碩士 / 國立屏東科技大學 / 水產養殖系 / 91 / Abstract
The reproductive process of crustaceans is regulated primarily by vitellogenesis inhibiting hormone (VIH) and vitellogenesis stimulating hormone (VSH), respectively synthesized and released from x-organ sinus gland complex in eyestalks ,and brain or thoracic ganglia.The biogenic amines, dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) are known to be involved in the synthesis and release of many neurohormones. The objective of this research is aimed to understand the effects of DA or 5-HT on the vitellogenin (Vg) synthesis in vitro in hepatopancreas and ovarian tissues, which are incubated with various ganglic tisssues, and the regulatory pathway of these amines in vitellogenesis in the freshwater giant prawn, Macrobrachium rosenbergii.
The hepatopancreas and ovarian tissues along with various ganglia were respectively incubated with varying doses of DA or 5-HT ranging between 10-6 and10-8 M, and the Vg contents in the culture media collected at 2 hr intervals were quantified by ELISA. The results indicated that the synthesis of vitellogenin in hepatopancreas is inhibited by DA, most effective at the dose of 10-6 M DA, while the process is stimulated by 5-HT and the responses are the highest at the doses of 10-6 and 10-7 M. Neither DA nor 5-HT shows any notable effect on the vitellogenin synthesis in the ovarian tissue.The dopaminergic antagonists, D1-type (SCH23390) and D2-type (domperidone) were respectively supplemented into these culture conditions. The Vg production was recovered from the DA inhibition when 10-6 M SCH23390 was added, but not domperidone at the same dose. However, applications of these dopaminergic antagonists did not showed any effect on the Vg synthesis in the ovarian tissue. In similar experiment designs, the increase in the Vg production in the hepatopancreas was observed when DL-propranolol (5-HT1 serotonergic antagonist) was supplemented, but the Vg was notably depressed when cinanserin (5-HT2 serotonergic antagonist0 was used. These observations suggest that the stimulatory effect of 5-HT is mediated via 5-HT2-type serotonergic receptor. Furthermore, both DL-propranolol and cinanserin showed no influences on the Vg production in the ovarian tissue.In final, the effects of DA and 5-HT on the Vg synthesis in the hepatopancreas and ovarian tissues in vitro are in accordance to those obtained in vivo (Fang, 2001). It is therefore concluded that the hepatopancreas is the primary tissue of Vg synthesis in Macrobrachium rosenbergii.Inhibitory action of DA on Vg synthesis in the hepatopancreas is mediated through D1-dopaminergic receptor on the thoracic ganglion, where vitellogenesis stimulating hormone is synthesized and released. On the other hand, the stimulatory action of 5-HT on the Vg synthesis is channeled through 5-HT2 serotonergic receptor in all ganglic tissue examined.
Keywords: Freshwater giant prawn, dopamine, serotonin, vitellogenin,
regulatory pathways, antagonist.
| Identifer | oai:union.ndltd.org:TW/091NPUST086001 |
| Date | January 2003 |
| Creators | Chia-Che Wu, 吳嘉哲 |
| Contributors | Ching-Ming Kuo, Win-ton Cheng, 郭欽明, 鄭文騰 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 88 |
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