皱瘤海鞘神经递质和性类固醇激素含量与性腺发育成熟的关系

Relationship between neurotransmitter,sex steroid hormones contentsand gonadal development and maturation in Styela plicata

运用免疫组织化学和化学发光免疫分析方法研究了皱瘤海鞘(Styela plicata)神经递质多巴胺(DA)、5-羟色胺(5-HT)及其受体以及性类固醇激素含量与性腺发育成熟的关系.结果显示,DA和5-HT免疫活性定位在脑神经节中大小2种类型的神经细胞,DA免疫活性还定位在不同发育时期神经腺上皮细胞.5-HT受体免疫活性存在于脑神经节小型神经细胞和大生长期神经腺上皮细胞.在小生长期和大生长期性腺中均检测到DA、5-HT及其受体,提示DA和5-HT可能参与调节皱瘤海鞘的性腺发育.皱瘤海鞘为雌雄同体,化学发光免疫分析证实,海鞘性腺能够合成和分泌性类固醇激素,大生长期性腺中雄激素、孕激素和雌激素的含量分别为25.8±0.0、38.9±0.2和14.3±0.6pg/mg,提示性腺既是生殖组织也是内分泌组织.上述发现为证明尾索类海鞘可能像头索类文昌鱼一样,具有原始的生殖内分泌调控轴(脑神经节-神经腺-性腺)提供科学依据.

The relationship between neurotransmitter dopamine（DA）,5-hydorxytryptamine（5-HT） and its receptor,as well as the level of sex steroid hormones and the development and maturation of gonad in Styela plicata were investigated using immunohistochemistry and chemiluminescene immunoassay（CLIA） methods.The results showed that the immunoreactivities of DA and 5-HT are localized in the large-and small-neural cells of cerebral ganglia,and immunoreactivity of DA is also detected in epithelial cells of neural gland at different developmental stages.5-HT receptors are found in small-neural cells of cerebral ganglia and in epithelial cells of neural gland at large growth stage.DA and 5-HT and its receptor are all detected in gonad at small growth stage and large growth stage,suggesting that DA and 5-HT may be involved in regulating gonadal development in the ascidian.Styela plicata is hermaphroditic.The results of CLIA demonstrate that the gonads of Styela plicata can synthesize and secrete sex steroid hormones（androgen,estrogen and progestogen）,and the contents of androgen,progesterone and estrogen in the gonad at large growth stage of Styela plicata are 25.8±0.0,38.9±0.2 and 14.3±0.6 pg/mg,respectively.It suggests that the gonad（ovary and testis） of Styela plicata is both a reproductive organ and an endocrine tissue.The above results have provided scientific basis for confirmation of an existence of primordial reproductive endocrine regulation axis,namely cerebral ganglia-neural gland-gonad in ascidian like amphioxus.