Wong F, Knight B W, Dodge F A
J Gen Physiol. 1980 Nov;76(5):517-37. doi: 10.1085/jgp.76.5.517.
To light stimuli of very low intensity, Limulus photoreceptors give a voltage response with a fluctuating delay. This phenomenon has been called "latency dispersion." If the generator potential is the superposition of discrete voltage events ("bumps"), and if the effect of light upon bump size is negligible, then the latency dispersion and the bump shape completely characterize the frequency response to sinusoidal flicker. For very low light intensities, the latency dispersion of the bumps, the bump shape, and the frequency response are measured. It is found that for data obtained at 20 degrees C, the frequency response can be accounted for completely by the latency dispersion and by the bump shape derived from steady-state noise characteristics. At 10 degrees C, the time scale of the response of the photoreceptor is lengthened. The dispersion of latencies and the bump shape are found not to have the same temperature dependence. However, just as those measured at 20 degrees C, the bump shape and the dispersion of latencies measured at 10 degrees C can predict the frequency response measured under the same conditions. These results strongly suggest that the major mechanisms involved in the generator potential are the latency process and the bump process. At high light intensities, the time scale of the generator potential shortens. The decrease in time scale of the generator potential can be attributed to the decreases in time scales of the bumps and of the latency dispersion process.
对于极低强度的光刺激，鲎的光感受器会给出一个延迟波动的电压响应。这种现象被称为“潜伏期离散”。如果发生器电位是离散电压事件（“脉冲”）的叠加，并且如果光对脉冲大小的影响可以忽略不计，那么潜伏期离散和脉冲形状就完全表征了对正弦闪烁的频率响应。对于极低的光强度，测量脉冲的潜伏期离散、脉冲形状和频率响应。结果发现，对于在20摄氏度下获得的数据，频率响应可以完全由潜伏期离散和从稳态噪声特性导出的脉冲形状来解释。在10摄氏度时，光感受器响应的时间尺度延长。发现潜伏期离散和脉冲形状没有相同的温度依赖性。然而，就像在20摄氏度下测量的那些一样，在10摄氏度下测量的脉冲形状和潜伏期离散可以预测在相同条件下测量的频率响应。这些结果强烈表明，发生器电位涉及的主要机制是潜伏期过程和脉冲过程。在高光强度下，发生器电位的时间尺度缩短。发生器电位时间尺度的缩短可归因于脉冲和潜伏期离散过程时间尺度的减小。
