Effects of different stimulus frequency and intensity on rat light adaptation flicker electrophysiology

    HOU Baoª²Ke, ZHANG Zuoª²Ming, GU Yongª²Hao, LI Li, GUO Qun

    Department of Aerospace Clinical Medicine, School of Aerospace Medicine, Fourth Military Medical University, Xi¡¯an 710033, China

    ¡¾Abstract¡¿ AIM: To explore the exact parameters (frequency and intensity of stimulus) which can isolate cone system electroretinogram (ERG) bª²wave under light adaptation in SD rats and to provide some clues for further study. METHODS: With RETIª²scan system, lightª²adapted ERG from SD albino rats were obtained. Eight frequencies (0.1, 0.5, 5.0, 10.0, 15.0, 20.0, 25.0 and 30.0 Hz) and seven intensities (0.11, 0.35, 1.10, 3.50, 11.00, 35.00 and 110.00 cd¡¤s¡¤m-2) were used. The intensity of adapting field luminance was 37.00 cd¡¤s¡¤m-2 and the adaptation time was 10 min. RESULTS: In the condition of lowª²frequencies(0.1, 0.5, 5.0 Hz), there was rod system intrusion and steady wave could not be recorded on the highª²frequencies(25.0, 30.0 Hz). No significant difference was found in the implicit times of different stimulus intensities but the amplitudes all had a tendency of increasing first and then decreasing, and reached the peak when the intensity was 3.50 cd¡¤s¡¤m-2. CONCLUSION: When the stimulus frequency is between 15.0 and 20.0 Hz and the intensity is 3.50 cd¡¤s¡¤m-2, the function of cone system can be well isolated on lightª²adapted ERG in SD rats. ......