| 摘要: |
| 采用膜片钳技术测定了不同甾醇类物质对河蟹眼柄视神经节端髓X器官(MTXO)神经分泌细胞钙离子通道电流(ICa)的作用,探讨河蟹眼柄神经肽类激素分泌和养殖河蟹性早熟的调控机制。结果表明,河蟹眼柄MTXO三种类型神经分泌细胞均表达高电压激活L型钙通道,激活电压为-30mV，+10mV达到峰值。甾醇类物质中,只有胆固醇对河蟹眼柄B型神经内分泌细胞的钙电流存在抑制作用,其作用具有浓度依赖性,抑制强度不随时间的延长而加强。1μmol/L的胆固醇作用4h可抑制B型细胞50.49%±5.98%的钙电流。 |
| 关键词: 河蟹 MTXO 神经分泌细胞 甾醇类激素 钙电流 早熟 |
| DOI： |
| 分类号: |
| 基金项目:国家973重点基础研究项目资助,G1999012007号;天津市农业攻关项目资助,003120511号 |
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| EFFECTS OF SEVERAL STEROIDS ON ICa FROM NEUROSECRETORY CELLS IN THE EYESTALK OF ERIOCHEIR SINENSIS |
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SUN Jin Sheng1, LIU An Xi2, HE Bing Jun2, CHEN Jia Tong2, XIANG Jian-Hai3
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1.Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071, Tianjin Fishery Institute, Tianjin, 300221;2.Department of Biology, Nankai University, Tianjin, 300074;3.Institute of Oceanology, The Chinese Academy of Sciences, Qingdao, 266071
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| Abstract: |
| The whole-cell patch clamp technique was used to examine the effects of several steroids on the ICa resolved from the neurosecretory cells dissociated from the X-organ terminalia (MTXO) of optic ganglion in the eyestalk of Chinese mitten crab (Eriocheir sinensis). When solution that suppressed the outward currents was used, a slow (time to peak current 6–8ms at +10mV), Cd2+-sensitive Ca2+ current (ICa) was resolved in three cell types. In the presence of TTX, ICa was activated at potential -40mV, was maximal at +10mV, and the form of the Ca2+ current I(V) was unchanged by changes of holding potential between -40mV and -70mV. The size and feature of ICa evoked from cell types A, B, C dissociated from MTXO in the eyestalk of cultured juvenile crabs were unchanged in the presence or absence of β-ecdysone, β-estradiol, daidzein, juvenile hormone (JH III), but only in the presence of cholesterol, the size of ICa evoked from cultured cell type B decreased depending on concentrations. In the presence of 1μmol/L cholesterol, 50.49%±5. 98% of ICa was inhibited after 4h, the releasing amounts of neuropeptide were also inhibited. The result suggest that Cholesterol was excessive accumulated in the body of cultured crabs due to the high content of Cholesterol in the feeds. Over-dose Cholesterol promotes the synthesis and the release of MH in the Y-organ by inhibiting the neuropeptide secretion from the neurosecretory cells in the XO-SG complex. Furthermore, MH shortens molting period and accelerating the gonadial development. This is the major cause giving rise to precocious mature in the cultured Chinese mitten crab. |
| Key words: Eriocheir sinensis, MTXO, Neurosecretory cells, Steroids, ICa, Precocity |
