The effects of different anesthetic agents on short electroretinography protocol in dogs.
ABSTRACT The purpose of this article was to investigate the effects of sedatives and general anesthetics, such as tiletamine-zolazepam, medetomidine, and isoflurane on the short ERG protocol. Six healthy mongrel dogs were assessed by a convenient short ERG protocol with the owners' consent. The amplitudes of a-wave and b-wave, as well as the implicit time of ERG under different anesthesia statuses, were recorded and analyzed. The amplitudes of ERG waves were not significantly different between tiletamine-zolazepam and medetomidine groups, except in b-wave after 5 min dark adaptation (140 +/- 42 microV in tiletamine-zolazepam and 101 +/- 32 microV in medetomidine, p<0.01). The amplitude of ERG recorded in isoflurane (5 +/- 3 microV of a-wave and 12 +/- 6 microV of b-wave under light adaptation; 41 +/- 19 microV of b-wave after 1 min dark adaptation; 28 +/- 15 microV of a-wave and 58 +/- 32 microV of b-wave after 5 min dark adaptation) were significantly different from tiletamine-zolazepam (8 +/- 2 microV of a-wave and 24 +/- 9 microV of b-wave under light adaptation; 117 +/- 44 microV of b-wave after 1 min dark adaptation; 59 +/- 18 microV of a-wave and 140 +/- 42 microV of b-wave after 5 min dark adaptation), except in a-wave after 1 min dark adaptation (39 +/- 13 microV in tiletamine-zolazepam and 34 +/- 17 microV in isoflurane). Comment-General anesthesia had significantly lower amplitudes in the dark-adapted group compared with the sedation group. Therefore, tiletamine-zolazepam is a desirable choice for the short ERG protocol in dogs.
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ABSTRACT: High-resolution magnetic resonance imaging (MRI) provides non-invasive images of retinal anatomy, physiology, and function with depth-resolved laminar resolution. Eye movement and drift, however, could limit high spatial resolution imaging, and anesthetics that minimize eye move-ment could significantly attenuate retinal function. The aim of this study was to determine the optimal anesthetic preparations to minimize eye movement and maximize visual-evoked retinal response in rats. Eye movements were examined by imaging of the cornea with a charge-coupled device (CCD) camera under isoflurane, urethane, ketamine/xylazine, and propofol anesthesia at typical dosages in rats. Com-bination of the paralytic pancuronium bromide with isoflurane or ketamine/xylazine anesthesia was also examined for the eye movement studies. Visual-evoked retinal responses were evaluated using full-field electroretinography (ERG) under isoflurane, ketamine/xylazine, urethane, and ketamine/xylazine ? pancuronium anesthesia in rats. The degree of eye movement, measured as displacement per unit time, Govind Nair and Moon Kim contributed equally to this manuscript.