Meguro Reiko, Hishida Ryuichi, Tsukano Hiroaki, Yoshitake Kohei, Imamura Ryota, Tohmi Manavu, Kitsukawa Takashi, Hirabayashi Takahiro, Yagi Takeshi, Takebayashi Hirohide, Shibuki Katsuei
Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
J Neurochem. 2015 Apr;133(1):66-72. doi: 10.1111/jnc.13053. Epub 2015 Feb 25.
Clustered protocadherins (cPcdhs) comprising cPcdh-α, -β, and -γ, encode a large family of cadherin-like cell-adhesion molecules specific to neurons. Impairment of cPcdh-α results in abnormal neuronal projection patterns in specific brain areas. To elucidate the role of cPcdh-α in retinogeniculate projections, we investigated the morphological patterns of retinogeniculate terminals in the lateral geniculate (LG) nucleus of mice with impaired cPcdh-α. We found huge aggregated retinogeniculate terminals in the dorsal LG nucleus, whereas no such aggregated terminals derived from the retina were observed in the olivary pretectal nucleus and the ventral LG nucleus. These aggregated terminals appeared between P10 and P14, just before eye opening and at the beginning of the refinement stage of the retinogeniculate projections. Reduced visual acuity was observed in adult mice with impaired cPcdh-α, whereas the orientation selectivity and direction selectivity of neurons in the primary visual cortex were apparently normal. These findings suggest that cPcdh-α is required for adequate spacing of retinogeniculate projections, which may be essential for normal development of visual acuity.
成簇原钙黏蛋白（cPcdhs）由cPcdh-α、-β和-γ组成，编码一类对神经元特异的、类似钙黏蛋白的细胞黏附分子大家族。cPcdh-α功能受损会导致特定脑区的神经元投射模式异常。为阐明cPcdh-α在视网膜膝状体投射中的作用，我们研究了cPcdh-α功能受损小鼠外侧膝状体（LG）核中视网膜膝状体终末的形态模式。我们在背侧LG核中发现了巨大的聚集性视网膜膝状体终末，而在橄榄顶盖前核和腹侧LG核中未观察到源自视网膜的此类聚集终末。这些聚集终末出现在出生后第10天至第14天之间，就在睁眼之前以及视网膜膝状体投射精细化阶段开始时。在cPcdh-α功能受损的成年小鼠中观察到视力下降，而初级视觉皮层中神经元的方向选择性和方向选择性显然正常。这些发现表明，cPcdh-α对于视网膜膝状体投射的适当间隔是必需的，这可能对视敏度的正常发育至关重要。
