eoe sub articles

EoE Sub Articles

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Pre-implantation of Chronic visual evoked potential (VEP) Electrodes
NOTE: If concurrent electroretinogram (ERG) and VEP signals are to be collected animals must be surgically implanted with VEP electrodes at least 1 week prior to signal collection.
<ol>
	<li>Sterilize the surgical bench prior to experimentation by cleaning with chlorhexidine (0.5% in 70% ethanol). Autoclave all surgical equipment before use. Cover the animal with a sterilized surgical drape. Ensure all experimenters wear surgical masks, gowns, and sterilized gloves.</li>
	<li>Induce anesthesia with 3 - 3.5% isoflurane with O2&#160;at a flow rate of 3 L/min. Maintain anesthesia at 1.5% and 2 L/min throughout the surgery. Ensure sufficient depth of anesthesia by the absence of paw pinch reflex.</li>
	<li>Apply 1% carboxymethylcellulose sodium on the cornea to prevent drying of the eyes.</li>
	<li>Shave a 30 mm x 30 mm area over the forehead, posterior to the eyes and anterior to the ears.</li>
	<li>Place the animal on a heat pad (37&#730;C) to maintain body temperature and stabilize animal&#39;s head with a stereotaxic frame.</li>
	<li>Disinfect the shaved area with 10% povidone-iodine three times. For the area near the eye, avoid the use of alcohol-based antiseptics, consistent with the Standard of Practice set out by the Association of Surgical Technologists.</li>
	<li>Make a median-sagittal incision on the head with a scalpel and from this excise a ~ 20 mm diameter circle of dermal tissue to expose the cranial bone.</li>
	<li>Remove the underlying periosteum by scraping and drying with gauze to expose the coronal and sagittal cranial sutures.</li>
	<li>Using a dental burr attached to a drill, trepan two holes (0.7 mm diameter, depth ~ 1 mm) through the skull on both hemispheres at the stereotaxic coordinates: 7 mm caudal to bregma, 3 mm lateral to midline.</li>
	<li>Screw in stainless steel screws (diameter 0.7 mm, length 3 mm, sterilized with chlorhexidine) into the two pre-made holes up to a depth of ~ 1 mm (2 mm of screw exposed) to allow firm anchorage. This contacts the dura without damaging the underlying cortical tissue.</li>
	<li>Prepare the surgical area for dental amalgam by drying the cranial bone with gauze, and retracting loose skin with two 3 - 0 sutures at ~ 4 and 8 o&#39;clock.</li>
	<li>Spread dental amalgam over the exposed skull to secure the screw electrodes (stainless steel screws described in step 1.10) in place. Ensure ~ 1.5 mm of the screws remain exposed for recording.</li>
	<li>Remove the retraction sutures.</li>
	<li>Inject 0.5% carprofen subcutaneously (5 mg/kg) for analgesia and saline (sodium chloride 0.9%, 1.5 ml) subcutaneously for fluid replacement.</li>
	<li>Allow animals to recover in separate cages. Do not leave an animal unattended until it has regained sufficient consciousness to maintain sternal recumbency.</li>
	<li>Do not return animal to the company of other animals until it has fully recovered from surgery (minimum 5 days).</li>
	<li>Continue to administer 0.5% carprofen subcutaneously for analgesia (5 mg/kg) once a day for 4 days.</li>
	<li>Record ERG and VEP 1 week following surgery.</li>
</ol>
2. ERG and VEP Recording&#160;
<ol>
	<li>Data collection preparation&#8203;
	<ol>
		<li>Use computer software to simultaneously trigger stimulus and acquire data according to the settings recommended below.
		<ol>
			<li>Amplify the signals&#160;(ERG: &#215;1,000, VEP: x10,000) with the gain internally set by an isolated pre-amplifier and amplifier, and with both eyes matched for impedance.</li>
			<li>Set the sampling rate for the ERG to 4 kHz over a 650 msec recording window (2,560 points), To do this, click the tab for &#34;time base&#34; in the data acquisition software (for name and version of software see Table for Materials), select &#34;2,560&#34; for Samples, and &#34;500 ms&#34; for time which will return a 650 msec recording window.
			<ol>
				<li>Use the same method to set the sampling rate for the VEP to 10 kHz over a 250 msec epoch. Allow a 10 msec pre-stimulus baseline for both ERG and VEP recordings. To do this, click the &#34;Setup&#34; tab; select &#34;Stimulator&#34; to bring up a new dialogue window; in that window select &#34;pulse&#34; from the drop down list for &#34;Mode&#34;; and set the value for &#34;delay&#34; to &#34;10 ms&#34;.</li>
			</ol>
			</li>
			<li>Set ERG band-pass filtering to 0.3 - 1,000 Hz (- 3 dB). This is done by clicking &#34;Bio Amplifier&#34; in the data acquisition software. Then set the value for &#34;High Pass&#34; to &#34;0.3Hz&#34;, and the value for &#34;low pass&#34; to &#34;1 kHz&#34;.</li>
			<li>Using the abovementioned method in 2.1.1.3, set VEP band-pass settings to 0.1 - 100 Hz (- 3 dB) as recommended by the International Society for Clinical Electrophysiology of Vision (ISCEV) for human VEP recordings.</li>
		</ol>
		</li>
	</ol>
	</li>
</ol>
2. Electrode preparation
<ol>
	<li>Custom-make the ERG active/inactive and VEP active/inactive electrodes by attaching silver wire or an alligator clip to an electrode lead, respectively. Commercially obtain ground electrode.</li>
	<li>For the 4 custom-made electrodes, cut the male end from the electrode lead extension. Remove 1 cm of the outer polytetrafluoroethylene insulation coating with a scalpel blade ensuring the inner wire is not damaged.</li>
	<li>Pre-fashion the ERG inactive electrodes by cutting a 70 mm length of silver wire (0.3 mm thickness) and forming a loop ~ 8 mm in diameter to encircle the rat eye. Prepare a uniform circle by shaping the loop on a 1 ml pipette tip.</li>
	<li>Pre-fashion VEP inactive electrodes by cutting a 70 mm length of silver and forming an ellipse ~ 8 mm in lengthwise diameter to hook onto rat incisors.</li>
	<li>Pre-fashion the ERG active electrodes by cutting a 30 mm length of silver wire and forming a small loop to gently contact the rat cornea (~ 1-2 mm in diameter)</li>
	<li>Securely attach electrodes (2 ERG active, 2 ERG inactive, 1 VEP inactive) to the electrode lead by entwining the silver with the exposed inner wire.</li>
	<li>Insulate excess exposed metal with masking tape to reduce photovoltaic artifacts.</li>
	<li>On the ERG inactive electrodes stick a small piece of hook-and-loop fastener (~ 5 mm &#215; 20 mm) to the masking tape to enable stable attachment to the rodent neck strap.</li>
	<li>Attach the alligator clip to the inner wire of the electrode leads to make the VEP active electrodes.</li>
	<li>Prior to recordings, electroplate the exposed surfaces of the silver wires (i.e.,&#160;the inactive ring and active tip) with chloride using a 9 V DC source for 20 sec to improve signal conduction.
	<ol>
		<li>To do this, immerse the silver tip of the ERG electrode wire (acting as the anode of a primary cell) into normal saline; and connect the other end of this electrode wire to the positive terminal of a 9 V battery.</li>
		<li>Connect another wire (the cathode) to the negative terminal of the battery, and immerse the other end into saline as well. Disconnect after 20 sec and observe the silver tip of the ERG electrode wire to be coated evenly in white color. 
		NOTE: Prepare new ERG electrodes for each experimental session (~ up to 8 hr) to ensure patency of the chloride coating.</li>
	</ol>
	</li>
</ol>
3. Animal preparation
<ol>
	<li>Dark-adapt the animals overnight (&#8805; 8 hr) prior to recordings in a light-tight room. Ensure maximal dark adaptation by turning off room lights, and closing all doors and blinds. Minimize light leakage by placing light-proof materials around junctions of doors/windows and placing computer screens outside thick black curtains.</li>
	<li>Conduct animal preparation in a dark room with the aid of dim red light-emitting diode (LED; 17.4 cd.m-2, &#955;max&#160;= 600 nm) to sustain rod sensitivity.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</li>
	<li>Anesthetize the rat by injecting ketamine/xylazine (60: 5 mg/kg) intramuscularly. Confirm sufficient depth of anesthesia by the absence of a paw pinch reflex.</li>
	<li>To maintain sedation, administer a further dose of anesthesia (50% of initial dose) after 50 min if necessary.</li>
	<li>For additional topical anesthesia apply one drop of 0.5% proxymetacaine to each eye, and blink off excess fluid.</li>
	<li>For pupil dilation apply one drop of 0.5% tropicamide to each eye, then dry off excess fluid.</li>
</ol>
4. ERG and VEP electrode positioning
<ol>
	<li>Place the animal on the ERG platform in front of the Ganzfeld bowl situated in the Faraday cage. Avoid using an electrical heating pad, as it can introduce electrical noise into the electrophysiological recordings. 
	NOTE: The platform is attached to a circulated heated water platform to maintain body temperature.</li>
	<li>Secure the animal to the platform with a strip of hook-and-loop fastener placed firmly but not tightly around the nape.</li>
	<li>Hook the inactive VEP electrode around the bottom incisors of the anesthetized rat.</li>
	<li>Position the ERG inactive electrodes by encircling the scleral ring non-invasively around the eye&#39;s equator. Stabilize this by attaching electrodes to the hook-and-loop fastener strip around the nape. Repeat for the contralateral eye.</li>
	<li>Fasten VEP active electrodes by attaching alligator clips to stainless-steel screws pre-implanted on the skull.</li>
	<li>Place a small drop of 1% carboxymethylcellulose sodium on cornea prior to placement of the ERG active electrode to improve signal quality. 
	NOTE: The viscose fluid also helps maintain corneal hydration throughout experimentation to minimize the formation of desiccation-type cataract in rodents.</li>
	<li>Place a small drop of 1% carboxymethylcellulose sodium on the lower incisors to improve contact of the VEP inactive electrode and thus signal quality.</li>
	<li>Position the ERG active electrodes to lightly touch the central corneal surface using a micromanipulator attached to a custom-built stereotaxic arm.</li>
	<li>Insert 2 - 5 mm of the ground needle electrode (stainless steel) subcutaneously into the tail.</li>
	<li>If necessary, dry any excess fluid from the inferior eyelid prior to recording to improve signal quality.</li>
	<li>Slide platform closer to the Ganzfeld bowl ensuring the animal&#39;s eyes align with the opening of the bowl to enable even illumination of both retinas (see step 2.4.1).</li>
	<li>Close the Faraday cage to reduce extraneous noise.</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Alligator clip</td>
			<td>Generic brand</td>
			<td>HM3022</td>
			<td>Stainless steel 26 mm clip for connecting VEP screw electrodes to cables</td>
		</tr>
		<tr>
			<td>Bioamplifier</td>
			<td>ADInstruments</td>
			<td>ML 135</td>
			<td>For amplifying ERG and VEP signals</td>
		</tr>
		<tr>
			<td>Carboxymethylcellulose sodium 1.0%</td>
			<td>Allergan</td>
			<td>CAS 0009000-11-7</td>
			<td>Viscous fluid for improving signal quality of the active ERG electrode</td>
		</tr>
		<tr>
			<td>Carprofen 0.5%</td>
			<td>Pfizer Animal Health Group</td>
			<td>CAS 53716-49-7</td>
			<td>Proprietary name: Rimadyl injectable (50 mg/mL). For post-surgery analgesia, diluted to 0.5% (5 mg/mL) in normal saline</td>
		</tr>
		<tr>
			<td>Chlorhexadine 0.5%</td>
			<td>Orion Laboratories</td>
			<td>27411, 80085</td>
			<td>For disinfecting surgical instruments</td>
		</tr>
		<tr>
			<td>Circulating water bath</td>
			<td>Lauda-K&#246;nigshoffen</td>
			<td>MGW Lauda</td>
			<td>For maintaining body temperature of the anesthetized animal during surgery and electrophysiological recordings</td>
		</tr>
		<tr>
			<td>Dental amalgam</td>
			<td>DeguDent GmbH</td>
			<td>64020024</td>
			<td>For encasing the electrode-skull assembly to make it more robust</td>
		</tr>
		<tr>
			<td>Dental burr</td>
			<td>Storz Instruments, Bausch and Lomb</td>
			<td>#E0824A</td>
			<td>A miniature drill head of ~0.7mm diameter for making a small hole in the skull over each hemisphere to implant VEP screws</td>
		</tr>
		<tr>
			<td>Drill</td>
			<td>Bosch</td>
			<td>Dremel 300 series</td>
			<td>An automatic drill for trepanning</td>
		</tr>
		<tr>
			<td>Electrode lead</td>
			<td>Grass Telefactor&#160;</td>
			<td>F-E2-30</td>
			<td>Platinum cables for connecting silver wire electrodes to the amplifier</td>
		</tr>
		<tr>
			<td>Faraday Cage</td>
			<td>custom-made</td>
			<td></td>
			<td>Ensures light proof to maintain dark adaptation. Encloses the Ganzfeld setup to improve signal to noise ratio</td>
		</tr>
		<tr>
			<td>Gauze swabs</td>
			<td>Multigate Medical Products Pty Ltd</td>
			<td>57-100B</td>
			<td>For drying the surgical incision and exposed skull surface during surgery</td>
		</tr>
		<tr>
			<td>Ganzfeld integrating sphere</td>
			<td>Photometric Solutions International</td>
			<td></td>
			<td>Custom designed light stimulator: 36 mm diameter, 13 cm aperture size</td>
		</tr>
		<tr>
			<td>Velcro</td>
			<td>VELCRO Australia Pty Ltd</td>
			<td>VELCRO Brand Reusable Wrap</td>
			<td>Hook-and-loop fastener to secure the electrodes and the animal on the recording platform</td>
		</tr>
		<tr>
			<td>Isoflurane 99.9%</td>
			<td>Abbott Australasia Pty Ltd</td>
			<td>CAS 26675-46-7</td>
			<td>Proprietary Name: Isoflo(TM) Inhalation anaaesthetic. Pharmaceutical-grade inhalation anesthetic mixed with oxygen gas for VEP electrode implant surgery</td>
		</tr>
		<tr>
			<td>Ketamine&#160;</td>
			<td>Troy Laboratories</td>
			<td>Ilium Ketamil</td>
			<td>Proprietary name: Ketamil Injection, Brand: Ilium. Pharmaceutical-grade anesthetic for electrophysiological recording</td>
		</tr>
		<tr>
			<td>Luxeon LEDs</td>
			<td>Phillips Lighting Co.</td>
			<td></td>
			<td>For light stimulation twenty 5 watt and one 1 watt LEDs.</td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Harvard Apparatus</td>
			<td>BS4 50-2625</td>
			<td>Holds the ERG active electrode during recordings</td>
		</tr>
		<tr>
			<td>Needle electrode</td>
			<td>Grass Telefactor&#160;</td>
			<td>F-E2-30</td>
			<td>Subcutaneously inserted in the tail to serve as the ground electrode for both the ERG and VEP</td>
		</tr>
		<tr>
			<td>Phenylephrine 2.5% minims&#160;</td>
			<td>Bausch and Lomb</td>
			<td>CAS 61-76-7</td>
			<td>Instilled with Tropicamide to achieve maximal dilation for ERG recording</td>
		</tr>
		<tr>
			<td>Povidone iodine 10%</td>
			<td>Sanofi-Aventis</td>
			<td>CAS 25655-41-8</td>
			<td>Proprietory name: Betadine, Antiseptic to prepare the shaved skin for surgery 10%, 500 mL</td>
		</tr>
		<tr>
			<td>Powerlab data acquisition system</td>
			<td>ADInstruments</td>
			<td>ML 785</td>
			<td>Controls the LEDs</td>
		</tr>
		<tr>
			<td>Proxymetacaine 0.5%</td>
			<td>Alcon Laboratories&#160;</td>
			<td>CAS 5875-06-9</td>
			<td>For corneal anaesthesia during ERG recordings</td>
		</tr>
		<tr>
			<td>Saline solution</td>
			<td>Gelflex</td>
			<td></td>
			<td>Non-injectable, for electroplating silver wire electrodes</td>
		</tr>
		<tr>
			<td>Scope Software</td>
			<td>ADInstruments</td>
			<td>version 3.7.6</td>
			<td>Simultaneously triggers the stimulus via the Powerlab system and collects data</td>
		</tr>
		<tr>
			<td>Silver (fine round wire)</td>
			<td>A&#38;E metal</td>
			<td>0.3 mm</td>
			<td>Used to make active and inactive ERG electrodes, and the inactive VEP electrode</td>
		</tr>
		<tr>
			<td>Stainless streel screws&#160;</td>
			<td>MicroFasterners</td>
			<td></td>
			<td>0.7 mm shaft diameter, 3 mm in length to be implanted over the primary visual cortex and serve as the active VEP electrodes</td>
		</tr>
		<tr>
			<td>Stereotaxic frame</td>
			<td>David Kopf</td>
			<td>Model 900</td>
			<td>A small animal stereotaxic instrument for locating the primary visual cortices according to Paxinos &#38; Watson&#39;s 2007 rat brain atlas coordinates</td>
		</tr>
		<tr>
			<td>Surgical blade</td>
			<td>Swann-Morton Ltd.</td>
			<td>206</td>
			<td>For incising the area of skin overlaying the primary visual cortex to implant the VEP electrodes</td>
		</tr>
		<tr>
			<td>Suture</td>
			<td>Shanghai Pudong Jinhuan Medical Products Co.,Ltd</td>
			<td></td>
			<td>3-0 silk braided suture non-absorbable, for skin retraction during VEP electrode implantation surgery</td>
		</tr>
		<tr>
			<td>Tobramycine eye ointment 0.3%</td>
			<td>Alcon Laboratories&#160;</td>
			<td>CAS 32986-56-4</td>
			<td>Proprietary name: Tobrex. Prophylactic antibiotic ointment applied around the skin wound after surgery</td>
		</tr>
		<tr>
			<td>Tropicamide 0.5%</td>
			<td>Alcon Laboratories&#160;</td>
			<td>CAS 1508-75-4</td>
			<td>Proprietary name: 0.5% Mydriacyl eye drop, Instilled to achieve mydriasis for ERG recording</td>
		</tr>
		<tr>
			<td>Xylazine</td>
			<td>Troy Laboratories</td>
			<td>Ilium Xylazil-100</td>
			<td>Pharmaceutical-grade anesthetic for electrophysiological recording</td>
		</tr>
		<tr>
			<td>Pipette tip&#160;</td>
			<td>Eppendorf Pty Ltd</td>
			<td>0030 073.169</td>
			<td>Eppendorf epTIPS 100 - 5000 mL, for custom-made electrodes</td>
		</tr>
		<tr>
			<td>Lethabarb Euthanazia Injection</td>
			<td>Virbac (Australia) Pty Ltd</td>
			<td>LETHA450</td>
			<td>325 mg/mL pentobarbital sodium for rapid euthanazia</td>
		</tr>
		<tr>
			<td>Microsoft Office Excel</td>
			<td>Microsoft</td>
			<td>version 2010</td>
			<td>spreadsheet software for data analysis</td>
		</tr>
	</tbody>
</table>

preparing a rat model to assess visual pathway integrity using an electrophysiology setup

Source: Nguyen, C. T. et al., <a href="https://app.jove.com/v/54158">Simultaneous Recording of Electroretinography and Visual Evoked Potentials in Anesthetized Rats.</a>&#160;J. Vis. Exp. (2016)
This video demonstrates the preparation of a rat model to study retinal health and visual pathway integrity. Visual evoked potential and electroretinography reference and active electrodes are connected to the rat, followed by aligning the platform with the rat in front of the Ganzfeld bowl for even retinal illumination and closing the Faraday cage to avoid external interference.

Preparing a Rat Model to Assess Visual Pathway Integrity Using an Electrophysiology Setup

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. ...

Light stimulates the eye&#39;s photoreceptors, sending electrical signals to the visual cortex in the brain to process visual information.
To measure the integrity of this visual pathway, start with an anesthetized, dark-adapted rat in a dark room.
Position a reference VEP electrode around the rat&#39;s lower front teeth.
Secure the rat with a fastener strip on an ERG platform in front of a Ganzfeld bowl, a light-illuminating device within a Faraday cage.
Place the reference ERG electrodes around the eye&#39;s equator, encircling the scleral ring, and secure them.
Then, attach the VEP active electrodes to the pre-implanted skull screws to detect cortical signals.
Position the ERG electrodes with lubricant on the center of the eyes to measure their responses to light stimuli.
Remove excess lubricant and insert a ground electrode into the tail to reduce electrical noise.
Move the ERG platform closer to the Ganzfeld bowl and close the Faraday cage to minimize external interference.

preparing-rat-model-to-assess-visual-pathway-integrity-using-an

Universidad San Sebastian

Research

JoVE Encyclopedia of Experiments

Neuroscience

Neurophysiology

Electrophysiology Techniques

66 Views. Fonte: Nguyen, C. T. et al., Registrazione simultanea di elettroretinografia e potenziali evocati visivi in ratti anestetizzati.J. Vis. Exp. (2016) Questo video dimostra la preparazione di un modello di ratto per studiare la salute della retina e l'integrità del percorso visivo. Il potenziale evocato visivo e il riferimento per l'elettroretinografia e gli elettrodi attivi sono collegati al ratto, seguiti dall'allineamento della piattaforma con il ratto davanti alla ciotola di Ganzfeld per un'i...

Video: Preparazione di un modello di ratto per valutare l'integrità del percorso visivo utilizzando una configurazione di elettrofisiologia - Concept

Implantation and Recording of Wireless Electroretinogram and Visual Evoked Potential in Conscious Rats

The full-field electroretinogram (ERG) and visual evoked potential (VEP) are useful tools to assess retinal and visual pathway integrity in both laboratory and clinical settings. Currently, preclinical ERG and VEP measurements are performed with anesthesia to ensure stable electrode placements. However, the very presence of anesthesia has been shown to contaminate normal physiological responses. To overcome these anesthesia confounds, we develop a novel platform to assay ERG and VEP in conscious rats. Electrodes are surgically implanted sub-conjunctivally on the eye to assay the ERG and epidurally over the visual cortex to measure the VEP. A range of amplitude and sensitivity/timing parameters are assayed for both the ERG and VEP at increasing luminous energies. The ERG and VEP signals are shown to be stable and repeatable for at least 4 weeks post surgical implantation. This ability to record ERG and VEP signals without anesthesia confounds in the preclinical setting should provide superior translation to clinical data.

We show surgical implantation and Recording procedures to measure visual electrophysiological signals from the eye (electroretinogram) and brain (visual evoked potential) in conscious rats, which is more analogous to the human condition where recordings are conducted without anesthesia confounds.

L&#39;impianto e la registrazione di Wireless Elettroretinogramma e potenziale visivo evocato ratto conscio

The full-field electroretinogram (ERG) and visual evoked potential (VEP) are useful tools to assess retinal and visual pathway integrity in both ...

Ricerca

JoVE Journal

Comportamento

Using the Electroretinogram to Assess Function in the Rodent Retina and the Protective Effects of Remote Limb Ischemic Preconditioning

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 &#8216;flash&#8217; 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.

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.

Utilizzando il Elettroretinogramma per valutare la funzione in roditori Retina e gli effetti protettivi del Remote Limb ischemico precondizionamento

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 ...

Neuroscienze

Optimizing the Setup and Conditions for Ex Vivo Electroretinogram to Study Retina Function in Small and Large Eyes

Measurements of retinal neuronal light responses are critical to investigating the physiology of the healthy retina, determining pathological changes in retinal diseases, and testing therapeutic interventions. The ex vivo electroretinogram (ERG) allows the quantification of contributions from individual cell types in the isolated retina by addition of specific pharmacological agents and evaluation of tissue-intrinsic changes independently of systemic influences. Retinal light responses can be measured using a specialized ex vivo ERG specimen holder and recording setup, modified from existing patch clamp or microelectrode array equipment. Particularly, the study of ON-bipolar cells, but also of photoreceptors, has been hampered by the slow but progressive decline of light responses in the ex vivo ERG over time. Increased perfusion speed and adjustment of the perfusate temperature improve ex vivo retinal function and maximize response amplitude and stability. The ex vivo ERG uniquely allows the study of individual retinal neuronal cell types. In addition, improvements to maximize response amplitudes and stability allow the investigation of light responses in retina samples from large animals, as well as human donor eyes, making the ex vivo ERG a valuable addition to the repertoire of techniques used to investigate retinal function.

Optimizing the Setup and Conditions for Ex Vivo Electroretinogram to Study Retina Function in Small and Large Eyes

Modification of existing multielectrode array or patch clamp equipment makes the ex vivo electroretinogram more widely accessible. Improved methods to record and maintain ex vivo light responses facilitate the study of photoreceptor and ON-bipolar cell function in the healthy retina, animal models of eye diseases, and human donor retinas.

Ottimizzazione della configurazione e delle condizioni per l'elettroretinogramma ex vivo per studiare la funzione della retina in occhi piccoli e grandi

Measurements of retinal neuronal light responses are critical to investigating the physiology of the healthy retina, determining pathological changes in ...

Preparing a Rat Model to Assess Visual Pathway Integrity Using an Electrophysiology Setup

Trascrizione

Preparing a Rat Model to Assess Visual Pathway Integrity Using an Electrophysiology Setup