An electroretinogram protocol for toxicological screening in the canine model

Jones, Randy D.; Brenneke, Chris J.; Hoss, H.; Loney, M.Lynn

doi:10.1016/0378-4274(94)90166-x

Cited by 13 publications

(5 citation statements)

References 28 publications

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“…The waveforms obtained were comparable to those of previous reports using each of the three anesthetic protocols [9,10,17,21,22]. A previous study regarding the effects of isoflurane on the ERG of dogs using the human ERG protocol [17], recommended by the International Society for Clinical Electrophysiology of Vision [23], with similarities to the protocol used in the present study, showed that the resultant waveform elicited by each ERG stimulus was comparable to those obtained in the present study. Some of the waveforms illustrated in Fig.…”

Section: Discussionsupporting

confidence: 92%

“…The anesthetics that have been used are medetomidineketamine (MK), xylazine-ketamine (XK), isoflurane, halothane, sevoflurane, and propofol [9,10,14,[16][17][18]. It is therefore reasonable for investigating the effects of different anesthetic combinations on the ERG to directly compare the ERG results obtained using a standardized ERG and anesthetic protocol in the same animal.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

et al. 2009

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The objective of this study is to compare the effects of three different anesthetic combinations on the electroretinogram in the same animals under similar laboratory conditions. Thiopental-isoflurane (TI), medetomidine-ketamine (MK), and xylazine-ketamine (XK) were used on each of 12 healthy miniature schnauzer dogs (MS) with a period of at least 3 weeks in between subsequent anesthesia protocols, using the Dog Standard Protocol. The scotopic ERGs consisted of scotopic low stimulus strength (S) responses designated S1, S2, S3, S4, and S5, at 1, 5, 10, 15, and 20 min after dark adaptation, respectively, and scotopic standard stimulus strength (S-ST) responses. The photopic ERGs consisted of a photopic single flash (P) response and 31 Hz flicker (P-FL) responses. For S-ST (2.5 cd s/m(2)), the amplitude of the a-wave using TI was significantly lower than that using MK (adjusted P = 0.05) and XK (adjusted P = 0.03), and the implicit time of the a-wave was significantly shorter than that using MK (adjusted P = 0.04). For P (2.5 cd s/m(2)), the amplitude of the b-wave using XK was significantly higher than that using MK (adjusted P = 0.01). The implicit times of the b-wave using TI was significantly longer and shorter than that of MK for S1, S2 and P-FL and for S4 and S-ST, respectively, and than that of XK for S2 and P-FL and for S5 and S-ST, respectively. The results of the present study showed that TI affected both the amplitude and the implicit time of the a-wave for S-ST and the implicit time of the b-wave relatively more so than was the case when using XK or MK. Therefore, it appears that either XK or MK could be advantageous to use rather than TI for clinical studies.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

et al. 2009

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“…ERG of affected dogs in our study failed to confirm the abnormalities reported by Chaudieu 5 . Although a shortened a‐wave latency in affected dogs was statistically significant, this difference is not clinically significant because mean a‐wave latency of both groups was consistent with previous reports in dogs 23,24 . PRA was definitively ruled out as the etiology for these focal and multifocal lesions in Borzoi by normal scotopic and photopic full‐field and flicker ERG in animals older than 1 year 8,9 .…”

Section: Discussionsupporting

confidence: 84%

Multifocal chorioretinal lesions in Borzoi dogs

Storey¹,

Grahn²,

Alcorn

2005

Veterinary Ophthalmology

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Borzoi chorioretinopathy is an acquired condition that initially manifests as focal retinal edema and loss of choriocapillaris and tapetum. With time the retina degenerates becoming hyper-reflective and with RPE hyper-pigmentation and clumping within the borders of the tapetal lesions. Choriocapillaris remains hypofluorescent on fluorescein angiography. Progressive retinal atrophy was excluded as an etiology of multifocal chorioretinopathy in Borzois dogs. This condition is not inherited by simple autosomal dominant or sex-linked modes of inheritance.

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“…An established five-step canine ERG protocol (Jones et al, 1994a) was used, with step 1 (scotopic, single flash, Blue 10 dB) for rod response; step 2 (scotopic, single flash) for maximal response; step 3 (scotopic, single flash) for oscillatory potentials; step 4 (photopic, single flash) for cone response; and step 5 (photopic, 30 Hz flicker) for flicker cone response of the ERG waveform. The dogs were observed at least once daily for signs of disease, and all activities, planned or unplanned, associated with the animals or their room were documented.…”

Section: Methodsmentioning

confidence: 99%

The effects of physostigmine on the electroretinogram in the beagle dog

1995

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The purpose of the study was to correlate electroretinogram (ERG) parameters with increasing levels of plasma, erythrocyte and ocular tissue cholinesterase inhibition using the beagle dog as a model for human neurovisual toxicity. The anticholinesterase compound physostigmine was administered at various steady-state intravenous infusion rates based on pharmacokinetic estimates of plasma and red blood cell cholinesterase inhibition. The most sensitive parameter was the b-wave amplitude of the rod response, which was significantly depressed compared to pretreatment at all levels of acute cholinesterase depression. The overall maximal ERG response demonstrated a trend of declining a- and b-wave amplitudes, which corresponded with the increased levels of cholinesterase depression, but these differences were not significant. The depression of the electroretinogram rod and cone amplitudes appeared to parallel plasma cholinesterase inhibition more closely than erythrocyte cholinesterase activity. Ocular tissue cholinesterase activity was significantly depressed in the retina (70%), cornea (60%) and dorsal rectus extraocular muscle (46%). Electroretinography may be a useful physiological tool for evaluating the ocular toxicity of certain chemicals or pharmaceuticals associated with cholinesterase biomarker activity.

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An electroretinogram protocol for toxicological screening in the canine model

Cited by 13 publications

References 28 publications

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

Multifocal chorioretinal lesions in Borzoi dogs

The effects of physostigmine on the electroretinogram in the beagle dog

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