目的:研究SD大鼠暗视阈值反应(scotopic threshold response,STR)的特点。方法:SD大鼠21只,随机分成3组,每组7只,完全暗适应12h,麻醉后采用RETI-port系统(Roland Consult,德国)分别记录不同通频带(0.1~50,0.1~100,0.1~300,1~50,5~50Hz),不同刺激频率(0.25,0.50,0.75,1,2Hz),不同闪光强度(-6.3,-6.0,-5.7,-5.4log(cd·s)/m^2)下的STR。结果:本实验条件下可以记录到稳定的STR,分为正向的pSTR和负向的nSTR。通频带对STR有影响,随着高频段的增大,附加在波形上的杂波比较多,pSTR和nSTR潜伏期和振幅变化不明显。随着低频段升高,nSTR逐渐消失,尤其是低频段达到5Hz时,振幅有显著差异(P〈0.05)。刺激频率小于1.0Hz时,pSTR和nSTR波形比较稳定,而且nSTR振幅和潜伏期没有明显差异。当刺激频率大于2Hz时,负向波消失,并且正向波振幅明显升高(P〈0.05)。随着刺激光强的增加,pSTR振幅增大,尤其是在光强为-5.7,-5.4log(cd·s)/m^2时,振幅有显著差异(P〈0.05),nSTR逐渐平坦消失,未见a波。结论:SD大鼠STR波形记录与刺激和记录参数密切相关,在完全暗适应条件下,低光强刺激(-6.3和-6.0log(cd·s)/m^2)、低通带(0.1~50Hz)、适当刺激频率(〈1Hz)下可以记录到完整的稳定的STR波形。
AIM: To investigate the scotopic threshold response (STR) character of SD rats. METHODS: Twenty-one SD rats were divided into three groups, seven in each group. After twelve-hour dark- adaption, we used RETI-port (Roland Consult, Germany) to record STR in different bandpasses (0.1-50, 0.1-100, 0.1-300, 1-50, 5-50Hz), frequencies of stimulation (0.25, 0.50, 0.75, 1, 2Hz), flash intensities (-6.3, -6.0, -5.7, 5.4log(cd · s)/m^2). RESULTS: We could record stable STR in this condition, including pSTR and nSTR. The noise wave on to the STR became obvious with the high frequency segmental increased, but latency and amplitude of pSTR and nSTR were not change significantly. Opposite to high frequency segmental, nSTR disappeared with low frequency segmental increased (from 1.0 to 5 Hz), but pSTR did not significantly affect, the amplitude of pSTR in 1.0and5 Hz (P〈0.05). Amplitude and latency of pSTR and nSTR were stable and insignificant when frequency of stimulation was lower than 1.0 Hz. nSTR was disappeared, and the amplitude of pSTR increased significantly (P〈 0.05) when frequency of stimulation was higher than 2Hz. Amplitude of pSTR enhanced and nSTR became flat with flash intensity increased, especially in -5.7, -5.4 Iog(cd · s)/m^2(P〈0.05), and there was no a wave. CONCLUSION; STR recording parameters has an close correlation with and can be stably recorded in the condition of complete dark-adaption, low intensity of stimulation, narrow low bandpass (0.1-50Hz), low frequency of stimulation ( 〈 1 Hz) .