マウス青斑核の微細構造

FINE STRUCTURE OF THE LOCUS COERULEUS IN THE MOUSE

　抄録　マウス青斑核（LC）の検索のため，体重15〜20gのdd Y雄マウスを使用した。

　光顕的にはアミン湿式螢光法により，LCのLC細胞質内に強い螢光と細胞間neuropilに多数のバリコシティーが存在することを確かめ，強い螢光を持つLC細胞を数えると，一側で1,326±64個存在していた。

　電顕的にはグリオキシル酸一過マンガン酸カリ（KMnO₄）固定標本によりLCの細胞をノルアドレナリン（NA）を産生するLC細胞とNAを産生しない小形細胞に分け，さらにLC細胞を細胞質内小器官の発達程度により2種類に分けた。またLCの細胞間neuropilにおいて，NA顆粒の指標である大小有芯顆粒を持つ軸索末端（AT）を数えると，種々の全AT （10,545個）に対して2.2（±0.67）％すなわち232個存在しており，その終末像は樹状突起に接着するもの100個，自由終末121個，LC細胞体に接着するもの11個であった。また同時に有芯顆粒を持つ樹状突起でその断面の長径が2.5μm以下のものを数えると，有芯顆粒を持つATの6.15倍存在していた。

The aim of this study is to clarify the fine struc-tural organization of the mouse locus coeruleus (LC), which has not been throughly investigated yet, by a light and electron microscope.

In a light microscopic study we used the wet fluorescent method and counted numbers of fluo-rescent LC cells and obtained 1326±64 in oneside, and many processes of LC cells reached and ex-panded into the latero-dorsal tegmental nucleus and nucl. parabrachialis medialis and lateralis.

By EM study of glyoxylic acid and permanganate fixed material, LC cells (the principal cells, (16. 8± 2.9)×(27.8±5.1)μm), which contained small and large cored vesicles characteristic for NA, were divided into 2 types. The one was rich in Golgi apparatuses, ER and other cell organelles, the other being poor in these cell organelles. Another types of cells, devoid of cored vesicles, were small in size (12×15 pm) and poor in cell organelles.

In the neuropil of LC, the % of axon terminals containing NA cored vesicles amounted to 2. 2 (±0.67) % of all axon terminals (a total of 10,545). Counted NA terminals (a total of 232) showed ap-position to dendrites at 43%, free endings at 52%, contacts to LC cells at 5%. Moderate number of dendrites containing cored vesicles contacted with LC cell bodies or their dendrites especially in the caudal part of LC.