td> Sylgard Silikon Elastomer Takımı </td><td> Dünya Hassas Aletler </td><td> SYLG184 </td><td> Coat Petri diseksiyon çanak yapmak </td></tr><tr><td> Diseksiyon Pins </td><td> Çeşitli </td><td></td><td> Diseksiyon sırasında embriyo tutar </td></tr><tr><td> NaCL </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> KCl </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td&gt; </tr><tr><td> KH 2 PO 4 </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> NaHCO 3 </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> Glikoz </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> CaCl2 </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> MgSO4 </td><td> Çeşitli </td><td></td><td> aCSF tarifi parçası </td></tr><tr><td> ACSF için Konteyner. Kapaklı saydam geniş ağız Nalgene kavanoz, 500 ml (16 oz) sonuçları. </td><td> CPLabSafety </td><td> QP-PLC-03717 </td><td> Cam bubling kök için kapağın üst Delik açma sıvı nüfuz </td></tr><tr><td> Boş 5 ml bir cam şişe ya da karşılaştırılabilir saydam şişe </td><td> Amerikan İlaç Ortaklar, Inc </td><td> 6332300105 </td><td&gt; birbirlerinden ve köpüren akışından örnekleri ayrı tutmak aCSF inkübasyon sırasında kullanın </td></tr><tr><td> Carbogen Tank (% 95 O 2 /% 5 CO 2) bubbler için boru ile bağlı </td><td> Çeşitli </td><td></td><td> ACSF içine infüzyon için cam kök bubbler için tüp tarafından takın </td></tr><tr><td> Cam kök bubbler </td><td> Çeşitli </td><td></td><td> ACSF içine carbogen demlenmeye için </td></tr><tr><td> Eğri uçlu forseps </td><td> Dünya Hassas Aletler </td><td> 501008 </td><td> Yumurtadan embriyo baş kaldırmak için </td></tr><tr><td> İki ince uçlu forseps </td><td> Dünya Hassas Aletler </td><td> 501985 </td><td> Mikro diseksiyon için </td></tr><tr><td> 50 ml Beher </td><td> çeşitli </td><td></td><td></td></tr><tr><td> Rodamin Dekstran Amin (BKİ) </td><td> Invitrogen </td><td> çeşitli </td><td> Floresan akson tracer </td></tr><tr><td> Triton X-100 </td><td> ICN Biomedicals </td><td></td><td></td></tr><tr><td> Fosfat (1X PBS), Tamponlu Salin </td><td> Çeşitli </td><td></td><td> Standart laboratuar reaktifi </td></tr><tr><td> İnce Duvarlı Cam kılcal, 1.2 OD, .9 ID 4 &quot;(100 mm) uzunluğu </td><td> Dünya Hassas Aletler </td><td> TW120F-4 </td><td> BKİ ile yükleyin. Her kılcal iki cam mikropipetler yapar </td></tr><tr><td> İğne / Pipet çektirme </td><td> David Kopf Instruments </td><td> Model 720 </td><td> Kullanılan Ayarlar: Isı 16.4, Solenoid 2.2 </td></tr><tr><td> Picospritzer </td><td> Parker Enstrümantasyon </td><td> çeşitli </td><td> Cam mikropipet ince boru ile bağlayın </td></tr><tr><td> Mikromanipülatör </td><td> Narishige </td><td> çeşitli </td><td></td></tr><tr><td> Floresan ile Diseksiyon mikroskobu </td><td> Çeşitli </td><td></td><td></td&gt; </tr><tr><td> 4% Paraformaldehyde </td><td> Çeşitli </td><td></td><td> Standart laboratuar reaktifi </td></tr><tr><td> Anti-Nörofilaman antikor, isteğe bağlı </td><td> Millipore </td><td> AB1991 </td><td> Üretici tarafından önerilen histolojik protokol izleyin </td></tr><tr><td> Kriyostat ve kesit için ilgili maddeler </td><td> Leica </td><td> çeşitli </td><td></td></tr><tr><td> Görüntüleme için Epifluorescent mikroskop </td><td> Çeşitli Zeiss, </td><td></td><td></td></tr></tbody></table>

selective tracing of auditory fibers in the avian embryonic vestibulocochlear nerve

Embriyonik civciv periferik ve santral gangliyon hücre projeksiyonlar çalışma için yaygın olarak kullanılan bir modeldir. Işitsel sisteminde, sekizinci kranial sinir olan işitsel akson seçici etiketleme merkezi işitme devre geliştirme çalışması artıracaktır. Iç kulakta birden duyu organları VIII.yy. sinirin 1. katkıda çünkü bu yaklaşım zordur. Ayrıca, güvenilir bir kuş VIII.yy. sinir içinde akson vestibüler gruplar karşısında işitsel ayırt işaretleyicileri tespit edilmesi henüz. Devreler oluşur önce duyu-uyarılmış yanıtlar mevcut değil gibi işitsel ve vestibüler yolları, erken embriyo işlevsel olarak ayırt edilemez. Merkezi projelendirme VIII.yy. sinir aksonlar bazı çalışmalar takip edilmiştir, ama işitsel akson etiketleme diğer VIII.yy. sinir bileşenler 2,3 dan etiketleme eşlik etti. Burada, seçici labe için akustik gangliyondan anterograd izleme için bir yöntem açıklanmaktadırGelişmekte VIII.yy. sinir içinde l işitsel aksonlar. İlk olarak, oksijenli yapay beyin omurilik sıvısına batırılmış bir 8 günlük civciv embriyo ön sefalik bölgede kısmi diseksiyon sonrası, koklear kanal anatomik işaretlemeler ile tanımlanır. Daha sonra, bir ince çekilmiş cam mikropipet akustik ganglion hücreleri bulunan kanal ve komşu bölge içine derin rodamin dekstran amin küçük bir miktar enjekte etmek için konumlandırılmıştır. Enjeksiyonu takiben otuz dakika içinde, işitsel aksonlar arka beyin içine merkezi izlenir ve daha sonra histolojik hazırlanmasını takiben canlandırılabilir. Bu yöntem, merkezi işitsel devre oluşumu periferik gelişimsel çalışmalar için kullanışlı bir araç sağlar.

VIII.yy. sinir ve sinir kendisi anatomisi bileşenleri (Şekil 1, 3), karmaşık ve karışık vardır. Seçici olarak akustik ganglion hücre kaynaklanan lifler izleme tarafından VIII sinir hem de beyin sapı içindeki birincil işitsel afferent kesimleri temiz bir şekilde takip edilebilir ve bunların muadilleri vestibüler (Şekil 2, 3) ayırt edilir. Aynı şekilde, bu tekniğin akustik ganglion hücrelerinin periferik projeksiyonları (Şekil 3G) incelemek için ...

Watch this Scientific Journal Video about Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve at JoVE.com

Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

Burada sinir ve arka beyin işitsel akson liflerinin izleme seçici için erken civciv embriyo akustik ganglion içine floresan boya enjeksiyonu takiben mikrodiseksiyon tekniği tarif.

Kuş Embriyonik vestibülokoklear sinir İşitsel Elyaf seçici Aydınger

The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling ...

selective-tracing-auditory-fibers-avian-embryonic-vestibulocochlear

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

9.1K Görüntüleme.  University of California, Irvine. Burada sinir ve arka beyin işitsel akson liflerinin izleme seçici için erken civciv embriyo akustik ganglion içine floresan boya enjeksiyonu takiben mikrodiseksiyon tekniği tarif.

Video: Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

Culture of Embryonic Mouse Cochlear Explants and Gene Transfer by Electroporation

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair cells are aligned in one row of inner hair cells and three rows of outer hair cells that extend along the basal to apical axis of the cochlea. The explant culture technique described here provides an efficient method to isolate and maintain cochlear explants from the embryonic mouse inner ear. Also, the morphology and molecular characteristics of sensory hair cells and nonsensory supporting cells within the cochlear explant cultures resemble those observed in vivo and can be studied within its intrinsic cellular environment. The cochlear explants can serve as important experimental tools for the identification and characterization of molecular and genetic pathways that are involved in cellular specification and patterning. Although transgenic mouse models provide an effective approach for gene expression studies, a considerable number of mouse mutants die during embryonic development thereby hindering the analysis and interpretation of developmental phenotypes. The organ of Corti from mutant mice that die before birth can be cultured so that their in vitro development and responses to different factors can be analyzed. Additionally, we describe a technique for electroporating embryonic cochlear explants ex vivo which can be used to downregulate or overexpress specific gene(s) and analyze their potential endogenous function and test whether specific gene product is necessary or sufficient in a given context to influence mammalian cochlear development1-8.

We present a method that describes isolation and culture of cochlear explants from embryonic mouse inner ear. We also demonstrate a method for gene transfer into cochlear explants via square-wave electroporation. The in vitro explant culture coupled with gene transfer technique enables researchers to study the effects of altering gene expression during development.

Elektroporasyon tarafından Embriyonik Fare Koklear Eksplantlarından Kültür ve Gen Transferi

Auditory hair cells located within the mouse organ of Corti detect and transmit sound information to the central nervous system. The mechanosensory hair ...

Gelişim Biyolojisi

Postsynaptic Recordings at Afferent Dendrites Contacting Cochlear Inner Hair Cells: Monitoring Multivesicular Release at a Ribbon Synapse

The afferent synapse between the inner hair cell (IHC) and the auditory nerve fiber provides an electrophysiologically accessible site for recording the postsynaptic activity of a single ribbon synapse 1-4. Ribbon synapses of sensory cells release neurotransmitter continuously, the rate of which is modulated in response to graded changes in IHC membrane potential 5. Ribbon synapses have been shown to operate by multivesicular release, where multiple vesicles can be released simultaneously to evoke excitatory postsynaptic currents (EPSCs) of varying amplitudes 1, 4, 6-11. Neither the role of the presynaptic ribbon, nor the mechanism underlying multivesicular release is currently well understood.
The IHC is innervated by 10-20 auditory nerve fibers, and every fiber contacts the IHC with a unmyelinated single ending to form a single ribbon synapse. The small size of the afferent boutons contacting IHCs (approximately 1 &mu;m in diameter) enables recordings with exceptional temporal resolution to be made. Furthermore, the technique can be adapted to record from both pre- and postsynaptic cells simultaneously, allowing the transfer function at the synapse to be studied directly 2. This method therefore provides a means by which fundamental aspects of neurotransmission can be studied, from multivesicular release to the elusive function of the ribbon in sensory cells.

Whole-cell patch-clamp recordings from auditory nerve fiber dendrites at the inner hair cell ribbon synapse in the mammalian cochlea.

Koklear İç Saç Hücreleri Ulaşın Afferent Dendritler postsinaptik Kayıtlar: Şerit Synapse Multivesicular Yayın İzleme

The afferent synapse between the inner hair cell (IHC) and the auditory nerve fiber provides an electrophysiologically accessible site for recording the ...

Nörobilim

Preparation and Culture of Chicken Auditory Brainstem Slices

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at discreet periods of development 1-4 as well as mechanisms for temporal coding in the central nervous system 5-7.
Here we present a method to prepare chicken auditory brainstem slices that can be used for acute experimental procedures or to culture organotypic slices for long-term experimental manipulations.
The chicken auditory brainstem is composed of nucleus angularis, magnocellularis, laminaris and superior olive. These nuclei are responsible for binaural sound processing and single coronal slice preparations preserve the entire circuitry. Ultimately, organotypic slice cultures can provide the opportunity to manipulate several developmental parameters such as synaptic activity, expression of pre and postsynaptic components, expression of aspects controlling excitability and differential gene expression
This approach can be used to broaden general knowledge about neural circuit development, refinement and maturation.

The chicken auditory brainstem is comprised of nuclei responsible for binaural sound processing. A single coronal slice preparation maintains the entire circuitry while the cultured approach provides a unique preparation to study the development of neuronal structure and auditory function at the molecular, cellular and network levels.

Tavuk İşitsel Beyin Sapı Dilimleri hazırlanması ve Kültür

The chicken auditory brainstem is a well-established model system that has been widely used to study the anatomy and physiology of auditory processing at ...

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. The inner ear auditory sensory organ is critical for our ability to hear. It houses a highly specialized sensory epithelium that consists of mechano-transducing hair cells (HCs) and surrounding glial-like supporting cells (SCs). Despite structural differences in the auditory organs, molecular mechanisms regulating the development of the auditory organ are evolutionarily conserved between mammals and aves. In ovo electroporation is largely limited to early stages at E1 - E3. Due to the relative late development of the auditory organ at E5, manipulations of the auditory organ by in ovo electroporation past E3 are difficult due to the advanced development of the chicken embryo at later stages. The method presented here is a transient gene transfer method for targeting genes of interest at stage E4 - E4.5 in the developing chicken auditory sensory organ via in ovo micro-electroporation. This method is applicable for gain- and loss-of-functions with conventional plasmid DNA-based expression vectors and can be combined with in ovo cell proliferation assay by adding EdU (5-ethynyl-2&#180;-deoxyuridine) to the whole embryo at the time of electroporation. The use of green or red fluorescent protein (GFP or RFP) expression plasmids allows the experimenter to quickly determine whether the electroporation successfully targeted the auditory portion of the developing inner ear. In this method paper, representative examples of GFP electroporated specimens are illustrated; embryos were harvested 18 - 96 hr&#160;after electroporation and targeting of GFP to the pro-sensory area of the auditory organ was confirmed by RNA in situ hybridization. The method paper also provides an optimized protocol for the use of the thymidine analog EdU to analyze cell proliferation; an example of an EdU based cell proliferation assay that combines immuno-labeling and click EdU chemistry is provided.

Gene Transfer into the Chicken Auditory Organ by In Ovo Micro-electroporation

The auditory organ mediates hearing. Here we present a modified in ovo micro-electroporation method optimized for studying auditory progenitor cell proliferation and differentiation in the developing chicken auditory organ.

Tavuk İşitsel Organ gen Transferi tarafından<em&gt; Ovo olarak</em&gt; Mikro-elektroporasyon

Chicken embryos are ideal model systems for studying embryonic development as manipulations of gene function can be conducted with relative ease in ovo. ...

In Ovo Electroporation in the Chicken Auditory Brainstem

Electroporation is a method that introduces genes of interest into biologically relevant organisms like the chicken embryo. It is long established that the chicken embryo is an effective research model for studying basic biological functions of auditory system development. More recently, the chicken embryo has become particularly valuable in studying gene expression, regulation and function associated with hearing. In ovo electroporation can be used to target auditory brainstem regions responsible for highly specialized auditory functions. These regions include the chicken nucleus magnocellularis (NM) and nucleus laminaris (NL). NM and NL neurons arise from distinct precursors of rhombomeres 5 and 6 (R5/R6). Here, we present in ovo electroporation of plasmid-encoded genes to study gene-related properties in these regions. We show a method for spatial and temporal control of gene expression that promote either gain or loss of functional phenotypes. By targeting auditory neural progenitor regions associated with R5/R6, we show plasmid transfection in NM and NL. Temporal regulation of gene expression can be achieved by adopting a tet-on vector system. This is a drug inducible procedure that expresses the genes of interest in the presence of doxycycline (Dox). The in ovo electroporation technique &#8211; together with either biochemical, pharmacological, and or in vivo functional assays &#8211; provides an innovative approach to study auditory neuron development and associated pathophysiological phenomena.

In Ovo Electroporation in the Chicken Auditory Brainstem

Auditory brainstem neurons of avians and mammals are specialized for fast neural encoding, a fundamental process for normal hearing functions. These neurons arise from distinct precursors of embryonic hindbrain. We present techniques utilizing electroporation to express genes in the hindbrain of chicken embryos to study gene function during auditory development.

Tavuk İşitsel Beyinsapındaki Ovo Elektroporasyonunda

Electroporation is a method that introduces genes of interest into biologically relevant organisms like the chicken embryo. It is long established that ...

In Ovo and Ex Ovo Methods to Study Avian Inner Ear Development

The inner ear perceives sound and maintains balance using the cochlea and vestibule. It does this by using a dedicated mechanosensory cell type known as the hair cell. Basic research in the inner ear has led to a deep understanding of how the hair cell functions, and how dysregulation can lead to hearing loss and vertigo. For this research, the mouse has been the pre-eminent model system. However, mice, like all mammals, have lost the ability to replace hair cells. Thus, when trying to understand cellular therapies for restoring inner ear function, complementary studies in other vertebrate species could provide further insights. The auditory epithelium of birds, the basilar papilla (BP), is a sheet of epithelium composed of mechanosensory hair cells (HCs) intercalated by supporting cells (SCs). Although the anatomical architecture of the basilar papilla and the mammalian cochlea differ, the molecular mechanisms of inner ear development and hearing are similar. This makes the basilar papilla a useful system for not only comparative studies but also to understand regeneration. Here, we describe dissection and manipulation techniques for the chicken inner ear. The technique shows genetic and small molecule inhibition methods, which offer a potent tool for studying the molecular mechanisms of inner ear development. In this paper, we discuss in ovo electroporation techniques to genetically perturb the basilar papilla using CRIPSR-Cas9 deletions, followed by dissection of the basilar papilla. We also demonstrate the BP organ culture and optimal use of culture matrices, to observe the development of the epithelium and the hair cells.

In Ovo and Ex Ovo Methods to Study Avian Inner Ear Development

The chick is a cost-effective, accessible, and widely available model organism for a variety of studies. Here, a series of protocols is detailed to understand the molecular mechanisms underlying avian inner ear development and regeneration.

Ovo ve Ex Ovo'da Kuş İç Kulak Gelişimini İnceleme Yöntemleri

The inner ear perceives sound and maintains balance using the cochlea and vestibule. It does this by using a dedicated mechanosensory cell type known as ...

Slicing the Embryonic Chicken Auditory Brainstem to Evaluate Tonotopic Gradients and Microcircuits

The chicken embryo is a widely accepted animal model to study the auditory brainstem, composed of highly specialized microcircuitry and neuronal topology differentially oriented along a tonotopic (i.e., frequency) axis. The tonotopic axis permits the segregated encoding of high-frequency sounds in the rostral-medial plane and low-frequency encoding in caudo-lateral regions. Traditionally, coronal brainstem slices of embryonic tissue permit the study of relative individual iso-frequency lamina. Although sufficient to investigate anatomical and physiological questions pertaining to individual iso-frequency regions, the study of tonotopic variation and its development across larger auditory brainstem areas is somewhat limited. This protocol reports brainstem slicing techniques from chicken embryos that encompass larger gradients of frequency regions in the lower auditory brainstem. The utilization of different slicing methods for chicken auditory brainstem tissue permits electrophysiological and anatomical experiments within one brainstem slice, where larger gradients of tonotopic properties and developmental trajectories are better preserved than coronal sections. Multiple slicing techniques allow for improved investigation of the diverse anatomical, biophysical, and tonotopic properties of auditory brainstem microcircuits.

Here we present a protocol for obtaining non-coronal auditory brainstem slices of the chicken embryo for the investigation of tonotopic properties and developmental trajectories within one brainstem slice. These slices include sagittal, horizontal, and horizontal/transverse sections encompassing larger tonotopic regions within an individual slice plane that the traditional coronal sections.

Tonotopik gradyanları ve mikrodevreleri değerlendirmek için embriyonik tavuk işitsel beyin sapının dilimlenmesi

The chicken embryo is a widely accepted animal model to study the auditory brainstem, composed of highly specialized microcircuitry and neuronal topology ...

Evaluation of Auditory Brainstem Response in Chicken Hatchlings

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ABRs in measuring auditory neural synchrony and estimating hearing sensitivity in other vertebrate model systems, methods for recording ABRs in the chicken have not been reported in nearly four decades. Chickens provide a robust animal research model because their auditory system is near functional maturation during late embryonic and early hatchling stages. We have demonstrated methods used to elicit one or two-channel ABR recordings using subdermal needle electrode arrays in chicken hatchlings. Regardless of electrode recording configuration (i.e., montage), ABR recordings included 3-4 positive-going peak waveforms within the first 6 ms of a suprathreshold click stimulus. Peak-to-trough waveform amplitudes ranged from 2-11 &#181;V at high-intensity levels, with positive peaks exhibiting expected latency-intensity functions (i.e., increase in latency as a function of decreased intensity). Standardized earphone position was critical for optimal recordings as loose skin can occlude the ear canal, and animal movement can dislodge the stimulus transducer. Peak amplitudes were smaller, and latencies were longer as animal body temperature lowered, supporting the need for maintaining physiological body temperature. For young hatchlings (&#60;3 h post-hatch day 1), thresholds were elevated by ~5 dB, peak latencies increased ~1-2 ms, and peak to trough amplitudes were decreased ~1 &#181;V compared to older hatchlings. This suggests a potential conductive-related issue (i.e., fluid in the middle ear cavity) and should be considered for young hatchlings. Overall, the ABR methods outlined here permit accurate and reproducible recording of in-vivo auditory function in chicken hatchlings that could be applied to different stages of development. Such findings are easily compared to human and mammalian models of hearing loss, aging, or other auditory-related manipulations.

We have used standard auditory brainstem response (ABR) techniques and applied them to hatchling chickens, a precocious avian model for auditory function. The protocol outlines animal preparation and ABR acquisition techniques in detail, with steps that could translate to other avian or rodent models.

Tavuk Yavrularında İşitsel Beyin Sapı Yanıtının Değerlendirilmesi

The auditory brainstem response (ABR) is an invaluable assay in clinical audiology, non-human animals, and human research. Despite the widespread use of ...

Dissecting Cell-Autonomous Function of Fragile X Mental Retardation Protein in an Auditory Circuit by In Ovo Electroporation

Fragile X mental retardation protein (FMRP) is an mRNA-binding protein that regulates local protein translation. FMRP loss or dysfunction leads to aberrant neuronal and synaptic activities in fragile X syndrome (FXS), which is characterized by intellectual disability, sensory abnormalities, and social communication problems. Studies of FMRP function and FXS pathogenesis have primarily been conducted with Fmr1 (the gene encoding FMRP) knockout in transgenic animals. Here we report an in vivo method for determining the cell-autonomous function of FMRP during the period of circuit assembly and synaptic formation using chicken embryos. This method employs stage-, site-, and direction-specific electroporation of a drug-inducible vector system containing Fmr1 small hairpin RNA (shRNA) and an EGFP reporter. With this method, we achieved selective FMRP knockdown in the auditory ganglion (AG) and in one of its brainstem targets, the nucleus magnocellularis (NM), thus providing a component-specific manipulation within the AG-NM circuit. Additionally, the mosaic pattern of the transfection allows within-animal controls and neighboring neuron/fiber comparisons for enhanced reliability and sensitivity in data analyzing. The inducible vector system provides temporal control of gene editing onset to minimize accumulating developmental effects. The combination of these strategies provides an innovative tool to dissect the cell-autonomous function of FMRP in synaptic and circuit development.

Dissecting Cell-Autonomous Function of Fragile X Mental Retardation Protein in an Auditory Circuit by In Ovo Electroporation

Using in ovo electroporation, we devised a method to selectively transfect the auditory inner ear and cochlear nucleus in chicken embryos to achieve a cell-group-specific knockdown of fragile X mental retardation protein during discrete periods of circuit assembly.

In Ovo Electroporation tarafından İşitsel Bir Devrede Kırılgan X Mental Retardasyon Proteininin Hücre Otonom Fonksiyonunun Diseksiyonu

Fragile X mental retardation protein (FMRP) is an mRNA-binding protein that regulates local protein translation. FMRP loss or dysfunction leads to ...

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.

Patch-Clamp Kayıtları için Yenidoğan Kemirgenlerinden Vestibüler ve Spiral Ganglion Somata'nın İzole Edilmesi ve Kültürlenmesi

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