[Electrical responses from the inner retina of rats with streptozotocin-induced early diabetes mellitus].
OBJECTIVE
To evaluate behavior of the scotopic threshold response (STR) and the oscillatory potential (OP) in the electroretinogram (ERG) in streptozotocin (STZ)-induced diabetic rats (DM rats).


METHODS
The amplitude of the STR and the OP 3, the implicit time of the STR, and the peak latency of the OP 3 of the DM rats were measured.


RESULTS
No significant differences were observed in the mean amplitude or the mean implicit time of the STR between the control and the DM rats. On the other hand, the mean peak latency of OP 3 of the DM rats was significantly prolonged up to 125% of the control rats (p < 0.01), although there were no significant differences between the two groups in the mean OP 3 amplitude.


CONCLUSIONS
Although both STR and OP were of inner retinal origin, their behavior was different in DM rats. This result supported some reports describing how dopaminergic amacrine cells generate OP and glycinergic or GABAergic amacrine cells generate STR. In the early stage of diabetic retinopathy, there may be not only minor ischemia but also disorder of neurotransmission of the amacrine cells in the inner retinal layers.
Kaneko
M
M
Department of Ophthalmology, Iwate Medical University School of Medicine, 19-1 Uchimaru, Morioka 020-8505, Japan.
Sugawara
T
T
Tazawa
Y
Y
D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D004596:Electroretinography; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley