Ultrastructure of neurosecretory cells in the cerebral and pleuropedal ganglia of Haliotis asinina Linnaeus

摘要

The ultrastructure of all three types of neurosecretory cells (NS_1, NS_2 and NS_3) in the cerebral and pleuropedal ganglia of Haliotis asinina was studied. NS_1 cells contained a euchromatic nucleus, and the cytoplasm contained RER, Golgi complexes, mitochondria and ribosomes. There were two types of neurosecretory granules in the NS_1 of cerebral ganglia: type 1 were large osmiophilic membrane-bound granules and type 2 were small electron-dense spherical granules. The NS_1 cells of pleuropedal ganglia only had one type of round cytoplasmic granule with a moderate to strong electron-dense matrix. NS_2 cells contained blocks of heterochromatin in the nucleus. The cytoplasm of the NS_2 of cerebral ganglia contained the usual organelles similar to those of NS_1 cells and large membrane-bound granules containing crystalline structures embedded in a moderately dense osmiophilic matrix. The NS_2 cells of pleuropedal ganglia contained one type of granule that had a dense matrix. NS_3 cells were smallerthan NS_1 and NS_2. The nucleus contained thick heterochromatin strands. The organelles in the cytoplasm appeared to be fewer than those of NS_1 and NS_2. The secretory granules of NS_3 of both cerebral and pleuropedal ganglia were composed of aggregates of dense osmiophilic globules of various sizes.