Characterization of the pupil light reflex, electroretinogram and tonometric parameters in healthy rat eyes.
OBJECTIVE
To characterize the pupil light reflex (PLR), electroretinographic (ERG) and tonometric parameters in healthy rat eyes.


METHODS
Brown Norway rats were used for experiments. The PLR was evaluated with a computerized pupillometer (n = 27), ERGs were recorded simultaneously from both eyes (n = 27) and IOP was measured with a Tonopen (n = 15).


RESULTS
The analysis of the PLR parameters confirmed that the consensual PLR had a significantly smaller amplitude (0.1-0.2 mm; p = 0.03) and an increased latency time (p = 0.001) compared to the direct PLR. Electroretinography revealed an a-wave amplitude of 207.2 +/- 13 microV with a latency of 25.6 +/- 0.7 ms, and a b-wave 554.3 +/- 24.5 microV with a latency of 21.4 + 1.8 ms. The flicker ERG recording revealed amplitudes of 40.6 +/- 2.4 microV. Tonometry measurements revealed that isoflurane, but not halothane, anesthesia suppressed the IOP (non-anesthetized: 25.3 +/- 1.0 mmHg; 1% halothane + 30% NO: 26.2 +/- 1.1 (p > 0.1); 1% isoflurane + 30% NO: 20.1 + 1.6 (p < 0.05)).


CONCLUSIONS
Consensual PLR in rats has a relative deficit compared to the direct PLR. Isoflurane anesthesia has a suppressive effect on the IOP in healthy rat eyes.
Grozdanic
Sinisa
S
Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA. sgrozdan@iastate.edu
Sakaguchi
Donald S
DS
Kwon
Young H
YH
Kardon
Randy H
RH
Sonea
Ioana M
IM
D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D004596:Electroretinography; D006221:Halothane / Q000008:administration & dosage; D007429:Intraocular Pressure / Q000187:drug effects / Q000502:physiology*; D007530:Isoflurane / Q000008:administration & dosage; D008027:Light; D023421:Models, Animal; D051381:Rats; D011914:Rats, Inbred BN; D012025:Reflex, Pupillary / Q000502:physiology*; D012160:Retina / Q000502:physiology*; D014065:Tonometry, Ocular
D018685:Anesthetics, Inhalation; D007530:Isoflurane; D006221:Halothane