Properties of rat cone response during light adaptation

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

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

    ¡¾Abstract¡¿ AIM: To investigate the properties of rat cone response during light adaptation. METHODS: Thirty rats were divided into 3 groups. Their 0.5 Hz and 20 Hz cone response was recorded respectively in adapted dark and 10 s, 5, 10, 15, 20, 25 and 30 min after background light was turned on. The stimulus intensities for the three group were 1.1, 3.5 and 11.0 cd¡¤s¡¤m-2, respectively. RESULTS: There were some small oscillatory waves overlapped on the 0.5 Hz response bª²wave. For the 0.5 Hz response, with light adaptation, all three intensities' implicit time were shortened after the lightª²on, shortest at about 10 min, and prolonged again after then. The amplitudes also decreased after the lightª²on. However, with high intensity, the amplitude began to increased at about 5 min, reached an asymptotic state at 10-15 min but didn't reach the dark adapted level. For the 20 Hz response, the low intensity's implicit time delayed during light adaptation while that of the high intensity's shortened in the whole course. The low intensity's amplitude decreased after the lightª²on while that of high intensity' increased and reached an asymptotic state at 10-15 min, which was larger than that in dark adapted level. CONCLUSION: The stimulus frequency of 20 Hz, with the intensity of at least 3.5 cd¡¤s¡¤m-2 and the duration for light adaptation more than 10 minutes, is proved better in recording the rat cone response. The changes of rat cone response during the light adaptation may reflect the summary effects of rods, cones and more neuromodulatary cells. ......