家鷄 網膜의 電子顯微鏡的 硏究

An Electron Microscopy of the Retina in the Gallus domesticus B.

닭(Gallus domesticus B.)의 視細胞 外절과 內절의 移行部에는 他 脊椎動物에서 흔히 觀察되는 纖維가 極히 적었는데 이것은 鳥類視細胞의 特徵이며 內절에 많은 미토콘드리아가 存在함은 모든 脊椎動物에서와 같은 現象이지만 鳥類에서는 內部 절의 構造가 多樣하게 變化되어 나타나고 있다. 視細胞核 部位에 存在하는 外境界膜의 屈曲이 심한 것도 닭에서뿐 아니라 참새나 비둘기 等 鳥類에서 보이고 있는 特徵的인 構造이지만 外절의 層板 構造라든가 色素上皮細胞, 外顆粒層과의 連結部位등 一般的인 視細胞의 構造들은 거의 모든 脊椎動物에서 비슷하게 나타나고 있음을 알 수 있었다. 一般的인 電顯方法으로 實驗하였으나 보통 쓰이고 있는 phosphate buffer 代身 cacodylate buffer를 사용한 것이 다를 뿐이다.

This investigation was undertaken to establish the ultrastructural organization of the retina in domestic fowl (Gallus domesticus B.) comparing with the ultrastructure that has been indicated in other Aves by several workers. The electron microscope observations were made on selected segments of retinal tissue prefixed for 2 hrs in 1.25% glutaraldehyde buffered with 0.2 M cacodylate at pH 7.2 and then postfixed in cold 1% osmium tetroxide in 0.4 M cacodylate buffer for 2 hrs. After postfixation, tissues were dehydrated in alcohol series, embedded in Epon 812 mixture from propylene oxide and stained with saturated uranyl acetate and $Pb(NO_3)_2$ solution. Specimens were examined with a Hitachi HS-7S electron microscope. The pigment epithelia cells contain numerous mitochondria with prominent dense granules and several changeful spaped Golgi bodies. The internal fine structure of the receptor outer segments revealed the characteristic stacks or arrays of bimembranous disks. The ellipsoid outer portion of the cone inner segments is composed of a tightly packed mass of extraordinarily large mitochondria. The outer limiting membrane is seen to contain many junctional complexes, the fibrillar material of which is electron-dense.