Watanabe S, Matthews G
Department of Neurobiology and Behavior, State University of New York, Stony Brook 11794.
J Neurosci. 1988 Jul;8(7):2334-7. doi: 10.1523/JNEUROSCI.08-07-02334.1988.
In patch-clamp recordings from excised membrane patches, the distribution of cGMP-activated channels in the plasma membrane of the rod photoreceptor was examined. These channels have been shown to be the light-sensitive channels that carry the inward dark current in the rod outer segment, where phototransduction occurs (Matthews, 1987); thus, they are centrally involved in photoreceptor transduction. In the outer segment, cGMP-activated channels were present at high density. In the inner segment, cGMP-activated channels were also present, but their density was much lower than in the outer segment. Calcium-activated potassium channels had the opposite distribution, with a higher density in the inner segment. The results suggest that there is a barrier preventing the unrestricted spread of membrane proteins between the inner and outer segments.
在从分离的细胞膜片进行的膜片钳记录中，研究了视杆光感受器质膜中cGMP激活通道的分布。这些通道已被证明是在视杆外段携带内向暗电流的光敏感通道，光转导在此发生（马修斯，1987年）；因此，它们在光感受器转导中起核心作用。在外段，cGMP激活通道以高密度存在。在内段，也存在cGMP激活通道，但其密度远低于外段。钙激活钾通道的分布则相反，在内段密度较高。结果表明，存在一个屏障，阻止膜蛋白在内段和外段之间不受限制地扩散。
