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Del Sole MJ, Nejamkin P, Cavilla V, Schaiquevich P, Moreno L. Comparison of two sedation protocols for short electroretinography in cats. J Feline Med Surg 2018; 20:172-178. [PMID: 28379112 PMCID: PMC11129254 DOI: 10.1177/1098612x17703011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Objectives The objectives were to compare two different sedative combinations, xylazine-ketamine and dexmedetomidine-ketamine, for the short electroretinography (ERG) protocol and their impact on sedative effect, reversal times and physiological variables in cats. Methods Six healthy spayed female domestic cats were sedated using one of two ketamine-containing protocols: intramuscular xylazine hydrochloride (1 mg/kg) plus ketamine hydrochloride (3 mg/kg) (XK), and dexmedetomidine hydrochloride (5 µg/kg) plus ketamine hydrochloride (3 mg/kg) (DK). A short ERG protocol was recorded from the left eye of each cat under XK and DK sedation. Thirty minutes later, the effects were reversed with yohimbine or atipamezole for the XK and DK treatment, respectively. The cats were evaluated for time to recumbency, time to head elevation, and time to standing position after reversal treatments. Other variables recorded were: systolic blood pressure, cardiac rhythm, heart rate, pulse oximetry and respiratory rate. Recorded ERG variables included a- and b-wave amplitudes and implicit times under photopic, scotopic and scotopic mixed ERG conditions. Results Time to lateral recumbency with XK was shorter than for DK ( P <0.05). After reversal, head elevation and standing position times were significantly longer for the XK than the DK group ( P <0.05). Heart rate increased and systolic blood pressure decreased from baseline in both groups ( P <0.05), but there were no significant differences between treatment groups. The b-wave amplitude recorded in the photopic study of cats treated with XK was lower than in animals treated with DK ( P <0.05). No other significant differences in ERG variables were observed between treatment groups ( P >0.05). Conclusions and relevance The present study shows that XK and DK treatments are chemical restraint alternatives for ERG recording in cats, with significant differences only in the photopic b-wave amplitude.
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Affiliation(s)
- María J Del Sole
- Laboratory of Pharmacology, Tandil Center of Veterinary Investigation (CIVETAN, CONICET-CICPBA), Faculty of Veterinary Science, National University of the Center of Buenos Aires Province, University Campus, Tandil, Argentina
- Teaching Hospital, Faculty of Veterinary Science, National University of the Center of Buenos Aires Province, University Campus, Tandil, Argentina
| | - Pablo Nejamkin
- Teaching Hospital, Faculty of Veterinary Science, National University of the Center of Buenos Aires Province, University Campus, Tandil, Argentina
| | - Verónica Cavilla
- Endocrinology Laboratory, Department of Pathophysiology, Faculty of Veterinary Science, National University of the Center of Buenos Aires Province, University Campus, Tandil, Argentina
| | - Paula Schaiquevich
- National Council of Scientific and Technical Research, CONICET, Buenos Aires, Argentina
- Unit of Clinical Pharmacokinetics, Juan Pedro Garrahan Pediatric Hospital, Buenos Aires, Argentina
| | - Laura Moreno
- Laboratory of Pharmacology, Tandil Center of Veterinary Investigation (CIVETAN, CONICET-CICPBA), Faculty of Veterinary Science, National University of the Center of Buenos Aires Province, University Campus, Tandil, Argentina
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Preliminary study of the safety and efficacy of medium-chain triglycerides for use as an intraocular tamponading agent in minipigs. Graefes Arch Clin Exp Ophthalmol 2017; 255:1593-1604. [DOI: 10.1007/s00417-017-3695-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/24/2017] [Accepted: 05/09/2017] [Indexed: 11/27/2022] Open
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Lavoie J, Rosolen SG, Chalier C, Hébert M. Negative impact of melatonin ingestion on the photopic electroretinogram of dogs. Neurosci Lett 2013; 543:78-83. [PMID: 23562505 DOI: 10.1016/j.neulet.2013.02.070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 01/22/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
Abstract
Melatonin follows a circadian rhythm entrained by the light/dark cycle and plays a role in promoting light sensitivity at night. It has been suggested that melatonin and dopamine reciprocal inhibition may contribute to the switch between day and night vision. The purpose of this study was to investigate the impact of a high dose of melatonin administration on the photopic and scotopic electroretinogram (ERG) of dogs in the daytime, when it is not thought to be present. Photopic and scotopic ERG luminance response functions were obtained from 7 anaesthetized beagle dogs (3 males and 4 females), once without melatonin (control) and once after oral administration of melatonin (90 mg/dog). Vmax (maximal b-wave amplitude achieved) and logK (retinal sensitivity) were calculated from the derived luminance response function. Photopic flicker ERG was also recorded. In photopic condition, a-wave amplitude (control: -126.90 μV; with melatonin: -49.64 μV; p<0.001) and Vmax (control: 252.50 μV; with melatonin: 115.40 μV; p<0.001) were decreased. A significant reduction of the photopic flicker ERG amplitude was observed after melatonin ingestion. In scotopic condition, an overall difference was reported before and after melatonin ingestion for the a- and b-wave amplitude, but no change was significant for Vmax. Melatonin ingestion at a high dose during the day decreases the photopic amplitude of a- and b-wave, but has no impact on implicit time. This negative impact of melatonin on photopic system may serve to promote night vision.
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Affiliation(s)
- Joëlle Lavoie
- Centre de recherche de l'Institut Universitaire en santé mentale de Québec, Quebec City, Canada
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Augsburger AS, Haag V, Leuillet S, Legrand JJ, Forster R. Recording of the full-field electroretinogram in minipigs. Vet Ophthalmol 2012; 15 Suppl 2:84-93. [PMID: 22830305 DOI: 10.1111/j.1463-5224.2012.01052.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To test a simple electroretinographic protocol on a representative sample of minipigs. ANIMAL STUDIED Minipig. PROCEDURES Electroretinogram recordings were conducted on 162 healthy minipigs (81 males and 81 females) aged 4-6 months. After a 1.5-h light-adaptation period, the animals were anesthetized with general anesthesia. First, binocular full-field photopic electroretinogram recordings were conducted under photopic conditions. Subsequently, scotopic electroretinogram recordings were conducted during dark-adaptation periods every 4 min for a 20-min period. At the end of this period, the maximal combined rod-cone response was recorded by measuring the retinal response to a single high-intensity flash. We used sclerocorneal clip electrodes as active electrodes and needle electrodes as reference and ground electrodes. RESULTS The a-wave and b-wave peak times and amplitudes have been measured and statistically analyzed. For each of the statistical comparisons, normality and homogeneity of variances were evaluated. No significant gender differences were observed, with the exception of a higher b-wave amplitude for the photopic ERG recordings observed in females when compared to males (48.14 ± 12.909 μV vs. 42.88 ± 10.666 μV; P = 0.005). The process of dark adaptation was evaluated, and the maximal combined rod-cone response was measured (a- and b-waves amplitude and peak time). CONCLUSIONS We conducted photopic and scotopic electroretinogram recordings from a protocol based on light adaptation followed by dark adaptation using sclerocorneal clip electrodes, which allows quick assembly and examination.
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Rosolen SG, Lamory B, Harms F, Sahel JA, Picaud S, LeGargasson JF. Cellular-resolution in vivo imaging of the feline retina using adaptive optics: preliminary results. Vet Ophthalmol 2011; 13:369-76. [PMID: 21182721 DOI: 10.1111/j.1463-5224.2010.00829.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To perform cellular-level in vivo imaging of the feline retina using an adaptive optics flood illumination fundus camera (AO FIFC) designed for the human eye. MATERIALS AND METHODS Cellular-level images were obtained from three eyes of two normal sedated cats. Ocular aberrations were corrected using an AO system based on a 52-acuator electromagnetic deformable mirror and a 1024 lenslet Hartmann-Shack sensor (both Imagine Eyes, Orsay, France). A square 3°×3° area of the ocular fundus was flood-illuminated by a pulsed LED emitting at 850 nm and imaged onto a low-noise, high-resolution CCD camera. The animal's pupils were dilated and the effective pupil size was set to 7.5 mm. Conjunctival atraumatic clips were used to avoid eyeball movements and eyelid closure. The cornea was artificially hydrated throughout the experiments. Each acquisition consisted of 20 consecutive images, out of which 10 were numerically averaged to produce an enhanced final image. RESULTS The total amount of ocular aberrations was greatly reduced by the AO correction, from 2.4 to 0.21 microns root mean square on average. The resulting images presented white dots distributed at a density similar to that of cone photoreceptors and they allowed us to visualize small blood vessels and nerve fiber bundles at a higher resolution than classically obtained with conventional fundus photography. CONCLUSION Retinal imaging with cellular resolution was feasible in cats under sedation using an AO FIFC designed for human eyes without any optical modification. The AO FIFC technology could find new applications in clinical, pharmacological, and toxicological investigations.
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Affiliation(s)
- Serge G Rosolen
- Clinique Veterinaire Voltaire, 119 Boulevard Voltaire, Asnières, France
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Varela Lopez O, Alvarez Vazquez JC, Gonzalez Cantalapiedra A, Rosolen SG. Effects of hypercapnia on the electroretinogram in sevoflurane and isoflurane anaesthetized dogs. Doc Ophthalmol 2010; 121:9-20. [DOI: 10.1007/s10633-010-9223-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 02/01/2010] [Indexed: 10/19/2022]
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Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs. Doc Ophthalmol 2009; 119:79-88. [DOI: 10.1007/s10633-009-9173-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 03/28/2009] [Indexed: 10/20/2022]
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Durieux P, Rigaudière F, LeGargasson JF, Rosolen SG. ERG findings in three hypothyroid adult dogs with and without levothyroxine treatment. Vet Ophthalmol 2009; 11:406-11. [PMID: 19046283 DOI: 10.1111/j.1463-5224.2008.00656.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the effects of levothyroxine (LTh) on the electroretinogram (ERG) of adult dogs. MATERIAL AND METHODS Binocular, full field photopic and scotopic ERGs were recorded from an anesthetized Maltese Bichon cross (MB), a Yorkshire Terrier (YT) and a Shetland Sheepdog (SS) affected with hypothyroidism and treated with a daily dose of LTh at 20 microg/kg. The photopic ERGs were evoked to 12 different intensities ranging from 0.81 to -2.19 log cd.s/m(2) and presented under photopic conditions in order to assess (from the derived luminance-response curves) Vmax and b : a amplitude ratio parameters. Photopic flicker ERGs were obtained at 30 Hz. The scotopic ERGs (intensity: -3.09 log cd.s/m(2)) were recorded while the retina was dark-adapting and after 32 min of dark adaptation. This procedure was performed on two separate sessions: following a 3-day interruption of LTh treatment (S1) and following 30 days without interruption of LTh treatment (S2). RESULTS The mean photopic a-wave peak times were 9.8 ms at S1 and 5.0 ms at S2, respectively. The mean photopic b-wave peak times were 23.3 ms at S1 and 11.5 ms at S2, respectively, and the mean scotopic b-wave peak times (after 32 min of dark adaptation) were 45.2 ms at S1 and 26.0 ms at S2, respectively. No other significant ERG changes were observed. CONCLUSION Our results indicate that a dose of 20 microg/kg of LTh given to adult dogs was accompanied by a marked peak time shortening of both photopic and scotopic ERGs, without affecting other ERG parameters.
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Rosolen SG, Kolomiets B, Varela O, Picaud S. Retinal electrophysiology for toxicology studies: applications and limits of ERG in animals and ex vivo recordings. ACTA ACUST UNITED AC 2008; 60:17-32. [PMID: 18294830 DOI: 10.1016/j.etp.2007.11.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Accepted: 11/02/2007] [Indexed: 11/16/2022]
Abstract
Assessing retinal drug toxicity is becoming increasingly important as different molecules are now developed for the treatment of neurodegenerative diseases and vascular disorders. In pharmacology and toxicology, the electroretinogram (ERG) and the multielectrode array (MEA) recording techniques can be used to quantify the possible side effects of retino-active xenobiotics. Toxicity testing requires the use of rodent as well as non-rodent models for extrapolation to the human model when determining risk and safety. Animal species differ in their retinal anatomo-physiology: most rodents used in toxicology studies are essentially nocturnal species, whereas the non-rodent laboratory species normally used (e.g. dogs, pigs and monkeys) are diurnal. The ratio between the photoreceptor populations which varies from species to species, should be considered when designing the experiment protocol and the interpretation. The described ERG procedures are designed to comply with all applicable good laboratory practice standards. Use of these procedures should yield an acceptable level of intra- and inter-subject variability for compiling a historical database, and for detecting possible retinal toxicity in animal studies. They could therefore be used as specific and standardized tools for screening of potential retinotoxic molecules in drug discovery and development in order to compare methods and results with those obtained in human electrophysiological assessments. Recording of ganglion cell light responses on ex vivo retina with the MEA technique can further demonstrate how retino-active xenobiotics affect retinal visual information processing by eliminating potential obstacles related to bioavailability and blood barrier permeability.
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Rosolen SG, Chalier C, Rigaudière F, Lachapelle P. The ERG of the Beagle Dog: Evidence Associating a Post b-wave Negativity with the Tapetum Lucidum. Doc Ophthalmol 2005; 110:145-53. [PMID: 16328922 DOI: 10.1007/s10633-005-1816-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2005] [Indexed: 10/25/2022]
Abstract
As previously reported in the literature, the electroretinogram (ERG) of the Beagle dog includes a large post b-wave negativity, the origin of which is not yet established. In the course of our investigations on the electroretinogram in dogs, we examined two Beagle dogs (2 years apart) who had one eye devoid of a Tapetum Lucidum (TL). Photopic (cone-mediated) and scotopic (rod-mediated) ERGs were obtained according to the guidelines for clinical electroretinography in dog. In both dogs the short-latency ERG components (i.e. a- and b-waves) were found to be within the normal range in amplitude, peak time and morphology O.U. However, the large negative component that, in Beagle dogs, normally follow the b-wave was absent from the photopic as well as the scotopic signals obtained from the TL-free eye. Our results thus suggest a possible contribution of the TL to the ERG of Beagle dogs.
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Affiliation(s)
- Serge G Rosolen
- Clinique Vétérinaire Voltaire, 119 boulevard Voltaire, 92600, Asnières, France.
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Brigell M, Dong CJ, Rosolen S, Tzekov R. An Overview of Drug Development with Special Emphasis on the Role of Visual Electrophysiological Testing. Doc Ophthalmol 2005; 110:3-13. [PMID: 16249953 DOI: 10.1007/s10633-005-7338-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Visual electrophysiological techniques, such as electroretinography (ERG) and visual evoked potentials (VEP) can provide useful information on the safety, efficacy, and proper dosing of chemical entities under development as new drug therapies. During post-marketing safety surveillance, a variety of visual electrophysiological measures can be used to objectively assess and document individual patient response to ophthalmic drugs and ocular or visual system side effects of non-ophthalmic drugs. In this paper, the discovery, exploratory development, full-development and post-marketing stages of drug development are briefly outlined. The potential role of visual electrophysiological techniques in each of these stages is described and discussed.
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Affiliation(s)
- Mitchell Brigell
- Clinical Technology, Pfizer Global Research & Development, 2800 Plymouth Road, Ann Arbor, MI 48105, USA.
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Rosolen SG, Rigaudière F, LeGargasson JF, Chalier C, Rufiange M, Racine J, Joly S, Lachapelle P. Comparing the photopic ERG i-wave in different species. Vet Ophthalmol 2004; 7:189-92. [PMID: 15091327 DOI: 10.1111/j.1463-5224.2004.04022.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The i-wave, a post b-wave component of the human photopic electroretinogram (ERG), is claimed to originate at the level of the retinal ganglion cells (RGC) or more distally. We investigated whether this wave is a feature common to all species. Photopic ERGs were obtained from the following species: Beagle dog, European cat, New Zealand white rabbit, Göttingen minipig, Cynomolgus monkey, Sprague-Dawley and brown Norway rats, Hartley guinea pig, and CD1 and C57BL6 mice. Results were compared with those obtained from normal human subjects. Except for rats and mice, all species yielded a well-demarcated i-wave, easily identifiable and separated from the a-b-wave complex by approximately 20 ms. Our sample suggests that the i-wave is a feature common to the photopic ERG of most species including humans. In view of its suggested origin, the i-wave would offer a unique opportunity to test, with the flash ERG, the functional integrity of the retinal ganglion cells in animals where use of a pattern stimulus is not always easily obtained.
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Affiliation(s)
- Serge G Rosolen
- Clinique Vétérinaire Voltaire, 119 boulevard Voltaire, 92600 Asnières, France
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