相关实验视频
Updated: Aug 15, 2026

08:38
Transretinal ERG Recordings from Mouse Retina: Rod and Cone Photoresponses
Published on: March 14, 2012
概括
脊椎动物的光受体.
科学领域:
- 视觉科学和细胞生理学.
- 光受体细胞的功能和信号传递.
背景情况:
- 脊椎动物的光受体在暴露于光线时产生膜极极化.
- 这种反应传统上归因于 (Na) 选择性电导率的下降.
- 一个主要的假设涉及光诱导的细胞内 (Ca) 增加阻断Na导电,通过Na-Ca交换器挤出Ca.
研究的目的:
- 为了研究光感受体外段中光敏导电的离子透性.
- 阐明外部离子在调节这种导电性的作用.
- 为了解释光响应的观察到的逆转潜力.
主要方法:
- 来自光受体细胞的电生理记录.
- 在外部溶液中进行离子替代实验.
- 通过光敏电导率对离子透的分析.
主要成果:
- 棒中的光敏导电性不仅仅是Na-选择性,而且对 (K) 也具有很高的透性.
- 外部Na离子倾向于保持电导率开放,而外部K离子倾向于关闭它,这可能是由Na-Ca交换器介导的.
- 导电性允许其他单价 (Li,Rb,Cs) 和双价 (Ca,Sr,Ba) 的透.
结论:
- 光感受器中的光传导率表现出广泛的阴离子透性,包括K.
- 外部Na和K对导电的对立作用,可能通过Na-Ca交换器,有助于调节光受体反应.
- 对Na和K的透性解释了以前令人困惑的光响应在0到+10mV的逆转潜力.
相关概念视频
The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...

