齧歯類網膜とリモート四肢虚血プレコンディショニングの保護効果に機能を評価するために電図を用いて、
Summary
The electroretinogram (ERG) is an electrical potential generated by the retina in response to light. This paper describes how to use the ERG to assess retinal function, in dark-adapted rats, and how it can be can be used to assess a neuroprotective intervention, in the present case remote ischemic preconditioning.
Abstract
The ERG is the sum of all retinal activity. The ERG is usually recorded from the cornea, which acts as an antenna that collects and sums signals from the retina. The ERG is a sensitive measure of changes in retinal function that are pan-retinal, but is less effective for detecting damage confined to a small area of retina. In the present work we describe how to record the ‘flash’ ERG, which is the potential generated when the retina is exposed to a brief light flash. We describe methods of anaesthesia, mydriasis and corneal management during recording; how to keep the retina dark adapted; electrode materials and placement; the range and calibration of stimulus energy; recording parameters and the extraction of data. We also describe a method of inducing ischemia in one limb, and how to use the ERG to assess the effects of this remote-from-the-retina ischemia on retinal function after light damage. A two-flash protocol is described which allows isolation of the cone-driven component of the dark-adapted ERG, and thereby the separation of the rod and cone components. Because it can be recorded with techniques that are minimally invasive, the ERG has been widely used in studies of the physiology, pharmacology and toxicology of the retina. We describe one example of this usefulness, in which the ERG is used to assess the function of the light-damaged retina, with and without a neuroprotective intervention; preconditioning by remote ischemia.
Introduction
ERGは、光に応答して、網膜によって生成され、眼の角膜表面から記録された電位です。記録条件は、慎重に管理されている場合、ERGは、網膜機能を評価するための種々の方法で使用することができます。ここでは、「フラッシュERG」、網膜が全体野の背景に提示簡単な、明るいフラッシュにさらされたときに発生する電位を記録する方法を説明しました。全体野が均一に光を分散し、光のフラッシュがほぼ均一に全体の網膜に到達します。網膜は、暗い記録前適応、及び動物の記録のために準備されるように暗順応を維持し、ERGが得られた場合、ロッドと錐体光受容体の両方によって生成されます。
暗順応フラッシュERGは、次の2つの方法で分析された特徴的な波形を有しています。まず、ERG波形の初期および後期成分を区別し、神経細胞の配列に関連しています網膜中のAlの活性化。最古のコンポーネントは、短い待ち時間負に向かう可能性のある、A波（ 図1）です。これは、b波と呼ばれ、正方向電位が続きます。 b波の立ち上がり位相が別の構成要素（振動電位またはOPS）と考えられている振動を示しています。 A波は、内顆粒層の細胞、およびアマクリン細胞による1のOPによってb波、光受容体によって発生すると考えられます。
刺激強度に基づいて、非常に薄暗いフラッシュへの対応は、暗順応閾値応答が可能であると呼ばれます。暗順応の閾値応答は、網膜神経節細胞2-4から生成されていると理解されます。第二に、フラッシュERGは明順応により分離することができる、または2つのフラッシュプロトコルによって棒状と円錐駆動コンポーネントに、以下に説明します。明所視条件下では、円錐集団が低いため、A波は、ラットでは検出可能ではなく、のOP及びb波であります5明確。その網膜高いコーン集団を持つ霊長類では、ロッド状と円錐経路の両方は、検出波6を発生させます。
多くの場合、フラッシュERGから抽出された2つの有用な尺度は、図2に示される典型的なフラッシュの応答と、 図1のように測定し、A-の振幅とb波である。感光体集団はdamagingly明るいへの曝露によって、例えば、低減された場合光、ERGのすべてのコンポーネントが低減されます。このような遠隔虚血プレコンディショニング（RIP）などの神経保護の介入は、A及びB波（ 図3）の振幅を維持することによって検証することができます。要約すると、ERGの分析は、健康、光損傷を受けたとneuroprotected網膜の間の比較を可能にします。
Protocol
Representative Results
Discussion
上記の暗順応フラッシュERG方法は、ラットの網膜機能を評価するための信頼できる方法です。 A波とB波の両方は、光損傷によって減少しました。リモート虚血プレコンディショニングは、A波とB波の光損傷誘導減少を軽減します。網膜機能のこの保存は遠隔虚血プレコンディショニングは、低酸素症、虚血および運動8-10などの保護事前調整の他の形態に似ている、神経保護を誘?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
著者らは、げっ歯類の監視、取り扱いや実験で夫人シャロンSpanaの支援を感謝しています。博士課程の資金援助は、ビジョンに優秀シドニー大学とオーストラリア研究センターにより提供されています。
Materials
| PC computer | |||
| Powerlab, 4 channel acquistion hardware | AD Instruments | PL 35044 | Acquistion of ERG |
| Animal Bio Amp | AD Instruments | FE 136 | Amplifier for ERG |
| Lab chart | AD Instruments | Signal collection software | |
| Ganzfield | Photometric solutions | FS-250A | Light stimulus |
| Ganzfield operating system | Photometric solutions | ||
| Research Radiometer | International light technologies | ILT-1700 | calibrate light series |
| Lux meter | LX-1010B | check red light illumanation | |
| Excel | microsoft | ||
| Lead wires | AD Instruments | Connect postive, negative ground electrodes to amplifier | |
| Lead wires -aligator | AD Instruments | ground ganzfield and acquistion hardware to computer | |
| Platinum wire 95% | A&E metals | postive electrode | |
| Mouth electrode Ag/AgCl Pellet | SDR | E205 | negative electode |
| 26 gauge needle | BD | ground electode | |
| Water pump | |||
| Water bath | |||
| Tubing | |||
| Homeothermic blanket system with flexible probe | Harvard Appartus | 507222F | |
| Atropine 1% w/v | Bausch & Lomb | topical mydriasis | |
| Proxmethycaine 0.5% w/v | Bausch & Lomb | topical anaesthetic | |
| Visco tears eye drops | Novartis | carbomer polymer | |
| Thread | retract eye lid | ||
| Tweezers | |||
| Reusable adhesive | Blu tac | Dim red headlamp. Affix electrodes | |
| Absorbent bedding | |||
| Ketamil – ketamine 100 mg/ml – 50 ml | Troy Laboratories Pty Ltd | dissociative | |
| Xylium – Xylazine 100 mg/ml – 50 ml | Troy Laboratories Pty Ltd | muscle relaxant | |
| Scale |
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