Gianfranceschi L, Fiorentini A, Maffei L
Scuola Normale Superiore, Pisa, Italy.
Vision Res. 1999 Feb;39(3):569-74. doi: 10.1016/s0042-6989(98)00169-2.
Since the advent of gene manipulating techniques, it has become increasingly important to study the neural functional properties of the mouse. The bcl2 gene has a powerful inhibitory action on naturally occurring cell death. As a consequence the brain of bcl2 overexpressing mouse is 1.5 times bigger than the brain of a wild type animal and the retina has more than twice the ganglion cells than normal (Martinou, Dubois-Dauphin, Staple, Rodriguez, Frankowski, Missotten, Albertini, Talabot, Catsicas, Pietra, & Huarte (1994). Neuron, 13: 1017-1030). Since in most mammals the upper limit of behavioural visual acuity is imposed by ganglion cells density, the visual acuity should be higher in bcl2 mice than in wild type mice. We measured behavioural visual acuity in wild type and transgenic mice and, contrary to the expectation, we found it to be of the same order (0.5-0.6 c/deg) in the two groups of animals, indicating that an increase in ganglion cells density is not effective in improving visual resolution.
自从基因操纵技术出现以来，对小鼠神经功能特性的研究变得越来越重要。bcl2基因对自然发生的细胞死亡具有强大的抑制作用。因此，过表达bcl2的小鼠的大脑比野生型动物的大脑大1.5倍，视网膜中的神经节细胞比正常情况多两倍以上（Martinou, Dubois-Dauphin, Staple, Rodriguez, Frankowski, Missotten, Albertini, Talabot, Catsicas, Pietra, & Huarte (1994). Neuron, 13: 1017 - 1030）。由于在大多数哺乳动物中，行为视觉敏锐度的上限由神经节细胞密度决定，因此bcl2小鼠的视觉敏锐度应该比野生型小鼠更高。我们测量了野生型和转基因小鼠的行为视觉敏锐度，与预期相反，我们发现两组动物的视觉敏锐度处于同一水平（0.5 - 0.6 c/deg），这表明神经节细胞密度的增加并不能有效提高视觉分辨率。
