The photic sensitivity of ciona intestinalis.
The photic sensitivity of ciona intestinalis.
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DOI：
10.1085/jgp.1.2.147
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发表时间：
1918-11-01
影响因子：
3.8
通讯作者：
Hecht, S
中科院分区：
文献类型：
--
作者：
Hecht, S
1. Ciona 有两种响应光照强度增加的方法。一种是通过局部反应；另一种是通过整个身体的回缩反射。 2.“单眼”不是光感受器。光敏区域位于包含神经团的虹吸管间区域。该区域不含色素。 3. 对光的反应时间由敏化期和潜伏期组成，在敏化期期间海藻必须暴露在光下，在潜伏期中不需要光照即可对敏化期内收到的刺激做出反应。 4. 反应时间的持续时间与强度成反比。分析表明潜伏期是恒定的。敏化周期与强度之间的关系遵循本生-罗斯科规则。 5. 在暗适应过程中，反应时间首先很长，然后减少，直到达到恒定的最小值。 6. 为了解释所观察到的现象，建议使用由可逆反应组成的光化学系统。该系统包括光敏物质及其前体，反应动力学密切遵循玻璃海鞘光敏性的特性。 7. 事实证明，为了产生反应，被刺激分解的敏感物质的量与先前分解的量之间必须达到恒定的比例。 8. 根据化学系统提出了某些实验预测。实际的实验准确地验证了这些预测。 9. 通过定期重复刺激获得的结果不仅不能显示学习过程或“高级行为”存在的任何基础，而且遵循之前建议的光化学系统的要求。
1. Ciona possesses two means of responding to an increase in the intensity of illumination. One is by means of a local reaction; the other is by a retraction reflex of the body as a whole. 2. The "ocelli" are not photoreceptors. The photosensitive area is in the intersiphonal region containing the neural mass. This area contains no pigment. 3. The reaction time to light is composed of a sensitization period during which Ciona must be exposed to the light, and of a latent period during which it need not be illuminated in order to react to the stimulus received during the sensitization period. 4. The duration of the reaction time varies inversely as the intensity. Analysis shows the latent period to be constant. The relation between the sensitization period and the intensity follows the Bunsen-Roscoe rule. 5. During dark adaptation the reaction time is at first large, then it decreases until a constant minimum is reached. 6. A photochemical system consisting of a reversible reaction is suggested in order to account for the phenomena observed. This system includes a photosensitive substance and its precursor, the dynamics of the reaction following closely the peculiarities of the photosensitivity of Ciona. 7. It is shown that in order to produce a reaction, a constant ratio must be reached between the amount of sensitive substance broken down by the stimulus and the amount previously broken down. 8. From the chemical system suggested certain experimental predictions were made. The actual experiments verified these predictions exactly. 9. The results obtained with regularly repeated stimulation not only fail to show any basis for a learning process or for the presence of a "higher behavior," but follow the requirements of the photochemical system suggested before.