| According to the reproductive regulation axis subpeduncle lobe/olfactory lobe—optic gland—gonads, the research on mature Sepiella maindroni consisted of three parts:firstly, the brain structure of S. maindroni was performed by paraffin section observations; secondly, the structure and ultrastructure of the optic gland, an endocrine organ, were obtained; thirdly, whether a gonadotropin-releasing hormone (GnRH)-like peptide existed in the brain and gonads of S. maindroni was examined by performing an immunohistochemistry method.1. The morphology structure of mature S. maindroni brain was observed originally. The brain was divided into three parts: supraoesophageal mass, suboesophageal mass and two advanced optic lobes laterally, referring to the esophagus. Supraoesophageal mass included vertical lobe complex, anterior and posterior basal lobes, optic tract region, precommissural lobe and subpeduncle lobe. Optic tract region was involved in regulation of reproduction. Suboesophageal mass could be devided into three regions and each region could be subdivided into different lobes.2. The microstructure and ultrastructure of the optic gland revealed that the secretoy cells produced protein hormone. The gland covered by a thin connective layer was sited on each optic tract and very close to the optic lobe. It was just between the olfactory lobe and the dorsal lateral lobe. There existed abundant secretory cells with a diameter of nucleus 10μm approximately. The ultrastructure of the secretory cells was examined using Transmission Electron Microscope (TEM). There were numerous rough endoplasmic reticula, Golgi apparatus and electron dense granules in the cells. Blood vessels around secretory cells made it possible for hormones to transport. These results will provide cytomorphology basis for the research on physiology and development of optic glands in S. maindroni.3. The localization and distribution of gonadotropin-releasing hormone(GnRH) in S. maindroni were showed through immunohistochemistry. Location of GnRH was detected by mammal GnRH as a primary antibody. Observations by microscope were indicated that the optic lobe, basal lateral lobe,vertical lobe and olfactory lobe were the sites where GnRH existed. All of the lobes were in supraoesophageal mass and surrounded the optic gland. The presence of GnRH was also detected in nidamental gland and testis. The result suggested that GnRH ccould act on the gonads in S. maindroni directly. |
