Nitric oxide donors inhibit the acetylcholine-induced Cl− current in identified Onchidium neurons

The present study was undertaken to assess the effects of sodium nitroprusside (SNP) and diethylamine NO(C₂H₅)₂N[N(O)NO]⁻Na⁺ (DEA/NO), NO donors, on an acetylcholine (ACh)-induced Cl⁻ current in identified Onchidium neurons using voltage-clamp and pressure ejection techniques. Bath-applied SNP (10 μM) and DEA/NO (5–10 μM) reduced the ACh-induced Cl⁻ current in the neurons without affecting the resting membrane conductance and holding current. The suppressing effects of NO donors were concentration-dependent and completely reversible. Pretreatment with 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (1 μM), a specific inhibitor of NO-stimulated guanylate cyclase, and hemoglobin (50 μM), a nitric oxide scavenger, decreased the SNP-induced inhibition of the ACh-induced current. Intracellular injection of guanosine 3′,5′-cyclic monophosphate (cGMP) or bath-application of 3-isobutyl-1-methylxanthine (50 μM), a non-specific phosphodiesterase inhibitor, inhibited the ACh-induced current, mimicking the effect of NO donors. These results suggest that SNP and DEA/NO inhibit the ACh-induced Cl⁻ current and that this effect is mediated by an increase in intracellular cGMP. © 1998 John Wiley & Sons, Inc. J Neurobiol 35: 388–394, 1998     

瘤背石磺的形态、习性和生殖行为

2003年5月～2004年5月研究了上海崇明瘤背石磺(Onchidium struma)的形态特征、生活习性,分别对其消化、呼吸、循环、排泄、生殖、神经等六大系统进行了阐述。结果表明,瘤背石磺生活在潮间带高潮区滩涂的芦苇丛里,摄食泥滩上的有机质和单胞藻类;雌雄同体、异体交配、卵生。生殖系统包括生殖器和雌、雄交接器三部分：生殖器由两性腺、卵黄腺和蛋白腺组成;雄性交接器由输精管、附性腺、阴茎、刺激器等组成,雄性生殖孔位于右侧第一触角中部;雌性交接器由输卵管、受精囊、阴道等组成,雌性生殖孔位于肛门右侧约5．0mm处的腹足与外套膜的交界处。本文并详细描述了石磺的交配行为。     

石磺消化系统的组织学观察

对石磺消化系统各部分结构进行组织学观察.石磺的消化系统由消化道和消化腺两部分组成.消化道包括口、食道、贲门胃、幽门胃、中肠和后肠,不具吻;消化腺包括肝胰腺、唾液腺和肛门腺.在光学显微镜下,消化道由粘膜层、粘膜下层、肌层和外膜4层组成;肌层主要为环肌,粘膜层主要为柱状细胞.肝胰腺甚为发达,组织结构显示肝胰腺由很多分支的腺管组成,腺管由腺细胞、分泌细胞等组成.唾液腺和肛门腺发达.     

Hormonal control of blood chloride in the marine pulmonate,onchidium verruculatum

A search for endocrinological factors inO. verruculatum revealed that three hours after right pleural ganglion extirpation blood chloride is significantly (P<0.01) sinked. Administration of right pleural ganglion homogenate (I gang/animal) into depleuralised snails significantly (P<0.001) enhances the blood chloride level after three hrs. Removal of the ganglia other than the right pleural provokes a significant (P<0.01) decline in blood chloride profile in these animals. However, replacement therapy either via homogenate injection or reimplantation of the particular ganglion into extrapleural ganglionectomised animals is ineffective in restoring the chloride levels. It is argued that only right pleural ganglia control blood chloride via vascular channels.     

A Review on Metabolites from Onchidium Genus: Chemistry and Bioactivity

The Onchidium genus (Mollusca, Gastropoda, Pulmonata, Systellommatophora, Onchidiidae family) is used as the important economical shellfish, due to the high nutritional value and medicinal value. Research over the previous decades indicated that Onchidium sp. mainly contains polypropionates, depsipeptides, terpenoids and other chemical components. Many biological activities of Onchidium (e. g., cytotoxic activities against tumor cells, anti-viral and anti-bacterial activities) have been reported. This review reports a total of 60 compounds, synthetic work and biological studies on Onchidium genus, covering the literature from 1978 to date, with a view to providing a reference and helping for the in-depth research of this genus.     

Experimental ecology and hibernation of Onchidium struma (Gastropoda: Pulmonata: Systellommatophora)

This study investigated both laboratory-reared and pond-cultured subjects to explore the habit and hibernation patterns of the sea slug Onchidium struma (Mollusca, Gastropoda, Systellommatophora, Onchidioidea, Onchidiidae) from Shanghai and Zhejiang in China. Movement and feeding habits and the process of hibernation were observed in culturing tanks from June 2004 to March 2008. Our results showed that the conditions of movement are as follows: a minimum air temperature of 12 °C; a maximum light intensity of 25 lux and a minimum relative air humidity of 72%. Major movement is usually at dusk and during the night, and the average temperatures for fasting and beginning hibernation are 13.8 °C and 11.4 °C respectively. The analysis showed that the temperature is an essential factor affecting movement and feeding of O. struma and that RH and light intensity also play an important role, but are not necessarily required at the same time. In this study, the survival rate of O. struma through hibernation in high-biodiversity culturing tanks is 77.57% ± 2.86%.     

两种石磺齿舌形态差异分析

显微观察了瘤背石磺(Onchidiumstruma)和石磺(O. verruculatum)齿舌的形态结构。运用差异系数法对两种石磺齿舌参数进行比较分析。利用SPSS10.0对瘤背石磺、石磺齿舌参数(齿舌长、齿舌头宽、齿舌中宽、齿舌尾宽、横列数、每排最少齿片数和每排最多齿片数)与个体参数(体长、体宽、体高、足长、足宽和体重)作回归分析。结果表明,两种石磺齿舌都很发达,外观呈长统靴状;齿片排成许多横列,每一横列均有中央齿一枚,侧齿若干无缘齿;两种石磺的齿舌头宽、齿舌中宽和齿舌尾宽差异极显著,但差异系数小于1.28,认为两种石磺的齿片形态存在明显的种间差异,但齿舌参数不适合作为石磺属贝类的分类依据;瘤背石磺的体宽和石磺的体重在评估各自齿舌生物学性状方面起到比较重要的作用。     

瘤背石磺产卵前后脂类和脂肪酸组成的变化

本研究测定了瘤背石磺产卵前后肌肉、肝胰腺、两性腺、卵蛋白腺、雄性附性腺和黏液腺指数、水分含量、总脂含量、脂类和脂肪酸组成.结果表明:(1) 瘤背石磺产卵后的肝胰腺指数(HIS)、两性腺指数(DGSI)和卵蛋白腺指数(EAGI)都显著下降(P＜0.05), 其水分含量显著上升, 而脂肪含量显著下降; (2) 瘤背石磺各种组织总脂主要有磷脂(PL)、胆固醇(Cho)、游离脂肪酸(FFA)和甘油三酰(TG), 仅在肝胰腺中检测出少量甘油一酰(MG), 产卵后肝胰腺中的FFA含量和两性腺中的PL含量大幅度下降, 分别下降了41.36%和80.53%, 其它组织中的脂类成分变化幅度不大;(3) 产卵后瘤背石磺肝胰腺中的C16:1n7、C20:5n3(EPA)和C22:6n3(DHA)显著下降, 而饱和脂肪酸(∑SFA)含量显著上升.产卵后两性腺中的C20:2n6、C22:2n6和C22:5n3(DPA)显著下降, 而C20:4n6(AA)含量显著上升.产卵后雄性附性腺和黏液腺中的AA和EPA含量均有所下降, 而C16:0和C18:1n9却有所上升.结果表明:卵蛋白腺和黏液腺对于瘤背石磺产卵和胚胎的形成具有重要的作用, PL和多不饱和脂肪酸(PUFA)对瘤背石磺的两性腺发育具有十分重要的作用, 肝胰腺中的脂肪可能是瘤背石磺产卵过程中主要的能源物质之一, 性腺发育过程中肝胰腺中的PUFA可能被转运到两性腺中.     

不同体重瘤背石磺性腺发育规律

利用组织学方法研究了瘤背石磺体重(2—28g)与性腺发育、性腺指数与肝胰腺指数或卵黄腺指数间的关系,不同体重瘤背石磺性腺内各期生殖细胞的组成与比例以及瘤背石磺卵子和精子发生的规律。结果表明,(1)瘤背石磺的性腺指数有随体重增加而增加的特点:10g以上个体性腺指数达到最高且基本无变化;不同体重瘤背石磺性腺指数与肝胰腺指数和卵黄腺指数有明显的正相关性(P<0.05);(2)6g以下组的瘤背石磺性腺滤泡管内未发现有雌性生殖细胞,6g以上组的性腺滤泡管内雄性与雌性生殖细胞并存;(3)所有瘤背石磺个体性腺内均有精子分布,6g以下个体雄性生殖细胞组成以次级精母细胞为主,而6g以上个体则以精子为主;6g以上组的雌性生殖细胞成熟程度随体重增加有明显增加,其中6—8g以卵原细胞为主(57%),8—10g开始出现外源性卵黄合成期的卵母细胞,10—14g时的外源性卵黄合成期的卵母细胞约为69%,且开始出现成熟卵母细胞。(4)卵子发生共经历6期:分别为卵原细胞期、卵黄合成前卵母细胞期、内源性卵黄合成期、外源性卵黄合成期、近成熟期和成熟卵母细胞期,成熟卵母细胞直径约为(59.36±3.88)μm。精子发生经历精原细胞、初级精母细胞、次级精母细胞、精子细胞和精子共5个阶段,精子长约(52.44±20.65)μm。石磺体重与性腺发育程度密切相关,10g以上的个体可做为亲本使用。