Differences in the Effects of Pentobarbital Anesthetic and Combination of Medetomidine Hydrochloride, Midazolam, and Butorphanol Tartrate Anesthetic on Electroretinogram in Spontaneously Diabetic Torii Fatty Rats

Purpose: The aim of this study was to investigate the effects of different anesthetic agents on electroretinograms (ERGs) in Spontaneously Diabetic Torii fatty rats (SDT fatty rats). Methods: The ERG recordings were measured under general anesthesia using pentobarbital or a combination of medetomidine hydrochloride, midazolam, and butorphanol (MMB) tartrate anesthesia in 12 9-week-old normal Sprague-Dawley rats (Jcl:SD rats) and 16 SDT fatty rats. Each animal model was divided into 2 groups, the pentobarbital group and MMB group. The amplitudes and peak times of the a- and b-waves and oscillatory potentials (OPs) were measured from 0.0001 candela per square meter (cd.s/m2) to 10.0 cd.s/m2. Results: The amplitude of the a-wave was significantly higher in the MMB group of Jcl:SD rats, but there was no significant difference in amplitude between the two groups of SDT fatty rats. There was no significant difference in the OP1 amplitude between both groups of Jcl:SD rats, but the OP1 amplitude was significantly higher in the MMB group of SDT fatty rats. The OP2 amplitude was significantly higher in the pentobarbital group in both the Jcl:SD rats and SDT fatty rats. There was no significant difference in the OP3 amplitude between the Jcl:SD and SDT fatty rat groups. The amplitude of the OP4 waves was significantly higher in the MMB group for both Jcl:SD and SDT fatty rats. There was no significant difference in the sums of the OP1 to OP4 (ΣOPs) amplitudes between the Jcl:SD and SDT fatty rat groups. There was no significant difference in the b-wave amplitude between the Jcl:SD rat groups, but the b-wave amplitude was significantly higher in the SDT fatty rats that received pentobarbital. The peak times for a-wave, OP1, OP2, OP3, OP4, and ΣOPs were significantly longer in the pentobarbital group of SD rats. The peak time of the b-wave was significantly longer in the MMB group of Jcl:SD rats, but the same result was obtained in the SDT fatty rats except that there was no significant difference in the a-wave. Conclusion: The overall ERG results vary depending on the anesthetic agent used. The OPs can be observed in detail when using MMB. Since the SDT fatty rat is a diabetic model animal, we recommend MMB as the anesthesia of choice when studying the OP waves in detail.