レセルピン投与マウス脈絡叢上皮細胞におけるグリコゲンの発現について

THE EFFECT OF RESERPINE ON GLYCOGEN IN THE CHOROIDAL EPITHELIAL CELLS OF THE ADULT MOUSE AS OBSERVED BY LIGHT AND ELECTRON MICROSCOPY

はじめに

　哺乳動物の脈絡叢上皮細胞には，その分化発達の早期に多量のグリコゲンが出現する（Schaltenbrand, 1955）^1）。しかしながら，上皮細胞の分化とともに細胞内グリコゲンは急速に減少消失し，ヒトでは出生後はみとめられないし（Kappers, 1958^2）；　Shuangshoti　＆　Netsky, 1966^3）），ウサギ（Tennyson　＆　Pappas, 1961）^4），ラット（Canci—lla, Zimmerman　＆　Becker, 1966）^5），マウス（Dohrman1970^6）；　鈴木，1972^7））でも，生後早期に脈絡叢上皮細胞が分化するとともに，そのグリコゲンは急速に減少し，生後ほぼ2週で消失し，したがつて成体では一般に組織化学的に細胞内グリコゲンはみとめられない。しかしながら，私は成体マウスにおいてレセルピンを投与すると，脈絡叢上皮細胞にきわめて多量のグリコゲンが出現することをみとめた。このような現象は今日なお記載がないので，系統的に組織化学的，電子顕微鏡的に観察した。

Adult dd-mice were intraperitoneally injected with 3.5 mg/kg or 0.35mg/kg of reserpine, and their choroidal epithelia in the lateral, third and fourth ventricles were examined after varying intervals ranging from 3 to 48 hours after injec-tion.

In mice injected with a large dose of reserpine, glycogen often appeared in small amounts in the choroidal epithelial cells in the lateral and fourth ventricles at 3 hours after injection. Glycogen gradually increased in amount until 12 hours after injection when it attained maximum, thus far ex-amined. At 24 hours, the glycogen content in the epithelial cells was decreased in amount so that glycogen was observed in only small amount. At 36 hours and later, no glycogen was seen in the epithelium. On the other hand, the epithelial cells of the third ventricle had relatively ,small a mounts of glycogen granules firstat 6 hours after reserpine injection. The glycogen content reached to maximum at 12 and 24 hours. Even at 36 hours, the epithelial cells often contained small amounts of glycogen granules. At 48 hours, glycogen dis-appeared entirely in the epithelium.

Administration of a smaller dose of reserpine also induced an increase in glycogen content in the choroidal epithelial cells of the lateral and fourth ventricles, but not in those of the third ventricle. In addition, glycogen was generally smaller in amount than in the mice treated with a large dose, and it disappeared earlier.

Electron microscopy revealed that the glycogen granules were generally 30 to 40mμ in diameter, appearing in the form of so-called β-particles. Glycogen granules were scattered throughout the cytoplasm. When present abundantly, they showed a tendency to accumulate at the basal portion of the cytoplasm. Otherwise, no appreciable changes were observed in the cytological features.

Administration of nialamide, known as mono-amine oxidase inhibitor, prior to reserpine injection caused no increase in glycogen content in the choroidal epithelium, whereas that after reserpine injection induced an increase in glycogen content as was the case with reserpine injection alone.