REVERSIBLE EVENTS IN THE TRANSDUCTION PROCESS OF PHOTORECEPTORS
REVERSIBLE EVENTS IN THE TRANSDUCTION PROCESS OF PHOTORECEPTORS
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DOI：
10.1038/283859a0
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发表时间：
1980-01-01
期刊：
影响因子：
64.8
通讯作者：
KIRSCHFELD, K
中科院分区：
文献类型：
--
作者：
HAMDORF, K;KIRSCHFELD, K
在光感受器中，即使对于强光刺激，在光量子的吸收和晚感受器电位的发生之间也经过许多毫秒的潜伏期。令人惊讶的是，这比电导变化所需的时间要长得多，例如发生在神经元或肌肉的膜中，由化学递质介导。对于长的感光器潜伏期有几种可能的解释。(1)这可能是由于视觉色素分子的性质。例如，与受体信号发生的时间巧合的间-rhodospin II表明，Meta I-间II转换可能是脊椎动物photoreception 1的电响应的触发器。(2)这可以用输运过程的性质来解释。这样一个耗时的过程可能是内部“递质物质”的扩散，其扩散到受体膜中的“孔”。(3)第三种可能性是产生和积累化学物质所需的时间。光诱导的视觉色素分子的变化可能会触发一个化学反应链，其中前一步的产物触发下一步。这里描述的实验表明，光感受的长潜伏期的相当一部分是由于定位在视觉色素分子水平的过程。
In photoreceptors, a latency of many milliseconds elapses between the absorption of a light quantum and the occurrence of the late receptor potential, even for strong light stimuli. Surprisingly, this is much longer than the time necessary for conductance changes such as occur in membranes of neurones or muscles, mediated by chemical transmitters. There are several possible explanations for the long photoreceptor latency. (1) It may be due to properties of the visual pigment molecules. For instance, the temporal coincidence of the occurrence of meta-rhodospin II with the receptor signal indicates that the meta I–meta II transition might be the trigger for the electrical response in vertebrate photoreception1. (2) It may be explained by properties of transport processes. Such a time consuming process could be the diffusion of an internal ‘transmitter substance’, which diffuses to a ‘pore’ in the receptor membrane. (3) A third possibility is the time needed to produce and accumulate chemical substances. The light-induced change of the visual pigment molecule might trigger a chemical reaction chain, in which the product of an earlier step triggers the next one. The experiments described here show that a considerable part of the long latency in photoreception is due to processes that are localised at the level of the visual pigment molecule.