Chinchilla 달팽이핵에서 Calbindin D-28ka 면역반응세포의 미세구조에 관한 연구

Ultrastructural Localization of the Immunoreactive Calbindin D-28ka Neurons in the Cochlear Nucleus of the Chinchilla

A unique class cells, strongly immunopositive for anti-calbindin D-28ka were observed in and near the cochlear nucleus of the chinchilla (chinchilla laniger). They were preferentially located in the dorsal cochlear nucleus, as well as in the adjacent superior olivary nucleus. The calbindin D-28ka positive neurons had relatively large cell bodies with thick, heavy spinal dendrites, and were typically situated in the immediate subpial position. The calbindin D-28ka immunoreactive neurons were very varied morphologically; bitufted， bipolar, muItipolar and horizontal cells in shape, and the diameters of the neurons are 16-30 |im have been described in the cochlear nucleus of the chinchilla. Also, the calbindin D-28ka positive dendrites were considerably more densely arrayed than those of other cochlear nuclear cells, including the cartwheel cells of the dorsal cochlear nucleus. The fine structure of the cells in the cochlear nucleus in the chinchilla(chinchilla laniger) was sUidied by transmission electron microscopy. The neurons had a large, round, centrally located nucleus, and their cytoplasm contained numerous mitochondria, myelinated axon, dense granular endoplasmic reticulum, abundant Golgi apparatus，groups of free ribosomes, some heterogeneous particles and neurofilaments. Cell surfaces were studied irregularly with small spinous processes, and they contained a few fine irregularly arranged neurofilaments and some granular endoplasmic reticulum. Boutons contacting the soma and dendrites of the cochlear nucleus neurons were defined as the axosomatic synapses. Based on differences in the bouton and vesicle morphology, the four synaptic bouton types were identified; 1. Asymmetrical and symmetrical synapses with small rounded vesicles. 2. Asymmerical synapses with pleomorphic admixture contained predominantly spherical vesicles. 3. Symmerical synapses with pleomorphic vesicles of flattened, spherical and dense-core vesicles. 4. Asymmetrical as well as symmetrical synapses with heterogeneous and large dense-core vesicles. Synaptic boutons containing the rounded vesicles and the large densecore vesicles were most frequently observed.