Time-dependent course of electroretinograms in the spontaneous diabetic Goto-Kakizaki rat.
OBJECTIVE
This study evaluates the relevance to human retinopathy of electroretinograms (ERGs) from the spontaneously diabetic Goto-Kakizaki (GK) rat.


METHODS
Starting from 4 weeks of age, we obtained ERGs every 4 weeks from six GK rats and seven Wistar (control) rats, and from two GK and two Wistar rats at 14 days of age. The a-wave, b-wave, and oscillatory potentials (OPs) were recorded after stimulation with a single bright flash. We compared the amplitudes and implicit times and measured a-wave latencies to evaluate photoreceptor function.


RESULTS
The amplitudes of the a-wave, b-wave, and OPs (O1 and O2) of the GK rats were reduced between 4 and 48 weeks of age. The time-dependent courses of change in a-wave, b-wave, and O2 amplitude did not differ between the two groups. The a-wave latencies in GK rats were significantly prolonged, but not the implicit times of OPs. At 14 days of age, the a-wave amplitudes were significantly smaller in GK than in Wistar rats.


CONCLUSIONS
Functional abnormalities of photoreceptors might be induced by inheritable degeneration at an early age in the GK rat. Although hyperglycemia would cause retinal hypoxia, it would not be severe enough to disturb the generation of OPs.
Matsubara
Hisashi
H
Department of Ophthalmology, Mie University School of Medicine, Tsu, Mie, Japan. hisashi@doc.medic.mie-u.ac.jp
Kuze
Manami
M
Sasoh
Mikio
M
Ma
Ning
N
Furuta
Motoyasu
M
Uji
Yukitaka
Y
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000503:physiopathology*; D004596:Electroretinography; D005500:Follow-Up Studies; D008297:Male; D010775:Photic Stimulation; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D001786:Blood Glucose